From: "tip-bot2 for Mathieu Desnoyers" <tip-bot2@linutronix.de>
To: linux-tip-commits@vger.kernel.org
Cc: Oleg Nesterov <oleg@redhat.com>,
Mathieu Desnoyers <mathieu.desnoyers@efficios.com>,
"Peter Zijlstra (Intel)" <peterz@infradead.org>,
Chris Metcalf <cmetcalf@ezchip.com>,
Christoph Lameter <cl@linux.com>,
"Eric W. Biederman" <ebiederm@xmission.com>,
Kirill Tkhai <tkhai@yandex.ru>,
Linus Torvalds <torvalds@linux-foundation.org>,
Mike Galbraith <efault@gmx.de>,
"Paul E. McKenney" <paulmck@linux.ibm.com>,
"Russell King - ARM Linux admin" <linux@armlinux.org.uk>,
Thomas Gleixner <tglx@linutronix.de>,
Ingo Molnar <mingo@kernel.org>, Borislav Petkov <bp@alien8.de>,
linux-kernel@vger.kernel.org
Subject: [tip: sched/urgent] sched/membarrier: Remove redundant check
Date: Fri, 27 Sep 2019 08:10:43 -0000 [thread overview]
Message-ID: <156957184378.9866.15796834930588841787.tip-bot2@tip-bot2> (raw)
In-Reply-To: <20190919173705.2181-3-mathieu.desnoyers@efficios.com>
The following commit has been merged into the sched/urgent branch of tip:
Commit-ID: 09554009c0cad4cb2223dd943c813c9257c6883a
Gitweb: https://git.kernel.org/tip/09554009c0cad4cb2223dd943c813c9257c6883a
Author: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
AuthorDate: Thu, 19 Sep 2019 13:37:00 -04:00
Committer: Ingo Molnar <mingo@kernel.org>
CommitterDate: Wed, 25 Sep 2019 17:42:30 +02:00
sched/membarrier: Remove redundant check
Checking that the number of threads is 1 is redundant with checking
mm_users == 1.
No change in functionality intended.
Suggested-by: Oleg Nesterov <oleg@redhat.com>
Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Chris Metcalf <cmetcalf@ezchip.com>
Cc: Christoph Lameter <cl@linux.com>
Cc: Eric W. Biederman <ebiederm@xmission.com>
Cc: Kirill Tkhai <tkhai@yandex.ru>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Paul E. McKenney <paulmck@linux.ibm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Russell King - ARM Linux admin <linux@armlinux.org.uk>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: https://lkml.kernel.org/r/20190919173705.2181-3-mathieu.desnoyers@efficios.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
---
kernel/sched/membarrier.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/kernel/sched/membarrier.c b/kernel/sched/membarrier.c
index d48b95f..7ccbd0e 100644
--- a/kernel/sched/membarrier.c
+++ b/kernel/sched/membarrier.c
@@ -186,7 +186,7 @@ static int membarrier_register_global_expedited(void)
MEMBARRIER_STATE_GLOBAL_EXPEDITED_READY)
return 0;
atomic_or(MEMBARRIER_STATE_GLOBAL_EXPEDITED, &mm->membarrier_state);
- if (atomic_read(&mm->mm_users) == 1 && get_nr_threads(p) == 1) {
+ if (atomic_read(&mm->mm_users) == 1) {
/*
* For single mm user, single threaded process, we can
* simply issue a memory barrier after setting
@@ -232,7 +232,7 @@ static int membarrier_register_private_expedited(int flags)
if (flags & MEMBARRIER_FLAG_SYNC_CORE)
atomic_or(MEMBARRIER_STATE_PRIVATE_EXPEDITED_SYNC_CORE,
&mm->membarrier_state);
- if (!(atomic_read(&mm->mm_users) == 1 && get_nr_threads(p) == 1)) {
+ if (atomic_read(&mm->mm_users) != 1) {
/*
* Ensure all future scheduler executions will observe the
* new thread flag state for this process.
next prev parent reply other threads:[~2019-09-27 8:11 UTC|newest]
Thread overview: 22+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-09-19 17:36 [RFC PATCH for 5.4 0/7] Membarrier fixes and cleanups Mathieu Desnoyers
2019-09-19 17:36 ` [RFC PATCH for 5.4 1/7] Fix: sched/membarrier: Private expedited registration check Mathieu Desnoyers
2019-09-27 8:10 ` [tip: sched/urgent] sched/membarrier: Fix private " tip-bot2 for Mathieu Desnoyers
2019-09-19 17:37 ` [RFC PATCH for 5.4 2/7] Cleanup: sched/membarrier: Remove redundant check Mathieu Desnoyers
2019-09-27 8:10 ` tip-bot2 for Mathieu Desnoyers [this message]
2019-09-19 17:37 ` [RFC PATCH for 5.4 3/7] Cleanup: sched/membarrier: Only sync_core before usermode for same mm Mathieu Desnoyers
2019-09-27 8:10 ` [tip: sched/urgent] sched/membarrier: Call sync_core only " tip-bot2 for Mathieu Desnoyers
2019-09-19 17:37 ` [RFC PATCH for 5.4 4/7] Fix: sched/membarrier: p->mm->membarrier_state racy load (v4) Mathieu Desnoyers
2019-09-27 8:10 ` [tip: sched/urgent] sched/membarrier: Fix p->mm->membarrier_state racy load tip-bot2 for Mathieu Desnoyers
2019-10-01 8:44 ` Ingo Molnar
2019-10-01 8:50 ` Peter Zijlstra
2019-10-01 19:34 ` [tip: sched/urgent] membarrier: Fix RCU locking bug caused by faulty merge tip-bot2 for Peter Zijlstra
2019-09-19 17:37 ` [RFC PATCH for 5.4 5/7] selftests: sched/membarrier: Add multi-threaded test Mathieu Desnoyers
2019-09-27 8:10 ` [tip: sched/urgent] selftests, " tip-bot2 for Mathieu Desnoyers
2019-09-19 17:37 ` [RFC PATCH for 5.4 6/7] sched/membarrier: Skip IPIs when mm->mm_users == 1 Mathieu Desnoyers
2019-09-27 8:10 ` [tip: sched/urgent] " tip-bot2 for Mathieu Desnoyers
2019-09-19 17:37 ` [RFC PATCH for 5.4 7/7] sched/membarrier: Return -ENOMEM to userspace on memory allocation failure Mathieu Desnoyers
2019-09-27 8:10 ` [tip: sched/urgent] " tip-bot2 for Mathieu Desnoyers
2019-09-23 9:06 ` [RFC PATCH for 5.4 0/7] Membarrier fixes and cleanups Peter Zijlstra
2019-09-23 14:55 ` Mathieu Desnoyers
2019-09-25 8:07 ` Peter Zijlstra
2019-09-25 15:50 ` Mathieu Desnoyers
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