From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-we0-f177.google.com (mail-we0-f177.google.com [74.125.82.177]) by kanga.kvack.org (Postfix) with ESMTP id 38B956B0037 for ; Wed, 28 May 2014 18:44:57 -0400 (EDT) Received: by mail-we0-f177.google.com with SMTP id x48so12095811wes.36 for ; Wed, 28 May 2014 15:44:56 -0700 (PDT) Received: from mail.zytor.com (terminus.zytor.com. [2001:1868:205::10]) by mx.google.com with ESMTPS id e17si16903570wiw.8.2014.05.28.15.44.54 for (version=TLSv1.2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Wed, 28 May 2014 15:44:55 -0700 (PDT) Message-ID: <5386664A.5060304@zytor.com> Date: Wed, 28 May 2014 15:42:18 -0700 From: "H. Peter Anvin" MIME-Version: 1.0 Subject: Re: [RFC 2/2] x86_64: expand kernel stack to 16K References: <1401260039-18189-1-git-send-email-minchan@kernel.org> <1401260039-18189-2-git-send-email-minchan@kernel.org> <20140528101401.43853563@gandalf.local.home> <20140528221118.GN8554@dastard> In-Reply-To: <20140528221118.GN8554@dastard> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org List-ID: To: Dave Chinner Cc: Steven Rostedt , Minchan Kim , Linus Torvalds , linux-kernel@vger.kernel.org, Andrew Morton , linux-mm@kvack.org, Ingo Molnar , Peter Zijlstra , Mel Gorman , Rik van Riel , Johannes Weiner , Hugh Dickins , rusty@rustcorp.com.au, mst@redhat.com, Dave Hansen On 05/28/2014 03:11 PM, Dave Chinner wrote: > On Wed, May 28, 2014 at 07:23:23AM -0700, H. Peter Anvin wrote: >> We tried for 4K on x86-64, too, for b quite a while as I recall. >> The kernel stack is a one of the main costs for a thread. I would >> like to decouple struct thread_info from the kernel stack (PJ >> Waskewicz was working on that before he left Intel) but that >> doesn't buy us all that much. >> >> 8K additional per thread is a huge hit. XFS has indeed always >> been a canary, or troublespot, I suspect because it originally >> came from another kernel where this was not an optimization >> target. > > > > Always blame XFS for stack usage problems. > > Even when the reported problem is from IO to an ext4 filesystem. > You were the one calling it a canary. -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