From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail144.messagelabs.com (mail144.messagelabs.com [216.82.254.51]) by kanga.kvack.org (Postfix) with ESMTP id 81B0D6B00DD for ; Tue, 6 Jan 2009 03:43:18 -0500 (EST) Date: Tue, 6 Jan 2009 09:43:12 +0100 From: Nick Piggin Subject: Re: [patch] mm: fix lockless pagecache reordering bug (was Re: BUG: soft lockup - is this XFS problem?) Message-ID: <20090106084312.GC16738@wotan.suse.de> References: <49623384.2070801@aon.at> <20090105164135.GC32675@wotan.suse.de> <20090105180008.GE32675@wotan.suse.de> <20090105201258.GN6959@linux.vnet.ibm.com> <20090105215727.GQ6959@linux.vnet.ibm.com> <20090106020550.GA819@wotan.suse.de> <49631877.3090803@aon.at> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <49631877.3090803@aon.at> Sender: owner-linux-mm@kvack.org To: Peter Klotz Cc: "Paul E. McKenney" , Linus Torvalds , stable@kernel.org, Linux Memory Management List , Christoph Hellwig , Roman Kononov , linux-kernel@vger.kernel.org, xfs@oss.sgi.com, Andrew Morton List-ID: On Tue, Jan 06, 2009 at 09:38:15AM +0100, Peter Klotz wrote: > >Index: linux-2.6/include/linux/radix-tree.h > >=================================================================== > >--- linux-2.6.orig/include/linux/radix-tree.h > >+++ linux-2.6/include/linux/radix-tree.h > >@@ -136,7 +136,7 @@ do { \ > > */ > > static inline void *radix_tree_deref_slot(void **pslot) > > { > >- void *ret = *pslot; > >+ void *ret = rcu_dereference(*pslot); > > if (unlikely(radix_tree_is_indirect_ptr(ret))) > > ret = RADIX_TREE_RETRY; > > return ret; > > > > > > The patch above fixes my problem. I did two complete test runs that > normally fail rather quickly. OK, thanks for reporting and testing. I think this patch is a candidate for -stable too. Thanks, Nick -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org