From: "Michael S. Tsirkin" <mst@redhat.com>
To: Peter Zijlstra <peterz@infradead.org>
Cc: Davidlohr Bueso <dave@stgolabs.net>,
Davidlohr Bueso <dbueso@suse.de>,
the arch/x86 maintainers <x86@kernel.org>,
linux-kernel@vger.kernel.org,
virtualization <virtualization@lists.linux-foundation.org>,
Borislav Petkov <bp@alien8.de>, "H. Peter Anvin" <hpa@zytor.com>,
Thomas Gleixner <tglx@linutronix.de>,
"Paul E. McKenney" <paulmck@linux.vnet.ibm.com>,
Linus Torvalds <torvalds@linux-foundation.org>,
Ingo Molnar <mingo@kernel.org>
Subject: Re: [PATCH v2 0/3] x86: faster mb()+other barrier.h tweaks
Date: Wed, 27 Jan 2016 16:18:45 +0200 [thread overview]
Message-ID: <20160127161731-mutt-send-email-mst@redhat.com> (raw)
In-Reply-To: <20160127141409.GQ6357@twins.programming.kicks-ass.net>
On Wed, Jan 27, 2016 at 03:14:09PM +0100, Peter Zijlstra wrote:
> On Wed, Jan 27, 2016 at 04:07:56PM +0200, Michael S. Tsirkin wrote:
> > mwait_idle is the only one that calls smp_mb and not mb()
> > I couldn't figure out why - original patches did mb()
> > there.
>
> That probably wants changing. That said, running UP kernels on affected
> hardware is 'unlikely' :-)
OK that's nice. After changing that one place, everyone calls
mb() around clflush so it should be safe to change smp_mb away
from mfence without breaking things.
I'm testing v4 that does this.
--
MST
WARNING: multiple messages have this Message-ID (diff)
From: "Michael S. Tsirkin" <mst@redhat.com>
To: Peter Zijlstra <peterz@infradead.org>
Cc: "H. Peter Anvin" <hpa@zytor.com>,
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>,
virtualization <virtualization@lists.linux-foundation.org>,
Borislav Petkov <bp@alien8.de>
Subject: Re: [PATCH v2 0/3] x86: faster mb()+other barrier.h tweaks
Date: Wed, 27 Jan 2016 16:18:45 +0200 [thread overview]
Message-ID: <20160127161731-mutt-send-email-mst@redhat.com> (raw)
In-Reply-To: <20160127141409.GQ6357@twins.programming.kicks-ass.net>
On Wed, Jan 27, 2016 at 03:14:09PM +0100, Peter Zijlstra wrote:
> On Wed, Jan 27, 2016 at 04:07:56PM +0200, Michael S. Tsirkin wrote:
> > mwait_idle is the only one that calls smp_mb and not mb()
> > I couldn't figure out why - original patches did mb()
> > there.
>
> That probably wants changing. That said, running UP kernels on affected
> hardware is 'unlikely' :-)
OK that's nice. After changing that one place, everyone calls
mb() around clflush so it should be safe to change smp_mb away
from mfence without breaking things.
I'm testing v4 that does this.
--
MST
next prev parent reply other threads:[~2016-01-27 14:18 UTC|newest]
Thread overview: 26+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-01-12 22:10 [PATCH v2 0/3] x86: faster mb()+other barrier.h tweaks Michael S. Tsirkin
2016-01-12 22:10 ` Michael S. Tsirkin
2016-01-12 22:10 ` [PATCH v2 1/3] x86: drop mfence in favor of lock+addl Michael S. Tsirkin
2016-01-12 22:10 ` Michael S. Tsirkin
2016-01-12 22:10 ` [PATCH v2 2/3] x86: drop a comment left over from X86_OOSTORE Michael S. Tsirkin
2016-01-12 22:10 ` Michael S. Tsirkin
2016-01-12 22:25 ` One Thousand Gnomes
2016-01-12 22:25 ` One Thousand Gnomes
2016-01-12 22:10 ` [PATCH v2 3/3] x86: tweak the comment about use of wmb for IO Michael S. Tsirkin
2016-01-12 22:10 ` Michael S. Tsirkin
2016-01-12 22:25 ` [PATCH v2 0/3] x86: faster mb()+other barrier.h tweaks H. Peter Anvin
2016-01-12 22:25 ` H. Peter Anvin
2016-01-26 8:20 ` Michael S. Tsirkin
2016-01-26 8:20 ` Michael S. Tsirkin
2016-01-26 21:37 ` H. Peter Anvin
2016-01-26 21:37 ` H. Peter Anvin
2016-01-27 14:07 ` Michael S. Tsirkin
2016-01-27 14:07 ` Michael S. Tsirkin
2016-01-27 14:14 ` Peter Zijlstra
2016-01-27 14:14 ` Peter Zijlstra
2016-01-27 14:18 ` Michael S. Tsirkin [this message]
2016-01-27 14:18 ` Michael S. Tsirkin
2018-10-11 17:37 ` Andres Freund
2018-10-11 18:11 ` Michael S. Tsirkin
2018-10-11 18:11 ` Michael S. Tsirkin
2018-10-11 18:21 ` Andres Freund
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