From mboxrd@z Thu Jan 1 00:00:00 1970 Date: Thu, 29 Aug 2002 18:46:15 -0300 (BRT) From: Rik van Riel Subject: Re: [PATCH] low-latency zap_page_range() In-Reply-To: <3D6E9084.820B2608@zip.com.au> Message-ID: MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: owner-linux-mm@kvack.org Return-Path: To: Andrew Morton Cc: Robert Love , linux-kernel@vger.kernel.org, linux-mm@kvack.org List-ID: On Thu, 29 Aug 2002, Andrew Morton wrote: > > So we know it is held forever and a day... but is there contention? > > I'm sure there is, but nobody has measured the right workload. > > Two CLONE_MM threads, one running mmap()/munmap(), the other trying > to fault in some pages. I'm sure someone has some vital application > which does exactly this. They always do :( Can't fix this one. The mmap()/munmap() needs to have the mmap_sem for writing as long as its setting up or tearing down a VMA while the pagefault path takes the mmap_sem for reading. It might be fixable in some dirty way, but I doubt that'll ever be worth it. regards, Rik -- Bravely reimplemented by the knights who say "NIH". http://www.surriel.com/ http://distro.conectiva.com/ -- 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/