From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-yk0-f172.google.com (mail-yk0-f172.google.com [209.85.160.172]) by kanga.kvack.org (Postfix) with ESMTP id E906B6B0036 for ; Mon, 7 Jul 2014 18:50:18 -0400 (EDT) Received: by mail-yk0-f172.google.com with SMTP id 142so1977092ykq.17 for ; Mon, 07 Jul 2014 15:50:18 -0700 (PDT) Received: from mail.zytor.com (terminus.zytor.com. [2001:1868:205::10]) by mx.google.com with ESMTPS id n12si48600322yhh.165.2014.07.07.15.50.17 for (version=TLSv1.2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Mon, 07 Jul 2014 15:50:17 -0700 (PDT) Message-ID: <53BB240C.30400@zytor.com> Date: Mon, 07 Jul 2014 15:49:48 -0700 From: "H. Peter Anvin" MIME-Version: 1.0 Subject: Re: fallout of 16K stacks References: <20140707223001.GD18735@two.firstfloor.org> In-Reply-To: <20140707223001.GD18735@two.firstfloor.org> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org List-ID: To: Andi Kleen , torvalds@linux-foundation.org Cc: linux-mm@kvack.org, linux-kernel@vger.kernel.org On 07/07/2014 03:30 PM, Andi Kleen wrote: > > Since the 16K stack change I noticed a number of problems with > my usual stress tests. They have a tendency to bomb out > because something cannot fork. As in ENOMEM or does something worse happen? > - AIM7 on a dual socket socket system now cannot reliably run >> 1000 parallel jobs. ... with how much RAM? > - LTP stress + memhog stress in parallel to something else > usually doesn't survive the night. > > Do we need to strengthen the memory allocator to try > harder for 16K? Can we even? The probability of success goes down exponentially in the order requested. Movable pages can help, of course, but still, there is a very real cost to this :( -hpa -- 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: email@kvack.org