posix-cpu-timers: cleanup rlimits usage
Jiri Slaby [Fri, 5 Mar 2010 21:42:53 +0000 (13:42 -0800)]
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>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: john stultz <johnstul@us.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

kernel/posix-cpu-timers.c

index 438ff45..dbb16bf 100644 (file)
@@ -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",
@@ -1121,6 +1121,7 @@ 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 soft;
 
        /*
         * Don't sample the current process CPU clocks if there are no timers.
@@ -1193,11 +1194,12 @@ static void check_process_timers(struct task_struct *tsk,
                         SIGPROF);
        check_cpu_itimer(tsk, &sig->it[CPUCLOCK_VIRT], &virt_expires, utime,
                         SIGVTALRM);
-
-       if (sig->rlim[RLIMIT_CPU].rlim_cur != RLIM_INFINITY) {
+       soft = sig->rlim[RLIMIT_CPU].rlim_cur;
+       if (soft != 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 >= soft) {
                        /*
                         * 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 (soft < hard) {
+                               soft++;
+                               sig->rlim[RLIMIT_CPU].rlim_cur = soft;
                        }
                }
-               x = secs_to_cputime(sig->rlim[RLIMIT_CPU].rlim_cur);
+               x = secs_to_cputime(soft);
                if (cputime_eq(prof_expires, cputime_zero) ||
                    cputime_lt(x, prof_expires)) {
                        prof_expires = x;