From: tip-bot for Pan Xinhui <tipbot@zytor.com>
To: linux-tip-commits@vger.kernel.org
Cc: hpa@zytor.com, xinhui.pan@linux.vnet.ibm.com,
torvalds@linux-foundation.org, peterz@infradead.org,
linux-kernel@vger.kernel.org, mingo@kernel.org,
tglx@linutronix.de
Subject: [tip:locking/core] locking/pvqspinlock: Don't wait if vCPU is preempted
Date: Thu, 12 Jan 2017 02:06:45 -0800 [thread overview]
Message-ID: <tip-75437bb304b20a2b350b9a8e9f9238d5e24e12ba@git.kernel.org> (raw)
In-Reply-To: <1484035006-6787-1-git-send-email-xinhui.pan@linux.vnet.ibm.com>
Commit-ID: 75437bb304b20a2b350b9a8e9f9238d5e24e12ba
Gitweb: http://git.kernel.org/tip/75437bb304b20a2b350b9a8e9f9238d5e24e12ba
Author: Pan Xinhui <xinhui.pan@linux.vnet.ibm.com>
AuthorDate: Tue, 10 Jan 2017 02:56:46 -0500
Committer: Ingo Molnar <mingo@kernel.org>
CommitDate: Thu, 12 Jan 2017 09:35:57 +0100
locking/pvqspinlock: Don't wait if vCPU is preempted
If prev node is not in running state or its vCPU is preempted, we can give
up our vCPU slices in pv_wait_node() ASAP.
Signed-off-by: Pan Xinhui <xinhui.pan@linux.vnet.ibm.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: longman@redhat.com
Link: http://lkml.kernel.org/r/1484035006-6787-1-git-send-email-xinhui.pan@linux.vnet.ibm.com
[ Fixed typos in the changelog, removed ugly linebreak from the code. ]
Signed-off-by: Ingo Molnar <mingo@kernel.org>
---
kernel/locking/qspinlock_paravirt.h | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/kernel/locking/qspinlock_paravirt.h b/kernel/locking/qspinlock_paravirt.h
index e3b5520..e6b2f7a 100644
--- a/kernel/locking/qspinlock_paravirt.h
+++ b/kernel/locking/qspinlock_paravirt.h
@@ -263,7 +263,7 @@ pv_wait_early(struct pv_node *prev, int loop)
if ((loop & PV_PREV_CHECK_MASK) != 0)
return false;
- return READ_ONCE(prev->state) != vcpu_running;
+ return READ_ONCE(prev->state) != vcpu_running || vcpu_is_preempted(prev->cpu);
}
/*
prev parent reply other threads:[~2017-01-12 10:07 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-01-10 7:56 [PATCH v2] locking/pvqspinlock: Wait early " Pan Xinhui
2017-01-12 10:06 ` tip-bot for Pan Xinhui [this message]
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