From mboxrd@z Thu Jan 1 00:00:00 1970 Date: Tue, 11 Apr 2006 12:33:06 -0700 (PDT) From: Christoph Lameter Subject: Re: [PATCH 2.6.17-rc1-mm1 2/6] Migrate-on-fault - check for misplaced page In-Reply-To: <1144783687.5160.66.camel@localhost.localdomain> Message-ID: References: <1144441108.5198.36.camel@localhost.localdomain> <1144441382.5198.40.camel@localhost.localdomain> <1144783687.5160.66.camel@localhost.localdomain> MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: owner-linux-mm@kvack.org Return-Path: To: Lee Schermerhorn Cc: linux-mm , ak@suse.de List-ID: On Tue, 11 Apr 2006, Lee Schermerhorn wrote: > > The misplaced page function should not consider the vma policy if the page > > is mapped because the VM does not handle vma policies for file > > mapped pages yet. This version may be checking for a policy that would > > not be applied to the page for regular allocations. > > When you say "mapped" here, you mean a mmap()ed file? As opposed to > "mapped by a pte" such that page_mapcount(page) != 0, right? Because if > the mapcount() isn't zero, we won't even look for misplaced pages. And, > with the V0.2 series, I'm only checking for misplaced pages with > mapcount == 0 in the anon page fault path. If necessary, I can skip > pages in VMAs that have non-NULL vm_file. Do we get these in the anon > fault path? You would need to skip evaluating the vma policy for file backed pages for the misplaced page check. > > You need to use the task policy instead of the vma policy if the page is > > file backed because vma policies do not apply in that case. > > OK, but again, I haven't hooked up migrate-on-fault for file backed > pages yet. Here, you're saying that if I DID hook it up before fixing > how file back pages are handled, then to be consistent with current > behavior, I should use task policy for file back pages? If this applied only to anonymous pages then its okay. > How about shmem backed pages? Those have a valid policy even when they are unmapped. -- 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