From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753003AbZIZVcH (ORCPT ); Sat, 26 Sep 2009 17:32:07 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1752780AbZIZVcF (ORCPT ); Sat, 26 Sep 2009 17:32:05 -0400 Received: from one.firstfloor.org ([213.235.205.2]:51947 "EHLO one.firstfloor.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752712AbZIZVcE (ORCPT ); Sat, 26 Sep 2009 17:32:04 -0400 Date: Sat, 26 Sep 2009 23:32:04 +0200 From: Andi Kleen To: Nick Piggin Cc: Hugh Dickins , Wu Fengguang , Andrew Morton , Andi Kleen , linux-mm@kvack.org, LKML Subject: Re: [RFC][PATCH] HWPOISON: remove the unsafe __set_page_locked() Message-ID: <20090926213204.GX30185@one.firstfloor.org> References: <20090926031537.GA10176@localhost> <20090926190645.GB14368@wotan.suse.de> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20090926190645.GB14368@wotan.suse.de> User-Agent: Mutt/1.4.2.2i Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org > This is a bit tricky to do right now; you have a chicken and egg > problem between locking the page and pinning the inode mapping. One possibly simple solution would be to just allocate the page locked (GFP_LOCKED). When the allocator clears the flags it already modifies the state, so it could as well set the lock bit too. No atomics needed. And then clearing it later is also atomic free. Would that satisfy the concerns? Again another way is to just ignore it. -Andi