From mboxrd@z Thu Jan 1 00:00:00 1970 Message-ID: <4615B043.8060001@yahoo.com.au> Date: Fri, 06 Apr 2007 12:28:19 +1000 From: Nick Piggin MIME-Version: 1.0 Subject: Re: missing madvise functionality References: <46128051.9000609@redhat.com> <46128CC2.9090809@redhat.com> <20070403172841.GB23689@one.firstfloor.org> <20070403125903.3e8577f4.akpm@linux-foundation.org> <4612B645.7030902@redhat.com> <20070403202937.GE355@devserv.devel.redhat.com> <4614A5CC.5080508@redhat.com> <46151F73.50602@redhat.com> In-Reply-To: <46151F73.50602@redhat.com> Content-Type: text/plain; charset=us-ascii; format=flowed Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org Return-Path: To: Ulrich Drepper Cc: Rik van Riel , Jakub Jelinek , Andrew Morton , Andi Kleen , Linux Kernel , linux-mm@kvack.org, Hugh Dickins List-ID: Ulrich Drepper wrote: > In case somebody wants to play around with Rik patch or another > madvise-based patch, I have x86-64 glibc binaries which can use it: > > http://people.redhat.com/drepper/rpms > > These are based on the latest Fedora rawhide version. They should work > on older systems, too, but you screw up your updates. Use them only if > you know what you do. > > By default madvise(MADV_DONTNEED) is used. With the environment variable Cool. According to my thinking, madvise(MADV_DONTNEED) even in today's kernels using down_write(mmap_sem) for MADV_DONTNEED is better than mmap/mprotect, which have more fundamental locking requirements, more overhead and no benefits (except debugging, I suppose). MADV_DONTNEED is twice as fast in single threaded performance, and an order of magnitude faster for multiple threads, when MADV_DONTNEED only takes mmap_sem for read. Do you plan to include this change in general glibc releases? Maybe it will make google malloc obsolete? ;) (I don't suppose you'd be able to get any tests done, Andrew?) -- SUSE Labs, Novell Inc. -- 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