From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from psmtp.com (na3sys010amx180.postini.com [74.125.245.180]) by kanga.kvack.org (Postfix) with SMTP id F0B706B005A for ; Fri, 16 Nov 2012 12:26:56 -0500 (EST) Message-ID: <50A67751.1090306@redhat.com> Date: Fri, 16 Nov 2012 12:26:41 -0500 From: Rik van Riel MIME-Version: 1.0 Subject: Re: [PATCH 06/43] mm: numa: Make pte_numa() and pmd_numa() a generic implementation References: <1353064973-26082-1-git-send-email-mgorman@suse.de> <1353064973-26082-7-git-send-email-mgorman@suse.de> <50A648FF.2040707@redhat.com> <20121116144109.GA8218@suse.de> <20121116160852.GA4302@gmail.com> <20121116165606.GE8218@suse.de> In-Reply-To: <20121116165606.GE8218@suse.de> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org List-ID: To: Mel Gorman Cc: Ingo Molnar , Linus Torvalds , Peter Zijlstra , Andrea Arcangeli , Johannes Weiner , Hugh Dickins , Thomas Gleixner , Andrew Morton , Linux-MM , LKML On 11/16/2012 11:56 AM, Mel Gorman wrote: >> b33467764d8a mm/migrate: Introduce migrate_misplaced_page() > > bolts onto the side of migration and introduces MIGRATE_FAULT which > should not have been necessary. Already complained about. > > The alternative uses the existing migrate_pages() function but has > different requirements for taking a reference to the page. Indeed, NACK to b33467764d8a Mel's tree implements this in a much cleaner way. >> ca2ea0747a5b mm/mpol: Add MPOL_MF_LAZY > > We more or less share this except I backed out the userspace visible bits > in a separate patch because I didn't think it had been carefully reviewed > how an application should use it and if it was a good idea. Covered in an > earlier review. Agreed, these bits should not be userspace visible, at least not for now. >> cd203e33c39d mm/mpol: Add MPOL_MF_NOOP > > I have a patch that backs this out on the grounds that I don't think we > have adequately discussed if it was the correct userspace interface. I > know Peter put a lot of time into it so it's probably correct but > without man pages or spending time writing an example program that used > it, I played safe. Ditto. >> 6fe64360a759 mm: Only flush the TLB when clearing an accessible pte > > I missed this. Stupid stupid stupid! It would reduce the TLB flushes from > migration context. However, Ingo's tree still incurs the double page fault for migrated pages. Both trees could use a little improvement in this area :) >> e9df40bfeb25 x86/mm: Introduce pte_accessible() > > prot_none. This one is x86 specific, and would work as well with Andrea's _PAGE_NUMA as it would with _PAGE_PROTNONE. >> is a good foundation already with no WIP policy bits in it. >> >> Mel, could you please work on this basis, or point out the bits >> you don't agree with so I can fix it? >> > > My main hangup is the prot_none choice and I know it's something we have > butted heads on without progress. I feel it is a lot cleaner to have > the _PAGE_NUMA bit (even if it's PROT_NONE underneath) and the helpers > avoid function calls where possible. I am pretty neutral on whether we use _PAGE_NUMA with _PAGE_PROTNONE underneath, or the slightly higher overhead actual prot_none stuff. I can live with whichever of these Linus ends up merging. -- All rights reversed -- 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