From mboxrd@z Thu Jan 1 00:00:00 1970 Date: Tue, 28 Jun 2005 07:19:03 -0700 From: William Lee Irwin III Subject: Re: [patch 2] mm: speculative get_page Message-ID: <20050628141903.GR3334@holomorphy.com> References: <42C0AAF8.5090700@yahoo.com.au> <20050628040608.GQ3334@holomorphy.com> <42C0D717.2080100@yahoo.com.au> <20050627.220827.21920197.davem@davemloft.net> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20050627.220827.21920197.davem@davemloft.net> Sender: owner-linux-mm@kvack.org Return-Path: To: "David S. Miller" Cc: nickpiggin@yahoo.com.au, linux-kernel@vger.kernel.org, linux-mm@kvack.org List-ID: On Mon, Jun 27, 2005 at 10:08:27PM -0700, David S. Miller wrote: > 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. The affected architectures have only recently changed in this regard. ppc64 was the most notable case, where it had a barrier for MMIO (eieio) but not a general memory barrier. PA-RISC likewise formerly had no such barrier and was a more normal case, with no barrier whatsoever. Both have since been altered, ppc64 acquiring a heavyweight sync (arch nomenclature), and PA-RISC acquiring 2 memory barriers. -- wli -- 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