3461 lines
102 KiB
C
3461 lines
102 KiB
C
// SPDX-License-Identifier: GPL-2.0-only
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/*
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* mm/percpu.c - percpu memory allocator
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*
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* Copyright (C) 2009 SUSE Linux Products GmbH
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* Copyright (C) 2009 Tejun Heo <tj@kernel.org>
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*
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* Copyright (C) 2017 Facebook Inc.
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* Copyright (C) 2017 Dennis Zhou <dennis@kernel.org>
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*
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* The percpu allocator handles both static and dynamic areas. Percpu
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* areas are allocated in chunks which are divided into units. There is
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* a 1-to-1 mapping for units to possible cpus. These units are grouped
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* based on NUMA properties of the machine.
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*
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* c0 c1 c2
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* ------------------- ------------------- ------------
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* | u0 | u1 | u2 | u3 | | u0 | u1 | u2 | u3 | | u0 | u1 | u
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* ------------------- ...... ------------------- .... ------------
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*
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* Allocation is done by offsets into a unit's address space. Ie., an
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* area of 512 bytes at 6k in c1 occupies 512 bytes at 6k in c1:u0,
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* c1:u1, c1:u2, etc. On NUMA machines, the mapping may be non-linear
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* and even sparse. Access is handled by configuring percpu base
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* registers according to the cpu to unit mappings and offsetting the
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* base address using pcpu_unit_size.
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*
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* There is special consideration for the first chunk which must handle
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* the static percpu variables in the kernel image as allocation services
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* are not online yet. In short, the first chunk is structured like so:
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*
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* <Static | [Reserved] | Dynamic>
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*
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* The static data is copied from the original section managed by the
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* linker. The reserved section, if non-zero, primarily manages static
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* percpu variables from kernel modules. Finally, the dynamic section
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* takes care of normal allocations.
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*
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* The allocator organizes chunks into lists according to free size and
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* memcg-awareness. To make a percpu allocation memcg-aware the __GFP_ACCOUNT
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* flag should be passed. All memcg-aware allocations are sharing one set
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* of chunks and all unaccounted allocations and allocations performed
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* by processes belonging to the root memory cgroup are using the second set.
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*
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* The allocator tries to allocate from the fullest chunk first. Each chunk
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* is managed by a bitmap with metadata blocks. The allocation map is updated
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* on every allocation and free to reflect the current state while the boundary
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* map is only updated on allocation. Each metadata block contains
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* information to help mitigate the need to iterate over large portions
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* of the bitmap. The reverse mapping from page to chunk is stored in
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* the page's index. Lastly, units are lazily backed and grow in unison.
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*
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* There is a unique conversion that goes on here between bytes and bits.
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* Each bit represents a fragment of size PCPU_MIN_ALLOC_SIZE. The chunk
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* tracks the number of pages it is responsible for in nr_pages. Helper
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* functions are used to convert from between the bytes, bits, and blocks.
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* All hints are managed in bits unless explicitly stated.
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*
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* To use this allocator, arch code should do the following:
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*
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* - define __addr_to_pcpu_ptr() and __pcpu_ptr_to_addr() to translate
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* regular address to percpu pointer and back if they need to be
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* different from the default
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*
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* - use pcpu_setup_first_chunk() during percpu area initialization to
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* setup the first chunk containing the kernel static percpu area
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*/
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#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
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#include <linux/bitmap.h>
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#include <linux/cpumask.h>
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#include <linux/memblock.h>
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#include <linux/err.h>
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#include <linux/lcm.h>
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#include <linux/list.h>
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#include <linux/log2.h>
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#include <linux/mm.h>
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#include <linux/module.h>
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#include <linux/mutex.h>
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#include <linux/percpu.h>
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#include <linux/pfn.h>
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#include <linux/slab.h>
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#include <linux/spinlock.h>
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#include <linux/vmalloc.h>
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#include <linux/workqueue.h>
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#include <linux/kmemleak.h>
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#include <linux/sched.h>
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#include <linux/sched/mm.h>
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#include <linux/memcontrol.h>
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#include <asm/cacheflush.h>
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#include <asm/sections.h>
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#include <asm/tlbflush.h>
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#include <asm/io.h>
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#define CREATE_TRACE_POINTS
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#include <trace/events/percpu.h>
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#include "percpu-internal.h"
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/*
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* The slots are sorted by the size of the biggest continuous free area.
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* 1-31 bytes share the same slot.
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*/
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#define PCPU_SLOT_BASE_SHIFT 5
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/* chunks in slots below this are subject to being sidelined on failed alloc */
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#define PCPU_SLOT_FAIL_THRESHOLD 3
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#define PCPU_EMPTY_POP_PAGES_LOW 2
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#define PCPU_EMPTY_POP_PAGES_HIGH 4
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#ifdef CONFIG_SMP
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/* default addr <-> pcpu_ptr mapping, override in asm/percpu.h if necessary */
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#ifndef __addr_to_pcpu_ptr
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#define __addr_to_pcpu_ptr(addr) \
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(void __percpu *)((unsigned long)(addr) - \
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(unsigned long)pcpu_base_addr + \
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(unsigned long)__per_cpu_start)
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#endif
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#ifndef __pcpu_ptr_to_addr
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#define __pcpu_ptr_to_addr(ptr) \
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(void __force *)((unsigned long)(ptr) + \
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(unsigned long)pcpu_base_addr - \
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(unsigned long)__per_cpu_start)
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#endif
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#else /* CONFIG_SMP */
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/* on UP, it's always identity mapped */
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#define __addr_to_pcpu_ptr(addr) (void __percpu *)(addr)
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#define __pcpu_ptr_to_addr(ptr) (void __force *)(ptr)
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#endif /* CONFIG_SMP */
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static int pcpu_unit_pages __ro_after_init;
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static int pcpu_unit_size __ro_after_init;
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static int pcpu_nr_units __ro_after_init;
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static int pcpu_atom_size __ro_after_init;
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int pcpu_nr_slots __ro_after_init;
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static int pcpu_free_slot __ro_after_init;
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int pcpu_sidelined_slot __ro_after_init;
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int pcpu_to_depopulate_slot __ro_after_init;
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static size_t pcpu_chunk_struct_size __ro_after_init;
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/* cpus with the lowest and highest unit addresses */
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static unsigned int pcpu_low_unit_cpu __ro_after_init;
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static unsigned int pcpu_high_unit_cpu __ro_after_init;
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/* the address of the first chunk which starts with the kernel static area */
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void *pcpu_base_addr __ro_after_init;
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static const int *pcpu_unit_map __ro_after_init; /* cpu -> unit */
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const unsigned long *pcpu_unit_offsets __ro_after_init; /* cpu -> unit offset */
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/* group information, used for vm allocation */
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static int pcpu_nr_groups __ro_after_init;
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static const unsigned long *pcpu_group_offsets __ro_after_init;
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static const size_t *pcpu_group_sizes __ro_after_init;
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/*
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* The first chunk which always exists. Note that unlike other
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* chunks, this one can be allocated and mapped in several different
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* ways and thus often doesn't live in the vmalloc area.
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*/
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struct pcpu_chunk *pcpu_first_chunk __ro_after_init;
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/*
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* Optional reserved chunk. This chunk reserves part of the first
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* chunk and serves it for reserved allocations. When the reserved
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* region doesn't exist, the following variable is NULL.
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*/
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struct pcpu_chunk *pcpu_reserved_chunk __ro_after_init;
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DEFINE_SPINLOCK(pcpu_lock); /* all internal data structures */
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static DEFINE_MUTEX(pcpu_alloc_mutex); /* chunk create/destroy, [de]pop, map ext */
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struct list_head *pcpu_chunk_lists __ro_after_init; /* chunk list slots */
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/* chunks which need their map areas extended, protected by pcpu_lock */
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static LIST_HEAD(pcpu_map_extend_chunks);
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/*
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* The number of empty populated pages, protected by pcpu_lock.
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* The reserved chunk doesn't contribute to the count.
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*/
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int pcpu_nr_empty_pop_pages;
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/*
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* The number of populated pages in use by the allocator, protected by
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* pcpu_lock. This number is kept per a unit per chunk (i.e. when a page gets
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* allocated/deallocated, it is allocated/deallocated in all units of a chunk
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* and increments/decrements this count by 1).
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*/
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static unsigned long pcpu_nr_populated;
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/*
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* Balance work is used to populate or destroy chunks asynchronously. We
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* try to keep the number of populated free pages between
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* PCPU_EMPTY_POP_PAGES_LOW and HIGH for atomic allocations and at most one
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* empty chunk.
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*/
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static void pcpu_balance_workfn(struct work_struct *work);
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static DECLARE_WORK(pcpu_balance_work, pcpu_balance_workfn);
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static bool pcpu_async_enabled __read_mostly;
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static bool pcpu_atomic_alloc_failed;
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static void pcpu_schedule_balance_work(void)
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{
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if (pcpu_async_enabled)
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schedule_work(&pcpu_balance_work);
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}
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/**
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* pcpu_addr_in_chunk - check if the address is served from this chunk
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* @chunk: chunk of interest
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* @addr: percpu address
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*
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* RETURNS:
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* True if the address is served from this chunk.
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*/
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static bool pcpu_addr_in_chunk(struct pcpu_chunk *chunk, void *addr)
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{
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void *start_addr, *end_addr;
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if (!chunk)
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return false;
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start_addr = chunk->base_addr + chunk->start_offset;
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end_addr = chunk->base_addr + chunk->nr_pages * PAGE_SIZE -
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chunk->end_offset;
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return addr >= start_addr && addr < end_addr;
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}
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static int __pcpu_size_to_slot(int size)
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{
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int highbit = fls(size); /* size is in bytes */
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return max(highbit - PCPU_SLOT_BASE_SHIFT + 2, 1);
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}
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static int pcpu_size_to_slot(int size)
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{
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if (size == pcpu_unit_size)
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return pcpu_free_slot;
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return __pcpu_size_to_slot(size);
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}
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static int pcpu_chunk_slot(const struct pcpu_chunk *chunk)
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{
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const struct pcpu_block_md *chunk_md = &chunk->chunk_md;
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if (chunk->free_bytes < PCPU_MIN_ALLOC_SIZE ||
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chunk_md->contig_hint == 0)
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return 0;
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return pcpu_size_to_slot(chunk_md->contig_hint * PCPU_MIN_ALLOC_SIZE);
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}
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/* set the pointer to a chunk in a page struct */
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static void pcpu_set_page_chunk(struct page *page, struct pcpu_chunk *pcpu)
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{
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page->index = (unsigned long)pcpu;
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}
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/* obtain pointer to a chunk from a page struct */
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static struct pcpu_chunk *pcpu_get_page_chunk(struct page *page)
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{
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return (struct pcpu_chunk *)page->index;
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}
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static int __maybe_unused pcpu_page_idx(unsigned int cpu, int page_idx)
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{
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return pcpu_unit_map[cpu] * pcpu_unit_pages + page_idx;
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}
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static unsigned long pcpu_unit_page_offset(unsigned int cpu, int page_idx)
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{
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return pcpu_unit_offsets[cpu] + (page_idx << PAGE_SHIFT);
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}
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static unsigned long pcpu_chunk_addr(struct pcpu_chunk *chunk,
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unsigned int cpu, int page_idx)
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{
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return (unsigned long)chunk->base_addr +
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pcpu_unit_page_offset(cpu, page_idx);
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}
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/*
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* The following are helper functions to help access bitmaps and convert
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* between bitmap offsets to address offsets.
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*/
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static unsigned long *pcpu_index_alloc_map(struct pcpu_chunk *chunk, int index)
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{
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return chunk->alloc_map +
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(index * PCPU_BITMAP_BLOCK_BITS / BITS_PER_LONG);
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}
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static unsigned long pcpu_off_to_block_index(int off)
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{
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return off / PCPU_BITMAP_BLOCK_BITS;
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}
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static unsigned long pcpu_off_to_block_off(int off)
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{
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return off & (PCPU_BITMAP_BLOCK_BITS - 1);
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}
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static unsigned long pcpu_block_off_to_off(int index, int off)
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{
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return index * PCPU_BITMAP_BLOCK_BITS + off;
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}
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/**
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* pcpu_check_block_hint - check against the contig hint
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* @block: block of interest
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* @bits: size of allocation
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* @align: alignment of area (max PAGE_SIZE)
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*
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* Check to see if the allocation can fit in the block's contig hint.
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* Note, a chunk uses the same hints as a block so this can also check against
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* the chunk's contig hint.
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*/
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static bool pcpu_check_block_hint(struct pcpu_block_md *block, int bits,
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size_t align)
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{
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int bit_off = ALIGN(block->contig_hint_start, align) -
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block->contig_hint_start;
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return bit_off + bits <= block->contig_hint;
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}
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/*
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* pcpu_next_hint - determine which hint to use
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* @block: block of interest
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* @alloc_bits: size of allocation
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*
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* This determines if we should scan based on the scan_hint or first_free.
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* In general, we want to scan from first_free to fulfill allocations by
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* first fit. However, if we know a scan_hint at position scan_hint_start
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* cannot fulfill an allocation, we can begin scanning from there knowing
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* the contig_hint will be our fallback.
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*/
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static int pcpu_next_hint(struct pcpu_block_md *block, int alloc_bits)
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{
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/*
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* The three conditions below determine if we can skip past the
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* scan_hint. First, does the scan hint exist. Second, is the
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* contig_hint after the scan_hint (possibly not true iff
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* contig_hint == scan_hint). Third, is the allocation request
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* larger than the scan_hint.
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*/
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if (block->scan_hint &&
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block->contig_hint_start > block->scan_hint_start &&
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alloc_bits > block->scan_hint)
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return block->scan_hint_start + block->scan_hint;
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return block->first_free;
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}
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/**
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* pcpu_next_md_free_region - finds the next hint free area
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* @chunk: chunk of interest
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* @bit_off: chunk offset
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* @bits: size of free area
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*
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* Helper function for pcpu_for_each_md_free_region. It checks
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* block->contig_hint and performs aggregation across blocks to find the
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* next hint. It modifies bit_off and bits in-place to be consumed in the
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* loop.
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*/
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static void pcpu_next_md_free_region(struct pcpu_chunk *chunk, int *bit_off,
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int *bits)
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{
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int i = pcpu_off_to_block_index(*bit_off);
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int block_off = pcpu_off_to_block_off(*bit_off);
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struct pcpu_block_md *block;
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*bits = 0;
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for (block = chunk->md_blocks + i; i < pcpu_chunk_nr_blocks(chunk);
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block++, i++) {
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/* handles contig area across blocks */
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if (*bits) {
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*bits += block->left_free;
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if (block->left_free == PCPU_BITMAP_BLOCK_BITS)
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continue;
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return;
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}
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/*
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* This checks three things. First is there a contig_hint to
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* check. Second, have we checked this hint before by
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* comparing the block_off. Third, is this the same as the
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* right contig hint. In the last case, it spills over into
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* the next block and should be handled by the contig area
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* across blocks code.
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*/
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*bits = block->contig_hint;
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if (*bits && block->contig_hint_start >= block_off &&
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*bits + block->contig_hint_start < PCPU_BITMAP_BLOCK_BITS) {
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*bit_off = pcpu_block_off_to_off(i,
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block->contig_hint_start);
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return;
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}
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/* reset to satisfy the second predicate above */
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block_off = 0;
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*bits = block->right_free;
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*bit_off = (i + 1) * PCPU_BITMAP_BLOCK_BITS - block->right_free;
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}
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}
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/**
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* pcpu_next_fit_region - finds fit areas for a given allocation request
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* @chunk: chunk of interest
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* @alloc_bits: size of allocation
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* @align: alignment of area (max PAGE_SIZE)
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* @bit_off: chunk offset
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* @bits: size of free area
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*
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* Finds the next free region that is viable for use with a given size and
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* alignment. This only returns if there is a valid area to be used for this
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* allocation. block->first_free is returned if the allocation request fits
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* within the block to see if the request can be fulfilled prior to the contig
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* hint.
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*/
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static void pcpu_next_fit_region(struct pcpu_chunk *chunk, int alloc_bits,
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int align, int *bit_off, int *bits)
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{
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int i = pcpu_off_to_block_index(*bit_off);
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int block_off = pcpu_off_to_block_off(*bit_off);
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struct pcpu_block_md *block;
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*bits = 0;
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for (block = chunk->md_blocks + i; i < pcpu_chunk_nr_blocks(chunk);
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block++, i++) {
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/* handles contig area across blocks */
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if (*bits) {
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*bits += block->left_free;
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if (*bits >= alloc_bits)
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return;
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if (block->left_free == PCPU_BITMAP_BLOCK_BITS)
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continue;
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}
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/* check block->contig_hint */
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*bits = ALIGN(block->contig_hint_start, align) -
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block->contig_hint_start;
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/*
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* This uses the block offset to determine if this has been
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* checked in the prior iteration.
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*/
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if (block->contig_hint &&
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block->contig_hint_start >= block_off &&
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block->contig_hint >= *bits + alloc_bits) {
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int start = pcpu_next_hint(block, alloc_bits);
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*bits += alloc_bits + block->contig_hint_start -
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start;
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*bit_off = pcpu_block_off_to_off(i, start);
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return;
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}
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/* reset to satisfy the second predicate above */
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block_off = 0;
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*bit_off = ALIGN(PCPU_BITMAP_BLOCK_BITS - block->right_free,
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align);
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*bits = PCPU_BITMAP_BLOCK_BITS - *bit_off;
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*bit_off = pcpu_block_off_to_off(i, *bit_off);
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if (*bits >= alloc_bits)
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return;
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}
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/* no valid offsets were found - fail condition */
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*bit_off = pcpu_chunk_map_bits(chunk);
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}
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/*
|
|
* Metadata free area iterators. These perform aggregation of free areas
|
|
* based on the metadata blocks and return the offset @bit_off and size in
|
|
* bits of the free area @bits. pcpu_for_each_fit_region only returns when
|
|
* a fit is found for the allocation request.
|
|
*/
|
|
#define pcpu_for_each_md_free_region(chunk, bit_off, bits) \
|
|
for (pcpu_next_md_free_region((chunk), &(bit_off), &(bits)); \
|
|
(bit_off) < pcpu_chunk_map_bits((chunk)); \
|
|
(bit_off) += (bits) + 1, \
|
|
pcpu_next_md_free_region((chunk), &(bit_off), &(bits)))
|
|
|
|
#define pcpu_for_each_fit_region(chunk, alloc_bits, align, bit_off, bits) \
|
|
for (pcpu_next_fit_region((chunk), (alloc_bits), (align), &(bit_off), \
|
|
&(bits)); \
|
|
(bit_off) < pcpu_chunk_map_bits((chunk)); \
|
|
(bit_off) += (bits), \
|
|
pcpu_next_fit_region((chunk), (alloc_bits), (align), &(bit_off), \
|
|
&(bits)))
|
|
|
|
/**
|
|
* pcpu_mem_zalloc - allocate memory
|
|
* @size: bytes to allocate
|
|
* @gfp: allocation flags
|
|
*
|
|
* Allocate @size bytes. If @size is smaller than PAGE_SIZE,
|
|
* kzalloc() is used; otherwise, the equivalent of vzalloc() is used.
|
|
* This is to facilitate passing through whitelisted flags. The
|
|
* returned memory is always zeroed.
|
|
*
|
|
* RETURNS:
|
|
* Pointer to the allocated area on success, NULL on failure.
|
|
*/
|
|
static void *pcpu_mem_zalloc(size_t size, gfp_t gfp)
|
|
{
|
|
if (WARN_ON_ONCE(!slab_is_available()))
|
|
return NULL;
|
|
|
|
if (size <= PAGE_SIZE)
|
|
return kzalloc(size, gfp);
|
|
else
|
|
return __vmalloc(size, gfp | __GFP_ZERO);
|
|
}
|
|
|
|
/**
|
|
* pcpu_mem_free - free memory
|
|
* @ptr: memory to free
|
|
*
|
|
* Free @ptr. @ptr should have been allocated using pcpu_mem_zalloc().
|
|
*/
|
|
static void pcpu_mem_free(void *ptr)
|
|
{
|
|
kvfree(ptr);
|
|
}
|
|
|
|
static void __pcpu_chunk_move(struct pcpu_chunk *chunk, int slot,
|
|
bool move_front)
|
|
{
|
|
if (chunk != pcpu_reserved_chunk) {
|
|
if (move_front)
|
|
list_move(&chunk->list, &pcpu_chunk_lists[slot]);
|
|
else
|
|
list_move_tail(&chunk->list, &pcpu_chunk_lists[slot]);
|
|
}
|
|
}
|
|
|
|
static void pcpu_chunk_move(struct pcpu_chunk *chunk, int slot)
|
|
{
|
|
__pcpu_chunk_move(chunk, slot, true);
|
|
}
|
|
|
|
/**
|
|
* pcpu_chunk_relocate - put chunk in the appropriate chunk slot
|
|
* @chunk: chunk of interest
|
|
* @oslot: the previous slot it was on
|
|
*
|
|
* This function is called after an allocation or free changed @chunk.
|
|
* New slot according to the changed state is determined and @chunk is
|
|
* moved to the slot. Note that the reserved chunk is never put on
|
|
* chunk slots.
|
|
*
|
|
* CONTEXT:
|
|
* pcpu_lock.
|
|
*/
|
|
static void pcpu_chunk_relocate(struct pcpu_chunk *chunk, int oslot)
|
|
{
|
|
int nslot = pcpu_chunk_slot(chunk);
|
|
|
|
/* leave isolated chunks in-place */
|
|
if (chunk->isolated)
|
|
return;
|
|
|
|
if (oslot != nslot)
|
|
__pcpu_chunk_move(chunk, nslot, oslot < nslot);
|
|
}
|
|
|
|
static void pcpu_isolate_chunk(struct pcpu_chunk *chunk)
|
|
{
|
|
lockdep_assert_held(&pcpu_lock);
|
|
|
|
if (!chunk->isolated) {
|
|
chunk->isolated = true;
|
|
pcpu_nr_empty_pop_pages -= chunk->nr_empty_pop_pages;
|
|
}
|
|
list_move(&chunk->list, &pcpu_chunk_lists[pcpu_to_depopulate_slot]);
|
|
}
|
|
|
|
static void pcpu_reintegrate_chunk(struct pcpu_chunk *chunk)
|
|
{
|
|
lockdep_assert_held(&pcpu_lock);
|
|
|
|
if (chunk->isolated) {
|
|
chunk->isolated = false;
|
|
pcpu_nr_empty_pop_pages += chunk->nr_empty_pop_pages;
|
|
pcpu_chunk_relocate(chunk, -1);
|
|
}
|
|
}
|
|
|
|
/*
|
|
* pcpu_update_empty_pages - update empty page counters
|
|
* @chunk: chunk of interest
|
|
* @nr: nr of empty pages
|
|
*
|
|
* This is used to keep track of the empty pages now based on the premise
|
|
* a md_block covers a page. The hint update functions recognize if a block
|
|
* is made full or broken to calculate deltas for keeping track of free pages.
|
|
*/
|
|
static inline void pcpu_update_empty_pages(struct pcpu_chunk *chunk, int nr)
|
|
{
|
|
chunk->nr_empty_pop_pages += nr;
|
|
if (chunk != pcpu_reserved_chunk && !chunk->isolated)
|
|
pcpu_nr_empty_pop_pages += nr;
|
|
}
|
|
|
|
/*
|
|
* pcpu_region_overlap - determines if two regions overlap
|
|
* @a: start of first region, inclusive
|
|
* @b: end of first region, exclusive
|
|
* @x: start of second region, inclusive
|
|
* @y: end of second region, exclusive
|
|
*
|
|
* This is used to determine if the hint region [a, b) overlaps with the
|
|
* allocated region [x, y).
|
|
*/
|
|
static inline bool pcpu_region_overlap(int a, int b, int x, int y)
|
|
{
|
|
return (a < y) && (x < b);
|
|
}
|
|
|
|
/**
|
|
* pcpu_block_update - updates a block given a free area
|
|
* @block: block of interest
|
|
* @start: start offset in block
|
|
* @end: end offset in block
|
|
*
|
|
* Updates a block given a known free area. The region [start, end) is
|
|
* expected to be the entirety of the free area within a block. Chooses
|
|
* the best starting offset if the contig hints are equal.
|
|
*/
|
|
static void pcpu_block_update(struct pcpu_block_md *block, int start, int end)
|
|
{
|
|
int contig = end - start;
|
|
|
|
block->first_free = min(block->first_free, start);
|
|
if (start == 0)
|
|
block->left_free = contig;
|
|
|
|
if (end == block->nr_bits)
|
|
block->right_free = contig;
|
|
|
|
if (contig > block->contig_hint) {
|
|
/* promote the old contig_hint to be the new scan_hint */
|
|
if (start > block->contig_hint_start) {
|
|
if (block->contig_hint > block->scan_hint) {
|
|
block->scan_hint_start =
|
|
block->contig_hint_start;
|
|
block->scan_hint = block->contig_hint;
|
|
} else if (start < block->scan_hint_start) {
|
|
/*
|
|
* The old contig_hint == scan_hint. But, the
|
|
* new contig is larger so hold the invariant
|
|
* scan_hint_start < contig_hint_start.
|
|
*/
|
|
block->scan_hint = 0;
|
|
}
|
|
} else {
|
|
block->scan_hint = 0;
|
|
}
|
|
block->contig_hint_start = start;
|
|
block->contig_hint = contig;
|
|
} else if (contig == block->contig_hint) {
|
|
if (block->contig_hint_start &&
|
|
(!start ||
|
|
__ffs(start) > __ffs(block->contig_hint_start))) {
|
|
/* start has a better alignment so use it */
|
|
block->contig_hint_start = start;
|
|
if (start < block->scan_hint_start &&
|
|
block->contig_hint > block->scan_hint)
|
|
block->scan_hint = 0;
|
|
} else if (start > block->scan_hint_start ||
|
|
block->contig_hint > block->scan_hint) {
|
|
/*
|
|
* Knowing contig == contig_hint, update the scan_hint
|
|
* if it is farther than or larger than the current
|
|
* scan_hint.
|
|
*/
|
|
block->scan_hint_start = start;
|
|
block->scan_hint = contig;
|
|
}
|
|
} else {
|
|
/*
|
|
* The region is smaller than the contig_hint. So only update
|
|
* the scan_hint if it is larger than or equal and farther than
|
|
* the current scan_hint.
|
|
*/
|
|
if ((start < block->contig_hint_start &&
|
|
(contig > block->scan_hint ||
|
|
(contig == block->scan_hint &&
|
|
start > block->scan_hint_start)))) {
|
|
block->scan_hint_start = start;
|
|
block->scan_hint = contig;
|
|
}
|
|
}
|
|
}
|
|
|
|
/*
|
|
* pcpu_block_update_scan - update a block given a free area from a scan
|
|
* @chunk: chunk of interest
|
|
* @bit_off: chunk offset
|
|
* @bits: size of free area
|
|
*
|
|
* Finding the final allocation spot first goes through pcpu_find_block_fit()
|
|
* to find a block that can hold the allocation and then pcpu_alloc_area()
|
|
* where a scan is used. When allocations require specific alignments,
|
|
* we can inadvertently create holes which will not be seen in the alloc
|
|
* or free paths.
|
|
*
|
|
* This takes a given free area hole and updates a block as it may change the
|
|
* scan_hint. We need to scan backwards to ensure we don't miss free bits
|
|
* from alignment.
|
|
*/
|
|
static void pcpu_block_update_scan(struct pcpu_chunk *chunk, int bit_off,
|
|
int bits)
|
|
{
|
|
int s_off = pcpu_off_to_block_off(bit_off);
|
|
int e_off = s_off + bits;
|
|
int s_index, l_bit;
|
|
struct pcpu_block_md *block;
|
|
|
|
if (e_off > PCPU_BITMAP_BLOCK_BITS)
|
|
return;
|
|
|
|
s_index = pcpu_off_to_block_index(bit_off);
|
|
block = chunk->md_blocks + s_index;
|
|
|
|
/* scan backwards in case of alignment skipping free bits */
|
|
l_bit = find_last_bit(pcpu_index_alloc_map(chunk, s_index), s_off);
|
|
s_off = (s_off == l_bit) ? 0 : l_bit + 1;
|
|
|
|
pcpu_block_update(block, s_off, e_off);
|
|
}
|
|
|
|
/**
|
|
* pcpu_chunk_refresh_hint - updates metadata about a chunk
|
|
* @chunk: chunk of interest
|
|
* @full_scan: if we should scan from the beginning
|
|
*
|
|
* Iterates over the metadata blocks to find the largest contig area.
|
|
* A full scan can be avoided on the allocation path as this is triggered
|
|
* if we broke the contig_hint. In doing so, the scan_hint will be before
|
|
* the contig_hint or after if the scan_hint == contig_hint. This cannot
|
|
* be prevented on freeing as we want to find the largest area possibly
|
|
* spanning blocks.
|
|
*/
|
|
static void pcpu_chunk_refresh_hint(struct pcpu_chunk *chunk, bool full_scan)
|
|
{
|
|
struct pcpu_block_md *chunk_md = &chunk->chunk_md;
|
|
int bit_off, bits;
|
|
|
|
/* promote scan_hint to contig_hint */
|
|
if (!full_scan && chunk_md->scan_hint) {
|
|
bit_off = chunk_md->scan_hint_start + chunk_md->scan_hint;
|
|
chunk_md->contig_hint_start = chunk_md->scan_hint_start;
|
|
chunk_md->contig_hint = chunk_md->scan_hint;
|
|
chunk_md->scan_hint = 0;
|
|
} else {
|
|
bit_off = chunk_md->first_free;
|
|
chunk_md->contig_hint = 0;
|
|
}
|
|
|
|
bits = 0;
|
|
pcpu_for_each_md_free_region(chunk, bit_off, bits)
|
|
pcpu_block_update(chunk_md, bit_off, bit_off + bits);
|
|
}
|
|
|
|
/**
|
|
* pcpu_block_refresh_hint
|
|
* @chunk: chunk of interest
|
|
* @index: index of the metadata block
|
|
*
|
|
* Scans over the block beginning at first_free and updates the block
|
|
* metadata accordingly.
|
|
*/
|
|
static void pcpu_block_refresh_hint(struct pcpu_chunk *chunk, int index)
|
|
{
|
|
struct pcpu_block_md *block = chunk->md_blocks + index;
|
|
unsigned long *alloc_map = pcpu_index_alloc_map(chunk, index);
|
|
unsigned int start, end; /* region start, region end */
|
|
|
|
/* promote scan_hint to contig_hint */
|
|
if (block->scan_hint) {
|
|
start = block->scan_hint_start + block->scan_hint;
|
|
block->contig_hint_start = block->scan_hint_start;
|
|
block->contig_hint = block->scan_hint;
|
|
block->scan_hint = 0;
|
|
} else {
|
|
start = block->first_free;
|
|
block->contig_hint = 0;
|
|
}
|
|
|
|
block->right_free = 0;
|
|
|
|
/* iterate over free areas and update the contig hints */
|
|
for_each_clear_bitrange_from(start, end, alloc_map, PCPU_BITMAP_BLOCK_BITS)
|
|
pcpu_block_update(block, start, end);
|
|
}
|
|
|
|
/**
|
|
* pcpu_block_update_hint_alloc - update hint on allocation path
|
|
* @chunk: chunk of interest
|
|
* @bit_off: chunk offset
|
|
* @bits: size of request
|
|
*
|
|
* Updates metadata for the allocation path. The metadata only has to be
|
|
* refreshed by a full scan iff the chunk's contig hint is broken. Block level
|
|
* scans are required if the block's contig hint is broken.
|
|
*/
|
|
static void pcpu_block_update_hint_alloc(struct pcpu_chunk *chunk, int bit_off,
|
|
int bits)
|
|
{
|
|
struct pcpu_block_md *chunk_md = &chunk->chunk_md;
|
|
int nr_empty_pages = 0;
|
|
struct pcpu_block_md *s_block, *e_block, *block;
|
|
int s_index, e_index; /* block indexes of the freed allocation */
|
|
int s_off, e_off; /* block offsets of the freed allocation */
|
|
|
|
/*
|
|
* Calculate per block offsets.
|
|
* The calculation uses an inclusive range, but the resulting offsets
|
|
* are [start, end). e_index always points to the last block in the
|
|
* range.
|
|
*/
|
|
s_index = pcpu_off_to_block_index(bit_off);
|
|
e_index = pcpu_off_to_block_index(bit_off + bits - 1);
|
|
s_off = pcpu_off_to_block_off(bit_off);
|
|
e_off = pcpu_off_to_block_off(bit_off + bits - 1) + 1;
|
|
|
|
s_block = chunk->md_blocks + s_index;
|
|
e_block = chunk->md_blocks + e_index;
|
|
|
|
/*
|
|
* Update s_block.
|
|
* block->first_free must be updated if the allocation takes its place.
|
|
* If the allocation breaks the contig_hint, a scan is required to
|
|
* restore this hint.
|
|
*/
|
|
if (s_block->contig_hint == PCPU_BITMAP_BLOCK_BITS)
|
|
nr_empty_pages++;
|
|
|
|
if (s_off == s_block->first_free)
|
|
s_block->first_free = find_next_zero_bit(
|
|
pcpu_index_alloc_map(chunk, s_index),
|
|
PCPU_BITMAP_BLOCK_BITS,
|
|
s_off + bits);
|
|
|
|
if (pcpu_region_overlap(s_block->scan_hint_start,
|
|
s_block->scan_hint_start + s_block->scan_hint,
|
|
s_off,
|
|
s_off + bits))
|
|
s_block->scan_hint = 0;
|
|
|
|
if (pcpu_region_overlap(s_block->contig_hint_start,
|
|
s_block->contig_hint_start +
|
|
s_block->contig_hint,
|
|
s_off,
|
|
s_off + bits)) {
|
|
/* block contig hint is broken - scan to fix it */
|
|
if (!s_off)
|
|
s_block->left_free = 0;
|
|
pcpu_block_refresh_hint(chunk, s_index);
|
|
} else {
|
|
/* update left and right contig manually */
|
|
s_block->left_free = min(s_block->left_free, s_off);
|
|
if (s_index == e_index)
|
|
s_block->right_free = min_t(int, s_block->right_free,
|
|
PCPU_BITMAP_BLOCK_BITS - e_off);
|
|
else
|
|
s_block->right_free = 0;
|
|
}
|
|
|
|
/*
|
|
* Update e_block.
|
|
*/
|
|
if (s_index != e_index) {
|
|
if (e_block->contig_hint == PCPU_BITMAP_BLOCK_BITS)
|
|
nr_empty_pages++;
|
|
|
|
/*
|
|
* When the allocation is across blocks, the end is along
|
|
* the left part of the e_block.
|
|
*/
|
|
e_block->first_free = find_next_zero_bit(
|
|
pcpu_index_alloc_map(chunk, e_index),
|
|
PCPU_BITMAP_BLOCK_BITS, e_off);
|
|
|
|
if (e_off == PCPU_BITMAP_BLOCK_BITS) {
|
|
/* reset the block */
|
|
e_block++;
|
|
} else {
|
|
if (e_off > e_block->scan_hint_start)
|
|
e_block->scan_hint = 0;
|
|
|
|
e_block->left_free = 0;
|
|
if (e_off > e_block->contig_hint_start) {
|
|
/* contig hint is broken - scan to fix it */
|
|
pcpu_block_refresh_hint(chunk, e_index);
|
|
} else {
|
|
e_block->right_free =
|
|
min_t(int, e_block->right_free,
|
|
PCPU_BITMAP_BLOCK_BITS - e_off);
|
|
}
|
|
}
|
|
|
|
/* update in-between md_blocks */
|
|
nr_empty_pages += (e_index - s_index - 1);
|
|
for (block = s_block + 1; block < e_block; block++) {
|
|
block->scan_hint = 0;
|
|
block->contig_hint = 0;
|
|
block->left_free = 0;
|
|
block->right_free = 0;
|
|
}
|
|
}
|
|
|
|
if (nr_empty_pages)
|
|
pcpu_update_empty_pages(chunk, -nr_empty_pages);
|
|
|
|
if (pcpu_region_overlap(chunk_md->scan_hint_start,
|
|
chunk_md->scan_hint_start +
|
|
chunk_md->scan_hint,
|
|
bit_off,
|
|
bit_off + bits))
|
|
chunk_md->scan_hint = 0;
|
|
|
|
/*
|
|
* The only time a full chunk scan is required is if the chunk
|
|
* contig hint is broken. Otherwise, it means a smaller space
|
|
* was used and therefore the chunk contig hint is still correct.
|
|
*/
|
|
if (pcpu_region_overlap(chunk_md->contig_hint_start,
|
|
chunk_md->contig_hint_start +
|
|
chunk_md->contig_hint,
|
|
bit_off,
|
|
bit_off + bits))
|
|
pcpu_chunk_refresh_hint(chunk, false);
|
|
}
|
|
|
|
/**
|
|
* pcpu_block_update_hint_free - updates the block hints on the free path
|
|
* @chunk: chunk of interest
|
|
* @bit_off: chunk offset
|
|
* @bits: size of request
|
|
*
|
|
* Updates metadata for the allocation path. This avoids a blind block
|
|
* refresh by making use of the block contig hints. If this fails, it scans
|
|
* forward and backward to determine the extent of the free area. This is
|
|
* capped at the boundary of blocks.
|
|
*
|
|
* A chunk update is triggered if a page becomes free, a block becomes free,
|
|
* or the free spans across blocks. This tradeoff is to minimize iterating
|
|
* over the block metadata to update chunk_md->contig_hint.
|
|
* chunk_md->contig_hint may be off by up to a page, but it will never be more
|
|
* than the available space. If the contig hint is contained in one block, it
|
|
* will be accurate.
|
|
*/
|
|
static void pcpu_block_update_hint_free(struct pcpu_chunk *chunk, int bit_off,
|
|
int bits)
|
|
{
|
|
int nr_empty_pages = 0;
|
|
struct pcpu_block_md *s_block, *e_block, *block;
|
|
int s_index, e_index; /* block indexes of the freed allocation */
|
|
int s_off, e_off; /* block offsets of the freed allocation */
|
|
int start, end; /* start and end of the whole free area */
|
|
|
|
/*
|
|
* Calculate per block offsets.
|
|
* The calculation uses an inclusive range, but the resulting offsets
|
|
* are [start, end). e_index always points to the last block in the
|
|
* range.
|
|
*/
|
|
s_index = pcpu_off_to_block_index(bit_off);
|
|
e_index = pcpu_off_to_block_index(bit_off + bits - 1);
|
|
s_off = pcpu_off_to_block_off(bit_off);
|
|
e_off = pcpu_off_to_block_off(bit_off + bits - 1) + 1;
|
|
|
|
s_block = chunk->md_blocks + s_index;
|
|
e_block = chunk->md_blocks + e_index;
|
|
|
|
/*
|
|
* Check if the freed area aligns with the block->contig_hint.
|
|
* If it does, then the scan to find the beginning/end of the
|
|
* larger free area can be avoided.
|
|
*
|
|
* start and end refer to beginning and end of the free area
|
|
* within each their respective blocks. This is not necessarily
|
|
* the entire free area as it may span blocks past the beginning
|
|
* or end of the block.
|
|
*/
|
|
start = s_off;
|
|
if (s_off == s_block->contig_hint + s_block->contig_hint_start) {
|
|
start = s_block->contig_hint_start;
|
|
} else {
|
|
/*
|
|
* Scan backwards to find the extent of the free area.
|
|
* find_last_bit returns the starting bit, so if the start bit
|
|
* is returned, that means there was no last bit and the
|
|
* remainder of the chunk is free.
|
|
*/
|
|
int l_bit = find_last_bit(pcpu_index_alloc_map(chunk, s_index),
|
|
start);
|
|
start = (start == l_bit) ? 0 : l_bit + 1;
|
|
}
|
|
|
|
end = e_off;
|
|
if (e_off == e_block->contig_hint_start)
|
|
end = e_block->contig_hint_start + e_block->contig_hint;
|
|
else
|
|
end = find_next_bit(pcpu_index_alloc_map(chunk, e_index),
|
|
PCPU_BITMAP_BLOCK_BITS, end);
|
|
|
|
/* update s_block */
|
|
e_off = (s_index == e_index) ? end : PCPU_BITMAP_BLOCK_BITS;
|
|
if (!start && e_off == PCPU_BITMAP_BLOCK_BITS)
|
|
nr_empty_pages++;
|
|
pcpu_block_update(s_block, start, e_off);
|
|
|
|
/* freeing in the same block */
|
|
if (s_index != e_index) {
|
|
/* update e_block */
|
|
if (end == PCPU_BITMAP_BLOCK_BITS)
|
|
nr_empty_pages++;
|
|
pcpu_block_update(e_block, 0, end);
|
|
|
|
/* reset md_blocks in the middle */
|
|
nr_empty_pages += (e_index - s_index - 1);
|
|
for (block = s_block + 1; block < e_block; block++) {
|
|
block->first_free = 0;
|
|
block->scan_hint = 0;
|
|
block->contig_hint_start = 0;
|
|
block->contig_hint = PCPU_BITMAP_BLOCK_BITS;
|
|
block->left_free = PCPU_BITMAP_BLOCK_BITS;
|
|
block->right_free = PCPU_BITMAP_BLOCK_BITS;
|
|
}
|
|
}
|
|
|
|
if (nr_empty_pages)
|
|
pcpu_update_empty_pages(chunk, nr_empty_pages);
|
|
|
|
/*
|
|
* Refresh chunk metadata when the free makes a block free or spans
|
|
* across blocks. The contig_hint may be off by up to a page, but if
|
|
* the contig_hint is contained in a block, it will be accurate with
|
|
* the else condition below.
|
|
*/
|
|
if (((end - start) >= PCPU_BITMAP_BLOCK_BITS) || s_index != e_index)
|
|
pcpu_chunk_refresh_hint(chunk, true);
|
|
else
|
|
pcpu_block_update(&chunk->chunk_md,
|
|
pcpu_block_off_to_off(s_index, start),
|
|
end);
|
|
}
|
|
|
|
/**
|
|
* pcpu_is_populated - determines if the region is populated
|
|
* @chunk: chunk of interest
|
|
* @bit_off: chunk offset
|
|
* @bits: size of area
|
|
* @next_off: return value for the next offset to start searching
|
|
*
|
|
* For atomic allocations, check if the backing pages are populated.
|
|
*
|
|
* RETURNS:
|
|
* Bool if the backing pages are populated.
|
|
* next_index is to skip over unpopulated blocks in pcpu_find_block_fit.
|
|
*/
|
|
static bool pcpu_is_populated(struct pcpu_chunk *chunk, int bit_off, int bits,
|
|
int *next_off)
|
|
{
|
|
unsigned int start, end;
|
|
|
|
start = PFN_DOWN(bit_off * PCPU_MIN_ALLOC_SIZE);
|
|
end = PFN_UP((bit_off + bits) * PCPU_MIN_ALLOC_SIZE);
|
|
|
|
start = find_next_zero_bit(chunk->populated, end, start);
|
|
if (start >= end)
|
|
return true;
|
|
|
|
end = find_next_bit(chunk->populated, end, start + 1);
|
|
|
|
*next_off = end * PAGE_SIZE / PCPU_MIN_ALLOC_SIZE;
|
|
return false;
|
|
}
|
|
|
|
/**
|
|
* pcpu_find_block_fit - finds the block index to start searching
|
|
* @chunk: chunk of interest
|
|
* @alloc_bits: size of request in allocation units
|
|
* @align: alignment of area (max PAGE_SIZE bytes)
|
|
* @pop_only: use populated regions only
|
|
*
|
|
* Given a chunk and an allocation spec, find the offset to begin searching
|
|
* for a free region. This iterates over the bitmap metadata blocks to
|
|
* find an offset that will be guaranteed to fit the requirements. It is
|
|
* not quite first fit as if the allocation does not fit in the contig hint
|
|
* of a block or chunk, it is skipped. This errs on the side of caution
|
|
* to prevent excess iteration. Poor alignment can cause the allocator to
|
|
* skip over blocks and chunks that have valid free areas.
|
|
*
|
|
* RETURNS:
|
|
* The offset in the bitmap to begin searching.
|
|
* -1 if no offset is found.
|
|
*/
|
|
static int pcpu_find_block_fit(struct pcpu_chunk *chunk, int alloc_bits,
|
|
size_t align, bool pop_only)
|
|
{
|
|
struct pcpu_block_md *chunk_md = &chunk->chunk_md;
|
|
int bit_off, bits, next_off;
|
|
|
|
/*
|
|
* This is an optimization to prevent scanning by assuming if the
|
|
* allocation cannot fit in the global hint, there is memory pressure
|
|
* and creating a new chunk would happen soon.
|
|
*/
|
|
if (!pcpu_check_block_hint(chunk_md, alloc_bits, align))
|
|
return -1;
|
|
|
|
bit_off = pcpu_next_hint(chunk_md, alloc_bits);
|
|
bits = 0;
|
|
pcpu_for_each_fit_region(chunk, alloc_bits, align, bit_off, bits) {
|
|
if (!pop_only || pcpu_is_populated(chunk, bit_off, bits,
|
|
&next_off))
|
|
break;
|
|
|
|
bit_off = next_off;
|
|
bits = 0;
|
|
}
|
|
|
|
if (bit_off == pcpu_chunk_map_bits(chunk))
|
|
return -1;
|
|
|
|
return bit_off;
|
|
}
|
|
|
|
/*
|
|
* pcpu_find_zero_area - modified from bitmap_find_next_zero_area_off()
|
|
* @map: the address to base the search on
|
|
* @size: the bitmap size in bits
|
|
* @start: the bitnumber to start searching at
|
|
* @nr: the number of zeroed bits we're looking for
|
|
* @align_mask: alignment mask for zero area
|
|
* @largest_off: offset of the largest area skipped
|
|
* @largest_bits: size of the largest area skipped
|
|
*
|
|
* The @align_mask should be one less than a power of 2.
|
|
*
|
|
* This is a modified version of bitmap_find_next_zero_area_off() to remember
|
|
* the largest area that was skipped. This is imperfect, but in general is
|
|
* good enough. The largest remembered region is the largest failed region
|
|
* seen. This does not include anything we possibly skipped due to alignment.
|
|
* pcpu_block_update_scan() does scan backwards to try and recover what was
|
|
* lost to alignment. While this can cause scanning to miss earlier possible
|
|
* free areas, smaller allocations will eventually fill those holes.
|
|
*/
|
|
static unsigned long pcpu_find_zero_area(unsigned long *map,
|
|
unsigned long size,
|
|
unsigned long start,
|
|
unsigned long nr,
|
|
unsigned long align_mask,
|
|
unsigned long *largest_off,
|
|
unsigned long *largest_bits)
|
|
{
|
|
unsigned long index, end, i, area_off, area_bits;
|
|
again:
|
|
index = find_next_zero_bit(map, size, start);
|
|
|
|
/* Align allocation */
|
|
index = __ALIGN_MASK(index, align_mask);
|
|
area_off = index;
|
|
|
|
end = index + nr;
|
|
if (end > size)
|
|
return end;
|
|
i = find_next_bit(map, end, index);
|
|
if (i < end) {
|
|
area_bits = i - area_off;
|
|
/* remember largest unused area with best alignment */
|
|
if (area_bits > *largest_bits ||
|
|
(area_bits == *largest_bits && *largest_off &&
|
|
(!area_off || __ffs(area_off) > __ffs(*largest_off)))) {
|
|
*largest_off = area_off;
|
|
*largest_bits = area_bits;
|
|
}
|
|
|
|
start = i + 1;
|
|
goto again;
|
|
}
|
|
return index;
|
|
}
|
|
|
|
/**
|
|
* pcpu_alloc_area - allocates an area from a pcpu_chunk
|
|
* @chunk: chunk of interest
|
|
* @alloc_bits: size of request in allocation units
|
|
* @align: alignment of area (max PAGE_SIZE)
|
|
* @start: bit_off to start searching
|
|
*
|
|
* This function takes in a @start offset to begin searching to fit an
|
|
* allocation of @alloc_bits with alignment @align. It needs to scan
|
|
* the allocation map because if it fits within the block's contig hint,
|
|
* @start will be block->first_free. This is an attempt to fill the
|
|
* allocation prior to breaking the contig hint. The allocation and
|
|
* boundary maps are updated accordingly if it confirms a valid
|
|
* free area.
|
|
*
|
|
* RETURNS:
|
|
* Allocated addr offset in @chunk on success.
|
|
* -1 if no matching area is found.
|
|
*/
|
|
static int pcpu_alloc_area(struct pcpu_chunk *chunk, int alloc_bits,
|
|
size_t align, int start)
|
|
{
|
|
struct pcpu_block_md *chunk_md = &chunk->chunk_md;
|
|
size_t align_mask = (align) ? (align - 1) : 0;
|
|
unsigned long area_off = 0, area_bits = 0;
|
|
int bit_off, end, oslot;
|
|
|
|
lockdep_assert_held(&pcpu_lock);
|
|
|
|
oslot = pcpu_chunk_slot(chunk);
|
|
|
|
/*
|
|
* Search to find a fit.
|
|
*/
|
|
end = min_t(int, start + alloc_bits + PCPU_BITMAP_BLOCK_BITS,
|
|
pcpu_chunk_map_bits(chunk));
|
|
bit_off = pcpu_find_zero_area(chunk->alloc_map, end, start, alloc_bits,
|
|
align_mask, &area_off, &area_bits);
|
|
if (bit_off >= end)
|
|
return -1;
|
|
|
|
if (area_bits)
|
|
pcpu_block_update_scan(chunk, area_off, area_bits);
|
|
|
|
/* update alloc map */
|
|
bitmap_set(chunk->alloc_map, bit_off, alloc_bits);
|
|
|
|
/* update boundary map */
|
|
set_bit(bit_off, chunk->bound_map);
|
|
bitmap_clear(chunk->bound_map, bit_off + 1, alloc_bits - 1);
|
|
set_bit(bit_off + alloc_bits, chunk->bound_map);
|
|
|
|
chunk->free_bytes -= alloc_bits * PCPU_MIN_ALLOC_SIZE;
|
|
|
|
/* update first free bit */
|
|
if (bit_off == chunk_md->first_free)
|
|
chunk_md->first_free = find_next_zero_bit(
|
|
chunk->alloc_map,
|
|
pcpu_chunk_map_bits(chunk),
|
|
bit_off + alloc_bits);
|
|
|
|
pcpu_block_update_hint_alloc(chunk, bit_off, alloc_bits);
|
|
|
|
pcpu_chunk_relocate(chunk, oslot);
|
|
|
|
return bit_off * PCPU_MIN_ALLOC_SIZE;
|
|
}
|
|
|
|
/**
|
|
* pcpu_free_area - frees the corresponding offset
|
|
* @chunk: chunk of interest
|
|
* @off: addr offset into chunk
|
|
*
|
|
* This function determines the size of an allocation to free using
|
|
* the boundary bitmap and clears the allocation map.
|
|
*
|
|
* RETURNS:
|
|
* Number of freed bytes.
|
|
*/
|
|
static int pcpu_free_area(struct pcpu_chunk *chunk, int off)
|
|
{
|
|
struct pcpu_block_md *chunk_md = &chunk->chunk_md;
|
|
int bit_off, bits, end, oslot, freed;
|
|
|
|
lockdep_assert_held(&pcpu_lock);
|
|
pcpu_stats_area_dealloc(chunk);
|
|
|
|
oslot = pcpu_chunk_slot(chunk);
|
|
|
|
bit_off = off / PCPU_MIN_ALLOC_SIZE;
|
|
|
|
/* find end index */
|
|
end = find_next_bit(chunk->bound_map, pcpu_chunk_map_bits(chunk),
|
|
bit_off + 1);
|
|
bits = end - bit_off;
|
|
bitmap_clear(chunk->alloc_map, bit_off, bits);
|
|
|
|
freed = bits * PCPU_MIN_ALLOC_SIZE;
|
|
|
|
/* update metadata */
|
|
chunk->free_bytes += freed;
|
|
|
|
/* update first free bit */
|
|
chunk_md->first_free = min(chunk_md->first_free, bit_off);
|
|
|
|
pcpu_block_update_hint_free(chunk, bit_off, bits);
|
|
|
|
pcpu_chunk_relocate(chunk, oslot);
|
|
|
|
return freed;
|
|
}
|
|
|
|
static void pcpu_init_md_block(struct pcpu_block_md *block, int nr_bits)
|
|
{
|
|
block->scan_hint = 0;
|
|
block->contig_hint = nr_bits;
|
|
block->left_free = nr_bits;
|
|
block->right_free = nr_bits;
|
|
block->first_free = 0;
|
|
block->nr_bits = nr_bits;
|
|
}
|
|
|
|
static void pcpu_init_md_blocks(struct pcpu_chunk *chunk)
|
|
{
|
|
struct pcpu_block_md *md_block;
|
|
|
|
/* init the chunk's block */
|
|
pcpu_init_md_block(&chunk->chunk_md, pcpu_chunk_map_bits(chunk));
|
|
|
|
for (md_block = chunk->md_blocks;
|
|
md_block != chunk->md_blocks + pcpu_chunk_nr_blocks(chunk);
|
|
md_block++)
|
|
pcpu_init_md_block(md_block, PCPU_BITMAP_BLOCK_BITS);
|
|
}
|
|
|
|
/**
|
|
* pcpu_alloc_first_chunk - creates chunks that serve the first chunk
|
|
* @tmp_addr: the start of the region served
|
|
* @map_size: size of the region served
|
|
*
|
|
* This is responsible for creating the chunks that serve the first chunk. The
|
|
* base_addr is page aligned down of @tmp_addr while the region end is page
|
|
* aligned up. Offsets are kept track of to determine the region served. All
|
|
* this is done to appease the bitmap allocator in avoiding partial blocks.
|
|
*
|
|
* RETURNS:
|
|
* Chunk serving the region at @tmp_addr of @map_size.
|
|
*/
|
|
static struct pcpu_chunk * __init pcpu_alloc_first_chunk(unsigned long tmp_addr,
|
|
int map_size)
|
|
{
|
|
struct pcpu_chunk *chunk;
|
|
unsigned long aligned_addr, lcm_align;
|
|
int start_offset, offset_bits, region_size, region_bits;
|
|
size_t alloc_size;
|
|
|
|
/* region calculations */
|
|
aligned_addr = tmp_addr & PAGE_MASK;
|
|
|
|
start_offset = tmp_addr - aligned_addr;
|
|
|
|
/*
|
|
* Align the end of the region with the LCM of PAGE_SIZE and
|
|
* PCPU_BITMAP_BLOCK_SIZE. One of these constants is a multiple of
|
|
* the other.
|
|
*/
|
|
lcm_align = lcm(PAGE_SIZE, PCPU_BITMAP_BLOCK_SIZE);
|
|
region_size = ALIGN(start_offset + map_size, lcm_align);
|
|
|
|
/* allocate chunk */
|
|
alloc_size = struct_size(chunk, populated,
|
|
BITS_TO_LONGS(region_size >> PAGE_SHIFT));
|
|
chunk = memblock_alloc(alloc_size, SMP_CACHE_BYTES);
|
|
if (!chunk)
|
|
panic("%s: Failed to allocate %zu bytes\n", __func__,
|
|
alloc_size);
|
|
|
|
INIT_LIST_HEAD(&chunk->list);
|
|
|
|
chunk->base_addr = (void *)aligned_addr;
|
|
chunk->start_offset = start_offset;
|
|
chunk->end_offset = region_size - chunk->start_offset - map_size;
|
|
|
|
chunk->nr_pages = region_size >> PAGE_SHIFT;
|
|
region_bits = pcpu_chunk_map_bits(chunk);
|
|
|
|
alloc_size = BITS_TO_LONGS(region_bits) * sizeof(chunk->alloc_map[0]);
|
|
chunk->alloc_map = memblock_alloc(alloc_size, SMP_CACHE_BYTES);
|
|
if (!chunk->alloc_map)
|
|
panic("%s: Failed to allocate %zu bytes\n", __func__,
|
|
alloc_size);
|
|
|
|
alloc_size =
|
|
BITS_TO_LONGS(region_bits + 1) * sizeof(chunk->bound_map[0]);
|
|
chunk->bound_map = memblock_alloc(alloc_size, SMP_CACHE_BYTES);
|
|
if (!chunk->bound_map)
|
|
panic("%s: Failed to allocate %zu bytes\n", __func__,
|
|
alloc_size);
|
|
|
|
alloc_size = pcpu_chunk_nr_blocks(chunk) * sizeof(chunk->md_blocks[0]);
|
|
chunk->md_blocks = memblock_alloc(alloc_size, SMP_CACHE_BYTES);
|
|
if (!chunk->md_blocks)
|
|
panic("%s: Failed to allocate %zu bytes\n", __func__,
|
|
alloc_size);
|
|
|
|
#ifdef CONFIG_MEMCG_KMEM
|
|
/* first chunk is free to use */
|
|
chunk->obj_cgroups = NULL;
|
|
#endif
|
|
pcpu_init_md_blocks(chunk);
|
|
|
|
/* manage populated page bitmap */
|
|
chunk->immutable = true;
|
|
bitmap_fill(chunk->populated, chunk->nr_pages);
|
|
chunk->nr_populated = chunk->nr_pages;
|
|
chunk->nr_empty_pop_pages = chunk->nr_pages;
|
|
|
|
chunk->free_bytes = map_size;
|
|
|
|
if (chunk->start_offset) {
|
|
/* hide the beginning of the bitmap */
|
|
offset_bits = chunk->start_offset / PCPU_MIN_ALLOC_SIZE;
|
|
bitmap_set(chunk->alloc_map, 0, offset_bits);
|
|
set_bit(0, chunk->bound_map);
|
|
set_bit(offset_bits, chunk->bound_map);
|
|
|
|
chunk->chunk_md.first_free = offset_bits;
|
|
|
|
pcpu_block_update_hint_alloc(chunk, 0, offset_bits);
|
|
}
|
|
|
|
if (chunk->end_offset) {
|
|
/* hide the end of the bitmap */
|
|
offset_bits = chunk->end_offset / PCPU_MIN_ALLOC_SIZE;
|
|
bitmap_set(chunk->alloc_map,
|
|
pcpu_chunk_map_bits(chunk) - offset_bits,
|
|
offset_bits);
|
|
set_bit((start_offset + map_size) / PCPU_MIN_ALLOC_SIZE,
|
|
chunk->bound_map);
|
|
set_bit(region_bits, chunk->bound_map);
|
|
|
|
pcpu_block_update_hint_alloc(chunk, pcpu_chunk_map_bits(chunk)
|
|
- offset_bits, offset_bits);
|
|
}
|
|
|
|
return chunk;
|
|
}
|
|
|
|
static struct pcpu_chunk *pcpu_alloc_chunk(gfp_t gfp)
|
|
{
|
|
struct pcpu_chunk *chunk;
|
|
int region_bits;
|
|
|
|
chunk = pcpu_mem_zalloc(pcpu_chunk_struct_size, gfp);
|
|
if (!chunk)
|
|
return NULL;
|
|
|
|
INIT_LIST_HEAD(&chunk->list);
|
|
chunk->nr_pages = pcpu_unit_pages;
|
|
region_bits = pcpu_chunk_map_bits(chunk);
|
|
|
|
chunk->alloc_map = pcpu_mem_zalloc(BITS_TO_LONGS(region_bits) *
|
|
sizeof(chunk->alloc_map[0]), gfp);
|
|
if (!chunk->alloc_map)
|
|
goto alloc_map_fail;
|
|
|
|
chunk->bound_map = pcpu_mem_zalloc(BITS_TO_LONGS(region_bits + 1) *
|
|
sizeof(chunk->bound_map[0]), gfp);
|
|
if (!chunk->bound_map)
|
|
goto bound_map_fail;
|
|
|
|
chunk->md_blocks = pcpu_mem_zalloc(pcpu_chunk_nr_blocks(chunk) *
|
|
sizeof(chunk->md_blocks[0]), gfp);
|
|
if (!chunk->md_blocks)
|
|
goto md_blocks_fail;
|
|
|
|
#ifdef CONFIG_MEMCG_KMEM
|
|
if (!mem_cgroup_kmem_disabled()) {
|
|
chunk->obj_cgroups =
|
|
pcpu_mem_zalloc(pcpu_chunk_map_bits(chunk) *
|
|
sizeof(struct obj_cgroup *), gfp);
|
|
if (!chunk->obj_cgroups)
|
|
goto objcg_fail;
|
|
}
|
|
#endif
|
|
|
|
pcpu_init_md_blocks(chunk);
|
|
|
|
/* init metadata */
|
|
chunk->free_bytes = chunk->nr_pages * PAGE_SIZE;
|
|
|
|
return chunk;
|
|
|
|
#ifdef CONFIG_MEMCG_KMEM
|
|
objcg_fail:
|
|
pcpu_mem_free(chunk->md_blocks);
|
|
#endif
|
|
md_blocks_fail:
|
|
pcpu_mem_free(chunk->bound_map);
|
|
bound_map_fail:
|
|
pcpu_mem_free(chunk->alloc_map);
|
|
alloc_map_fail:
|
|
pcpu_mem_free(chunk);
|
|
|
|
return NULL;
|
|
}
|
|
|
|
static void pcpu_free_chunk(struct pcpu_chunk *chunk)
|
|
{
|
|
if (!chunk)
|
|
return;
|
|
#ifdef CONFIG_MEMCG_KMEM
|
|
pcpu_mem_free(chunk->obj_cgroups);
|
|
#endif
|
|
pcpu_mem_free(chunk->md_blocks);
|
|
pcpu_mem_free(chunk->bound_map);
|
|
pcpu_mem_free(chunk->alloc_map);
|
|
pcpu_mem_free(chunk);
|
|
}
|
|
|
|
/**
|
|
* pcpu_chunk_populated - post-population bookkeeping
|
|
* @chunk: pcpu_chunk which got populated
|
|
* @page_start: the start page
|
|
* @page_end: the end page
|
|
*
|
|
* Pages in [@page_start,@page_end) have been populated to @chunk. Update
|
|
* the bookkeeping information accordingly. Must be called after each
|
|
* successful population.
|
|
*/
|
|
static void pcpu_chunk_populated(struct pcpu_chunk *chunk, int page_start,
|
|
int page_end)
|
|
{
|
|
int nr = page_end - page_start;
|
|
|
|
lockdep_assert_held(&pcpu_lock);
|
|
|
|
bitmap_set(chunk->populated, page_start, nr);
|
|
chunk->nr_populated += nr;
|
|
pcpu_nr_populated += nr;
|
|
|
|
pcpu_update_empty_pages(chunk, nr);
|
|
}
|
|
|
|
/**
|
|
* pcpu_chunk_depopulated - post-depopulation bookkeeping
|
|
* @chunk: pcpu_chunk which got depopulated
|
|
* @page_start: the start page
|
|
* @page_end: the end page
|
|
*
|
|
* Pages in [@page_start,@page_end) have been depopulated from @chunk.
|
|
* Update the bookkeeping information accordingly. Must be called after
|
|
* each successful depopulation.
|
|
*/
|
|
static void pcpu_chunk_depopulated(struct pcpu_chunk *chunk,
|
|
int page_start, int page_end)
|
|
{
|
|
int nr = page_end - page_start;
|
|
|
|
lockdep_assert_held(&pcpu_lock);
|
|
|
|
bitmap_clear(chunk->populated, page_start, nr);
|
|
chunk->nr_populated -= nr;
|
|
pcpu_nr_populated -= nr;
|
|
|
|
pcpu_update_empty_pages(chunk, -nr);
|
|
}
|
|
|
|
/*
|
|
* Chunk management implementation.
|
|
*
|
|
* To allow different implementations, chunk alloc/free and
|
|
* [de]population are implemented in a separate file which is pulled
|
|
* into this file and compiled together. The following functions
|
|
* should be implemented.
|
|
*
|
|
* pcpu_populate_chunk - populate the specified range of a chunk
|
|
* pcpu_depopulate_chunk - depopulate the specified range of a chunk
|
|
* pcpu_post_unmap_tlb_flush - flush tlb for the specified range of a chunk
|
|
* pcpu_create_chunk - create a new chunk
|
|
* pcpu_destroy_chunk - destroy a chunk, always preceded by full depop
|
|
* pcpu_addr_to_page - translate address to physical address
|
|
* pcpu_verify_alloc_info - check alloc_info is acceptable during init
|
|
*/
|
|
static int pcpu_populate_chunk(struct pcpu_chunk *chunk,
|
|
int page_start, int page_end, gfp_t gfp);
|
|
static void pcpu_depopulate_chunk(struct pcpu_chunk *chunk,
|
|
int page_start, int page_end);
|
|
static void pcpu_post_unmap_tlb_flush(struct pcpu_chunk *chunk,
|
|
int page_start, int page_end);
|
|
static struct pcpu_chunk *pcpu_create_chunk(gfp_t gfp);
|
|
static void pcpu_destroy_chunk(struct pcpu_chunk *chunk);
|
|
static struct page *pcpu_addr_to_page(void *addr);
|
|
static int __init pcpu_verify_alloc_info(const struct pcpu_alloc_info *ai);
|
|
|
|
#ifdef CONFIG_NEED_PER_CPU_KM
|
|
#include "percpu-km.c"
|
|
#else
|
|
#include "percpu-vm.c"
|
|
#endif
|
|
|
|
/**
|
|
* pcpu_chunk_addr_search - determine chunk containing specified address
|
|
* @addr: address for which the chunk needs to be determined.
|
|
*
|
|
* This is an internal function that handles all but static allocations.
|
|
* Static percpu address values should never be passed into the allocator.
|
|
*
|
|
* RETURNS:
|
|
* The address of the found chunk.
|
|
*/
|
|
static struct pcpu_chunk *pcpu_chunk_addr_search(void *addr)
|
|
{
|
|
/* is it in the dynamic region (first chunk)? */
|
|
if (pcpu_addr_in_chunk(pcpu_first_chunk, addr))
|
|
return pcpu_first_chunk;
|
|
|
|
/* is it in the reserved region? */
|
|
if (pcpu_addr_in_chunk(pcpu_reserved_chunk, addr))
|
|
return pcpu_reserved_chunk;
|
|
|
|
/*
|
|
* The address is relative to unit0 which might be unused and
|
|
* thus unmapped. Offset the address to the unit space of the
|
|
* current processor before looking it up in the vmalloc
|
|
* space. Note that any possible cpu id can be used here, so
|
|
* there's no need to worry about preemption or cpu hotplug.
|
|
*/
|
|
addr += pcpu_unit_offsets[raw_smp_processor_id()];
|
|
return pcpu_get_page_chunk(pcpu_addr_to_page(addr));
|
|
}
|
|
|
|
#ifdef CONFIG_MEMCG_KMEM
|
|
static bool pcpu_memcg_pre_alloc_hook(size_t size, gfp_t gfp,
|
|
struct obj_cgroup **objcgp)
|
|
{
|
|
struct obj_cgroup *objcg;
|
|
|
|
if (!memcg_kmem_enabled() || !(gfp & __GFP_ACCOUNT))
|
|
return true;
|
|
|
|
objcg = get_obj_cgroup_from_current();
|
|
if (!objcg)
|
|
return true;
|
|
|
|
if (obj_cgroup_charge(objcg, gfp, pcpu_obj_full_size(size))) {
|
|
obj_cgroup_put(objcg);
|
|
return false;
|
|
}
|
|
|
|
*objcgp = objcg;
|
|
return true;
|
|
}
|
|
|
|
static void pcpu_memcg_post_alloc_hook(struct obj_cgroup *objcg,
|
|
struct pcpu_chunk *chunk, int off,
|
|
size_t size)
|
|
{
|
|
if (!objcg)
|
|
return;
|
|
|
|
if (likely(chunk && chunk->obj_cgroups)) {
|
|
chunk->obj_cgroups[off >> PCPU_MIN_ALLOC_SHIFT] = objcg;
|
|
|
|
rcu_read_lock();
|
|
mod_memcg_state(obj_cgroup_memcg(objcg), MEMCG_PERCPU_B,
|
|
pcpu_obj_full_size(size));
|
|
rcu_read_unlock();
|
|
} else {
|
|
obj_cgroup_uncharge(objcg, pcpu_obj_full_size(size));
|
|
obj_cgroup_put(objcg);
|
|
}
|
|
}
|
|
|
|
static void pcpu_memcg_free_hook(struct pcpu_chunk *chunk, int off, size_t size)
|
|
{
|
|
struct obj_cgroup *objcg;
|
|
|
|
if (unlikely(!chunk->obj_cgroups))
|
|
return;
|
|
|
|
objcg = chunk->obj_cgroups[off >> PCPU_MIN_ALLOC_SHIFT];
|
|
if (!objcg)
|
|
return;
|
|
chunk->obj_cgroups[off >> PCPU_MIN_ALLOC_SHIFT] = NULL;
|
|
|
|
obj_cgroup_uncharge(objcg, pcpu_obj_full_size(size));
|
|
|
|
rcu_read_lock();
|
|
mod_memcg_state(obj_cgroup_memcg(objcg), MEMCG_PERCPU_B,
|
|
-pcpu_obj_full_size(size));
|
|
rcu_read_unlock();
|
|
|
|
obj_cgroup_put(objcg);
|
|
}
|
|
|
|
#else /* CONFIG_MEMCG_KMEM */
|
|
static bool
|
|
pcpu_memcg_pre_alloc_hook(size_t size, gfp_t gfp, struct obj_cgroup **objcgp)
|
|
{
|
|
return true;
|
|
}
|
|
|
|
static void pcpu_memcg_post_alloc_hook(struct obj_cgroup *objcg,
|
|
struct pcpu_chunk *chunk, int off,
|
|
size_t size)
|
|
{
|
|
}
|
|
|
|
static void pcpu_memcg_free_hook(struct pcpu_chunk *chunk, int off, size_t size)
|
|
{
|
|
}
|
|
#endif /* CONFIG_MEMCG_KMEM */
|
|
|
|
/**
|
|
* pcpu_alloc - the percpu allocator
|
|
* @size: size of area to allocate in bytes
|
|
* @align: alignment of area (max PAGE_SIZE)
|
|
* @reserved: allocate from the reserved chunk if available
|
|
* @gfp: allocation flags
|
|
*
|
|
* Allocate percpu area of @size bytes aligned at @align. If @gfp doesn't
|
|
* contain %GFP_KERNEL, the allocation is atomic. If @gfp has __GFP_NOWARN
|
|
* then no warning will be triggered on invalid or failed allocation
|
|
* requests.
|
|
*
|
|
* RETURNS:
|
|
* Percpu pointer to the allocated area on success, NULL on failure.
|
|
*/
|
|
static void __percpu *pcpu_alloc(size_t size, size_t align, bool reserved,
|
|
gfp_t gfp)
|
|
{
|
|
gfp_t pcpu_gfp;
|
|
bool is_atomic;
|
|
bool do_warn;
|
|
struct obj_cgroup *objcg = NULL;
|
|
static int warn_limit = 10;
|
|
struct pcpu_chunk *chunk, *next;
|
|
const char *err;
|
|
int slot, off, cpu, ret;
|
|
unsigned long flags;
|
|
void __percpu *ptr;
|
|
size_t bits, bit_align;
|
|
|
|
gfp = current_gfp_context(gfp);
|
|
/* whitelisted flags that can be passed to the backing allocators */
|
|
pcpu_gfp = gfp & (GFP_KERNEL | __GFP_NORETRY | __GFP_NOWARN);
|
|
is_atomic = (gfp & GFP_KERNEL) != GFP_KERNEL;
|
|
do_warn = !(gfp & __GFP_NOWARN);
|
|
|
|
/*
|
|
* There is now a minimum allocation size of PCPU_MIN_ALLOC_SIZE,
|
|
* therefore alignment must be a minimum of that many bytes.
|
|
* An allocation may have internal fragmentation from rounding up
|
|
* of up to PCPU_MIN_ALLOC_SIZE - 1 bytes.
|
|
*/
|
|
if (unlikely(align < PCPU_MIN_ALLOC_SIZE))
|
|
align = PCPU_MIN_ALLOC_SIZE;
|
|
|
|
size = ALIGN(size, PCPU_MIN_ALLOC_SIZE);
|
|
bits = size >> PCPU_MIN_ALLOC_SHIFT;
|
|
bit_align = align >> PCPU_MIN_ALLOC_SHIFT;
|
|
|
|
if (unlikely(!size || size > PCPU_MIN_UNIT_SIZE || align > PAGE_SIZE ||
|
|
!is_power_of_2(align))) {
|
|
WARN(do_warn, "illegal size (%zu) or align (%zu) for percpu allocation\n",
|
|
size, align);
|
|
return NULL;
|
|
}
|
|
|
|
if (unlikely(!pcpu_memcg_pre_alloc_hook(size, gfp, &objcg)))
|
|
return NULL;
|
|
|
|
if (!is_atomic) {
|
|
/*
|
|
* pcpu_balance_workfn() allocates memory under this mutex,
|
|
* and it may wait for memory reclaim. Allow current task
|
|
* to become OOM victim, in case of memory pressure.
|
|
*/
|
|
if (gfp & __GFP_NOFAIL) {
|
|
mutex_lock(&pcpu_alloc_mutex);
|
|
} else if (mutex_lock_killable(&pcpu_alloc_mutex)) {
|
|
pcpu_memcg_post_alloc_hook(objcg, NULL, 0, size);
|
|
return NULL;
|
|
}
|
|
}
|
|
|
|
spin_lock_irqsave(&pcpu_lock, flags);
|
|
|
|
/* serve reserved allocations from the reserved chunk if available */
|
|
if (reserved && pcpu_reserved_chunk) {
|
|
chunk = pcpu_reserved_chunk;
|
|
|
|
off = pcpu_find_block_fit(chunk, bits, bit_align, is_atomic);
|
|
if (off < 0) {
|
|
err = "alloc from reserved chunk failed";
|
|
goto fail_unlock;
|
|
}
|
|
|
|
off = pcpu_alloc_area(chunk, bits, bit_align, off);
|
|
if (off >= 0)
|
|
goto area_found;
|
|
|
|
err = "alloc from reserved chunk failed";
|
|
goto fail_unlock;
|
|
}
|
|
|
|
restart:
|
|
/* search through normal chunks */
|
|
for (slot = pcpu_size_to_slot(size); slot <= pcpu_free_slot; slot++) {
|
|
list_for_each_entry_safe(chunk, next, &pcpu_chunk_lists[slot],
|
|
list) {
|
|
off = pcpu_find_block_fit(chunk, bits, bit_align,
|
|
is_atomic);
|
|
if (off < 0) {
|
|
if (slot < PCPU_SLOT_FAIL_THRESHOLD)
|
|
pcpu_chunk_move(chunk, 0);
|
|
continue;
|
|
}
|
|
|
|
off = pcpu_alloc_area(chunk, bits, bit_align, off);
|
|
if (off >= 0) {
|
|
pcpu_reintegrate_chunk(chunk);
|
|
goto area_found;
|
|
}
|
|
}
|
|
}
|
|
|
|
spin_unlock_irqrestore(&pcpu_lock, flags);
|
|
|
|
/*
|
|
* No space left. Create a new chunk. We don't want multiple
|
|
* tasks to create chunks simultaneously. Serialize and create iff
|
|
* there's still no empty chunk after grabbing the mutex.
|
|
*/
|
|
if (is_atomic) {
|
|
err = "atomic alloc failed, no space left";
|
|
goto fail;
|
|
}
|
|
|
|
if (list_empty(&pcpu_chunk_lists[pcpu_free_slot])) {
|
|
chunk = pcpu_create_chunk(pcpu_gfp);
|
|
if (!chunk) {
|
|
err = "failed to allocate new chunk";
|
|
goto fail;
|
|
}
|
|
|
|
spin_lock_irqsave(&pcpu_lock, flags);
|
|
pcpu_chunk_relocate(chunk, -1);
|
|
} else {
|
|
spin_lock_irqsave(&pcpu_lock, flags);
|
|
}
|
|
|
|
goto restart;
|
|
|
|
area_found:
|
|
pcpu_stats_area_alloc(chunk, size);
|
|
spin_unlock_irqrestore(&pcpu_lock, flags);
|
|
|
|
/* populate if not all pages are already there */
|
|
if (!is_atomic) {
|
|
unsigned int page_end, rs, re;
|
|
|
|
rs = PFN_DOWN(off);
|
|
page_end = PFN_UP(off + size);
|
|
|
|
for_each_clear_bitrange_from(rs, re, chunk->populated, page_end) {
|
|
WARN_ON(chunk->immutable);
|
|
|
|
ret = pcpu_populate_chunk(chunk, rs, re, pcpu_gfp);
|
|
|
|
spin_lock_irqsave(&pcpu_lock, flags);
|
|
if (ret) {
|
|
pcpu_free_area(chunk, off);
|
|
err = "failed to populate";
|
|
goto fail_unlock;
|
|
}
|
|
pcpu_chunk_populated(chunk, rs, re);
|
|
spin_unlock_irqrestore(&pcpu_lock, flags);
|
|
}
|
|
|
|
mutex_unlock(&pcpu_alloc_mutex);
|
|
}
|
|
|
|
if (pcpu_nr_empty_pop_pages < PCPU_EMPTY_POP_PAGES_LOW)
|
|
pcpu_schedule_balance_work();
|
|
|
|
/* clear the areas and return address relative to base address */
|
|
for_each_possible_cpu(cpu)
|
|
memset((void *)pcpu_chunk_addr(chunk, cpu, 0) + off, 0, size);
|
|
|
|
ptr = __addr_to_pcpu_ptr(chunk->base_addr + off);
|
|
kmemleak_alloc_percpu(ptr, size, gfp);
|
|
|
|
trace_percpu_alloc_percpu(reserved, is_atomic, size, align,
|
|
chunk->base_addr, off, ptr);
|
|
|
|
pcpu_memcg_post_alloc_hook(objcg, chunk, off, size);
|
|
|
|
return ptr;
|
|
|
|
fail_unlock:
|
|
spin_unlock_irqrestore(&pcpu_lock, flags);
|
|
fail:
|
|
trace_percpu_alloc_percpu_fail(reserved, is_atomic, size, align);
|
|
|
|
if (!is_atomic && do_warn && warn_limit) {
|
|
pr_warn("allocation failed, size=%zu align=%zu atomic=%d, %s\n",
|
|
size, align, is_atomic, err);
|
|
dump_stack();
|
|
if (!--warn_limit)
|
|
pr_info("limit reached, disable warning\n");
|
|
}
|
|
if (is_atomic) {
|
|
/* see the flag handling in pcpu_balance_workfn() */
|
|
pcpu_atomic_alloc_failed = true;
|
|
pcpu_schedule_balance_work();
|
|
} else {
|
|
mutex_unlock(&pcpu_alloc_mutex);
|
|
}
|
|
|
|
pcpu_memcg_post_alloc_hook(objcg, NULL, 0, size);
|
|
|
|
return NULL;
|
|
}
|
|
|
|
/**
|
|
* __alloc_percpu_gfp - allocate dynamic percpu area
|
|
* @size: size of area to allocate in bytes
|
|
* @align: alignment of area (max PAGE_SIZE)
|
|
* @gfp: allocation flags
|
|
*
|
|
* Allocate zero-filled percpu area of @size bytes aligned at @align. If
|
|
* @gfp doesn't contain %GFP_KERNEL, the allocation doesn't block and can
|
|
* be called from any context but is a lot more likely to fail. If @gfp
|
|
* has __GFP_NOWARN then no warning will be triggered on invalid or failed
|
|
* allocation requests.
|
|
*
|
|
* RETURNS:
|
|
* Percpu pointer to the allocated area on success, NULL on failure.
|
|
*/
|
|
void __percpu *__alloc_percpu_gfp(size_t size, size_t align, gfp_t gfp)
|
|
{
|
|
return pcpu_alloc(size, align, false, gfp);
|
|
}
|
|
EXPORT_SYMBOL_GPL(__alloc_percpu_gfp);
|
|
|
|
/**
|
|
* __alloc_percpu - allocate dynamic percpu area
|
|
* @size: size of area to allocate in bytes
|
|
* @align: alignment of area (max PAGE_SIZE)
|
|
*
|
|
* Equivalent to __alloc_percpu_gfp(size, align, %GFP_KERNEL).
|
|
*/
|
|
void __percpu *__alloc_percpu(size_t size, size_t align)
|
|
{
|
|
return pcpu_alloc(size, align, false, GFP_KERNEL);
|
|
}
|
|
EXPORT_SYMBOL_GPL(__alloc_percpu);
|
|
|
|
/**
|
|
* __alloc_reserved_percpu - allocate reserved percpu area
|
|
* @size: size of area to allocate in bytes
|
|
* @align: alignment of area (max PAGE_SIZE)
|
|
*
|
|
* Allocate zero-filled percpu area of @size bytes aligned at @align
|
|
* from reserved percpu area if arch has set it up; otherwise,
|
|
* allocation is served from the same dynamic area. Might sleep.
|
|
* Might trigger writeouts.
|
|
*
|
|
* CONTEXT:
|
|
* Does GFP_KERNEL allocation.
|
|
*
|
|
* RETURNS:
|
|
* Percpu pointer to the allocated area on success, NULL on failure.
|
|
*/
|
|
void __percpu *__alloc_reserved_percpu(size_t size, size_t align)
|
|
{
|
|
return pcpu_alloc(size, align, true, GFP_KERNEL);
|
|
}
|
|
|
|
/**
|
|
* pcpu_balance_free - manage the amount of free chunks
|
|
* @empty_only: free chunks only if there are no populated pages
|
|
*
|
|
* If empty_only is %false, reclaim all fully free chunks regardless of the
|
|
* number of populated pages. Otherwise, only reclaim chunks that have no
|
|
* populated pages.
|
|
*
|
|
* CONTEXT:
|
|
* pcpu_lock (can be dropped temporarily)
|
|
*/
|
|
static void pcpu_balance_free(bool empty_only)
|
|
{
|
|
LIST_HEAD(to_free);
|
|
struct list_head *free_head = &pcpu_chunk_lists[pcpu_free_slot];
|
|
struct pcpu_chunk *chunk, *next;
|
|
|
|
lockdep_assert_held(&pcpu_lock);
|
|
|
|
/*
|
|
* There's no reason to keep around multiple unused chunks and VM
|
|
* areas can be scarce. Destroy all free chunks except for one.
|
|
*/
|
|
list_for_each_entry_safe(chunk, next, free_head, list) {
|
|
WARN_ON(chunk->immutable);
|
|
|
|
/* spare the first one */
|
|
if (chunk == list_first_entry(free_head, struct pcpu_chunk, list))
|
|
continue;
|
|
|
|
if (!empty_only || chunk->nr_empty_pop_pages == 0)
|
|
list_move(&chunk->list, &to_free);
|
|
}
|
|
|
|
if (list_empty(&to_free))
|
|
return;
|
|
|
|
spin_unlock_irq(&pcpu_lock);
|
|
list_for_each_entry_safe(chunk, next, &to_free, list) {
|
|
unsigned int rs, re;
|
|
|
|
for_each_set_bitrange(rs, re, chunk->populated, chunk->nr_pages) {
|
|
pcpu_depopulate_chunk(chunk, rs, re);
|
|
spin_lock_irq(&pcpu_lock);
|
|
pcpu_chunk_depopulated(chunk, rs, re);
|
|
spin_unlock_irq(&pcpu_lock);
|
|
}
|
|
pcpu_destroy_chunk(chunk);
|
|
cond_resched();
|
|
}
|
|
spin_lock_irq(&pcpu_lock);
|
|
}
|
|
|
|
/**
|
|
* pcpu_balance_populated - manage the amount of populated pages
|
|
*
|
|
* Maintain a certain amount of populated pages to satisfy atomic allocations.
|
|
* It is possible that this is called when physical memory is scarce causing
|
|
* OOM killer to be triggered. We should avoid doing so until an actual
|
|
* allocation causes the failure as it is possible that requests can be
|
|
* serviced from already backed regions.
|
|
*
|
|
* CONTEXT:
|
|
* pcpu_lock (can be dropped temporarily)
|
|
*/
|
|
static void pcpu_balance_populated(void)
|
|
{
|
|
/* gfp flags passed to underlying allocators */
|
|
const gfp_t gfp = GFP_KERNEL | __GFP_NORETRY | __GFP_NOWARN;
|
|
struct pcpu_chunk *chunk;
|
|
int slot, nr_to_pop, ret;
|
|
|
|
lockdep_assert_held(&pcpu_lock);
|
|
|
|
/*
|
|
* Ensure there are certain number of free populated pages for
|
|
* atomic allocs. Fill up from the most packed so that atomic
|
|
* allocs don't increase fragmentation. If atomic allocation
|
|
* failed previously, always populate the maximum amount. This
|
|
* should prevent atomic allocs larger than PAGE_SIZE from keeping
|
|
* failing indefinitely; however, large atomic allocs are not
|
|
* something we support properly and can be highly unreliable and
|
|
* inefficient.
|
|
*/
|
|
retry_pop:
|
|
if (pcpu_atomic_alloc_failed) {
|
|
nr_to_pop = PCPU_EMPTY_POP_PAGES_HIGH;
|
|
/* best effort anyway, don't worry about synchronization */
|
|
pcpu_atomic_alloc_failed = false;
|
|
} else {
|
|
nr_to_pop = clamp(PCPU_EMPTY_POP_PAGES_HIGH -
|
|
pcpu_nr_empty_pop_pages,
|
|
0, PCPU_EMPTY_POP_PAGES_HIGH);
|
|
}
|
|
|
|
for (slot = pcpu_size_to_slot(PAGE_SIZE); slot <= pcpu_free_slot; slot++) {
|
|
unsigned int nr_unpop = 0, rs, re;
|
|
|
|
if (!nr_to_pop)
|
|
break;
|
|
|
|
list_for_each_entry(chunk, &pcpu_chunk_lists[slot], list) {
|
|
nr_unpop = chunk->nr_pages - chunk->nr_populated;
|
|
if (nr_unpop)
|
|
break;
|
|
}
|
|
|
|
if (!nr_unpop)
|
|
continue;
|
|
|
|
/* @chunk can't go away while pcpu_alloc_mutex is held */
|
|
for_each_clear_bitrange(rs, re, chunk->populated, chunk->nr_pages) {
|
|
int nr = min_t(int, re - rs, nr_to_pop);
|
|
|
|
spin_unlock_irq(&pcpu_lock);
|
|
ret = pcpu_populate_chunk(chunk, rs, rs + nr, gfp);
|
|
cond_resched();
|
|
spin_lock_irq(&pcpu_lock);
|
|
if (!ret) {
|
|
nr_to_pop -= nr;
|
|
pcpu_chunk_populated(chunk, rs, rs + nr);
|
|
} else {
|
|
nr_to_pop = 0;
|
|
}
|
|
|
|
if (!nr_to_pop)
|
|
break;
|
|
}
|
|
}
|
|
|
|
if (nr_to_pop) {
|
|
/* ran out of chunks to populate, create a new one and retry */
|
|
spin_unlock_irq(&pcpu_lock);
|
|
chunk = pcpu_create_chunk(gfp);
|
|
cond_resched();
|
|
spin_lock_irq(&pcpu_lock);
|
|
if (chunk) {
|
|
pcpu_chunk_relocate(chunk, -1);
|
|
goto retry_pop;
|
|
}
|
|
}
|
|
}
|
|
|
|
/**
|
|
* pcpu_reclaim_populated - scan over to_depopulate chunks and free empty pages
|
|
*
|
|
* Scan over chunks in the depopulate list and try to release unused populated
|
|
* pages back to the system. Depopulated chunks are sidelined to prevent
|
|
* repopulating these pages unless required. Fully free chunks are reintegrated
|
|
* and freed accordingly (1 is kept around). If we drop below the empty
|
|
* populated pages threshold, reintegrate the chunk if it has empty free pages.
|
|
* Each chunk is scanned in the reverse order to keep populated pages close to
|
|
* the beginning of the chunk.
|
|
*
|
|
* CONTEXT:
|
|
* pcpu_lock (can be dropped temporarily)
|
|
*
|
|
*/
|
|
static void pcpu_reclaim_populated(void)
|
|
{
|
|
struct pcpu_chunk *chunk;
|
|
struct pcpu_block_md *block;
|
|
int freed_page_start, freed_page_end;
|
|
int i, end;
|
|
bool reintegrate;
|
|
|
|
lockdep_assert_held(&pcpu_lock);
|
|
|
|
/*
|
|
* Once a chunk is isolated to the to_depopulate list, the chunk is no
|
|
* longer discoverable to allocations whom may populate pages. The only
|
|
* other accessor is the free path which only returns area back to the
|
|
* allocator not touching the populated bitmap.
|
|
*/
|
|
while (!list_empty(&pcpu_chunk_lists[pcpu_to_depopulate_slot])) {
|
|
chunk = list_first_entry(&pcpu_chunk_lists[pcpu_to_depopulate_slot],
|
|
struct pcpu_chunk, list);
|
|
WARN_ON(chunk->immutable);
|
|
|
|
/*
|
|
* Scan chunk's pages in the reverse order to keep populated
|
|
* pages close to the beginning of the chunk.
|
|
*/
|
|
freed_page_start = chunk->nr_pages;
|
|
freed_page_end = 0;
|
|
reintegrate = false;
|
|
for (i = chunk->nr_pages - 1, end = -1; i >= 0; i--) {
|
|
/* no more work to do */
|
|
if (chunk->nr_empty_pop_pages == 0)
|
|
break;
|
|
|
|
/* reintegrate chunk to prevent atomic alloc failures */
|
|
if (pcpu_nr_empty_pop_pages < PCPU_EMPTY_POP_PAGES_HIGH) {
|
|
reintegrate = true;
|
|
goto end_chunk;
|
|
}
|
|
|
|
/*
|
|
* If the page is empty and populated, start or
|
|
* extend the (i, end) range. If i == 0, decrease
|
|
* i and perform the depopulation to cover the last
|
|
* (first) page in the chunk.
|
|
*/
|
|
block = chunk->md_blocks + i;
|
|
if (block->contig_hint == PCPU_BITMAP_BLOCK_BITS &&
|
|
test_bit(i, chunk->populated)) {
|
|
if (end == -1)
|
|
end = i;
|
|
if (i > 0)
|
|
continue;
|
|
i--;
|
|
}
|
|
|
|
/* depopulate if there is an active range */
|
|
if (end == -1)
|
|
continue;
|
|
|
|
spin_unlock_irq(&pcpu_lock);
|
|
pcpu_depopulate_chunk(chunk, i + 1, end + 1);
|
|
cond_resched();
|
|
spin_lock_irq(&pcpu_lock);
|
|
|
|
pcpu_chunk_depopulated(chunk, i + 1, end + 1);
|
|
freed_page_start = min(freed_page_start, i + 1);
|
|
freed_page_end = max(freed_page_end, end + 1);
|
|
|
|
/* reset the range and continue */
|
|
end = -1;
|
|
}
|
|
|
|
end_chunk:
|
|
/* batch tlb flush per chunk to amortize cost */
|
|
if (freed_page_start < freed_page_end) {
|
|
spin_unlock_irq(&pcpu_lock);
|
|
pcpu_post_unmap_tlb_flush(chunk,
|
|
freed_page_start,
|
|
freed_page_end);
|
|
cond_resched();
|
|
spin_lock_irq(&pcpu_lock);
|
|
}
|
|
|
|
if (reintegrate || chunk->free_bytes == pcpu_unit_size)
|
|
pcpu_reintegrate_chunk(chunk);
|
|
else
|
|
list_move_tail(&chunk->list,
|
|
&pcpu_chunk_lists[pcpu_sidelined_slot]);
|
|
}
|
|
}
|
|
|
|
/**
|
|
* pcpu_balance_workfn - manage the amount of free chunks and populated pages
|
|
* @work: unused
|
|
*
|
|
* For each chunk type, manage the number of fully free chunks and the number of
|
|
* populated pages. An important thing to consider is when pages are freed and
|
|
* how they contribute to the global counts.
|
|
*/
|
|
static void pcpu_balance_workfn(struct work_struct *work)
|
|
{
|
|
/*
|
|
* pcpu_balance_free() is called twice because the first time we may
|
|
* trim pages in the active pcpu_nr_empty_pop_pages which may cause us
|
|
* to grow other chunks. This then gives pcpu_reclaim_populated() time
|
|
* to move fully free chunks to the active list to be freed if
|
|
* appropriate.
|
|
*/
|
|
mutex_lock(&pcpu_alloc_mutex);
|
|
spin_lock_irq(&pcpu_lock);
|
|
|
|
pcpu_balance_free(false);
|
|
pcpu_reclaim_populated();
|
|
pcpu_balance_populated();
|
|
pcpu_balance_free(true);
|
|
|
|
spin_unlock_irq(&pcpu_lock);
|
|
mutex_unlock(&pcpu_alloc_mutex);
|
|
}
|
|
|
|
/**
|
|
* free_percpu - free percpu area
|
|
* @ptr: pointer to area to free
|
|
*
|
|
* Free percpu area @ptr.
|
|
*
|
|
* CONTEXT:
|
|
* Can be called from atomic context.
|
|
*/
|
|
void free_percpu(void __percpu *ptr)
|
|
{
|
|
void *addr;
|
|
struct pcpu_chunk *chunk;
|
|
unsigned long flags;
|
|
int size, off;
|
|
bool need_balance = false;
|
|
|
|
if (!ptr)
|
|
return;
|
|
|
|
kmemleak_free_percpu(ptr);
|
|
|
|
addr = __pcpu_ptr_to_addr(ptr);
|
|
|
|
spin_lock_irqsave(&pcpu_lock, flags);
|
|
|
|
chunk = pcpu_chunk_addr_search(addr);
|
|
off = addr - chunk->base_addr;
|
|
|
|
size = pcpu_free_area(chunk, off);
|
|
|
|
pcpu_memcg_free_hook(chunk, off, size);
|
|
|
|
/*
|
|
* If there are more than one fully free chunks, wake up grim reaper.
|
|
* If the chunk is isolated, it may be in the process of being
|
|
* reclaimed. Let reclaim manage cleaning up of that chunk.
|
|
*/
|
|
if (!chunk->isolated && chunk->free_bytes == pcpu_unit_size) {
|
|
struct pcpu_chunk *pos;
|
|
|
|
list_for_each_entry(pos, &pcpu_chunk_lists[pcpu_free_slot], list)
|
|
if (pos != chunk) {
|
|
need_balance = true;
|
|
break;
|
|
}
|
|
} else if (pcpu_should_reclaim_chunk(chunk)) {
|
|
pcpu_isolate_chunk(chunk);
|
|
need_balance = true;
|
|
}
|
|
|
|
trace_percpu_free_percpu(chunk->base_addr, off, ptr);
|
|
|
|
spin_unlock_irqrestore(&pcpu_lock, flags);
|
|
|
|
if (need_balance)
|
|
pcpu_schedule_balance_work();
|
|
}
|
|
EXPORT_SYMBOL_GPL(free_percpu);
|
|
|
|
bool __is_kernel_percpu_address(unsigned long addr, unsigned long *can_addr)
|
|
{
|
|
#ifdef CONFIG_SMP
|
|
const size_t static_size = __per_cpu_end - __per_cpu_start;
|
|
void __percpu *base = __addr_to_pcpu_ptr(pcpu_base_addr);
|
|
unsigned int cpu;
|
|
|
|
for_each_possible_cpu(cpu) {
|
|
void *start = per_cpu_ptr(base, cpu);
|
|
void *va = (void *)addr;
|
|
|
|
if (va >= start && va < start + static_size) {
|
|
if (can_addr) {
|
|
*can_addr = (unsigned long) (va - start);
|
|
*can_addr += (unsigned long)
|
|
per_cpu_ptr(base, get_boot_cpu_id());
|
|
}
|
|
return true;
|
|
}
|
|
}
|
|
#endif
|
|
/* on UP, can't distinguish from other static vars, always false */
|
|
return false;
|
|
}
|
|
|
|
/**
|
|
* is_kernel_percpu_address - test whether address is from static percpu area
|
|
* @addr: address to test
|
|
*
|
|
* Test whether @addr belongs to in-kernel static percpu area. Module
|
|
* static percpu areas are not considered. For those, use
|
|
* is_module_percpu_address().
|
|
*
|
|
* RETURNS:
|
|
* %true if @addr is from in-kernel static percpu area, %false otherwise.
|
|
*/
|
|
bool is_kernel_percpu_address(unsigned long addr)
|
|
{
|
|
return __is_kernel_percpu_address(addr, NULL);
|
|
}
|
|
|
|
/**
|
|
* per_cpu_ptr_to_phys - convert translated percpu address to physical address
|
|
* @addr: the address to be converted to physical address
|
|
*
|
|
* Given @addr which is dereferenceable address obtained via one of
|
|
* percpu access macros, this function translates it into its physical
|
|
* address. The caller is responsible for ensuring @addr stays valid
|
|
* until this function finishes.
|
|
*
|
|
* percpu allocator has special setup for the first chunk, which currently
|
|
* supports either embedding in linear address space or vmalloc mapping,
|
|
* and, from the second one, the backing allocator (currently either vm or
|
|
* km) provides translation.
|
|
*
|
|
* The addr can be translated simply without checking if it falls into the
|
|
* first chunk. But the current code reflects better how percpu allocator
|
|
* actually works, and the verification can discover both bugs in percpu
|
|
* allocator itself and per_cpu_ptr_to_phys() callers. So we keep current
|
|
* code.
|
|
*
|
|
* RETURNS:
|
|
* The physical address for @addr.
|
|
*/
|
|
phys_addr_t per_cpu_ptr_to_phys(void *addr)
|
|
{
|
|
void __percpu *base = __addr_to_pcpu_ptr(pcpu_base_addr);
|
|
bool in_first_chunk = false;
|
|
unsigned long first_low, first_high;
|
|
unsigned int cpu;
|
|
|
|
/*
|
|
* The following test on unit_low/high isn't strictly
|
|
* necessary but will speed up lookups of addresses which
|
|
* aren't in the first chunk.
|
|
*
|
|
* The address check is against full chunk sizes. pcpu_base_addr
|
|
* points to the beginning of the first chunk including the
|
|
* static region. Assumes good intent as the first chunk may
|
|
* not be full (ie. < pcpu_unit_pages in size).
|
|
*/
|
|
first_low = (unsigned long)pcpu_base_addr +
|
|
pcpu_unit_page_offset(pcpu_low_unit_cpu, 0);
|
|
first_high = (unsigned long)pcpu_base_addr +
|
|
pcpu_unit_page_offset(pcpu_high_unit_cpu, pcpu_unit_pages);
|
|
if ((unsigned long)addr >= first_low &&
|
|
(unsigned long)addr < first_high) {
|
|
for_each_possible_cpu(cpu) {
|
|
void *start = per_cpu_ptr(base, cpu);
|
|
|
|
if (addr >= start && addr < start + pcpu_unit_size) {
|
|
in_first_chunk = true;
|
|
break;
|
|
}
|
|
}
|
|
}
|
|
|
|
if (in_first_chunk) {
|
|
if (!is_vmalloc_addr(addr))
|
|
return __pa(addr);
|
|
else
|
|
return page_to_phys(vmalloc_to_page(addr)) +
|
|
offset_in_page(addr);
|
|
} else
|
|
return page_to_phys(pcpu_addr_to_page(addr)) +
|
|
offset_in_page(addr);
|
|
}
|
|
|
|
/**
|
|
* pcpu_alloc_alloc_info - allocate percpu allocation info
|
|
* @nr_groups: the number of groups
|
|
* @nr_units: the number of units
|
|
*
|
|
* Allocate ai which is large enough for @nr_groups groups containing
|
|
* @nr_units units. The returned ai's groups[0].cpu_map points to the
|
|
* cpu_map array which is long enough for @nr_units and filled with
|
|
* NR_CPUS. It's the caller's responsibility to initialize cpu_map
|
|
* pointer of other groups.
|
|
*
|
|
* RETURNS:
|
|
* Pointer to the allocated pcpu_alloc_info on success, NULL on
|
|
* failure.
|
|
*/
|
|
struct pcpu_alloc_info * __init pcpu_alloc_alloc_info(int nr_groups,
|
|
int nr_units)
|
|
{
|
|
struct pcpu_alloc_info *ai;
|
|
size_t base_size, ai_size;
|
|
void *ptr;
|
|
int unit;
|
|
|
|
base_size = ALIGN(struct_size(ai, groups, nr_groups),
|
|
__alignof__(ai->groups[0].cpu_map[0]));
|
|
ai_size = base_size + nr_units * sizeof(ai->groups[0].cpu_map[0]);
|
|
|
|
ptr = memblock_alloc(PFN_ALIGN(ai_size), PAGE_SIZE);
|
|
if (!ptr)
|
|
return NULL;
|
|
ai = ptr;
|
|
ptr += base_size;
|
|
|
|
ai->groups[0].cpu_map = ptr;
|
|
|
|
for (unit = 0; unit < nr_units; unit++)
|
|
ai->groups[0].cpu_map[unit] = NR_CPUS;
|
|
|
|
ai->nr_groups = nr_groups;
|
|
ai->__ai_size = PFN_ALIGN(ai_size);
|
|
|
|
return ai;
|
|
}
|
|
|
|
/**
|
|
* pcpu_free_alloc_info - free percpu allocation info
|
|
* @ai: pcpu_alloc_info to free
|
|
*
|
|
* Free @ai which was allocated by pcpu_alloc_alloc_info().
|
|
*/
|
|
void __init pcpu_free_alloc_info(struct pcpu_alloc_info *ai)
|
|
{
|
|
memblock_free(ai, ai->__ai_size);
|
|
}
|
|
|
|
/**
|
|
* pcpu_dump_alloc_info - print out information about pcpu_alloc_info
|
|
* @lvl: loglevel
|
|
* @ai: allocation info to dump
|
|
*
|
|
* Print out information about @ai using loglevel @lvl.
|
|
*/
|
|
static void pcpu_dump_alloc_info(const char *lvl,
|
|
const struct pcpu_alloc_info *ai)
|
|
{
|
|
int group_width = 1, cpu_width = 1, width;
|
|
char empty_str[] = "--------";
|
|
int alloc = 0, alloc_end = 0;
|
|
int group, v;
|
|
int upa, apl; /* units per alloc, allocs per line */
|
|
|
|
v = ai->nr_groups;
|
|
while (v /= 10)
|
|
group_width++;
|
|
|
|
v = num_possible_cpus();
|
|
while (v /= 10)
|
|
cpu_width++;
|
|
empty_str[min_t(int, cpu_width, sizeof(empty_str) - 1)] = '\0';
|
|
|
|
upa = ai->alloc_size / ai->unit_size;
|
|
width = upa * (cpu_width + 1) + group_width + 3;
|
|
apl = rounddown_pow_of_two(max(60 / width, 1));
|
|
|
|
printk("%spcpu-alloc: s%zu r%zu d%zu u%zu alloc=%zu*%zu",
|
|
lvl, ai->static_size, ai->reserved_size, ai->dyn_size,
|
|
ai->unit_size, ai->alloc_size / ai->atom_size, ai->atom_size);
|
|
|
|
for (group = 0; group < ai->nr_groups; group++) {
|
|
const struct pcpu_group_info *gi = &ai->groups[group];
|
|
int unit = 0, unit_end = 0;
|
|
|
|
BUG_ON(gi->nr_units % upa);
|
|
for (alloc_end += gi->nr_units / upa;
|
|
alloc < alloc_end; alloc++) {
|
|
if (!(alloc % apl)) {
|
|
pr_cont("\n");
|
|
printk("%spcpu-alloc: ", lvl);
|
|
}
|
|
pr_cont("[%0*d] ", group_width, group);
|
|
|
|
for (unit_end += upa; unit < unit_end; unit++)
|
|
if (gi->cpu_map[unit] != NR_CPUS)
|
|
pr_cont("%0*d ",
|
|
cpu_width, gi->cpu_map[unit]);
|
|
else
|
|
pr_cont("%s ", empty_str);
|
|
}
|
|
}
|
|
pr_cont("\n");
|
|
}
|
|
|
|
/**
|
|
* pcpu_setup_first_chunk - initialize the first percpu chunk
|
|
* @ai: pcpu_alloc_info describing how to percpu area is shaped
|
|
* @base_addr: mapped address
|
|
*
|
|
* Initialize the first percpu chunk which contains the kernel static
|
|
* percpu area. This function is to be called from arch percpu area
|
|
* setup path.
|
|
*
|
|
* @ai contains all information necessary to initialize the first
|
|
* chunk and prime the dynamic percpu allocator.
|
|
*
|
|
* @ai->static_size is the size of static percpu area.
|
|
*
|
|
* @ai->reserved_size, if non-zero, specifies the amount of bytes to
|
|
* reserve after the static area in the first chunk. This reserves
|
|
* the first chunk such that it's available only through reserved
|
|
* percpu allocation. This is primarily used to serve module percpu
|
|
* static areas on architectures where the addressing model has
|
|
* limited offset range for symbol relocations to guarantee module
|
|
* percpu symbols fall inside the relocatable range.
|
|
*
|
|
* @ai->dyn_size determines the number of bytes available for dynamic
|
|
* allocation in the first chunk. The area between @ai->static_size +
|
|
* @ai->reserved_size + @ai->dyn_size and @ai->unit_size is unused.
|
|
*
|
|
* @ai->unit_size specifies unit size and must be aligned to PAGE_SIZE
|
|
* and equal to or larger than @ai->static_size + @ai->reserved_size +
|
|
* @ai->dyn_size.
|
|
*
|
|
* @ai->atom_size is the allocation atom size and used as alignment
|
|
* for vm areas.
|
|
*
|
|
* @ai->alloc_size is the allocation size and always multiple of
|
|
* @ai->atom_size. This is larger than @ai->atom_size if
|
|
* @ai->unit_size is larger than @ai->atom_size.
|
|
*
|
|
* @ai->nr_groups and @ai->groups describe virtual memory layout of
|
|
* percpu areas. Units which should be colocated are put into the
|
|
* same group. Dynamic VM areas will be allocated according to these
|
|
* groupings. If @ai->nr_groups is zero, a single group containing
|
|
* all units is assumed.
|
|
*
|
|
* The caller should have mapped the first chunk at @base_addr and
|
|
* copied static data to each unit.
|
|
*
|
|
* The first chunk will always contain a static and a dynamic region.
|
|
* However, the static region is not managed by any chunk. If the first
|
|
* chunk also contains a reserved region, it is served by two chunks -
|
|
* one for the reserved region and one for the dynamic region. They
|
|
* share the same vm, but use offset regions in the area allocation map.
|
|
* The chunk serving the dynamic region is circulated in the chunk slots
|
|
* and available for dynamic allocation like any other chunk.
|
|
*/
|
|
void __init pcpu_setup_first_chunk(const struct pcpu_alloc_info *ai,
|
|
void *base_addr)
|
|
{
|
|
size_t size_sum = ai->static_size + ai->reserved_size + ai->dyn_size;
|
|
size_t static_size, dyn_size;
|
|
struct pcpu_chunk *chunk;
|
|
unsigned long *group_offsets;
|
|
size_t *group_sizes;
|
|
unsigned long *unit_off;
|
|
unsigned int cpu;
|
|
int *unit_map;
|
|
int group, unit, i;
|
|
int map_size;
|
|
unsigned long tmp_addr;
|
|
size_t alloc_size;
|
|
|
|
#define PCPU_SETUP_BUG_ON(cond) do { \
|
|
if (unlikely(cond)) { \
|
|
pr_emerg("failed to initialize, %s\n", #cond); \
|
|
pr_emerg("cpu_possible_mask=%*pb\n", \
|
|
cpumask_pr_args(cpu_possible_mask)); \
|
|
pcpu_dump_alloc_info(KERN_EMERG, ai); \
|
|
BUG(); \
|
|
} \
|
|
} while (0)
|
|
|
|
/* sanity checks */
|
|
PCPU_SETUP_BUG_ON(ai->nr_groups <= 0);
|
|
#ifdef CONFIG_SMP
|
|
PCPU_SETUP_BUG_ON(!ai->static_size);
|
|
PCPU_SETUP_BUG_ON(offset_in_page(__per_cpu_start));
|
|
#endif
|
|
PCPU_SETUP_BUG_ON(!base_addr);
|
|
PCPU_SETUP_BUG_ON(offset_in_page(base_addr));
|
|
PCPU_SETUP_BUG_ON(ai->unit_size < size_sum);
|
|
PCPU_SETUP_BUG_ON(offset_in_page(ai->unit_size));
|
|
PCPU_SETUP_BUG_ON(ai->unit_size < PCPU_MIN_UNIT_SIZE);
|
|
PCPU_SETUP_BUG_ON(!IS_ALIGNED(ai->unit_size, PCPU_BITMAP_BLOCK_SIZE));
|
|
PCPU_SETUP_BUG_ON(ai->dyn_size < PERCPU_DYNAMIC_EARLY_SIZE);
|
|
PCPU_SETUP_BUG_ON(!ai->dyn_size);
|
|
PCPU_SETUP_BUG_ON(!IS_ALIGNED(ai->reserved_size, PCPU_MIN_ALLOC_SIZE));
|
|
PCPU_SETUP_BUG_ON(!(IS_ALIGNED(PCPU_BITMAP_BLOCK_SIZE, PAGE_SIZE) ||
|
|
IS_ALIGNED(PAGE_SIZE, PCPU_BITMAP_BLOCK_SIZE)));
|
|
PCPU_SETUP_BUG_ON(pcpu_verify_alloc_info(ai) < 0);
|
|
|
|
/* process group information and build config tables accordingly */
|
|
alloc_size = ai->nr_groups * sizeof(group_offsets[0]);
|
|
group_offsets = memblock_alloc(alloc_size, SMP_CACHE_BYTES);
|
|
if (!group_offsets)
|
|
panic("%s: Failed to allocate %zu bytes\n", __func__,
|
|
alloc_size);
|
|
|
|
alloc_size = ai->nr_groups * sizeof(group_sizes[0]);
|
|
group_sizes = memblock_alloc(alloc_size, SMP_CACHE_BYTES);
|
|
if (!group_sizes)
|
|
panic("%s: Failed to allocate %zu bytes\n", __func__,
|
|
alloc_size);
|
|
|
|
alloc_size = nr_cpu_ids * sizeof(unit_map[0]);
|
|
unit_map = memblock_alloc(alloc_size, SMP_CACHE_BYTES);
|
|
if (!unit_map)
|
|
panic("%s: Failed to allocate %zu bytes\n", __func__,
|
|
alloc_size);
|
|
|
|
alloc_size = nr_cpu_ids * sizeof(unit_off[0]);
|
|
unit_off = memblock_alloc(alloc_size, SMP_CACHE_BYTES);
|
|
if (!unit_off)
|
|
panic("%s: Failed to allocate %zu bytes\n", __func__,
|
|
alloc_size);
|
|
|
|
for (cpu = 0; cpu < nr_cpu_ids; cpu++)
|
|
unit_map[cpu] = UINT_MAX;
|
|
|
|
pcpu_low_unit_cpu = NR_CPUS;
|
|
pcpu_high_unit_cpu = NR_CPUS;
|
|
|
|
for (group = 0, unit = 0; group < ai->nr_groups; group++, unit += i) {
|
|
const struct pcpu_group_info *gi = &ai->groups[group];
|
|
|
|
group_offsets[group] = gi->base_offset;
|
|
group_sizes[group] = gi->nr_units * ai->unit_size;
|
|
|
|
for (i = 0; i < gi->nr_units; i++) {
|
|
cpu = gi->cpu_map[i];
|
|
if (cpu == NR_CPUS)
|
|
continue;
|
|
|
|
PCPU_SETUP_BUG_ON(cpu >= nr_cpu_ids);
|
|
PCPU_SETUP_BUG_ON(!cpu_possible(cpu));
|
|
PCPU_SETUP_BUG_ON(unit_map[cpu] != UINT_MAX);
|
|
|
|
unit_map[cpu] = unit + i;
|
|
unit_off[cpu] = gi->base_offset + i * ai->unit_size;
|
|
|
|
/* determine low/high unit_cpu */
|
|
if (pcpu_low_unit_cpu == NR_CPUS ||
|
|
unit_off[cpu] < unit_off[pcpu_low_unit_cpu])
|
|
pcpu_low_unit_cpu = cpu;
|
|
if (pcpu_high_unit_cpu == NR_CPUS ||
|
|
unit_off[cpu] > unit_off[pcpu_high_unit_cpu])
|
|
pcpu_high_unit_cpu = cpu;
|
|
}
|
|
}
|
|
pcpu_nr_units = unit;
|
|
|
|
for_each_possible_cpu(cpu)
|
|
PCPU_SETUP_BUG_ON(unit_map[cpu] == UINT_MAX);
|
|
|
|
/* we're done parsing the input, undefine BUG macro and dump config */
|
|
#undef PCPU_SETUP_BUG_ON
|
|
pcpu_dump_alloc_info(KERN_DEBUG, ai);
|
|
|
|
pcpu_nr_groups = ai->nr_groups;
|
|
pcpu_group_offsets = group_offsets;
|
|
pcpu_group_sizes = group_sizes;
|
|
pcpu_unit_map = unit_map;
|
|
pcpu_unit_offsets = unit_off;
|
|
|
|
/* determine basic parameters */
|
|
pcpu_unit_pages = ai->unit_size >> PAGE_SHIFT;
|
|
pcpu_unit_size = pcpu_unit_pages << PAGE_SHIFT;
|
|
pcpu_atom_size = ai->atom_size;
|
|
pcpu_chunk_struct_size = struct_size(chunk, populated,
|
|
BITS_TO_LONGS(pcpu_unit_pages));
|
|
|
|
pcpu_stats_save_ai(ai);
|
|
|
|
/*
|
|
* Allocate chunk slots. The slots after the active slots are:
|
|
* sidelined_slot - isolated, depopulated chunks
|
|
* free_slot - fully free chunks
|
|
* to_depopulate_slot - isolated, chunks to depopulate
|
|
*/
|
|
pcpu_sidelined_slot = __pcpu_size_to_slot(pcpu_unit_size) + 1;
|
|
pcpu_free_slot = pcpu_sidelined_slot + 1;
|
|
pcpu_to_depopulate_slot = pcpu_free_slot + 1;
|
|
pcpu_nr_slots = pcpu_to_depopulate_slot + 1;
|
|
pcpu_chunk_lists = memblock_alloc(pcpu_nr_slots *
|
|
sizeof(pcpu_chunk_lists[0]),
|
|
SMP_CACHE_BYTES);
|
|
if (!pcpu_chunk_lists)
|
|
panic("%s: Failed to allocate %zu bytes\n", __func__,
|
|
pcpu_nr_slots * sizeof(pcpu_chunk_lists[0]));
|
|
|
|
for (i = 0; i < pcpu_nr_slots; i++)
|
|
INIT_LIST_HEAD(&pcpu_chunk_lists[i]);
|
|
|
|
/*
|
|
* The end of the static region needs to be aligned with the
|
|
* minimum allocation size as this offsets the reserved and
|
|
* dynamic region. The first chunk ends page aligned by
|
|
* expanding the dynamic region, therefore the dynamic region
|
|
* can be shrunk to compensate while still staying above the
|
|
* configured sizes.
|
|
*/
|
|
static_size = ALIGN(ai->static_size, PCPU_MIN_ALLOC_SIZE);
|
|
dyn_size = ai->dyn_size - (static_size - ai->static_size);
|
|
|
|
/*
|
|
* Initialize first chunk.
|
|
* If the reserved_size is non-zero, this initializes the reserved
|
|
* chunk. If the reserved_size is zero, the reserved chunk is NULL
|
|
* and the dynamic region is initialized here. The first chunk,
|
|
* pcpu_first_chunk, will always point to the chunk that serves
|
|
* the dynamic region.
|
|
*/
|
|
tmp_addr = (unsigned long)base_addr + static_size;
|
|
map_size = ai->reserved_size ?: dyn_size;
|
|
chunk = pcpu_alloc_first_chunk(tmp_addr, map_size);
|
|
|
|
/* init dynamic chunk if necessary */
|
|
if (ai->reserved_size) {
|
|
pcpu_reserved_chunk = chunk;
|
|
|
|
tmp_addr = (unsigned long)base_addr + static_size +
|
|
ai->reserved_size;
|
|
map_size = dyn_size;
|
|
chunk = pcpu_alloc_first_chunk(tmp_addr, map_size);
|
|
}
|
|
|
|
/* link the first chunk in */
|
|
pcpu_first_chunk = chunk;
|
|
pcpu_nr_empty_pop_pages = pcpu_first_chunk->nr_empty_pop_pages;
|
|
pcpu_chunk_relocate(pcpu_first_chunk, -1);
|
|
|
|
/* include all regions of the first chunk */
|
|
pcpu_nr_populated += PFN_DOWN(size_sum);
|
|
|
|
pcpu_stats_chunk_alloc();
|
|
trace_percpu_create_chunk(base_addr);
|
|
|
|
/* we're done */
|
|
pcpu_base_addr = base_addr;
|
|
}
|
|
|
|
#ifdef CONFIG_SMP
|
|
|
|
const char * const pcpu_fc_names[PCPU_FC_NR] __initconst = {
|
|
[PCPU_FC_AUTO] = "auto",
|
|
[PCPU_FC_EMBED] = "embed",
|
|
[PCPU_FC_PAGE] = "page",
|
|
};
|
|
|
|
enum pcpu_fc pcpu_chosen_fc __initdata = PCPU_FC_AUTO;
|
|
|
|
static int __init percpu_alloc_setup(char *str)
|
|
{
|
|
if (!str)
|
|
return -EINVAL;
|
|
|
|
if (0)
|
|
/* nada */;
|
|
#ifdef CONFIG_NEED_PER_CPU_EMBED_FIRST_CHUNK
|
|
else if (!strcmp(str, "embed"))
|
|
pcpu_chosen_fc = PCPU_FC_EMBED;
|
|
#endif
|
|
#ifdef CONFIG_NEED_PER_CPU_PAGE_FIRST_CHUNK
|
|
else if (!strcmp(str, "page"))
|
|
pcpu_chosen_fc = PCPU_FC_PAGE;
|
|
#endif
|
|
else
|
|
pr_warn("unknown allocator %s specified\n", str);
|
|
|
|
return 0;
|
|
}
|
|
early_param("percpu_alloc", percpu_alloc_setup);
|
|
|
|
/*
|
|
* pcpu_embed_first_chunk() is used by the generic percpu setup.
|
|
* Build it if needed by the arch config or the generic setup is going
|
|
* to be used.
|
|
*/
|
|
#if defined(CONFIG_NEED_PER_CPU_EMBED_FIRST_CHUNK) || \
|
|
!defined(CONFIG_HAVE_SETUP_PER_CPU_AREA)
|
|
#define BUILD_EMBED_FIRST_CHUNK
|
|
#endif
|
|
|
|
/* build pcpu_page_first_chunk() iff needed by the arch config */
|
|
#if defined(CONFIG_NEED_PER_CPU_PAGE_FIRST_CHUNK)
|
|
#define BUILD_PAGE_FIRST_CHUNK
|
|
#endif
|
|
|
|
/* pcpu_build_alloc_info() is used by both embed and page first chunk */
|
|
#if defined(BUILD_EMBED_FIRST_CHUNK) || defined(BUILD_PAGE_FIRST_CHUNK)
|
|
/**
|
|
* pcpu_build_alloc_info - build alloc_info considering distances between CPUs
|
|
* @reserved_size: the size of reserved percpu area in bytes
|
|
* @dyn_size: minimum free size for dynamic allocation in bytes
|
|
* @atom_size: allocation atom size
|
|
* @cpu_distance_fn: callback to determine distance between cpus, optional
|
|
*
|
|
* This function determines grouping of units, their mappings to cpus
|
|
* and other parameters considering needed percpu size, allocation
|
|
* atom size and distances between CPUs.
|
|
*
|
|
* Groups are always multiples of atom size and CPUs which are of
|
|
* LOCAL_DISTANCE both ways are grouped together and share space for
|
|
* units in the same group. The returned configuration is guaranteed
|
|
* to have CPUs on different nodes on different groups and >=75% usage
|
|
* of allocated virtual address space.
|
|
*
|
|
* RETURNS:
|
|
* On success, pointer to the new allocation_info is returned. On
|
|
* failure, ERR_PTR value is returned.
|
|
*/
|
|
static struct pcpu_alloc_info * __init __flatten pcpu_build_alloc_info(
|
|
size_t reserved_size, size_t dyn_size,
|
|
size_t atom_size,
|
|
pcpu_fc_cpu_distance_fn_t cpu_distance_fn)
|
|
{
|
|
static int group_map[NR_CPUS] __initdata;
|
|
static int group_cnt[NR_CPUS] __initdata;
|
|
static struct cpumask mask __initdata;
|
|
const size_t static_size = __per_cpu_end - __per_cpu_start;
|
|
int nr_groups = 1, nr_units = 0;
|
|
size_t size_sum, min_unit_size, alloc_size;
|
|
int upa, max_upa, best_upa; /* units_per_alloc */
|
|
int last_allocs, group, unit;
|
|
unsigned int cpu, tcpu;
|
|
struct pcpu_alloc_info *ai;
|
|
unsigned int *cpu_map;
|
|
|
|
/* this function may be called multiple times */
|
|
memset(group_map, 0, sizeof(group_map));
|
|
memset(group_cnt, 0, sizeof(group_cnt));
|
|
cpumask_clear(&mask);
|
|
|
|
/* calculate size_sum and ensure dyn_size is enough for early alloc */
|
|
size_sum = PFN_ALIGN(static_size + reserved_size +
|
|
max_t(size_t, dyn_size, PERCPU_DYNAMIC_EARLY_SIZE));
|
|
dyn_size = size_sum - static_size - reserved_size;
|
|
|
|
/*
|
|
* Determine min_unit_size, alloc_size and max_upa such that
|
|
* alloc_size is multiple of atom_size and is the smallest
|
|
* which can accommodate 4k aligned segments which are equal to
|
|
* or larger than min_unit_size.
|
|
*/
|
|
min_unit_size = max_t(size_t, size_sum, PCPU_MIN_UNIT_SIZE);
|
|
|
|
/* determine the maximum # of units that can fit in an allocation */
|
|
alloc_size = roundup(min_unit_size, atom_size);
|
|
upa = alloc_size / min_unit_size;
|
|
while (alloc_size % upa || (offset_in_page(alloc_size / upa)))
|
|
upa--;
|
|
max_upa = upa;
|
|
|
|
cpumask_copy(&mask, cpu_possible_mask);
|
|
|
|
/* group cpus according to their proximity */
|
|
for (group = 0; !cpumask_empty(&mask); group++) {
|
|
/* pop the group's first cpu */
|
|
cpu = cpumask_first(&mask);
|
|
group_map[cpu] = group;
|
|
group_cnt[group]++;
|
|
cpumask_clear_cpu(cpu, &mask);
|
|
|
|
for_each_cpu(tcpu, &mask) {
|
|
if (!cpu_distance_fn ||
|
|
(cpu_distance_fn(cpu, tcpu) == LOCAL_DISTANCE &&
|
|
cpu_distance_fn(tcpu, cpu) == LOCAL_DISTANCE)) {
|
|
group_map[tcpu] = group;
|
|
group_cnt[group]++;
|
|
cpumask_clear_cpu(tcpu, &mask);
|
|
}
|
|
}
|
|
}
|
|
nr_groups = group;
|
|
|
|
/*
|
|
* Wasted space is caused by a ratio imbalance of upa to group_cnt.
|
|
* Expand the unit_size until we use >= 75% of the units allocated.
|
|
* Related to atom_size, which could be much larger than the unit_size.
|
|
*/
|
|
last_allocs = INT_MAX;
|
|
best_upa = 0;
|
|
for (upa = max_upa; upa; upa--) {
|
|
int allocs = 0, wasted = 0;
|
|
|
|
if (alloc_size % upa || (offset_in_page(alloc_size / upa)))
|
|
continue;
|
|
|
|
for (group = 0; group < nr_groups; group++) {
|
|
int this_allocs = DIV_ROUND_UP(group_cnt[group], upa);
|
|
allocs += this_allocs;
|
|
wasted += this_allocs * upa - group_cnt[group];
|
|
}
|
|
|
|
/*
|
|
* Don't accept if wastage is over 1/3. The
|
|
* greater-than comparison ensures upa==1 always
|
|
* passes the following check.
|
|
*/
|
|
if (wasted > num_possible_cpus() / 3)
|
|
continue;
|
|
|
|
/* and then don't consume more memory */
|
|
if (allocs > last_allocs)
|
|
break;
|
|
last_allocs = allocs;
|
|
best_upa = upa;
|
|
}
|
|
BUG_ON(!best_upa);
|
|
upa = best_upa;
|
|
|
|
/* allocate and fill alloc_info */
|
|
for (group = 0; group < nr_groups; group++)
|
|
nr_units += roundup(group_cnt[group], upa);
|
|
|
|
ai = pcpu_alloc_alloc_info(nr_groups, nr_units);
|
|
if (!ai)
|
|
return ERR_PTR(-ENOMEM);
|
|
cpu_map = ai->groups[0].cpu_map;
|
|
|
|
for (group = 0; group < nr_groups; group++) {
|
|
ai->groups[group].cpu_map = cpu_map;
|
|
cpu_map += roundup(group_cnt[group], upa);
|
|
}
|
|
|
|
ai->static_size = static_size;
|
|
ai->reserved_size = reserved_size;
|
|
ai->dyn_size = dyn_size;
|
|
ai->unit_size = alloc_size / upa;
|
|
ai->atom_size = atom_size;
|
|
ai->alloc_size = alloc_size;
|
|
|
|
for (group = 0, unit = 0; group < nr_groups; group++) {
|
|
struct pcpu_group_info *gi = &ai->groups[group];
|
|
|
|
/*
|
|
* Initialize base_offset as if all groups are located
|
|
* back-to-back. The caller should update this to
|
|
* reflect actual allocation.
|
|
*/
|
|
gi->base_offset = unit * ai->unit_size;
|
|
|
|
for_each_possible_cpu(cpu)
|
|
if (group_map[cpu] == group)
|
|
gi->cpu_map[gi->nr_units++] = cpu;
|
|
gi->nr_units = roundup(gi->nr_units, upa);
|
|
unit += gi->nr_units;
|
|
}
|
|
BUG_ON(unit != nr_units);
|
|
|
|
return ai;
|
|
}
|
|
|
|
static void * __init pcpu_fc_alloc(unsigned int cpu, size_t size, size_t align,
|
|
pcpu_fc_cpu_to_node_fn_t cpu_to_nd_fn)
|
|
{
|
|
const unsigned long goal = __pa(MAX_DMA_ADDRESS);
|
|
#ifdef CONFIG_NUMA
|
|
int node = NUMA_NO_NODE;
|
|
void *ptr;
|
|
|
|
if (cpu_to_nd_fn)
|
|
node = cpu_to_nd_fn(cpu);
|
|
|
|
if (node == NUMA_NO_NODE || !node_online(node) || !NODE_DATA(node)) {
|
|
ptr = memblock_alloc_from(size, align, goal);
|
|
pr_info("cpu %d has no node %d or node-local memory\n",
|
|
cpu, node);
|
|
pr_debug("per cpu data for cpu%d %zu bytes at 0x%llx\n",
|
|
cpu, size, (u64)__pa(ptr));
|
|
} else {
|
|
ptr = memblock_alloc_try_nid(size, align, goal,
|
|
MEMBLOCK_ALLOC_ACCESSIBLE,
|
|
node);
|
|
|
|
pr_debug("per cpu data for cpu%d %zu bytes on node%d at 0x%llx\n",
|
|
cpu, size, node, (u64)__pa(ptr));
|
|
}
|
|
return ptr;
|
|
#else
|
|
return memblock_alloc_from(size, align, goal);
|
|
#endif
|
|
}
|
|
|
|
static void __init pcpu_fc_free(void *ptr, size_t size)
|
|
{
|
|
memblock_free(ptr, size);
|
|
}
|
|
#endif /* BUILD_EMBED_FIRST_CHUNK || BUILD_PAGE_FIRST_CHUNK */
|
|
|
|
#if defined(BUILD_EMBED_FIRST_CHUNK)
|
|
/**
|
|
* pcpu_embed_first_chunk - embed the first percpu chunk into bootmem
|
|
* @reserved_size: the size of reserved percpu area in bytes
|
|
* @dyn_size: minimum free size for dynamic allocation in bytes
|
|
* @atom_size: allocation atom size
|
|
* @cpu_distance_fn: callback to determine distance between cpus, optional
|
|
* @cpu_to_nd_fn: callback to convert cpu to it's node, optional
|
|
*
|
|
* This is a helper to ease setting up embedded first percpu chunk and
|
|
* can be called where pcpu_setup_first_chunk() is expected.
|
|
*
|
|
* If this function is used to setup the first chunk, it is allocated
|
|
* by calling pcpu_fc_alloc and used as-is without being mapped into
|
|
* vmalloc area. Allocations are always whole multiples of @atom_size
|
|
* aligned to @atom_size.
|
|
*
|
|
* This enables the first chunk to piggy back on the linear physical
|
|
* mapping which often uses larger page size. Please note that this
|
|
* can result in very sparse cpu->unit mapping on NUMA machines thus
|
|
* requiring large vmalloc address space. Don't use this allocator if
|
|
* vmalloc space is not orders of magnitude larger than distances
|
|
* between node memory addresses (ie. 32bit NUMA machines).
|
|
*
|
|
* @dyn_size specifies the minimum dynamic area size.
|
|
*
|
|
* If the needed size is smaller than the minimum or specified unit
|
|
* size, the leftover is returned using pcpu_fc_free.
|
|
*
|
|
* RETURNS:
|
|
* 0 on success, -errno on failure.
|
|
*/
|
|
int __init pcpu_embed_first_chunk(size_t reserved_size, size_t dyn_size,
|
|
size_t atom_size,
|
|
pcpu_fc_cpu_distance_fn_t cpu_distance_fn,
|
|
pcpu_fc_cpu_to_node_fn_t cpu_to_nd_fn)
|
|
{
|
|
void *base = (void *)ULONG_MAX;
|
|
void **areas = NULL;
|
|
struct pcpu_alloc_info *ai;
|
|
size_t size_sum, areas_size;
|
|
unsigned long max_distance;
|
|
int group, i, highest_group, rc = 0;
|
|
|
|
ai = pcpu_build_alloc_info(reserved_size, dyn_size, atom_size,
|
|
cpu_distance_fn);
|
|
if (IS_ERR(ai))
|
|
return PTR_ERR(ai);
|
|
|
|
size_sum = ai->static_size + ai->reserved_size + ai->dyn_size;
|
|
areas_size = PFN_ALIGN(ai->nr_groups * sizeof(void *));
|
|
|
|
areas = memblock_alloc(areas_size, SMP_CACHE_BYTES);
|
|
if (!areas) {
|
|
rc = -ENOMEM;
|
|
goto out_free;
|
|
}
|
|
|
|
/* allocate, copy and determine base address & max_distance */
|
|
highest_group = 0;
|
|
for (group = 0; group < ai->nr_groups; group++) {
|
|
struct pcpu_group_info *gi = &ai->groups[group];
|
|
unsigned int cpu = NR_CPUS;
|
|
void *ptr;
|
|
|
|
for (i = 0; i < gi->nr_units && cpu == NR_CPUS; i++)
|
|
cpu = gi->cpu_map[i];
|
|
BUG_ON(cpu == NR_CPUS);
|
|
|
|
/* allocate space for the whole group */
|
|
ptr = pcpu_fc_alloc(cpu, gi->nr_units * ai->unit_size, atom_size, cpu_to_nd_fn);
|
|
if (!ptr) {
|
|
rc = -ENOMEM;
|
|
goto out_free_areas;
|
|
}
|
|
/* kmemleak tracks the percpu allocations separately */
|
|
kmemleak_free(ptr);
|
|
areas[group] = ptr;
|
|
|
|
base = min(ptr, base);
|
|
if (ptr > areas[highest_group])
|
|
highest_group = group;
|
|
}
|
|
max_distance = areas[highest_group] - base;
|
|
max_distance += ai->unit_size * ai->groups[highest_group].nr_units;
|
|
|
|
/* warn if maximum distance is further than 75% of vmalloc space */
|
|
if (max_distance > VMALLOC_TOTAL * 3 / 4) {
|
|
pr_warn("max_distance=0x%lx too large for vmalloc space 0x%lx\n",
|
|
max_distance, VMALLOC_TOTAL);
|
|
#ifdef CONFIG_NEED_PER_CPU_PAGE_FIRST_CHUNK
|
|
/* and fail if we have fallback */
|
|
rc = -EINVAL;
|
|
goto out_free_areas;
|
|
#endif
|
|
}
|
|
|
|
/*
|
|
* Copy data and free unused parts. This should happen after all
|
|
* allocations are complete; otherwise, we may end up with
|
|
* overlapping groups.
|
|
*/
|
|
for (group = 0; group < ai->nr_groups; group++) {
|
|
struct pcpu_group_info *gi = &ai->groups[group];
|
|
void *ptr = areas[group];
|
|
|
|
for (i = 0; i < gi->nr_units; i++, ptr += ai->unit_size) {
|
|
if (gi->cpu_map[i] == NR_CPUS) {
|
|
/* unused unit, free whole */
|
|
pcpu_fc_free(ptr, ai->unit_size);
|
|
continue;
|
|
}
|
|
/* copy and return the unused part */
|
|
memcpy(ptr, __per_cpu_load, ai->static_size);
|
|
pcpu_fc_free(ptr + size_sum, ai->unit_size - size_sum);
|
|
}
|
|
}
|
|
|
|
/* base address is now known, determine group base offsets */
|
|
for (group = 0; group < ai->nr_groups; group++) {
|
|
ai->groups[group].base_offset = areas[group] - base;
|
|
}
|
|
|
|
pr_info("Embedded %zu pages/cpu s%zu r%zu d%zu u%zu\n",
|
|
PFN_DOWN(size_sum), ai->static_size, ai->reserved_size,
|
|
ai->dyn_size, ai->unit_size);
|
|
|
|
pcpu_setup_first_chunk(ai, base);
|
|
goto out_free;
|
|
|
|
out_free_areas:
|
|
for (group = 0; group < ai->nr_groups; group++)
|
|
if (areas[group])
|
|
pcpu_fc_free(areas[group],
|
|
ai->groups[group].nr_units * ai->unit_size);
|
|
out_free:
|
|
pcpu_free_alloc_info(ai);
|
|
if (areas)
|
|
memblock_free(areas, areas_size);
|
|
return rc;
|
|
}
|
|
#endif /* BUILD_EMBED_FIRST_CHUNK */
|
|
|
|
#ifdef BUILD_PAGE_FIRST_CHUNK
|
|
#include <asm/pgalloc.h>
|
|
|
|
#ifndef P4D_TABLE_SIZE
|
|
#define P4D_TABLE_SIZE PAGE_SIZE
|
|
#endif
|
|
|
|
#ifndef PUD_TABLE_SIZE
|
|
#define PUD_TABLE_SIZE PAGE_SIZE
|
|
#endif
|
|
|
|
#ifndef PMD_TABLE_SIZE
|
|
#define PMD_TABLE_SIZE PAGE_SIZE
|
|
#endif
|
|
|
|
#ifndef PTE_TABLE_SIZE
|
|
#define PTE_TABLE_SIZE PAGE_SIZE
|
|
#endif
|
|
void __init __weak pcpu_populate_pte(unsigned long addr)
|
|
{
|
|
pgd_t *pgd = pgd_offset_k(addr);
|
|
p4d_t *p4d;
|
|
pud_t *pud;
|
|
pmd_t *pmd;
|
|
|
|
if (pgd_none(*pgd)) {
|
|
p4d_t *new;
|
|
|
|
new = memblock_alloc(P4D_TABLE_SIZE, P4D_TABLE_SIZE);
|
|
if (!new)
|
|
goto err_alloc;
|
|
pgd_populate(&init_mm, pgd, new);
|
|
}
|
|
|
|
p4d = p4d_offset(pgd, addr);
|
|
if (p4d_none(*p4d)) {
|
|
pud_t *new;
|
|
|
|
new = memblock_alloc(PUD_TABLE_SIZE, PUD_TABLE_SIZE);
|
|
if (!new)
|
|
goto err_alloc;
|
|
p4d_populate(&init_mm, p4d, new);
|
|
}
|
|
|
|
pud = pud_offset(p4d, addr);
|
|
if (pud_none(*pud)) {
|
|
pmd_t *new;
|
|
|
|
new = memblock_alloc(PMD_TABLE_SIZE, PMD_TABLE_SIZE);
|
|
if (!new)
|
|
goto err_alloc;
|
|
pud_populate(&init_mm, pud, new);
|
|
}
|
|
|
|
pmd = pmd_offset(pud, addr);
|
|
if (!pmd_present(*pmd)) {
|
|
pte_t *new;
|
|
|
|
new = memblock_alloc(PTE_TABLE_SIZE, PTE_TABLE_SIZE);
|
|
if (!new)
|
|
goto err_alloc;
|
|
pmd_populate_kernel(&init_mm, pmd, new);
|
|
}
|
|
|
|
return;
|
|
|
|
err_alloc:
|
|
panic("%s: Failed to allocate memory\n", __func__);
|
|
}
|
|
|
|
/**
|
|
* pcpu_page_first_chunk - map the first chunk using PAGE_SIZE pages
|
|
* @reserved_size: the size of reserved percpu area in bytes
|
|
* @cpu_to_nd_fn: callback to convert cpu to it's node, optional
|
|
*
|
|
* This is a helper to ease setting up page-remapped first percpu
|
|
* chunk and can be called where pcpu_setup_first_chunk() is expected.
|
|
*
|
|
* This is the basic allocator. Static percpu area is allocated
|
|
* page-by-page into vmalloc area.
|
|
*
|
|
* RETURNS:
|
|
* 0 on success, -errno on failure.
|
|
*/
|
|
int __init pcpu_page_first_chunk(size_t reserved_size, pcpu_fc_cpu_to_node_fn_t cpu_to_nd_fn)
|
|
{
|
|
static struct vm_struct vm;
|
|
struct pcpu_alloc_info *ai;
|
|
char psize_str[16];
|
|
int unit_pages;
|
|
size_t pages_size;
|
|
struct page **pages;
|
|
int unit, i, j, rc = 0;
|
|
int upa;
|
|
int nr_g0_units;
|
|
|
|
snprintf(psize_str, sizeof(psize_str), "%luK", PAGE_SIZE >> 10);
|
|
|
|
ai = pcpu_build_alloc_info(reserved_size, 0, PAGE_SIZE, NULL);
|
|
if (IS_ERR(ai))
|
|
return PTR_ERR(ai);
|
|
BUG_ON(ai->nr_groups != 1);
|
|
upa = ai->alloc_size/ai->unit_size;
|
|
nr_g0_units = roundup(num_possible_cpus(), upa);
|
|
if (WARN_ON(ai->groups[0].nr_units != nr_g0_units)) {
|
|
pcpu_free_alloc_info(ai);
|
|
return -EINVAL;
|
|
}
|
|
|
|
unit_pages = ai->unit_size >> PAGE_SHIFT;
|
|
|
|
/* unaligned allocations can't be freed, round up to page size */
|
|
pages_size = PFN_ALIGN(unit_pages * num_possible_cpus() *
|
|
sizeof(pages[0]));
|
|
pages = memblock_alloc(pages_size, SMP_CACHE_BYTES);
|
|
if (!pages)
|
|
panic("%s: Failed to allocate %zu bytes\n", __func__,
|
|
pages_size);
|
|
|
|
/* allocate pages */
|
|
j = 0;
|
|
for (unit = 0; unit < num_possible_cpus(); unit++) {
|
|
unsigned int cpu = ai->groups[0].cpu_map[unit];
|
|
for (i = 0; i < unit_pages; i++) {
|
|
void *ptr;
|
|
|
|
ptr = pcpu_fc_alloc(cpu, PAGE_SIZE, PAGE_SIZE, cpu_to_nd_fn);
|
|
if (!ptr) {
|
|
pr_warn("failed to allocate %s page for cpu%u\n",
|
|
psize_str, cpu);
|
|
goto enomem;
|
|
}
|
|
/* kmemleak tracks the percpu allocations separately */
|
|
kmemleak_free(ptr);
|
|
pages[j++] = virt_to_page(ptr);
|
|
}
|
|
}
|
|
|
|
/* allocate vm area, map the pages and copy static data */
|
|
vm.flags = VM_ALLOC;
|
|
vm.size = num_possible_cpus() * ai->unit_size;
|
|
vm_area_register_early(&vm, PAGE_SIZE);
|
|
|
|
for (unit = 0; unit < num_possible_cpus(); unit++) {
|
|
unsigned long unit_addr =
|
|
(unsigned long)vm.addr + unit * ai->unit_size;
|
|
|
|
for (i = 0; i < unit_pages; i++)
|
|
pcpu_populate_pte(unit_addr + (i << PAGE_SHIFT));
|
|
|
|
/* pte already populated, the following shouldn't fail */
|
|
rc = __pcpu_map_pages(unit_addr, &pages[unit * unit_pages],
|
|
unit_pages);
|
|
if (rc < 0)
|
|
panic("failed to map percpu area, err=%d\n", rc);
|
|
|
|
/*
|
|
* FIXME: Archs with virtual cache should flush local
|
|
* cache for the linear mapping here - something
|
|
* equivalent to flush_cache_vmap() on the local cpu.
|
|
* flush_cache_vmap() can't be used as most supporting
|
|
* data structures are not set up yet.
|
|
*/
|
|
|
|
/* copy static data */
|
|
memcpy((void *)unit_addr, __per_cpu_load, ai->static_size);
|
|
}
|
|
|
|
/* we're ready, commit */
|
|
pr_info("%d %s pages/cpu s%zu r%zu d%zu\n",
|
|
unit_pages, psize_str, ai->static_size,
|
|
ai->reserved_size, ai->dyn_size);
|
|
|
|
pcpu_setup_first_chunk(ai, vm.addr);
|
|
goto out_free_ar;
|
|
|
|
enomem:
|
|
while (--j >= 0)
|
|
pcpu_fc_free(page_address(pages[j]), PAGE_SIZE);
|
|
rc = -ENOMEM;
|
|
out_free_ar:
|
|
memblock_free(pages, pages_size);
|
|
pcpu_free_alloc_info(ai);
|
|
return rc;
|
|
}
|
|
#endif /* BUILD_PAGE_FIRST_CHUNK */
|
|
|
|
#ifndef CONFIG_HAVE_SETUP_PER_CPU_AREA
|
|
/*
|
|
* Generic SMP percpu area setup.
|
|
*
|
|
* The embedding helper is used because its behavior closely resembles
|
|
* the original non-dynamic generic percpu area setup. This is
|
|
* important because many archs have addressing restrictions and might
|
|
* fail if the percpu area is located far away from the previous
|
|
* location. As an added bonus, in non-NUMA cases, embedding is
|
|
* generally a good idea TLB-wise because percpu area can piggy back
|
|
* on the physical linear memory mapping which uses large page
|
|
* mappings on applicable archs.
|
|
*/
|
|
unsigned long __per_cpu_offset[NR_CPUS] __read_mostly;
|
|
EXPORT_SYMBOL(__per_cpu_offset);
|
|
|
|
void __init setup_per_cpu_areas(void)
|
|
{
|
|
unsigned long delta;
|
|
unsigned int cpu;
|
|
int rc;
|
|
|
|
/*
|
|
* Always reserve area for module percpu variables. That's
|
|
* what the legacy allocator did.
|
|
*/
|
|
rc = pcpu_embed_first_chunk(PERCPU_MODULE_RESERVE, PERCPU_DYNAMIC_RESERVE,
|
|
PAGE_SIZE, NULL, NULL);
|
|
if (rc < 0)
|
|
panic("Failed to initialize percpu areas.");
|
|
|
|
delta = (unsigned long)pcpu_base_addr - (unsigned long)__per_cpu_start;
|
|
for_each_possible_cpu(cpu)
|
|
__per_cpu_offset[cpu] = delta + pcpu_unit_offsets[cpu];
|
|
}
|
|
#endif /* CONFIG_HAVE_SETUP_PER_CPU_AREA */
|
|
|
|
#else /* CONFIG_SMP */
|
|
|
|
/*
|
|
* UP percpu area setup.
|
|
*
|
|
* UP always uses km-based percpu allocator with identity mapping.
|
|
* Static percpu variables are indistinguishable from the usual static
|
|
* variables and don't require any special preparation.
|
|
*/
|
|
void __init setup_per_cpu_areas(void)
|
|
{
|
|
const size_t unit_size =
|
|
roundup_pow_of_two(max_t(size_t, PCPU_MIN_UNIT_SIZE,
|
|
PERCPU_DYNAMIC_RESERVE));
|
|
struct pcpu_alloc_info *ai;
|
|
void *fc;
|
|
|
|
ai = pcpu_alloc_alloc_info(1, 1);
|
|
fc = memblock_alloc_from(unit_size, PAGE_SIZE, __pa(MAX_DMA_ADDRESS));
|
|
if (!ai || !fc)
|
|
panic("Failed to allocate memory for percpu areas.");
|
|
/* kmemleak tracks the percpu allocations separately */
|
|
kmemleak_free(fc);
|
|
|
|
ai->dyn_size = unit_size;
|
|
ai->unit_size = unit_size;
|
|
ai->atom_size = unit_size;
|
|
ai->alloc_size = unit_size;
|
|
ai->groups[0].nr_units = 1;
|
|
ai->groups[0].cpu_map[0] = 0;
|
|
|
|
pcpu_setup_first_chunk(ai, fc);
|
|
pcpu_free_alloc_info(ai);
|
|
}
|
|
|
|
#endif /* CONFIG_SMP */
|
|
|
|
/*
|
|
* pcpu_nr_pages - calculate total number of populated backing pages
|
|
*
|
|
* This reflects the number of pages populated to back chunks. Metadata is
|
|
* excluded in the number exposed in meminfo as the number of backing pages
|
|
* scales with the number of cpus and can quickly outweigh the memory used for
|
|
* metadata. It also keeps this calculation nice and simple.
|
|
*
|
|
* RETURNS:
|
|
* Total number of populated backing pages in use by the allocator.
|
|
*/
|
|
unsigned long pcpu_nr_pages(void)
|
|
{
|
|
return pcpu_nr_populated * pcpu_nr_units;
|
|
}
|
|
|
|
/*
|
|
* Percpu allocator is initialized early during boot when neither slab or
|
|
* workqueue is available. Plug async management until everything is up
|
|
* and running.
|
|
*/
|
|
static int __init percpu_enable_async(void)
|
|
{
|
|
pcpu_async_enabled = true;
|
|
return 0;
|
|
}
|
|
subsys_initcall(percpu_enable_async);
|