From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id ; Mon, 3 Jun 2002 06:29:04 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id ; Mon, 3 Jun 2002 06:29:03 -0400 Received: from holomorphy.com ([66.224.33.161]:18560 "EHLO holomorphy") by vger.kernel.org with ESMTP id ; Mon, 3 Jun 2002 06:29:02 -0400 Date: Mon, 3 Jun 2002 03:28:09 -0700 From: William Lee Irwin III To: Hugh Dickins Cc: linux-kernel@vger.kernel.org, trivial@rustcorp.com.au Subject: Re: remove mixture of non-atomic operations with page->flags which requires atomic operations to access Message-ID: <20020603102809.GA912@holomorphy.com> Mail-Followup-To: William Lee Irwin III , Hugh Dickins , linux-kernel@vger.kernel.org, trivial@rustcorp.com.au In-Reply-To: <20020602224422.GP14918@holomorphy.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline User-Agent: Mutt/1.3.25i Organization: The Domain of Holomorphy Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org On Sun, 2 Jun 2002, William Lee Irwin III wrote: >> page->flags is effectively a lock word as its various bits are updatable >> and accessible only by atomic operations. This patch removes the update >> of page->flags in __free_pages_ok() with non-atomic operations in favor >> of using atomic bit operations to update the bits to be cleared. >> ClearPageDirty(page); >> - page->flags &= ~(1<> + ClearPageUptodate(page); >> + ClearPageSlab(page); >> + ClearPageNosave(page); >> + ClearPageChecked(page); On Mon, Jun 03, 2002 at 11:14:43AM +0100, Hugh Dickins wrote: > Don't all those atomic volatile bitops slow down a hotpath for no real > gain? I'm all for clearing all possible flag bits at that point, but > would prefer just one mask myself. But given all the preceding tests, > and the ClearPageDirty, perhaps I'm foolish to question your additions. > And wasn't it originally clearing the referenced bit, now leaving it? > Hugh It should be clearing it, I'd retransmit if there weren't other objections to address... Cheers, Bill