From mboxrd@z Thu Jan 1 00:00:00 1970 From: Nick Piggin Subject: Re: [PATCH 0/4] futex: get_user_pages_fast() for shared futexes Date: Tue, 30 Sep 2008 17:21:51 +1000 References: <20080926173219.885155151@twins.programming.kicks-ass.net> <20080927161712.GA1525@elte.hu> In-Reply-To: <20080927161712.GA1525@elte.hu> MIME-Version: 1.0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: 7bit Content-Disposition: inline Message-Id: <200809301721.52148.nickpiggin@yahoo.com.au> Sender: owner-linux-mm@kvack.org Return-Path: To: Ingo Molnar Cc: Peter Zijlstra , Eric Dumazet , Thomas Gleixner , linux-kernel@vger.kernel.org, linux-mm@kvack.org List-ID: On Sunday 28 September 2008 02:17, Ingo Molnar wrote: > * Peter Zijlstra wrote: > > Since get_user_pages_fast() made it in, I thought to give this another > > try. Lightly tested by disabling the private futexes and running some > > java proglets. > > hm, very interesting. Since this is an important futex usecase i started > testing it in tip/core/futexes: > > cd33272: futex: cleanup fshared > a135356: futex: use fast_gup() > 39ce77b: futex: reduce mmap_sem usage > 0d7a336: futex: rely on get_user_pages() for shared futexes > > Nick, it would be nice to get an Acked-by/Reviewed-by from you, before > we think about whether it should go upstream. Yeah, these all look pretty good. It's nice to get rid of mmap sem here. Which reminds me, we need to put a might_lock mmap_sem into get_user_pages_fast... But these patches look good to me (last time we discussed them I thought there was a race with page truncate, but it looks like you've closed that by holding page lock over the whole operation...) Nice work, Peter. BTW. what kinds of things use inter-process futexes as of now? -- 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