From mboxrd@z Thu Jan 1 00:00:00 1970 From: Stefan Lankes Subject: Re: [RFC PATCH 0/4]: affinity-on-next-touch Date: Fri, 19 Jun 2009 23:19:34 +0200 Message-ID: <4A3C00E6.40703@lfbs.rwth-aachen.de> References: <000c01c9d212$4c244720$e46cd560$@rwth-aachen.de> <87zldjn597.fsf@basil.nowhere.org> <000001c9eac4$cb8b6690$62a233b0$@rwth-aachen.de> <20090612103251.GJ25568@one.firstfloor.org> <004001c9eb53$71991300$54cb3900$@rwth-aachen.de> <1245119977.6724.40.camel@lts-notebook> <003001c9ee8a$97e5b100$c7b11300$@rwth-aachen.de> <1245164395.15138.40.camel@lts-notebook> <000501c9ef1f$930fa330$b92ee990$@rwth-aachen.de> <1245299856.6431.30.camel@lts-notebook> <1245351882.1025.84.camel@lts-notebook> <1245425214.30101.32.camel@lts-notebook> Mime-Version: 1.0 Content-Transfer-Encoding: 7BIT Return-path: In-reply-to: <1245425214.30101.32.camel@lts-notebook> Sender: linux-numa-owner@vger.kernel.org List-ID: Content-Type: text/plain; charset="us-ascii"; format="flowed" To: Lee Schermerhorn Cc: 'Andi Kleen' , linux-kernel@vger.kernel.org, linux-numa@vger.kernel.org, Boris Bierbaum , 'Brice Goglin' , KAMEZAWA Hiroyuki , Balbir Singh , KOSAKI Motohiro Lee Schermerhorn wrote: > On Thu, 2009-06-18 at 15:04 -0400, Lee Schermerhorn wrote: >> On Thu, 2009-06-18 at 00:37 -0400, Lee Schermerhorn wrote: >>> On Wed, 2009-06-17 at 09:45 +0200, Stefan Lankes wrote: >>>>> I've placed the last rebased version in : >>>>> >>>>> http://free.linux.hp.com/~lts/Patches/PageMigration/2.6.28-rc4-mmotm- >>>>> 081110/ >>>>> >>>> OK! I will try to reconstruct the problem. >>> Stefan: >>> >>> Today I rebased the migrate on fault patches to 2.6.30-mmotm-090612... >>> [along with my shared policy series atop which they sit in my tree]. >>> Patches reside in: >>> >>> http://free.linux.hp.com/~lts/Patches/PageMigration/2.6.30-mmotm-090612-1220/ >>> >> I have updated the migrate-on-fault tarball in the above location to fix >> part of the problems I was seeing. See below. >> >>> I did a quick test. I'm afraid the patches have suffered some "bit rot" >>> vis a vis mainline/mmotm over the past several months. Two possibly >>> related issues: >>> >>> 1) lazy migration doesn't seem to work. Looks like >>> mbind(+MPOL_MF_MOVE+MPOL_MF_LAZY) is not unmapping the >>> pages so, of course, migrate on fault won't work. I suspect the >>> reference count handling has changed since I last tried this. [Note one >>> of the patch conflicts was in the MPOL_MF_LAZY addition to the mbind >>> flag definitions in mempolicy.h and I may have botched the resolution >>> thereof.] >>> >>> 2) When the pages get freed on exit/unmap, they are still PageLocked() >>> and free_pages_check()/bad_page() bugs out with bad page state. >>> >>> Note: This is independent of memcg--i.e., happens whether or not memcg >>> configured. >>> >> >> >> OK. Found time to look at this. Turns out I hadn't tested since >> trylock_page() was introduced. I did a one-for-one replacement of the >> old API [TestSetPageLocked()], not noticing that the sense of the return >> was inverted. Thus, I was bailing out of the migrate_pages_unmap_only() >> loop with the page locked, thinking someone else had locked it and would >> take care of it. Since the page wasn't unmapped from the page table[s], >> of course it wouldn't migrate on fault--wouldn't even fault! >> >> Fixed this. >> >> Now: lazy migration works w/ or w/o memcg configured, but NOT with the >> swap resource controller configured. I'll look at that as time permits. > > Update: I now can't reproduce the lazy migration failure with the swap > resource controller configured. Perhaps I had booted the wrong kernel > for the test reported above. Now the updated patch series mentioned > above seems to be working with both memory and swap resource controllers > configured for simple memtoy driven lazy migration. > The current version of your patch works fine on my system. I tested the patches with our test applications and got very good performance results! Stefan