From: Borislav Petkov <bp@alien8.de>
To: "Michael S. Tsirkin" <mst@redhat.com>
Cc: Davidlohr Bueso <dave@stgolabs.net>,
Davidlohr Bueso <dbueso@suse.de>,
Peter Zijlstra <peterz@infradead.org>,
the arch/x86 maintainers <x86@kernel.org>,
Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
Andy Lutomirski <luto@amacapital.net>,
Andy Lutomirski <luto@kernel.org>,
"H. Peter Anvin" <hpa@zytor.com>,
"Paul E. McKenney" <paulmck@linux.vnet.ibm.com>,
Thomas Gleixner <tglx@linutronix.de>,
virtualization <virtualization@lists.linux-foundation.org>,
Linus Torvalds <torvalds@linux-foundation.org>,
Ingo Molnar <mingo@kernel.org>
Subject: Re: [PATCH 3/4] x86,asm: Re-work smp_store_mb()
Date: Wed, 13 Jan 2016 17:53:20 +0100 [thread overview]
Message-ID: <20160113165319.GJ12897@pd.tnic> (raw)
In-Reply-To: <20160113184003-mutt-send-email-mst@redhat.com>
On Wed, Jan 13, 2016 at 06:42:48PM +0200, Michael S. Tsirkin wrote:
> Oh, I think this means we need a "cc" clobber.
Btw, does your microbenchmark do it too?
Because, the "cc" clobber should cause additional handling of flags,
depending on the context. It won't matter if the context doesn't need
rFLAGS handling in the benchmark but if we start using LOCK; ADD in the
kernel, I can imagine some places where mb() is used and rFLAGS are
live, causing gcc to either reorder code or stash them away...
--
Regards/Gruss,
Boris.
ECO tip #101: Trim your mails when you reply.
next prev parent reply other threads:[~2016-01-13 16:53 UTC|newest]
Thread overview: 20+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <1445975631-17047-1-git-send-email-dave@stgolabs.net>
[not found] ` <1445975631-17047-4-git-send-email-dave@stgolabs.net>
[not found] ` <CA+55aFw8d29E26o4eB8VgbZBC5Ot2y9K=T_yE5Dj0dFdyVgOUA@mail.gmail.com>
[not found] ` <20151027223744.GB11242@worktop.amr.corp.intel.com>
[not found] ` <20151102201535.GB1707@linux-uzut.site>
[not found] ` <CA+55aFynbkeuUGs9s-q+fLY6MeRBA6MjEyWWbbe7A5AaqsAknw@mail.gmail.com>
2016-01-12 13:57 ` [PATCH 3/4] x86,asm: Re-work smp_store_mb() Michael S. Tsirkin
[not found] ` <20160112150032-mutt-send-email-mst@redhat.com>
2016-01-12 17:20 ` Linus Torvalds
2016-01-12 17:45 ` Michael S. Tsirkin
2016-01-12 18:04 ` Linus Torvalds
2016-01-12 20:30 ` Andy Lutomirski
2016-01-12 20:54 ` Linus Torvalds
2016-01-12 20:59 ` Andy Lutomirski
2016-01-12 21:37 ` Linus Torvalds
2016-01-12 22:14 ` Michael S. Tsirkin
2016-01-13 16:20 ` Michael S. Tsirkin
2016-01-12 22:21 ` Michael S. Tsirkin
2016-01-12 22:55 ` H. Peter Anvin
2016-01-12 23:24 ` Linus Torvalds
[not found] ` <CA+55aFz44oYK5GD3=-Y2E7bNwmJ0Ko5GaZ+iMQDamLALiw7RqQ@mail.gmail.com>
2016-01-13 16:17 ` Borislav Petkov
2016-01-13 16:25 ` Michael S. Tsirkin
2016-01-13 16:33 ` Borislav Petkov
2016-01-13 16:42 ` Michael S. Tsirkin
2016-01-13 16:53 ` Borislav Petkov [this message]
2016-01-13 17:00 ` Michael S. Tsirkin
2016-01-13 18:38 ` Linus Torvalds
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