From mboxrd@z Thu Jan 1 00:00:00 1970 Received: by rv-out-0708.google.com with SMTP id f25so695053rvb.26 for ; Wed, 07 May 2008 22:27:47 -0700 (PDT) Message-ID: <84144f020805072227i3382465eleccded79d9fcf532@mail.gmail.com> Date: Thu, 8 May 2008 08:27:47 +0300 From: "Pekka Enberg" Subject: Re: [PATCH 08 of 11] anon-vma-rwsem In-Reply-To: <20080508052019.GA8276@duo.random> MIME-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Content-Disposition: inline References: <20080507153103.237ea5b6.akpm@linux-foundation.org> <20080507155914.d7790069.akpm@linux-foundation.org> <20080507233953.GM8276@duo.random> <20080508025652.GW8276@duo.random> <20080508034133.GY8276@duo.random> <20080508052019.GA8276@duo.random> Sender: owner-linux-mm@kvack.org Return-Path: To: Andrea Arcangeli Cc: Linus Torvalds , Christoph Lameter , Andrew Morton , steiner@sgi.com, holt@sgi.com, npiggin@suse.de, a.p.zijlstra@chello.nl, kvm-devel@lists.sourceforge.net, kanojsarcar@yahoo.com, rdreier@cisco.com, swise@opengridcomputing.com, linux-kernel@vger.kernel.org, avi@qumranet.com, linux-mm@kvack.org, general@lists.openfabrics.org, hugh@veritas.com, rusty@rustcorp.com.au, aliguori@us.ibm.com, chrisw@redhat.com, marcelo@kvack.org, dada1@cosmosbay.com, paulmck@us.ibm.com List-ID: On Thu, May 8, 2008 at 8:20 AM, Andrea Arcangeli wrote: > Actually I looked both at the struct and at the slab alignment just in > case it was changed recently. Now after reading your mail I also > compiled it just in case. > > @@ -27,6 +27,7 @@ struct anon_vma { > struct anon_vma { > > spinlock_t lock; /* Serialize access to vma list */ > > struct list_head head; /* List of private "related" vmas */ > + int flag:1; > }; You might want to read carefully what Linus wrote: > The one that already has a 4 byte padding thing on x86-64 just after the > spinlock? And that on 32-bit x86 (with less than 256 CPU's) would have two > bytes of padding if we didn't just make the spinlock type unconditionally > 32 bits rather than the 16 bits we actually _use_? So you need to add the flag _after_ ->lock and _before_ ->head.... Pekka -- 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