From mboxrd@z Thu Jan 1 00:00:00 1970 Date: Thu, 8 May 2008 07:20:19 +0200 From: Andrea Arcangeli Subject: Re: [PATCH 08 of 11] anon-vma-rwsem Message-ID: <20080508052019.GA8276@duo.random> References: <20080507153103.237ea5b6.akpm@linux-foundation.org> <20080507224406.GI8276@duo.random> <20080507155914.d7790069.akpm@linux-foundation.org> <20080507233953.GM8276@duo.random> <20080508025652.GW8276@duo.random> <20080508034133.GY8276@duo.random> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: Sender: owner-linux-mm@kvack.org Return-Path: To: Linus Torvalds Cc: 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 Wed, May 07, 2008 at 09:14:45PM -0700, Linus Torvalds wrote: > IOW, you didn't even look at it, did you? 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. 2.6.26-rc1 # name : tunables : slabdata anon_vma 260 576 24 144 1 : tunables 120 60 8 : slabdata 4 4 0 ^^ ^^^ 2.6.26-rc1 + below patch diff --git a/include/linux/rmap.h b/include/linux/rmap.h --- a/include/linux/rmap.h +++ b/include/linux/rmap.h @@ -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; }; #ifdef CONFIG_MMU # name : tunables : slabdata anon_vma 250 560 32 112 1 : tunables 120 60 8 : slabdata 5 5 0 ^^ ^^^ Not a big deal sure to grow it 33%, it's so small anyway, but I don't see the point in growing it. sort() can be interrupted by signals, and until it can we can cap it to 512 vmas making the worst case taking dozen usecs, I fail to see what you have against sort(). Again: if a vma bitflag + global lock could have avoided sort and run O(N) instead of current O(N*log(N)) I would have done that immediately, infact I was in the process of doing it when you posted the followup. Nothing personal here, just staying technical. Hope you too. -- 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