From: Eric Dumazet Subject: Re: [PATCH 3/3] mm: slub: Default slub_max_order to 0 Date: Thu, 12 May 2011 18:10:38 +0200 Message-ID: <1305216638.3795.36.camel@edumazet-laptop> References: <1305127773-10570-1-git-send-email-mgorman@suse.de> <1305127773-10570-4-git-send-email-mgorman@suse.de> <1305213359.2575.46.camel@mulgrave.site> <1305214993.2575.50.camel@mulgrave.site> Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: QUOTED-PRINTABLE Cc: James Bottomley , Mel Gorman , Andrew Morton , Colin King , Raghavendra D Prabhu , Jan Kara , Chris Mason , Pekka Enberg , Rik van Riel , Johannes Weiner , linux-fsdevel , linux-mm , linux-kernel , linux-ext4 To: Christoph Lameter Return-path: Received: from mail-ww0-f44.google.com ([74.125.82.44]:51284 "EHLO mail-ww0-f44.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1757916Ab1ELQKo (ORCPT ); Thu, 12 May 2011 12:10:44 -0400 In-Reply-To: Sender: linux-ext4-owner@vger.kernel.org List-ID: Le jeudi 12 mai 2011 =C3=A0 11:01 -0500, Christoph Lameter a =C3=A9crit= : > On Thu, 12 May 2011, James Bottomley wrote: >=20 > > > Debian and Ubuntu have been using SLUB for a long time > > > > Only from Squeeze, which has been released for ~3 months. That doe= sn't > > qualify as a "long time" in my book. >=20 > I am sorry but I have never used a Debian/Ubuntu system in the last 3 > years that did not use SLUB. And it was that by default. But then we > usually do not run the "released" Debian version. Typically one runs > testing. Ubuntu is different there we usually run releases. But those > have been SLUB for as long as I remember. >=20 > And so far it is rock solid and is widely rolled out throughout our > infrastructure (mostly 2.6.32 kernels). >=20 > > but a sample of one doeth not great testing make. > > > > However, since you admit even you see problems, let's concentrate o= n > > fixing them rather than recriminations? >=20 > I do not see problems here with earlier kernels. I only see these on = one > testing system with the latest kernels on Ubuntu 11.04. More fuel to this discussion with commit 6d4831c2 Something is wrong with high order allocations, on some machines. Maybe we can find real cause instead of limiting us to use order-0 page= s in the end... ;) commit 6d4831c283530a5f2c6bd8172c13efa236eb149d Author: Andrew Morton Date: Wed Apr 27 15:26:41 2011 -0700 vfs: avoid large kmalloc()s for the fdtable =20 Azurit reports large increases in system time after 2.6.36 when run= ning Apache. It was bisected down to a892e2d7dcdfa6c76e6 ("vfs: use kma= lloc() to allocate fdmem if possible"). =20 That patch caused the vfs to use kmalloc() for very large allocatio= ns and this is causing excessive work (and presumably excessive reclaim) w= ithin the page allocator. =20 Fix it by falling back to vmalloc() earlier - when the allocation a= ttempt would have been considered "costly" by reclaim. =20 =20 -- To unsubscribe from this list: send the line "unsubscribe linux-ext4" i= n the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html