linux-kernel - [PATCH v3 13/27] core: posix-cpu-timers, cleanup rlimits usage

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-Id: <1259363167-9347-13-git-send-email-jslaby@suse.cz>
Date:	Sat, 28 Nov 2009 00:05:53 +0100
From:	Jiri Slaby <jslaby@...e.cz>
To:	jirislaby@...il.com
Cc:	mingo@...e.hu, nhorman@...driver.com, sfr@...b.auug.org.au,
	linux-kernel@...r.kernel.org, akpm@...ux-foundation.org,
	marcin.slusarz@...il.com, tglx@...utronix.de, mingo@...hat.com,
	hpa@...or.com, torvalds@...ux-foundation.org, oleg@...hat.com,
	James Morris <jmorris@...ei.org>,
	Heiko Carstens <heiko.carstens@...ibm.com>,
	Peter Zijlstra <peterz@...radead.org>
Subject: [PATCH v3 13/27] core: posix-cpu-timers, cleanup rlimits usage

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@...e.cz>
Cc: James Morris <jmorris@...ei.org>
Cc: Heiko Carstens <heiko.carstens@...ibm.com>
Cc: Andrew Morton <akpm@...ux-foundation.org>
Cc: Ingo Molnar <mingo@...e.hu>
Cc: Peter Zijlstra <peterz@...radead.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 102c345..a7dcce1 100644
--- a/kernel/posix-cpu-timers.c
+++ b/kernel/posix-cpu-timers.c
@@ -983,6 +983,7 @@ 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;
@@ -1031,9 +1032,9 @@ 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)) {
@@ -1044,14 +1045,13 @@ 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",
@@ -1122,13 +1122,14 @@ 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])) {
@@ -1195,10 +1196,11 @@ 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.
@@ -1206,17 +1208,17 @@ 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;
-- 
1.6.5.3

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/