Return-Path: Received: from mx2.netapp.com ([216.240.18.37]:17936 "EHLO mx2.netapp.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751465Ab0HRTEV convert rfc822-to-8bit (ORCPT ); Wed, 18 Aug 2010 15:04:21 -0400 Subject: [PATCH] VM: kswapd should not do blocking memory allocations From: Trond Myklebust To: linux-mm@kvack.org Cc: linux-kernel@vger.kernel.org, linux-nfs@vger.kernel.org Content-Type: text/plain; charset="UTF-8" Date: Wed, 18 Aug 2010 15:04:01 -0400 Message-ID: <1282158241.8540.85.camel@heimdal.trondhjem.org> Sender: linux-nfs-owner@vger.kernel.org List-ID: MIME-Version: 1.0 From: Trond Myklebust Allowing kswapd to do GFP_KERNEL memory allocations (or any blocking memory allocations) is wrong and can cause deadlocks in try_to_release_page(), as the filesystem believes it is safe to allocate new memory and block, whereas kswapd is there specifically to clear a low-memory situation... Set the gfp_mask to GFP_IOFS instead. Signed-off-by: Trond Myklebust --- mm/vmscan.c | 2 +- 1 files changed, 1 insertions(+), 1 deletions(-) diff --git a/mm/vmscan.c b/mm/vmscan.c index ec5ddcc..716dd16 100644 --- a/mm/vmscan.c +++ b/mm/vmscan.c @@ -2095,7 +2095,7 @@ static unsigned long balance_pgdat(pg_data_t *pgdat, int order) unsigned long total_scanned; struct reclaim_state *reclaim_state = current->reclaim_state; struct scan_control sc = { - .gfp_mask = GFP_KERNEL, + .gfp_mask = GFP_IOFS, .may_unmap = 1, .may_swap = 1, /*