From: Peter Zijlstra <peterz@infradead.org>
To: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Will Deacon <will.deacon@arm.com>,
Stephen Rothwell <sfr@canb.auug.org.au>,
Christian Borntraeger <borntraeger@de.ibm.com>,
Thomas Gleixner <tglx@linutronix.de>, Ingo Molnar <mingo@elte.hu>,
"H. Peter Anvin" <hpa@zytor.com>,
"linux-next@vger.kernel.org" <linux-next@vger.kernel.org>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
Davidlohr Bueso <dave@stgolabs.net>,
Paul McKenney <paulmck@linux.vnet.ibm.com>
Subject: Re: linux-next: build warnings after merge of the access_once tree
Date: Thu, 26 Mar 2015 17:44:42 +0100 [thread overview]
Message-ID: <20150326164441.GH24151@twins.programming.kicks-ass.net> (raw)
In-Reply-To: <20150326163647.GC21418@twins.programming.kicks-ass.net>
On Thu, Mar 26, 2015 at 05:36:47PM +0100, Peter Zijlstra wrote:
> Can't we make an argument that these barrier calls are not required? The
> memcpy() call already guarantees we emit the loads and its opaque so the
> compiler cannot 'cache' the value. So I see not immediate reason for the
> dual memory clobber.
Oh wait, it needs to reassess the content of the target variable after
the memcpy of course.
Could we then at least make the 64bit case unconditional as well?
next prev parent reply other threads:[~2015-03-26 16:44 UTC|newest]
Thread overview: 22+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-03-26 8:31 linux-next: build warnings after merge of the access_once tree Stephen Rothwell
2015-03-26 10:11 ` Christian Borntraeger
2015-03-26 10:34 ` Peter Zijlstra
2015-03-26 13:27 ` Will Deacon
2015-03-26 14:22 ` Peter Zijlstra
2015-03-26 14:41 ` Will Deacon
2015-03-26 14:51 ` Peter Zijlstra
2015-03-26 15:08 ` Will Deacon
2015-03-26 16:15 ` Linus Torvalds
2015-03-26 16:21 ` Linus Torvalds
2015-03-26 16:36 ` Peter Zijlstra
2015-03-26 16:44 ` Peter Zijlstra [this message]
2015-03-26 16:45 ` Peter Zijlstra
[not found] ` <CA+55aFw1WHJqSj+z-mJGY-kxrg_OsGp9jK9VBi+wB4zPgCkv_w@mail.gmail.com>
2015-03-26 17:07 ` Peter Zijlstra
2015-03-26 17:17 ` Will Deacon
2015-03-26 17:23 ` Christian Borntraeger
2015-03-26 19:42 ` Christian Borntraeger
2015-03-26 16:28 ` Peter Zijlstra
[not found] ` <CA+55aFzUPPSHakwbp-Y-SaXB+o1=V6rOknz7L3AYNXNPU1MSfg@mail.gmail.com>
2015-03-26 17:12 ` Paul E. McKenney
2015-03-26 17:24 ` Christian Borntraeger
2015-03-26 17:52 ` Linus Torvalds
2015-03-26 18:54 ` Christian Borntraeger
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