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From: Thomas Gleixner <tglx@linutronix.de>
To: LKML <linux-kernel@vger.kernel.org>
Cc: Oleg Nesterov <oleg@redhat.com>, Ingo Molnar <mingo@kernel.org>,
	Peter Zijlstra <peterz@infradead.org>,
	John Stultz <john.stultz@linaro.org>,
	Frederic Weisbecker <frederic@kernel.org>,
	Anna-Maria Behnsen <anna-maria@linutronix.de>,
	Christoph Hellwig <hch@lst.de>
Subject: [patch V2 26/38] posix-cpu-timers: Make expiry checks array based
Date: Wed, 21 Aug 2019 21:09:13 +0200
Message-ID: <20190821192921.695481430@linutronix.de> (raw)
In-Reply-To: <20190821190847.665673890@linutronix.de>

The expiry cache is an array indexed by clock ids. The new sample functions
allow to retrieve a corresponding array of samples.

Convert the fastpath expiry checks to make use of the new sample functions
and do the comparisons on the sample and the expiry array.

Make the check for the expiry array being zero array based as well.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
---
 kernel/time/posix-cpu-timers.c |   85 +++++++++++++++++------------------------
 1 file changed, 36 insertions(+), 49 deletions(-)

--- a/kernel/time/posix-cpu-timers.c
+++ b/kernel/time/posix-cpu-timers.c
@@ -39,7 +39,7 @@ void posix_cputimers_group_init(struct p
 
 /*
  * Called after updating RLIMIT_CPU to run cpu timer and update
- * tsk->signal->posix_cputimers.cputime_expires expiration cache if
+ * tsk->signal->posix_cputimers.expiries expiration cache if
  * necessary. Needs siglock protection since other code may update
  * expiration cache as well.
  */
@@ -132,19 +132,9 @@ static void bump_cpu_timer(struct k_itim
 	}
 }
 
-/**
- * task_cputime_zero - Check a task_cputime struct for all zero fields.
- *
- * @cputime:	The struct to compare.
- *
- * Checks @cputime to see if all fields are zero.  Returns true if all fields
- * are zero, false if any field is nonzero.
- */
-static inline int task_cputime_zero(const struct task_cputime *cputime)
+static inline bool expiry_cache_is_zero(const u64 *ec)
 {
-	if (!cputime->utime && !cputime->stime && !cputime->sum_exec_runtime)
-		return 1;
-	return 0;
+	return !(ec[CPUCLOCK_PROF] | ec[CPUCLOCK_VIRT] | ec[CPUCLOCK_SCHED]);
 }
 
 static int
@@ -811,10 +801,10 @@ static void check_thread_timers(struct t
 		check_dl_overrun(tsk);
 
 	/*
-	 * If cputime_expires is zero, then there are no active
-	 * per thread CPU timers.
+	 * If the expiry cache is zero, then there are no active per thread
+	 * CPU timers.
 	 */
-	if (task_cputime_zero(&tsk->posix_cputimers.cputime_expires))
+	if (expiry_cache_is_zero(tsk->posix_cputimers.expiries))
 		return;
 
 	task_cputime(tsk, &utime, &stime);
@@ -860,7 +850,7 @@ static void check_thread_timers(struct t
 		}
 	}
 
-	if (task_cputime_zero(&tsk->posix_cputimers.cputime_expires))
+	if (expiry_cache_is_zero(tsk->posix_cputimers.expiries))
 		tick_dep_clear_task(tsk, TICK_DEP_BIT_POSIX_TIMER);
 }
 
@@ -983,7 +973,7 @@ static void check_process_timers(struct
 	sig->posix_cputimers.expiries[CPUCLOCK_VIRT] = virt_expires;
 	sig->posix_cputimers.expiries[CPUCLOCK_SCHED] = sched_expires;
 
-	if (task_cputime_zero(&sig->posix_cputimers.cputime_expires))
+	if (expiry_cache_is_zero(sig->posix_cputimers.expiries))
 		stop_process_timers(sig);
 
 	sig->cputimer.checking_timer = false;
@@ -1048,26 +1038,23 @@ static void posix_cpu_timer_rearm(struct
 }
 
 /**
- * task_cputime_expired - Compare two task_cputime entities.
+ * task_cputimers_expired - Compare two task_cputime entities.
  *
- * @sample:	The task_cputime structure to be checked for expiration.
- * @expires:	Expiration times, against which @sample will be checked.
+ * @samples:	Array of current samples for the CPUCLOCK clocks
+ * @expiries:	Array of expiry values for the CPUCLOCK clocks
  *
- * Checks @sample against @expires to see if any field of @sample has expired.
- * Returns true if any field of the former is greater than the corresponding
- * field of the latter if the latter field is set.  Otherwise returns false.
+ * Returns true if any mmember of @samples is greater than the corresponding
+ * member of @expiries if that member is non zero. False otherwise
  */
-static inline int task_cputime_expired(const struct task_cputime *sample,
-					const struct task_cputime *expires)
+static inline bool task_cputimers_expired(const u64 *sample, const u64 *expiries)
 {
-	if (expires->utime && sample->utime >= expires->utime)
-		return 1;
-	if (expires->stime && sample->utime + sample->stime >= expires->stime)
-		return 1;
-	if (expires->sum_exec_runtime != 0 &&
-	    sample->sum_exec_runtime >= expires->sum_exec_runtime)
-		return 1;
-	return 0;
+	int i;
+
+	for (i = 0; i < CPUCLOCK_MAX; i++) {
+		if (expiries[i] && sample[i] >= expiries[i])
+			return true;
+	}
+	return false;
 }
 
 /**
@@ -1080,18 +1067,17 @@ static inline int task_cputime_expired(c
  * timers and compare them with the corresponding expiration times.  Return
  * true if a timer has expired, else return false.
  */
-static inline int fastpath_timer_check(struct task_struct *tsk)
+static inline bool fastpath_timer_check(struct task_struct *tsk)
 {
+	u64 *expiries = tsk->posix_cputimers.expiries;
 	struct signal_struct *sig;
 
-	if (!task_cputime_zero(&tsk->posix_cputimers.cputime_expires)) {
-		struct task_cputime task_sample;
+	if (!expiry_cache_is_zero(expiries)) {
+		u64 samples[CPUCLOCK_MAX];
 
-		task_cputime(tsk, &task_sample.utime, &task_sample.stime);
-		task_sample.sum_exec_runtime = tsk->se.sum_exec_runtime;
-		if (task_cputime_expired(&task_sample,
-					 &tsk->posix_cputimers.cputime_expires))
-			return 1;
+		task_sample_cputime(tsk, samples);
+		if (task_cputimers_expired(samples, expiries))
+			return true;
 	}
 
 	sig = tsk->signal;
@@ -1111,19 +1097,20 @@ static inline int fastpath_timer_check(s
 	 */
 	if (READ_ONCE(sig->cputimer.running) &&
 	    !READ_ONCE(sig->cputimer.checking_timer)) {
-		struct task_cputime group_sample;
+		u64 samples[CPUCLOCK_MAX];
 
-		sample_cputime_atomic(&group_sample, &sig->cputimer.cputime_atomic);
+		proc_sample_cputime_atomic(&sig->cputimer.cputime_atomic,
+					   samples);
 
-		if (task_cputime_expired(&group_sample,
-					 &sig->posix_cputimers.cputime_expires))
-			return 1;
+		if (task_cputimers_expired(samples,
+					   sig->posix_cputimers.expiries))
+			return true;
 	}
 
 	if (dl_task(tsk) && tsk->dl.dl_overrun)
-		return 1;
+		return true;
 
-	return 0;
+	return false;
 }
 
 /*



  parent reply index

Thread overview: 137+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-08-21 19:08 [patch V2 00/38] posix-cpu-timers: Cleanup and consolidation Thomas Gleixner
2019-08-21 19:08 ` [patch V2 01/38] posix-cpu-timers: Provide task validation functions Thomas Gleixner
2019-08-21 22:33   ` Frederic Weisbecker
2019-08-21 23:03     ` Frederic Weisbecker
2019-08-23 15:33       ` Thomas Gleixner
2019-08-28 10:16   ` [tip: timers/core] " tip-bot2 for Thomas Gleixner
2019-08-21 19:08 ` [patch V2 02/38] posix-cpu-timers: Use common permission check in posix_cpu_clock_get() Thomas Gleixner
2019-08-21 23:40   ` Frederic Weisbecker
2019-08-28 10:16   ` [tip: timers/core] " tip-bot2 for Thomas Gleixner
2019-08-29 11:00     ` kbuild test robot
2019-08-29 11:21       ` Thomas Gleixner
2019-08-30  1:08         ` [kbuild-all] " Philip Li
2019-08-29 11:23     ` kbuild test robot
2019-08-21 19:08 ` [patch V2 03/38] posix-cpu-timers: Use common permission check in posix_cpu_timer_create() Thomas Gleixner
2019-08-21 23:49   ` Frederic Weisbecker
2019-08-28 10:16   ` [tip: timers/core] " tip-bot2 for Thomas Gleixner
2019-08-21 19:08 ` [patch V2 04/38] posix-cpu-timers: Provide quick sample function for itimer Thomas Gleixner
2019-08-22 12:13   ` Frederic Weisbecker
2019-08-28 10:16   ` [tip: timers/core] " tip-bot2 for Thomas Gleixner
2019-08-21 19:08 ` [patch V2 05/38] itimers: Use quick sample function Thomas Gleixner
2019-08-22 12:15   ` Frederic Weisbecker
2019-08-28 10:16   ` [tip: timers/core] " tip-bot2 for Thomas Gleixner
2019-08-29 23:47     ` kbuild test robot
2019-08-30  6:01       ` Thomas Gleixner
2019-08-21 19:08 ` [patch V2 06/38] posix-cpu-timers: Sample directly in timer check Thomas Gleixner
2019-08-22 12:30   ` Frederic Weisbecker
2019-08-28 10:16   ` [tip: timers/core] " tip-bot2 for Thomas Gleixner
2019-08-21 19:08 ` [patch V2 07/38] posix-cpu-timers: Rename thread_group_cputimer() and make it static Thomas Gleixner
2019-08-22 12:41   ` Frederic Weisbecker
2019-08-28 10:16   ` [tip: timers/core] " tip-bot2 for Thomas Gleixner
2019-08-21 19:08 ` [patch V2 08/38] posix-cpu-timers: Consolidate thread group sample code Thomas Gleixner
2019-08-22 13:49   ` Frederic Weisbecker
2019-08-28 10:16   ` [tip: timers/core] " tip-bot2 for Thomas Gleixner
2019-08-21 19:08 ` [patch V2 09/38] posix-cpu-timers: Use clock ID in posix_cpu_timer_set() Thomas Gleixner
2019-08-22 13:58   ` Frederic Weisbecker
2019-08-28 10:16   ` [tip: timers/core] " tip-bot2 for Thomas Gleixner
2019-08-21 19:08 ` [patch V2 10/38] posix-cpu-timers: Use clock ID in posix_cpu_timer_get() Thomas Gleixner
2019-08-22 14:07   ` Frederic Weisbecker
2019-08-28 10:16   ` [tip: timers/core] " tip-bot2 for Thomas Gleixner
2019-08-21 19:08 ` [patch V2 11/38] posix-cpu-timers: Use clock ID in posix_cpu_timer_rearm() Thomas Gleixner
2019-08-22 14:12   ` Frederic Weisbecker
2019-08-28 10:16   ` [tip: timers/core] " tip-bot2 for Thomas Gleixner
2019-08-21 19:08 ` [patch V2 12/38] posix-cpu-timers: Remove pointless return value check Thomas Gleixner
2019-08-22 14:15   ` Frederic Weisbecker
2019-08-28 10:16   ` [tip: timers/core] " tip-bot2 for Thomas Gleixner
2019-08-21 19:09 ` [patch V2 13/38] posix-cpu-timers: Simplify sample functions Thomas Gleixner
2019-08-22 14:20   ` Frederic Weisbecker
2019-08-28 10:16   ` [tip: timers/core] " tip-bot2 for Thomas Gleixner
2019-08-21 19:09 ` [patch V2 14/38] posix-cpu-timers: Get rid of pointer indirection Thomas Gleixner
2019-08-22 14:41   ` Frederic Weisbecker
2019-08-28 10:16   ` [tip: timers/core] " tip-bot2 for Thomas Gleixner
2019-08-21 19:09 ` [patch V2 15/38] posix-cpu-timers: Sample task times once in expiry check Thomas Gleixner
2019-08-22 15:00   ` Frederic Weisbecker
2019-08-28 10:16   ` [tip: timers/core] " tip-bot2 for Thomas Gleixner
2019-08-21 19:09 ` [patch V2 16/38] posix-cpu-timers: Move prof/virt_ticks into caller Thomas Gleixner
2019-08-22 15:05   ` Frederic Weisbecker
2019-08-28 10:16   ` [tip: timers/core] " tip-bot2 for Thomas Gleixner
2019-08-21 19:09 ` [patch V2 17/38] posix-cpu-timers: Create a container struct Thomas Gleixner
2019-08-22 15:32   ` Frederic Weisbecker
2019-08-23 15:34     ` Thomas Gleixner
2019-08-28 10:16   ` [tip: timers/core] " tip-bot2 for Thomas Gleixner
2019-08-21 19:09 ` [patch V2 19/38] posix-cpu-timers: Move expiry cache into struct posix_cputimers Thomas Gleixner
2019-08-22 16:29   ` Frederic Weisbecker
2019-08-28 10:16   ` [tip: timers/core] " tip-bot2 for Thomas Gleixner
2019-08-21 19:09 ` [patch V2 20/38] posix-cpu-timers: Provide array based access to expiry cache Thomas Gleixner
2019-08-23 17:33   ` Frederic Weisbecker
2019-08-28 10:16   ` [tip: timers/core] " tip-bot2 for Thomas Gleixner
2019-08-21 19:09 ` [patch V2 21/38] posix-cpu-timers: Simplify timer queueing Thomas Gleixner
2019-08-23 17:51   ` Frederic Weisbecker
2019-08-28 10:16   ` [tip: timers/core] " tip-bot2 for Thomas Gleixner
2019-08-21 19:09 ` [patch V2 22/38] posix-cpu-timers: Simplify set_process_cpu_timer() Thomas Gleixner
2019-08-23 18:00   ` Frederic Weisbecker
2019-08-28 10:16   ` [tip: timers/core] " tip-bot2 for Thomas Gleixner
2019-08-21 19:09 ` [patch V2 23/38] posix-cpu-timers: Switch check_*_timers() to array cache Thomas Gleixner
2019-08-23 18:13   ` Frederic Weisbecker
2019-08-28 10:16   ` [tip: timers/core] " tip-bot2 for Thomas Gleixner
2019-08-21 19:09 ` [patch V2 24/38] posix-cpu-timers: Remove the odd field rename defines Thomas Gleixner
2019-08-23 18:36   ` Frederic Weisbecker
2019-08-28 10:16   ` [tip: timers/core] " tip-bot2 for Thomas Gleixner
2019-08-21 19:09 ` [patch V2 25/38] posix-cpu-timers: Provide array based sample functions Thomas Gleixner
2019-08-23 22:08   ` Frederic Weisbecker
2019-08-28 10:16   ` [tip: timers/core] " tip-bot2 for Thomas Gleixner
2019-08-21 19:09 ` Thomas Gleixner [this message]
2019-08-23 22:44   ` [patch V2 26/38] posix-cpu-timers: Make expiry checks array based Frederic Weisbecker
2019-08-28 10:16   ` [tip: timers/core] " tip-bot2 for Thomas Gleixner
2019-08-21 19:09 ` [patch V2 27/38] posix-cpu-timers: Remove cputime_expires Thomas Gleixner
2019-08-23 22:50   ` Frederic Weisbecker
2019-08-28 10:16   ` [tip: timers/core] " tip-bot2 for Thomas Gleixner
2019-08-21 19:09 ` [patch V2 28/38] posix-cpu-timers: Restructure expiry array Thomas Gleixner
2019-08-26 16:32   ` Frederic Weisbecker
2019-08-26 18:16     ` Thomas Gleixner
2019-08-26 18:22       ` [patch V3 " Thomas Gleixner
2019-08-26 19:45         ` Frederic Weisbecker
2019-08-28 10:16         ` [tip: timers/core] " tip-bot2 for Thomas Gleixner
2019-08-26 21:06   ` [patch V2 28/38] " Frederic Weisbecker
2019-08-26 21:46     ` Thomas Gleixner
2019-08-21 19:09 ` [patch V2 29/38] posix-cpu-timers: Switch thread group sampling to array Thomas Gleixner
2019-08-26 21:12   ` Frederic Weisbecker
2019-08-28 10:16   ` [tip: timers/core] " tip-bot2 for Thomas Gleixner
2019-08-21 19:09 ` [patch V2 30/38] posix-cpu-timers: Respect INFINITY for hard RTTIME limit Thomas Gleixner
2019-08-26 21:19   ` Frederic Weisbecker
2019-08-28 10:16   ` [tip: timers/core] " tip-bot2 for Thomas Gleixner
2019-08-21 19:09 ` [patch V2 31/38] rlimit: Rewrite non-sensical RLIMIT_CPU comment Thomas Gleixner
2019-08-26 21:41   ` Frederic Weisbecker
2019-08-28 10:16   ` [tip: timers/core] " tip-bot2 for Thomas Gleixner
2019-08-21 19:09 ` [patch V2 32/38] posix-cpu-timers: Get rid of zero checks Thomas Gleixner
2019-08-26 21:57   ` Frederic Weisbecker
2019-08-28 10:16   ` [tip: timers/core] " tip-bot2 for Thomas Gleixner
2019-08-21 19:09 ` [patch V2 33/38] posix-cpu-timers: Consolidate timer expiry further Thomas Gleixner
2019-08-26 22:29   ` Frederic Weisbecker
2019-08-28 10:16   ` [tip: timers/core] " tip-bot2 for Thomas Gleixner
2019-08-21 19:09 ` [patch V2 34/38] posix-cpu-timers: Get rid of 64bit divisions Thomas Gleixner
2019-08-26 22:51   ` Frederic Weisbecker
2019-08-28 10:16   ` [tip: timers/core] " tip-bot2 for Thomas Gleixner
2019-08-21 19:09 ` [patch V2 35/38] posix-cpu-timers: Remove pointless comparisons Thomas Gleixner
2019-08-26 22:59   ` Frederic Weisbecker
2019-08-28 10:16   ` [tip: timers/core] " tip-bot2 for Thomas Gleixner
2019-08-21 19:09 ` [patch V2 36/38] posix-cpu-timers: Deduplicate rlimit handling Thomas Gleixner
2019-08-26 23:13   ` Frederic Weisbecker
2019-08-28 10:16   ` [tip: timers/core] " tip-bot2 for Thomas Gleixner
2019-08-21 19:09 ` [patch V2 37/38] posix-cpu-timers: Move state tracking to struct posix_cputimers Thomas Gleixner
2019-08-26 23:28   ` Frederic Weisbecker
2019-08-26 23:33     ` Thomas Gleixner
2019-08-28 10:16   ` [tip: timers/core] " tip-bot2 for Thomas Gleixner
2019-08-21 19:09 ` [patch V2 38/38] posix-cpu-timers: Utilize timerqueue for storage Thomas Gleixner
2019-08-27  0:48   ` Frederic Weisbecker
2019-08-27  6:08     ` Thomas Gleixner
2019-08-27 13:17       ` Frederic Weisbecker
2019-08-27 13:46         ` Thomas Gleixner
2019-08-27 19:31           ` [patch V3 " Thomas Gleixner
2019-08-27 22:23             ` Frederic Weisbecker
2019-08-28 10:16             ` [tip: timers/core] " tip-bot2 for Thomas Gleixner
2019-08-22  0:54 ` [patch V2 00/38] posix-cpu-timers: Cleanup and consolidation Christoph Hellwig
2019-08-22  1:02   ` Frederic Weisbecker
2019-08-22  1:02     ` Christoph Hellwig
     [not found] ` <20190821192920.909530418@linutronix.de>
2019-08-22 16:06   ` [patch V2 18/38] sched: Move struct task_cputime to types.h Frederic Weisbecker
2019-08-28 10:16   ` [tip: timers/core] " tip-bot2 for Thomas Gleixner

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