Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754591Ab1BWWlC (ORCPT ); Wed, 23 Feb 2011 17:41:02 -0500 Received: from smtp1.linux-foundation.org ([140.211.169.13]:33926 "EHLO smtp1.linux-foundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754050Ab1BWWlA (ORCPT ); Wed, 23 Feb 2011 17:41:00 -0500 MIME-Version: 1.0 In-Reply-To: References: From: Linus Torvalds Date: Wed, 23 Feb 2011 14:33:54 -0800 Message-ID: Subject: Re: [PATCH] mm: prevent concurrent unmap_mapping_range() on the same inode To: Miklos Szeredi Cc: akpm@linux-foundation.org, hughd@google.com, gurudas.pai@oracle.com, lkml20101129@newton.leun.net, rjw@sisk.pl, florian@mickler.org, trond.myklebust@fys.uio.no, maciej.rutecki@gmail.com, linux-kernel@vger.kernel.org, linux-mm@kvack.org Content-Type: text/plain; charset=ISO-8859-1 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1337 Lines: 30 On Wed, Feb 23, 2011 at 4:49 AM, Miklos Szeredi wrote: > > This resolves Bug 25822 listed in the regressions since 2.6.36 (though > it's a bug much older than that, for some reason it only started > triggering for people recently). Gaah. I hate this patch. It is, in fact, a patch that makes me finally think that the mm preemptibility is actually worth it, because then i_mmap_lock turns into a mutex and makes the whole "drop the lock" thing hopefully a thing of the past (see the patch "mm: Remove i_mmap_mutex lockbreak"). Because as far as I can see, the only thing that makes this thing needed in the first place is that horribly ugly "we drop i_mmap_lock in the middle of random operations that really still need it". That said, I don't really see any alternatives - I guess we can't really just say "remove that crazy lock dropping". Even though I really really really would like to. Of course, we could also just decide that we should apply the mm preemptibility series instead. Can people confirm that that fixes the bug too? Linus -- 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/