Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id ; Mon, 28 Jan 2002 18:13:13 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id ; Mon, 28 Jan 2002 18:13:03 -0500 Received: from vsdc01.corp.publichost.com ([64.7.196.123]:48401 "EHLO vsdc01.corp.publichost.com") by vger.kernel.org with ESMTP id ; Mon, 28 Jan 2002 18:12:53 -0500 Message-ID: <3C55DAEF.7020500@vitalstream.com> Date: Mon, 28 Jan 2002 15:12:47 -0800 From: Rick Stevens User-Agent: Mozilla/5.0 (X11; U; Linux i686; en-US; rv:0.9.5) Gecko/20011012 X-Accept-Language: en-us MIME-Version: 1.0 To: linux-kernel@vger.kernel.org Subject: Re: Note describing poor dcache utilization under high memory pressure In-Reply-To:

<3C55C39A.8040203@vitalstream.com> Content-Type: text/plain; charset=us-ascii; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Daniel Phillips wrote: > Since the page was copied to the child, the child's page table must be > altered, and since it is shared, it must first be instantiated by the child. > So after all the dust settles, the parent and child have their own copies of > a page table page, which differ only at a single location: the child's page > table points at its freshly made CoW copy, and the parent's page table points > at the original page. > > The beauty of this is, the page table could just as easily have been shared > by a sibling of the child, not the parent at all, in the case that the parent > had already instantiated its own copy of the page table page because of an > earlier CoW. Ok. Still seems like a bit more copying than necessary. I'd have to look at it a bit more and do some noodling. > Confused yet? Welcome to the club ;-) Does my head exploding qualify for "confused"? If so, then I'm not yet "confused". I'm "concerned", since my ears are bleeding (a precursor to an explosion) ;-p ---------------------------------------------------------------------- - Rick Stevens, SSE, VitalStream, Inc. rstevens@vitalstream.com - - 949-743-2010 (Voice) http://www.vitalstream.com - - - - "More hay, Trigger?" "No thanks, Roy, I'm stuffed!" - ---------------------------------------------------------------------- - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/