From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from psmtp.com (na3sys010amx126.postini.com [74.125.245.126]) by kanga.kvack.org (Postfix) with SMTP id 592B96B0044 for ; Fri, 27 Jul 2012 04:43:01 -0400 (EDT) Date: Fri, 27 Jul 2012 09:42:54 +0100 From: Mel Gorman Subject: Re: [PATCH -alternative] mm: hugetlbfs: Close race during teardown of hugetlbfs shared page tables V2 (resend) Message-ID: <20120727084254.GA612@suse.de> References: <20120720134937.GG9222@suse.de> <20120720141108.GH9222@suse.de> <20120720143635.GE12434@tiehlicka.suse.cz> <20120720145121.GJ9222@suse.de> <50118182.8030308@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-15 Content-Disposition: inline In-Reply-To: <50118182.8030308@redhat.com> Sender: owner-linux-mm@kvack.org List-ID: To: Rik van Riel Cc: Hugh Dickins , Michal Hocko , Linux-MM , David Gibson , Ken Chen , Cong Wang , LKML , Larry Woodman On Thu, Jul 26, 2012 at 01:42:26PM -0400, Rik van Riel wrote: > On 07/23/2012 12:04 AM, Hugh Dickins wrote: > > >Please don't be upset if I say that I don't like either of your patches. > >Mainly for obvious reasons - I don't like Mel's because anything with > >trylock retries and nested spinlocks worries me before I can even start > >to think about it; and I don't like Michal's for the same reason as Mel, > >that it spreads more change around in common paths than we would like. > > I have a naive question. > > In huge_pmd_share, we protect ourselves by taking > the mapping->i_mmap_mutex. > > Is there any reason we could not take the i_mmap_mutex > in the huge_pmd_unshare path? > We do, in 3.4 at least - callers of __unmap_hugepage_range hold the i_mmap_mutex. Locking changes in mmotm and there is a patch there that needs to be reverted. What tree are you looking at? -- Mel Gorman SUSE Labs -- 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