From mboxrd@z Thu Jan 1 00:00:00 1970 Message-ID: <42C0E173.30406@yahoo.com.au> Date: Tue, 28 Jun 2005 15:34:43 +1000 From: Nick Piggin MIME-Version: 1.0 Subject: Re: [patch 2] mm: speculative get_page References: <42C0AAF8.5090700@yahoo.com.au> <20050628040608.GQ3334@holomorphy.com> <42C0D717.2080100@yahoo.com.au> <20050627.220827.21920197.davem@davemloft.net> In-Reply-To: <20050627.220827.21920197.davem@davemloft.net> Content-Type: text/plain; charset=us-ascii; format=flowed Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org Return-Path: To: "David S. Miller" Cc: wli@holomorphy.com, linux-kernel@vger.kernel.org, linux-mm@kvack.org List-ID: David S. Miller wrote: >From: Nick Piggin >Subject: Re: [patch 2] mm: speculative get_page >Date: Tue, 28 Jun 2005 14:50:31 +1000 > > >>William Lee Irwin III wrote: >> >> >>>On Tue, Jun 28, 2005 at 11:42:16AM +1000, Nick Piggin wrote: >>> >>>spin_unlock() does not imply a memory barrier. >>> >>> >>Intriguing... >> > >BTW, I disagree with this assertion. spin_unlock() does imply a >memory barrier. > >All memory operations before the release of the lock must execute >before the lock release memory operation is globally visible. > Yes, it appears that way from looking at a sample set of arch code too (ie. those without strictly ordered stores put an explicit barrier there). I've always understood spin_unlock to imply a barrier. Send instant messages to your online friends http://au.messenger.yahoo.com -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: aart@kvack.org