The patch titled
cpu-timers: simplify RLIMIT_CPU handling
has been added to the -mm tree. Its filename is
cpu-timers-simplify-rlimit_cpu-handling.patch
Before you just go and hit "reply", please:
a) Consider who else should be cc'ed
b) Prefer to cc a suitable mailing list as well
c) Ideally: find the original patch on the mailing list and do a
reply-to-all to that, adding suitable additional cc's
*** Remember to use Documentation/SubmitChecklist when testing your code ***
See http://userweb.kernel.org/~akpm/stuff/added-to-mm.txt to find
out what to do about this
The current -mm tree may be found at http://userweb.kernel.org/~akpm/mmotm/
------------------------------------------------------
Subject: cpu-timers: simplify RLIMIT_CPU handling
From: Stanislaw Gruszka <sgruszka@xxxxxxxxxx>
Let always set signal->cputime_expires expiration cache when setting new
itimer, POSIX 1.b timer, and RLIMIT_CPU. Since we are initializing
prof_exp expiration cache during fork(), this allow to remove "RLIMIT_CPU
!= inf" check from fastpath_timer_check() and do some other cleanups.
Checked against regression using test cases from:
http://marc.info/?l=linux-kernel&m=123749066504641&w=4
http://marc.info/?l=linux-kernel&m=123811277916642&w=2
Signed-off-by: Stanislaw Gruszka <sgruszka@xxxxxxxxxx>
Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Cc: Ingo Molnar <mingo@xxxxxxx>
Cc: Oleg Nesterov <oleg@xxxxxxxxxx>
Cc: Peter Zijlstra <a.p.zijlstra@xxxxxxxxx>
Cc: Hidetoshi Seto <seto.hidetoshi@xxxxxxxxxxxxxx>
Cc: Balbir Singh <balbir@xxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
kernel/posix-cpu-timers.c | 74 ++++++++++++------------------------
1 file changed, 26 insertions(+), 48 deletions(-)
diff -puN kernel/posix-cpu-timers.c~cpu-timers-simplify-rlimit_cpu-handling kernel/posix-cpu-timers.c
--- a/kernel/posix-cpu-timers.c~cpu-timers-simplify-rlimit_cpu-handling
+++ a/kernel/posix-cpu-timers.c
@@ -11,19 +11,17 @@
#include <trace/events/timer.h>
/*
- * Called after updating RLIMIT_CPU to set timer expiration if necessary.
+ * Called after updating RLIMIT_CPU to run cpu timer and update
+ * tsk->signal->cputime_expires expiration cache if necessary. Needs siglock
+ * protection since other code may update expiration cache as well.
*/
void update_rlimit_cpu(struct task_struct *task, unsigned long rlim_new)
{
cputime_t cputime = secs_to_cputime(rlim_new);
- struct signal_struct *const sig = task->signal;
- if (cputime_eq(sig->it[CPUCLOCK_PROF].expires, cputime_zero) ||
- cputime_gt(sig->it[CPUCLOCK_PROF].expires, cputime)) {
- spin_lock_irq(&task->sighand->siglock);
- set_process_cpu_timer(task, CPUCLOCK_PROF, &cputime, NULL);
- spin_unlock_irq(&task->sighand->siglock);
- }
+ spin_lock_irq(&task->sighand->siglock);
+ set_process_cpu_timer(task, CPUCLOCK_PROF, &cputime, NULL);
+ spin_unlock_irq(&task->sighand->siglock);
}
static int check_clock(const clockid_t which_clock)
@@ -564,7 +562,6 @@ static void arm_timer(struct k_itimer *t
struct list_head *head, *listpos;
struct cpu_timer_list *const nt = &timer->it.cpu;
struct cpu_timer_list *next;
- unsigned long i;
head = (CPUCLOCK_PERTHREAD(timer->it_clock) ?
p->cpu_timers : p->signal->cpu_timers);
@@ -630,20 +627,11 @@ static void arm_timer(struct k_itimer *t
default:
BUG();
case CPUCLOCK_VIRT:
- if (expires_le(sig->it[CPUCLOCK_VIRT].expires,
- exp->cpu))
- break;
- sig->cputime_expires.virt_exp = exp->cpu;
- break;
+ if (expires_gt(sig->cputime_expires.virt_exp, exp->cpu))
+ sig->cputime_expires.virt_exp = exp->cpu;
case CPUCLOCK_PROF:
- if (expires_le(sig->it[CPUCLOCK_PROF].expires,
- exp->cpu))
- break;
- i = sig->rlim[RLIMIT_CPU].rlim_cur;
- if (i != RLIM_INFINITY &&
- i <= cputime_to_secs(exp->cpu))
- break;
- sig->cputime_expires.prof_exp = exp->cpu;
+ if (expires_gt(sig->cputime_expires.prof_exp, exp->cpu))
+ sig->cputime_expires.prof_exp = exp->cpu;
break;
case CPUCLOCK_SCHED:
sig->cputime_expires.sched_exp = exp->sched;
@@ -1386,7 +1374,7 @@ static inline int fastpath_timer_check(s
return 1;
}
- return sig->rlim[RLIMIT_CPU].rlim_cur != RLIM_INFINITY;
+ return 0;
}
/*
@@ -1452,21 +1440,23 @@ void run_posix_cpu_timers(struct task_st
}
/*
- * Set one of the process-wide special case CPU timers.
+ * Set one of the process-wide special case CPU timers or RLIMIT_CPU.
* The tsk->sighand->siglock must be held by the caller.
- * The *newval argument is relative and we update it to be absolute, *oldval
- * is absolute and we update it to be relative.
*/
void set_process_cpu_timer(struct task_struct *tsk, unsigned int clock_idx,
cputime_t *newval, cputime_t *oldval)
{
union cpu_time_count now;
- struct list_head *head;
BUG_ON(clock_idx == CPUCLOCK_SCHED);
cpu_timer_sample_group(clock_idx, tsk, &now);
if (oldval) {
+ /*
+ * We are setting itimer. The *oldval is absolute and we update
+ * it to be relative, *newval argument is relative and we update
+ * it to be absolute.
+ */
if (!cputime_eq(*oldval, cputime_zero)) {
if (cputime_le(*oldval, now.cpu)) {
/* Just about to fire. */
@@ -1479,33 +1469,21 @@ void set_process_cpu_timer(struct task_s
if (cputime_eq(*newval, cputime_zero))
return;
*newval = cputime_add(*newval, now.cpu);
-
- /*
- * If the RLIMIT_CPU timer will expire before the
- * ITIMER_PROF timer, we have nothing else to do.
- */
- if (tsk->signal->rlim[RLIMIT_CPU].rlim_cur
- < cputime_to_secs(*newval))
- return;
}
/*
- * Check whether there are any process timers already set to fire
- * before this one. If so, we don't have anything more to do.
+ * Update expiration cache if we are the earliest timer, or eventually
+ * RLIMIT_CPU limit is earlier than prof_exp cpu timer expire.
*/
- head = &tsk->signal->cpu_timers[clock_idx];
- if (list_empty(head) ||
- cputime_ge(list_first_entry(head,
- struct cpu_timer_list, entry)->expires.cpu,
- *newval)) {
- switch (clock_idx) {
- case CPUCLOCK_PROF:
+ switch (clock_idx) {
+ case CPUCLOCK_PROF:
+ if (expires_gt(tsk->signal->cputime_expires.prof_exp, *newval))
tsk->signal->cputime_expires.prof_exp = *newval;
- break;
- case CPUCLOCK_VIRT:
+ break;
+ case CPUCLOCK_VIRT:
+ if (expires_gt(tsk->signal->cputime_expires.virt_exp, *newval))
tsk->signal->cputime_expires.virt_exp = *newval;
- break;
- }
+ break;
}
}
_
Patches currently in -mm which might be from sgruszka@xxxxxxxxxx are
posix-cpu-timers-reset-expire-cache-when-no-timer-is-running.patch
cpu-timers-simplify-rlimit_cpu-handling.patch
cpu-timers-cleanup-arm_timer.patch
cpu-timers-return-correct-previous-timer-reload-value.patch
cpu-timers-change-sigev_none-timer-implementation.patch
cpu-timers-assure-to-not-iterate-over-all-threads-in-fastpath_timer_check.patch
cpu-timers-optimize-run_posix_cpu_timers.patch
--
To unsubscribe from this list: send the line "unsubscribe mm-commits" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
