From mboxrd@z Thu Jan 1 00:00:00 1970 From: Peter Zijlstra Subject: Re: [15/17] SLUB: Support virtual fallback via SLAB_VFALLBACK Date: Sat, 29 Sep 2007 10:53:41 +0200 Message-ID: <1191056021.18147.104.camel@lappy> References: <20070919033605.785839297@sgi.com> <20070919033643.763818012@sgi.com> <200709280742.38262.nickpiggin@yahoo.com.au> <1191002119.18147.80.camel@lappy> <1191003950.18147.85.camel@lappy> <20070929011311.8b51dedb.akpm@linux-foundation.org> <1191055632.18147.101.camel@lappy> Mime-Version: 1.0 Content-Type: text/plain Content-Transfer-Encoding: 7bit Cc: Christoph Lameter , Nick Piggin , Christoph Hellwig , Mel Gorman , linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org, David Chinner , Jens Axboe To: Andrew Morton Return-path: Received: from pentafluge.infradead.org ([213.146.154.40]:56651 "EHLO pentafluge.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751725AbXI2I6S (ORCPT ); Sat, 29 Sep 2007 04:58:18 -0400 In-Reply-To: <1191055632.18147.101.camel@lappy> Sender: linux-fsdevel-owner@vger.kernel.org List-Id: linux-fsdevel.vger.kernel.org On Sat, 2007-09-29 at 10:47 +0200, Peter Zijlstra wrote: > Ah, right, that was the detail... all this lumpy reclaim is useless for > atomic allocations. And with SLUB using higher order pages, atomic !0 > order allocations will be very very common. > > One I can remember was: > > add_to_page_cache() > radix_tree_insert() > radix_tree_node_alloc() > kmem_cache_alloc() > > which is an atomic callsite. > > Which leaves us in a situation where we can load pages, because there is > free memory, but can't manage to allocate memory to track them.. Ah, I found a boot log of one of these sessions, its also full of order-2 OOMs.. :-/