From mboxrd@z Thu Jan 1 00:00:00 1970 Date: Wed, 7 Mar 2007 09:19:48 +0100 From: Nick Piggin Subject: Re: [patch 4/6] mm: merge populate and nopage into fault (fixes nonlinear) Message-ID: <20070307081948.GA9563@wotan.suse.de> References: <20070221023656.6306.246.sendpatchset@linux.site> <20070221023735.6306.83373.sendpatchset@linux.site> <20070306225101.f393632c.akpm@linux-foundation.org> <20070307070853.GB15877@wotan.suse.de> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20070307070853.GB15877@wotan.suse.de> Sender: owner-linux-mm@kvack.org Return-Path: To: Andrew Morton Cc: Linux Memory Management , Linux Kernel , Benjamin Herrenschmidt , Ingo Molnar List-ID: On Wed, Mar 07, 2007 at 08:08:53AM +0100, Nick Piggin wrote: > On Tue, Mar 06, 2007 at 10:51:01PM -0800, Andrew Morton wrote: > > > This patch seems to churn things around an awful lot for minimal benefit. > > Well it fixes the whole design of the nonlinear fault path. If it doesn't look very impressive, it could be because it leaves all the old crud around for backwards compatibility (the worst offenders are removed in patch 6/6). If you look at the patchset as a whole, it removes about 250 lines, mostly of (non trivial) duplicated code in filemap.c memory.c shmem.c fremap.c, that is nonlinear pages specific and doesn't get anywhere near the testing that the linear fault path does. A minimal fix for nonlinear pages would have required changing all ->populate handlers, which I simply thought was not very productive considering the testing and coverage issues, and that I was going to rewrite the nonlinear path anyway. If you like, you can consider patches 1,2,3 as the fix, and ignore nonlinear (hey, it doesn't even bother checking truncate_count today!). Then 4,5,6 is the fault/nonlinear rewrite, take it or leave it. I thought you would have liked the patches... -- 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