From mboxrd@z Thu Jan 1 00:00:00 1970 From: Daniel Phillips Subject: Re: [PATCH] dirty bit clearing on s390. Date: Thu, 22 May 2003 16:21:36 +0200 References: <20030522112000.GA2597@mschwid3.boeblingen.de.ibm.com> <1053603729.2360.0.camel@laptop.fenrus.com> In-Reply-To: <1053603729.2360.0.camel@laptop.fenrus.com> MIME-Version: 1.0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: 7bit Content-Disposition: inline Message-Id: <200305221621.36656.phillips@arcor.de> Sender: owner-linux-mm@kvack.org Return-Path: To: arjanv@redhat.com, Martin Schwidefsky Cc: linux-mm@kvack.org, akpm@digeo.com List-ID: On Thursday 22 May 2003 13:42, Arjan van de Ven wrote: > On Thu, 2003-05-22 at 13:20, Martin Schwidefsky wrote: > > Our solution is to move the clearing of the storage key (dirty bit) > > from set_pte to SetPageUptodate. A patch that implements this is > > attached. What do you think ? > > Is there anything that prevents a thread mmaping the page to redirty it > before the kernel marks it uptodate ? The storage key is only supposed to be cleared the first time a page is entered into any process page table. The theory is that the s390 hook in SetPageUptodate can figure that out reliably (this theory needs to be examined closely). If it can know that, then it also knows no other page table is mapping the page, so no dirty events can get lost. Regards, Daniel -- 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