Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755750Ab0BJQca (ORCPT ); Wed, 10 Feb 2010 11:32:30 -0500 Received: from smtp-out.google.com ([216.239.44.51]:6321 "EHLO smtp-out.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755632Ab0BJQcZ (ORCPT ); Wed, 10 Feb 2010 11:32:25 -0500 DomainKey-Signature: a=rsa-sha1; s=beta; d=google.com; c=nofws; q=dns; h=date:from:x-x-sender:to:cc:subject:in-reply-to:message-id: references:user-agent:mime-version:content-type:x-system-of-record; b=p5kAJSg8eWfbnarzonlr7w3wg+9l6sNmeA7nZk7fz2Ti5fi81bQIqf4qLr7MwHoX3 h0BI2hGFj5q8O13gbVGvQ== Date: Wed, 10 Feb 2010 08:32:21 -0800 (PST) From: David Rientjes X-X-Sender: rientjes@chino.kir.corp.google.com To: Andrew Morton cc: Rik van Riel , KAMEZAWA Hiroyuki , Nick Piggin , Andrea Arcangeli , Balbir Singh , Lubos Lunak , linux-kernel@vger.kernel.org, linux-mm@kvack.org Subject: [patch 6/7 -mm] oom: avoid oom killer for lowmem allocations In-Reply-To: Message-ID: References: User-Agent: Alpine 2.00 (DEB 1167 2008-08-23) MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII X-System-Of-Record: true Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1791 Lines: 41 If memory has been depleted in lowmem zones even with the protection afforded to it by /proc/sys/vm/lowmem_reserve_ratio, it is unlikely that killing current users will help. The memory is either reclaimable (or migratable) already, in which case we should not invoke the oom killer at all, or it is pinned by an application for I/O. Killing such an application may leave the hardware in an unspecified state and there is no guarantee that it will be able to make a timely exit. Lowmem allocations are now failed in oom conditions so that the task can perhaps recover or try again later. Killing current is an unnecessary result for simply making a GFP_DMA or GFP_DMA32 page allocation and no lowmem allocations use the now-deprecated __GFP_NOFAIL bit so retrying is unnecessary. Previously, the heuristic provided some protection for those tasks with CAP_SYS_RAWIO, but this is no longer necessary since we will not be killing tasks for the purposes of ISA allocations. Signed-off-by: David Rientjes --- mm/page_alloc.c | 3 +++ 1 files changed, 3 insertions(+), 0 deletions(-) diff --git a/mm/page_alloc.c b/mm/page_alloc.c --- a/mm/page_alloc.c +++ b/mm/page_alloc.c @@ -1914,6 +1914,9 @@ rebalance: * running out of options and have to consider going OOM */ if (!did_some_progress) { + /* The oom killer won't necessarily free lowmem */ + if (high_zoneidx < ZONE_NORMAL) + goto nopage; if ((gfp_mask & __GFP_FS) && !(gfp_mask & __GFP_NORETRY)) { if (oom_killer_disabled) goto nopage; -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/