Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1758478AbZJPKiM (ORCPT ); Fri, 16 Oct 2009 06:38:12 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1757981AbZJPKiK (ORCPT ); Fri, 16 Oct 2009 06:38:10 -0400 Received: from gir.skynet.ie ([193.1.99.77]:48110 "EHLO gir.skynet.ie" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1757514AbZJPKiH (ORCPT ); Fri, 16 Oct 2009 06:38:07 -0400 From: Mel Gorman To: Andrew Morton , stable Cc: "Rafael J. Wysocki" , David Miller , Frans Pop , reinette chatre , Kalle Valo , "John W. Linville" , Pekka Enberg , Bartlomiej Zolnierkiewicz , Karol Lewandowski , netdev@vger.kernel.org, linux-kernel@vger.kernel.org, "linux-mm@kvack.org\"" , Mel Gorman Subject: [PATCH 1/2] page allocator: Always wake kswapd when restarting an allocation attempt after direct reclaim failed Date: Fri, 16 Oct 2009 11:37:25 +0100 Message-Id: <1255689446-3858-2-git-send-email-mel@csn.ul.ie> X-Mailer: git-send-email 1.6.3.3 In-Reply-To: <1255689446-3858-1-git-send-email-mel@csn.ul.ie> References: <1255689446-3858-1-git-send-email-mel@csn.ul.ie> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1637 Lines: 40 If a direct reclaim makes no forward progress, it considers whether it should go OOM or not. Whether OOM is triggered or not, it may retry the application afterwards. In times past, this would always wake kswapd as well but currently, kswapd is not woken up after direct reclaim fails. For order-0 allocations, this makes little difference but if there is a heavy mix of higher-order allocations that direct reclaim is failing for, it might mean that kswapd is not rewoken for higher orders as much as it did previously. This patch wakes up kswapd when an allocation is being retried after a direct reclaim failure. It would be expected that kswapd is already awake, but this has the effect of telling kswapd to reclaim at the higher order as well. Signed-off-by: Mel Gorman --- mm/page_alloc.c | 2 +- 1 files changed, 1 insertions(+), 1 deletions(-) diff --git a/mm/page_alloc.c b/mm/page_alloc.c index bf72055..dfa4362 100644 --- a/mm/page_alloc.c +++ b/mm/page_alloc.c @@ -1817,9 +1817,9 @@ __alloc_pages_slowpath(gfp_t gfp_mask, unsigned int order, if (NUMA_BUILD && (gfp_mask & GFP_THISNODE) == GFP_THISNODE) goto nopage; +restart: wake_all_kswapd(order, zonelist, high_zoneidx); -restart: /* * OK, we're below the kswapd watermark and have kicked background * reclaim. Now things get more complex, so set up alloc_flags according -- 1.6.3.3 -- 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/