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From: Byungchul Park <byungchul.park@lge.com>
To: torvalds@linux-foundation.org
Cc: damien.lemoal@opensource.wdc.com, linux-ide@vger.kernel.org,
	adilger.kernel@dilger.ca, linux-ext4@vger.kernel.org,
	mingo@redhat.com, linux-kernel@vger.kernel.org,
	peterz@infradead.org, will@kernel.org, tglx@linutronix.de,
	rostedt@goodmis.org, joel@joelfernandes.org, sashal@kernel.org,
	daniel.vetter@ffwll.ch, chris@chris-wilson.co.uk,
	duyuyang@gmail.com, johannes.berg@intel.com, tj@kernel.org,
	tytso@mit.edu, willy@infradead.org, david@fromorbit.com,
	amir73il@gmail.com, bfields@fieldses.org,
	gregkh@linuxfoundation.org, kernel-team@lge.com,
	linux-mm@kvack.org, akpm@linux-foundation.org, mhocko@kernel.org,
	minchan@kernel.org, hannes@cmpxchg.org, vdavydov.dev@gmail.com,
	sj@kernel.org, jglisse@redhat.com, dennis@kernel.org,
	cl@linux.com, penberg@kernel.org, rientjes@google.com,
	vbabka@suse.cz, ngupta@vflare.org, linux-block@vger.kernel.org,
	paolo.valente@linaro.org, josef@toxicpanda.com,
	linux-fsdevel@vger.kernel.org, viro@zeniv.linux.org.uk,
	jack@suse.cz, jack@suse.com, jlayton@kernel.org,
	dan.j.williams@intel.com, hch@infradead.org, djwong@kernel.org,
	dri-devel@lists.freedesktop.org, airlied@linux.ie,
	rodrigosiqueiramelo@gmail.com, melissa.srw@gmail.com,
	hamohammed.sa@gmail.com
Subject: [PATCH v4 23/24] dept: Let it work with real sleeps in __schedule()
Date: Fri,  4 Mar 2022 16:06:42 +0900	[thread overview]
Message-ID: <1646377603-19730-24-git-send-email-byungchul.park@lge.com> (raw)
In-Reply-To: <1646377603-19730-1-git-send-email-byungchul.park@lge.com>

Dept commits the staged wait in __schedule() even if the corresponding
wake_up() has already woken up the task. Which means Dept considers the
case as a sleep. This would help Dept work for stronger detection but
also leads false positives.

It'd be better to let Dept work only with real sleeps conservatively for
now. So did it.

Signed-off-by: Byungchul Park <byungchul.park@lge.com>
---
 kernel/sched/core.c | 7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/kernel/sched/core.c b/kernel/sched/core.c
index 6a422aa..2ec7cf8 100644
--- a/kernel/sched/core.c
+++ b/kernel/sched/core.c
@@ -6192,7 +6192,12 @@ static void __sched notrace __schedule(unsigned int sched_mode)
 	local_irq_disable();
 	rcu_note_context_switch(!!sched_mode);
 
-	if (sched_mode == SM_NONE)
+	/*
+	 * Skip the commit if the current task does not actually go to
+	 * sleep.
+	 */
+	if (READ_ONCE(prev->__state) & TASK_NORMAL &&
+	    sched_mode == SM_NONE)
 		dept_ask_event_wait_commit(_RET_IP_);
 
 	/*
-- 
1.9.1


WARNING: multiple messages have this Message-ID (diff)
From: Byungchul Park <byungchul.park@lge.com>
To: torvalds@linux-foundation.org
Cc: hamohammed.sa@gmail.com, jack@suse.cz, peterz@infradead.org,
	daniel.vetter@ffwll.ch, amir73il@gmail.com, david@fromorbit.com,
	dri-devel@lists.freedesktop.org, chris@chris-wilson.co.uk,
	bfields@fieldses.org, linux-ide@vger.kernel.org,
	adilger.kernel@dilger.ca, joel@joelfernandes.org, cl@linux.com,
	will@kernel.org, duyuyang@gmail.com, sashal@kernel.org,
	paolo.valente@linaro.org, damien.lemoal@opensource.wdc.com,
	willy@infradead.org, hch@infradead.org, airlied@linux.ie,
	mingo@redhat.com, djwong@kernel.org, vdavydov.dev@gmail.com,
	rientjes@google.com, dennis@kernel.org,
	linux-ext4@vger.kernel.org, linux-mm@kvack.org,
	ngupta@vflare.org, johannes.berg@intel.com, jack@suse.com,
	dan.j.williams@intel.com, josef@toxicpanda.com,
	rostedt@goodmis.org, linux-block@vger.kernel.org,
	linux-fsdevel@vger.kernel.org, jglisse@redhat.com,
	viro@zeniv.linux.org.uk, tglx@linutronix.de, mhocko@kernel.org,
	vbabka@suse.cz, melissa.srw@gmail.com, sj@kernel.org,
	tytso@mit.edu, rodrigosiqueiramelo@gmail.com,
	kernel-team@lge.com, gregkh@linuxfoundation.org,
	jlayton@kernel.org, linux-kernel@vger.kernel.org,
	penberg@kernel.org, minchan@kernel.org, hannes@cmpxchg.org,
	tj@kernel.org, akpm@linux-foundation.org
Subject: [PATCH v4 23/24] dept: Let it work with real sleeps in __schedule()
Date: Fri,  4 Mar 2022 16:06:42 +0900	[thread overview]
Message-ID: <1646377603-19730-24-git-send-email-byungchul.park@lge.com> (raw)
In-Reply-To: <1646377603-19730-1-git-send-email-byungchul.park@lge.com>

Dept commits the staged wait in __schedule() even if the corresponding
wake_up() has already woken up the task. Which means Dept considers the
case as a sleep. This would help Dept work for stronger detection but
also leads false positives.

It'd be better to let Dept work only with real sleeps conservatively for
now. So did it.

Signed-off-by: Byungchul Park <byungchul.park@lge.com>
---
 kernel/sched/core.c | 7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/kernel/sched/core.c b/kernel/sched/core.c
index 6a422aa..2ec7cf8 100644
--- a/kernel/sched/core.c
+++ b/kernel/sched/core.c
@@ -6192,7 +6192,12 @@ static void __sched notrace __schedule(unsigned int sched_mode)
 	local_irq_disable();
 	rcu_note_context_switch(!!sched_mode);
 
-	if (sched_mode == SM_NONE)
+	/*
+	 * Skip the commit if the current task does not actually go to
+	 * sleep.
+	 */
+	if (READ_ONCE(prev->__state) & TASK_NORMAL &&
+	    sched_mode == SM_NONE)
 		dept_ask_event_wait_commit(_RET_IP_);
 
 	/*
-- 
1.9.1


  parent reply	other threads:[~2022-03-04  7:08 UTC|newest]

Thread overview: 76+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-03-04  7:06 [PATCH v4 00/24] DEPT(Dependency Tracker) Byungchul Park
2022-03-04  7:06 ` Byungchul Park
2022-03-04  7:06 ` [PATCH v4 01/24] llist: Move llist_{head,node} definition to types.h Byungchul Park
2022-03-04  7:06   ` Byungchul Park
2022-03-04  7:06 ` [PATCH v4 02/24] dept: Implement Dept(Dependency Tracker) Byungchul Park
2022-03-04  7:06   ` Byungchul Park
2022-03-09  7:21   ` kernel test robot
2022-03-09 23:43   ` kernel test robot
2022-03-04  7:06 ` [PATCH v4 03/24] dept: Embed Dept data in Lockdep Byungchul Park
2022-03-04  7:06   ` Byungchul Park
2022-03-04  7:06 ` [PATCH v4 04/24] dept: Add a API for skipping dependency check temporarily Byungchul Park
2022-03-04  7:06   ` Byungchul Park
2022-03-04  7:06 ` [PATCH v4 05/24] dept: Apply Dept to spinlock Byungchul Park
2022-03-04  7:06   ` Byungchul Park
2022-03-04  7:06 ` [PATCH v4 06/24] dept: Apply Dept to mutex families Byungchul Park
2022-03-04  7:06   ` Byungchul Park
2022-03-04  7:06 ` [PATCH v4 07/24] dept: Apply Dept to rwlock Byungchul Park
2022-03-04  7:06   ` Byungchul Park
2022-03-04  7:06 ` [PATCH v4 08/24] dept: Apply Dept to wait_for_completion()/complete() Byungchul Park
2022-03-04  7:06   ` Byungchul Park
2022-03-04  7:06 ` [PATCH v4 09/24] dept: Apply Dept to seqlock Byungchul Park
2022-03-04  7:06   ` Byungchul Park
2022-03-04  7:06 ` [PATCH v4 10/24] dept: Apply Dept to rwsem Byungchul Park
2022-03-04  7:06   ` Byungchul Park
2022-03-04  7:06 ` [PATCH v4 11/24] dept: Add proc knobs to show stats and dependency graph Byungchul Park
2022-03-04  7:06   ` Byungchul Park
2022-03-10  7:43   ` kernel test robot
2022-03-04  7:06 ` [PATCH v4 12/24] dept: Introduce split map concept and new APIs for them Byungchul Park
2022-03-04  7:06   ` Byungchul Park
2022-03-04  7:06 ` [PATCH v4 13/24] dept: Apply Dept to wait/event of PG_{locked,writeback} Byungchul Park
2022-03-04  7:06   ` [PATCH v4 13/24] dept: Apply Dept to wait/event of PG_{locked, writeback} Byungchul Park
2022-03-04  7:06 ` [PATCH v4 14/24] dept: Apply SDT to swait Byungchul Park
2022-03-04  7:06   ` Byungchul Park
2022-03-09  9:14   ` kernel test robot
2022-03-04  7:06 ` [PATCH v4 15/24] dept: Apply SDT to wait(waitqueue) Byungchul Park
2022-03-04  7:06   ` Byungchul Park
2022-03-04  7:06 ` [PATCH v4 16/24] locking/lockdep, cpu/hotplus: Use a weaker annotation in AP thread Byungchul Park
2022-03-04  7:06   ` Byungchul Park
2022-03-04 19:28   ` Sergei Shtylyov
2022-03-04 19:28     ` Sergei Shtylyov
2022-03-04 23:36     ` Byungchul Park
2022-03-04 23:36       ` Byungchul Park
2022-03-04  7:06 ` [PATCH v4 17/24] dept: Distinguish each syscall context from another Byungchul Park
2022-03-04  7:06   ` Byungchul Park
2022-03-04  7:06 ` [PATCH v4 18/24] dept: Distinguish each work " Byungchul Park
2022-03-04  7:06   ` Byungchul Park
2022-03-04  7:06 ` [PATCH v4 19/24] dept: Disable Dept within the wait_bit layer by default Byungchul Park
2022-03-04  7:06   ` Byungchul Park
2022-03-04  7:06 ` [PATCH v4 20/24] dept: Add nocheck version of init_completion() Byungchul Park
2022-03-04  7:06   ` Byungchul Park
2022-03-04  7:06 ` [PATCH v4 21/24] dept: Disable Dept on struct crypto_larval's completion for now Byungchul Park
2022-03-04  7:06   ` Byungchul Park
2022-03-04  7:06 ` [PATCH v4 22/24] dept: Don't create dependencies between different depths in any case Byungchul Park
2022-03-04  7:06   ` Byungchul Park
2022-03-04 11:39   ` Hyeonggon Yoo
2022-03-04 11:39     ` Hyeonggon Yoo
2022-03-04 23:38     ` Byungchul Park
2022-03-04 23:38       ` Byungchul Park
2022-03-04  7:06 ` Byungchul Park [this message]
2022-03-04  7:06   ` [PATCH v4 23/24] dept: Let it work with real sleeps in __schedule() Byungchul Park
2022-03-04  7:06 ` [PATCH v4 24/24] dept: Disable Dept on that map once it's been handled until next turn Byungchul Park
2022-03-04  7:06   ` Byungchul Park
2022-03-12  1:53 ` [PATCH v4 00/24] DEPT(Dependency Tracker) Hyeonggon Yoo
2022-03-12  1:53   ` Hyeonggon Yoo
2022-03-14  6:59   ` Byungchul Park
2022-03-14  6:59     ` Byungchul Park
2022-03-15 12:04     ` Hyeonggon Yoo
2022-03-15 12:04       ` Hyeonggon Yoo
2022-03-16  4:32   ` Byungchul Park
2022-03-16  4:32     ` Byungchul Park
2022-03-16  9:30     ` Hyeonggon Yoo
2022-03-16  9:30       ` Hyeonggon Yoo
2022-03-18  7:51       ` Byungchul Park
2022-03-18  7:51         ` Byungchul Park
2022-03-20 10:57         ` Byungchul Park
2022-03-20 10:57           ` Byungchul Park

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