From mboxrd@z Thu Jan 1 00:00:00 1970 Date: Wed, 7 May 2008 13:56:23 -0700 (PDT) From: Linus Torvalds Subject: Re: [PATCH 08 of 11] anon-vma-rwsem In-Reply-To: <6b384bb988786aa78ef0.1210170958@duo.random> Message-ID: References: <6b384bb988786aa78ef0.1210170958@duo.random> MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: owner-linux-mm@kvack.org Return-Path: To: Andrea Arcangeli Cc: Andrew Morton , Christoph Lameter , Jack Steiner , Robin Holt , Nick Piggin , Peter Zijlstra , kvm-devel@lists.sourceforge.net, Kanoj Sarcar , Roland Dreier , Steve Wise , linux-kernel@vger.kernel.org, Avi Kivity , linux-mm@kvack.org, general@lists.openfabrics.org, Hugh Dickins , Rusty Russell , Anthony Liguori , Chris Wright , Marcelo Tosatti , Eric Dumazet , "Paul E. McKenney" List-ID: On Wed, 7 May 2008, Andrea Arcangeli wrote: > > Convert the anon_vma spinlock to a rw semaphore. This allows concurrent > traversal of reverse maps for try_to_unmap() and page_mkclean(). It also > allows the calling of sleeping functions from reverse map traversal as > needed for the notifier callbacks. It includes possible concurrency. This also looks very debatable indeed. The only performance numbers quoted are: > This results in f.e. the Aim9 brk performance test to got down by 10-15%. which just seems like a total disaster. The whole series looks bad, in fact. Lack of authorship, bad single-line description, and the code itself sucks so badly that it's not even funny. NAK NAK NAK. All of it. It stinks. Linus -- 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