438 lines
11 KiB
C
438 lines
11 KiB
C
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// SPDX-License-Identifier: GPL-2.0
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/*
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* Virtual cpu timer based timer functions.
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*
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* Copyright IBM Corp. 2004, 2012
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* Author(s): Jan Glauber <jan.glauber@de.ibm.com>
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*/
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#include <linux/kernel_stat.h>
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#include <linux/sched/cputime.h>
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#include <linux/export.h>
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#include <linux/kernel.h>
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#include <linux/timex.h>
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#include <linux/types.h>
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#include <linux/time.h>
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#include <asm/vtimer.h>
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#include <asm/vtime.h>
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#include <asm/cpu_mf.h>
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#include <asm/smp.h>
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#include "entry.h"
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static void virt_timer_expire(void);
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static LIST_HEAD(virt_timer_list);
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static DEFINE_SPINLOCK(virt_timer_lock);
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static atomic64_t virt_timer_current;
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static atomic64_t virt_timer_elapsed;
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DEFINE_PER_CPU(u64, mt_cycles[8]);
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static DEFINE_PER_CPU(u64, mt_scaling_mult) = { 1 };
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static DEFINE_PER_CPU(u64, mt_scaling_div) = { 1 };
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static DEFINE_PER_CPU(u64, mt_scaling_jiffies);
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static inline u64 get_vtimer(void)
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{
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u64 timer;
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asm volatile("stpt %0" : "=m" (timer));
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return timer;
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}
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static inline void set_vtimer(u64 expires)
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{
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u64 timer;
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asm volatile(
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" stpt %0\n" /* Store current cpu timer value */
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" spt %1" /* Set new value imm. afterwards */
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: "=m" (timer) : "m" (expires));
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S390_lowcore.system_timer += S390_lowcore.last_update_timer - timer;
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S390_lowcore.last_update_timer = expires;
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}
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static inline int virt_timer_forward(u64 elapsed)
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{
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BUG_ON(!irqs_disabled());
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if (list_empty(&virt_timer_list))
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return 0;
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elapsed = atomic64_add_return(elapsed, &virt_timer_elapsed);
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return elapsed >= atomic64_read(&virt_timer_current);
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}
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static void update_mt_scaling(void)
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{
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u64 cycles_new[8], *cycles_old;
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u64 delta, fac, mult, div;
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int i;
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stcctm5(smp_cpu_mtid + 1, cycles_new);
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cycles_old = this_cpu_ptr(mt_cycles);
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fac = 1;
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mult = div = 0;
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for (i = 0; i <= smp_cpu_mtid; i++) {
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delta = cycles_new[i] - cycles_old[i];
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div += delta;
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mult *= i + 1;
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mult += delta * fac;
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fac *= i + 1;
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}
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div *= fac;
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if (div > 0) {
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/* Update scaling factor */
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__this_cpu_write(mt_scaling_mult, mult);
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__this_cpu_write(mt_scaling_div, div);
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memcpy(cycles_old, cycles_new,
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sizeof(u64) * (smp_cpu_mtid + 1));
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}
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__this_cpu_write(mt_scaling_jiffies, jiffies_64);
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}
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static inline u64 update_tsk_timer(unsigned long *tsk_vtime, u64 new)
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{
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u64 delta;
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delta = new - *tsk_vtime;
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*tsk_vtime = new;
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return delta;
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}
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static inline u64 scale_vtime(u64 vtime)
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{
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u64 mult = __this_cpu_read(mt_scaling_mult);
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u64 div = __this_cpu_read(mt_scaling_div);
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if (smp_cpu_mtid)
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return vtime * mult / div;
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return vtime;
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}
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static void account_system_index_scaled(struct task_struct *p, u64 cputime,
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enum cpu_usage_stat index)
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{
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p->stimescaled += cputime_to_nsecs(scale_vtime(cputime));
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account_system_index_time(p, cputime_to_nsecs(cputime), index);
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}
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/*
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* Update process times based on virtual cpu times stored by entry.S
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* to the lowcore fields user_timer, system_timer & steal_clock.
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*/
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static int do_account_vtime(struct task_struct *tsk)
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{
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u64 timer, clock, user, guest, system, hardirq, softirq, steal;
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timer = S390_lowcore.last_update_timer;
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clock = S390_lowcore.last_update_clock;
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asm volatile(
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" stpt %0\n" /* Store current cpu timer value */
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#ifdef CONFIG_HAVE_MARCH_Z9_109_FEATURES
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" stckf %1" /* Store current tod clock value */
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#else
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" stck %1" /* Store current tod clock value */
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#endif
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: "=m" (S390_lowcore.last_update_timer),
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"=m" (S390_lowcore.last_update_clock));
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clock = S390_lowcore.last_update_clock - clock;
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timer -= S390_lowcore.last_update_timer;
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if (hardirq_count())
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S390_lowcore.hardirq_timer += timer;
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else
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S390_lowcore.system_timer += timer;
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/* Update MT utilization calculation */
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if (smp_cpu_mtid &&
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time_after64(jiffies_64, this_cpu_read(mt_scaling_jiffies)))
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update_mt_scaling();
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/* Calculate cputime delta */
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user = update_tsk_timer(&tsk->thread.user_timer,
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READ_ONCE(S390_lowcore.user_timer));
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guest = update_tsk_timer(&tsk->thread.guest_timer,
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READ_ONCE(S390_lowcore.guest_timer));
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system = update_tsk_timer(&tsk->thread.system_timer,
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READ_ONCE(S390_lowcore.system_timer));
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hardirq = update_tsk_timer(&tsk->thread.hardirq_timer,
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READ_ONCE(S390_lowcore.hardirq_timer));
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softirq = update_tsk_timer(&tsk->thread.softirq_timer,
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READ_ONCE(S390_lowcore.softirq_timer));
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S390_lowcore.steal_timer +=
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clock - user - guest - system - hardirq - softirq;
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/* Push account value */
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if (user) {
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account_user_time(tsk, cputime_to_nsecs(user));
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tsk->utimescaled += cputime_to_nsecs(scale_vtime(user));
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}
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if (guest) {
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account_guest_time(tsk, cputime_to_nsecs(guest));
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tsk->utimescaled += cputime_to_nsecs(scale_vtime(guest));
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}
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if (system)
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account_system_index_scaled(tsk, system, CPUTIME_SYSTEM);
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if (hardirq)
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account_system_index_scaled(tsk, hardirq, CPUTIME_IRQ);
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if (softirq)
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account_system_index_scaled(tsk, softirq, CPUTIME_SOFTIRQ);
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steal = S390_lowcore.steal_timer;
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if ((s64) steal > 0) {
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S390_lowcore.steal_timer = 0;
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account_steal_time(cputime_to_nsecs(steal));
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}
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return virt_timer_forward(user + guest + system + hardirq + softirq);
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}
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void vtime_task_switch(struct task_struct *prev)
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{
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do_account_vtime(prev);
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prev->thread.user_timer = S390_lowcore.user_timer;
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prev->thread.guest_timer = S390_lowcore.guest_timer;
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prev->thread.system_timer = S390_lowcore.system_timer;
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prev->thread.hardirq_timer = S390_lowcore.hardirq_timer;
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prev->thread.softirq_timer = S390_lowcore.softirq_timer;
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S390_lowcore.user_timer = current->thread.user_timer;
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S390_lowcore.guest_timer = current->thread.guest_timer;
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S390_lowcore.system_timer = current->thread.system_timer;
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S390_lowcore.hardirq_timer = current->thread.hardirq_timer;
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S390_lowcore.softirq_timer = current->thread.softirq_timer;
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}
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/*
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* In s390, accounting pending user time also implies
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* accounting system time in order to correctly compute
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* the stolen time accounting.
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*/
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void vtime_flush(struct task_struct *tsk)
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{
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if (do_account_vtime(tsk))
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virt_timer_expire();
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}
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/*
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* Update process times based on virtual cpu times stored by entry.S
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* to the lowcore fields user_timer, system_timer & steal_clock.
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*/
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void vtime_account_irq_enter(struct task_struct *tsk)
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{
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u64 timer;
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timer = S390_lowcore.last_update_timer;
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S390_lowcore.last_update_timer = get_vtimer();
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timer -= S390_lowcore.last_update_timer;
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if ((tsk->flags & PF_VCPU) && (irq_count() == 0))
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S390_lowcore.guest_timer += timer;
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else if (hardirq_count())
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S390_lowcore.hardirq_timer += timer;
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else if (in_serving_softirq())
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S390_lowcore.softirq_timer += timer;
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else
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S390_lowcore.system_timer += timer;
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virt_timer_forward(timer);
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}
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EXPORT_SYMBOL_GPL(vtime_account_irq_enter);
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void vtime_account_system(struct task_struct *tsk)
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__attribute__((alias("vtime_account_irq_enter")));
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EXPORT_SYMBOL_GPL(vtime_account_system);
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/*
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* Sorted add to a list. List is linear searched until first bigger
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* element is found.
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*/
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static void list_add_sorted(struct vtimer_list *timer, struct list_head *head)
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{
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struct vtimer_list *tmp;
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list_for_each_entry(tmp, head, entry) {
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if (tmp->expires > timer->expires) {
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list_add_tail(&timer->entry, &tmp->entry);
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return;
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}
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}
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list_add_tail(&timer->entry, head);
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}
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/*
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* Handler for expired virtual CPU timer.
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*/
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static void virt_timer_expire(void)
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{
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struct vtimer_list *timer, *tmp;
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unsigned long elapsed;
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LIST_HEAD(cb_list);
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/* walk timer list, fire all expired timers */
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spin_lock(&virt_timer_lock);
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elapsed = atomic64_read(&virt_timer_elapsed);
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list_for_each_entry_safe(timer, tmp, &virt_timer_list, entry) {
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if (timer->expires < elapsed)
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/* move expired timer to the callback queue */
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list_move_tail(&timer->entry, &cb_list);
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else
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timer->expires -= elapsed;
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}
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if (!list_empty(&virt_timer_list)) {
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timer = list_first_entry(&virt_timer_list,
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struct vtimer_list, entry);
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atomic64_set(&virt_timer_current, timer->expires);
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}
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atomic64_sub(elapsed, &virt_timer_elapsed);
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spin_unlock(&virt_timer_lock);
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/* Do callbacks and recharge periodic timers */
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list_for_each_entry_safe(timer, tmp, &cb_list, entry) {
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list_del_init(&timer->entry);
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timer->function(timer->data);
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if (timer->interval) {
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/* Recharge interval timer */
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timer->expires = timer->interval +
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atomic64_read(&virt_timer_elapsed);
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spin_lock(&virt_timer_lock);
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list_add_sorted(timer, &virt_timer_list);
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spin_unlock(&virt_timer_lock);
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}
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}
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}
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void init_virt_timer(struct vtimer_list *timer)
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{
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timer->function = NULL;
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INIT_LIST_HEAD(&timer->entry);
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}
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EXPORT_SYMBOL(init_virt_timer);
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static inline int vtimer_pending(struct vtimer_list *timer)
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{
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return !list_empty(&timer->entry);
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}
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static void internal_add_vtimer(struct vtimer_list *timer)
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{
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if (list_empty(&virt_timer_list)) {
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/* First timer, just program it. */
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atomic64_set(&virt_timer_current, timer->expires);
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atomic64_set(&virt_timer_elapsed, 0);
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list_add(&timer->entry, &virt_timer_list);
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} else {
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/* Update timer against current base. */
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timer->expires += atomic64_read(&virt_timer_elapsed);
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if (likely((s64) timer->expires <
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(s64) atomic64_read(&virt_timer_current)))
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/* The new timer expires before the current timer. */
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atomic64_set(&virt_timer_current, timer->expires);
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/* Insert new timer into the list. */
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list_add_sorted(timer, &virt_timer_list);
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}
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}
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static void __add_vtimer(struct vtimer_list *timer, int periodic)
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{
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unsigned long flags;
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timer->interval = periodic ? timer->expires : 0;
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spin_lock_irqsave(&virt_timer_lock, flags);
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internal_add_vtimer(timer);
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spin_unlock_irqrestore(&virt_timer_lock, flags);
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}
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/*
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* add_virt_timer - add a oneshot virtual CPU timer
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*/
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void add_virt_timer(struct vtimer_list *timer)
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{
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__add_vtimer(timer, 0);
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}
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EXPORT_SYMBOL(add_virt_timer);
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/*
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* add_virt_timer_int - add an interval virtual CPU timer
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*/
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void add_virt_timer_periodic(struct vtimer_list *timer)
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{
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__add_vtimer(timer, 1);
|
||
|
|
}
|
||
|
|
EXPORT_SYMBOL(add_virt_timer_periodic);
|
||
|
|
|
||
|
|
static int __mod_vtimer(struct vtimer_list *timer, u64 expires, int periodic)
|
||
|
|
{
|
||
|
|
unsigned long flags;
|
||
|
|
int rc;
|
||
|
|
|
||
|
|
BUG_ON(!timer->function);
|
||
|
|
|
||
|
|
if (timer->expires == expires && vtimer_pending(timer))
|
||
|
|
return 1;
|
||
|
|
spin_lock_irqsave(&virt_timer_lock, flags);
|
||
|
|
rc = vtimer_pending(timer);
|
||
|
|
if (rc)
|
||
|
|
list_del_init(&timer->entry);
|
||
|
|
timer->interval = periodic ? expires : 0;
|
||
|
|
timer->expires = expires;
|
||
|
|
internal_add_vtimer(timer);
|
||
|
|
spin_unlock_irqrestore(&virt_timer_lock, flags);
|
||
|
|
return rc;
|
||
|
|
}
|
||
|
|
|
||
|
|
/*
|
||
|
|
* returns whether it has modified a pending timer (1) or not (0)
|
||
|
|
*/
|
||
|
|
int mod_virt_timer(struct vtimer_list *timer, u64 expires)
|
||
|
|
{
|
||
|
|
return __mod_vtimer(timer, expires, 0);
|
||
|
|
}
|
||
|
|
EXPORT_SYMBOL(mod_virt_timer);
|
||
|
|
|
||
|
|
/*
|
||
|
|
* returns whether it has modified a pending timer (1) or not (0)
|
||
|
|
*/
|
||
|
|
int mod_virt_timer_periodic(struct vtimer_list *timer, u64 expires)
|
||
|
|
{
|
||
|
|
return __mod_vtimer(timer, expires, 1);
|
||
|
|
}
|
||
|
|
EXPORT_SYMBOL(mod_virt_timer_periodic);
|
||
|
|
|
||
|
|
/*
|
||
|
|
* Delete a virtual timer.
|
||
|
|
*
|
||
|
|
* returns whether the deleted timer was pending (1) or not (0)
|
||
|
|
*/
|
||
|
|
int del_virt_timer(struct vtimer_list *timer)
|
||
|
|
{
|
||
|
|
unsigned long flags;
|
||
|
|
|
||
|
|
if (!vtimer_pending(timer))
|
||
|
|
return 0;
|
||
|
|
spin_lock_irqsave(&virt_timer_lock, flags);
|
||
|
|
list_del_init(&timer->entry);
|
||
|
|
spin_unlock_irqrestore(&virt_timer_lock, flags);
|
||
|
|
return 1;
|
||
|
|
}
|
||
|
|
EXPORT_SYMBOL(del_virt_timer);
|
||
|
|
|
||
|
|
/*
|
||
|
|
* Start the virtual CPU timer on the current CPU.
|
||
|
|
*/
|
||
|
|
void vtime_init(void)
|
||
|
|
{
|
||
|
|
/* set initial cpu timer */
|
||
|
|
set_vtimer(VTIMER_MAX_SLICE);
|
||
|
|
/* Setup initial MT scaling values */
|
||
|
|
if (smp_cpu_mtid) {
|
||
|
|
__this_cpu_write(mt_scaling_jiffies, jiffies);
|
||
|
|
__this_cpu_write(mt_scaling_mult, 1);
|
||
|
|
__this_cpu_write(mt_scaling_div, 1);
|
||
|
|
stcctm5(smp_cpu_mtid + 1, this_cpu_ptr(mt_cycles));
|
||
|
|
}
|
||
|
|
}
|