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Subject[PATCH] core: posix-cpu-timers, cleanup rlimits usage
Date
Fetch rlimit (both hard and soft) values only once and work on them.
It removes many accesses through sig structure and makes the code
cleaner.

Mostly a preparation for writable resource limits support.

Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Peter Zijlstra <peterz@infradead.org>
---
kernel/posix-cpu-timers.c | 32 +++++++++++++++++---------------
1 files changed, 17 insertions(+), 15 deletions(-)
diff --git a/kernel/posix-cpu-timers.c b/kernel/posix-cpu-timers.c
index 438ff45..de7bdb3 100644
--- a/kernel/posix-cpu-timers.c
+++ b/kernel/posix-cpu-timers.c
@@ -982,6 +982,7 @@ static void check_thread_timers(struct task_struct *tsk,
int maxfire;
struct list_head *timers = tsk->cpu_timers;
struct signal_struct *const sig = tsk->signal;
+ unsigned long soft;

maxfire = 20;
tsk->cputime_expires.prof_exp = cputime_zero;
@@ -1030,9 +1031,9 @@ static void check_thread_timers(struct task_struct *tsk,
/*
* Check for the special case thread timers.
*/
- if (sig->rlim[RLIMIT_RTTIME].rlim_cur != RLIM_INFINITY) {
+ soft = sig->rlim[RLIMIT_RTTIME].rlim_cur;
+ if (soft != RLIM_INFINITY) {
unsigned long hard = sig->rlim[RLIMIT_RTTIME].rlim_max;
- unsigned long *soft = &sig->rlim[RLIMIT_RTTIME].rlim_cur;

if (hard != RLIM_INFINITY &&
tsk->rt.timeout > DIV_ROUND_UP(hard, USEC_PER_SEC/HZ)) {
@@ -1043,14 +1044,13 @@ static void check_thread_timers(struct task_struct *tsk,
__group_send_sig_info(SIGKILL, SEND_SIG_PRIV, tsk);
return;
}
- if (tsk->rt.timeout > DIV_ROUND_UP(*soft, USEC_PER_SEC/HZ)) {
+ if (tsk->rt.timeout > DIV_ROUND_UP(soft, USEC_PER_SEC/HZ)) {
/*
* At the soft limit, send a SIGXCPU every second.
*/
- if (sig->rlim[RLIMIT_RTTIME].rlim_cur
- < sig->rlim[RLIMIT_RTTIME].rlim_max) {
- sig->rlim[RLIMIT_RTTIME].rlim_cur +=
- USEC_PER_SEC;
+ if (soft < hard) {
+ soft += USEC_PER_SEC;
+ sig->rlim[RLIMIT_RTTIME].rlim_cur = soft;
}
printk(KERN_INFO
"RT Watchdog Timeout: %s[%d]\n",
@@ -1121,13 +1121,14 @@ static void check_process_timers(struct task_struct *tsk,
unsigned long long sum_sched_runtime, sched_expires;
struct list_head *timers = sig->cpu_timers;
struct task_cputime cputime;
+ unsigned long cpu_cur_lim = sig->rlim[RLIMIT_CPU].rlim_cur;

/*
* Don't sample the current process CPU clocks if there are no timers.
*/
if (list_empty(&timers[CPUCLOCK_PROF]) &&
cputime_eq(sig->it[CPUCLOCK_PROF].expires, cputime_zero) &&
- sig->rlim[RLIMIT_CPU].rlim_cur == RLIM_INFINITY &&
+ cpu_cur_lim == RLIM_INFINITY &&
list_empty(&timers[CPUCLOCK_VIRT]) &&
cputime_eq(sig->it[CPUCLOCK_VIRT].expires, cputime_zero) &&
list_empty(&timers[CPUCLOCK_SCHED])) {
@@ -1194,10 +1195,11 @@ static void check_process_timers(struct task_struct *tsk,
check_cpu_itimer(tsk, &sig->it[CPUCLOCK_VIRT], &virt_expires, utime,
SIGVTALRM);

- if (sig->rlim[RLIMIT_CPU].rlim_cur != RLIM_INFINITY) {
+ if (cpu_cur_lim != RLIM_INFINITY) {
unsigned long psecs = cputime_to_secs(ptime);
+ unsigned long hard = sig->rlim[RLIMIT_CPU].rlim_max;
cputime_t x;
- if (psecs >= sig->rlim[RLIMIT_CPU].rlim_max) {
+ if (psecs >= hard) {
/*
* At the hard limit, we just die.
* No need to calculate anything else now.
@@ -1205,17 +1207,17 @@ static void check_process_timers(struct task_struct *tsk,
__group_send_sig_info(SIGKILL, SEND_SIG_PRIV, tsk);
return;
}
- if (psecs >= sig->rlim[RLIMIT_CPU].rlim_cur) {
+ if (psecs >= cpu_cur_lim) {
/*
* At the soft limit, send a SIGXCPU every second.
*/
__group_send_sig_info(SIGXCPU, SEND_SIG_PRIV, tsk);
- if (sig->rlim[RLIMIT_CPU].rlim_cur
- < sig->rlim[RLIMIT_CPU].rlim_max) {
- sig->rlim[RLIMIT_CPU].rlim_cur++;
+ if (cpu_cur_lim < hard) {
+ cpu_cur_lim++;
+ sig->rlim[RLIMIT_CPU].rlim_cur = cpu_cur_lim;
}
}
- x = secs_to_cputime(sig->rlim[RLIMIT_CPU].rlim_cur);
+ x = secs_to_cputime(cpu_cur_lim);
if (cputime_eq(prof_expires, cputime_zero) ||
cputime_lt(x, prof_expires)) {
prof_expires = x;
--
1.6.5.7


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