From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-pb0-f49.google.com (mail-pb0-f49.google.com [209.85.160.49]) by kanga.kvack.org (Postfix) with ESMTP id B63D66B0038 for ; Wed, 28 May 2014 19:17:19 -0400 (EDT) Received: by mail-pb0-f49.google.com with SMTP id jt11so11807238pbb.8 for ; Wed, 28 May 2014 16:17:19 -0700 (PDT) Received: from ipmail05.adl6.internode.on.net (ipmail05.adl6.internode.on.net. [2001:44b8:8060:ff02:300:1:6:5]) by mx.google.com with ESMTP id fl5si25427319pbb.220.2014.05.28.16.17.17 for ; Wed, 28 May 2014 16:17:18 -0700 (PDT) Date: Thu, 29 May 2014 09:17:08 +1000 From: Dave Chinner Subject: Re: [RFC 2/2] x86_64: expand kernel stack to 16K Message-ID: <20140528231708.GE6677@dastard> 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> <5386664A.5060304@zytor.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <5386664A.5060304@zytor.com> Sender: owner-linux-mm@kvack.org List-ID: To: "H. Peter Anvin" 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 Wed, May 28, 2014 at 03:42:18PM -0700, H. Peter Anvin wrote: > 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. That doesn't mean it's to blame. Don't shoot the messenger... Cheers, Dave. -- Dave Chinner david@fromorbit.com -- 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