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From: Peter Zijlstra <peterz@infradead.org>
To: "Michael S. Tsirkin" <mst@redhat.com>
Cc: linux-kernel@vger.kernel.org,
	Linus Torvalds <torvalds@linux-foundation.org>,
	Davidlohr Bueso <dave@stgolabs.net>,
	Ingo Molnar <mingo@kernel.org>,
	Thomas Gleixner <tglx@linutronix.de>,
	"Paul E. McKenney" <paulmck@linux.vnet.ibm.com>,
	the arch/x86 maintainers <x86@kernel.org>,
	Davidlohr Bueso <dbueso@suse.de>,
	"H. Peter Anvin" <hpa@zytor.com>,
	virtualization <virtualization@lists.linux-foundation.org>,
	Borislav Petkov <bp@alien8.de>,
	Mike Galbraith <bitbucket@online.de>,
	Ingo Molnar <mingo@redhat.com>, Andy Lutomirski <luto@kernel.org>,
	Oleg Nesterov <oleg@redhat.com>, Len Brown <len.brown@intel.com>
Subject: Re: [PATCH v5 4/5] x86: use mb() around clflush
Date: Thu, 28 Jan 2016 19:25:41 +0100	[thread overview]
Message-ID: <20160128182541.GW6356@twins.programming.kicks-ass.net> (raw)
In-Reply-To: <1453921746-16178-5-git-send-email-mst@redhat.com>

On Thu, Jan 28, 2016 at 07:02:51PM +0200, Michael S. Tsirkin wrote:
> commit f8e617f4582995f7c25ef25b4167213120ad122b ("sched/idle/x86:
> Optimize unnecessary mwait_idle() resched IPIs") adds
> memory barriers around clflush, but this seems wrong
> for UP since barrier() has no effect on clflush.
> We really want mfence so switch to mb() instead.
> 
> Cc: Mike Galbraith <bitbucket@online.de>
> Signed-off-by: Michael S. Tsirkin <mst@redhat.com>

Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>

  reply	other threads:[~2016-01-28 18:25 UTC|newest]

Thread overview: 11+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2016-01-28 17:02 [PATCH v5 0/5] x86: faster smp_mb()+documentation tweaks Michael S. Tsirkin
2016-01-28 17:02 ` [PATCH v5 1/5] x86: add cc clobber for addl Michael S. Tsirkin
2016-01-29 11:32   ` [tip:locking/core] locking/x86: Add cc clobber for ADDL tip-bot for Michael S. Tsirkin
2016-01-28 17:02 ` [PATCH v5 2/5] x86: drop a comment left over from X86_OOSTORE Michael S. Tsirkin
2016-01-29 11:32   ` [tip:locking/core] locking/x86: Drop " tip-bot for Michael S. Tsirkin
2016-01-28 17:02 ` [PATCH v5 3/5] x86: tweak the comment about use of wmb for IO Michael S. Tsirkin
2016-01-29 11:32   ` [tip:locking/core] locking/x86: Tweak the comment about use of wmb() " tip-bot for Michael S. Tsirkin
2016-01-28 17:02 ` [PATCH v5 4/5] x86: use mb() around clflush Michael S. Tsirkin
2016-01-28 18:25   ` Peter Zijlstra [this message]
2016-01-29 11:33   ` [tip:locking/core] locking/x86: Use mb() around clflush() tip-bot for Michael S. Tsirkin
2016-01-28 17:02 ` [PATCH v5 5/5] x86: drop mfence in favor of lock+addl Michael S. Tsirkin

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