From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755708AbZEHMJg (ORCPT ); Fri, 8 May 2009 08:09:36 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1753677AbZEHMJ0 (ORCPT ); Fri, 8 May 2009 08:09:26 -0400 Received: from mail-gx0-f166.google.com ([209.85.217.166]:61145 "EHLO mail-gx0-f166.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753371AbZEHMJZ convert rfc822-to-8bit (ORCPT ); Fri, 8 May 2009 08:09:25 -0400 DomainKey-Signature: a=rsa-sha1; c=nofws; d=gmail.com; s=gamma; h=mime-version:in-reply-to:references:date:message-id:subject:from:to :cc:content-type:content-transfer-encoding; b=ZMIhGKsc8zBLw32PbLIw3VeZT1KoChwx3/JHu0LXoGepqgY10jdCyKs+hh2fpjCT4i 8ejHHy/eEfP22qjb+oNpURCIPqXssjRYQ4mpHFXHxsXAoVd/USjv01iv9Eo68pwvUGNq Y4rUUxvpNJoT3om2fCCAxyHMaP+7Sd/wZkNDc= MIME-Version: 1.0 In-Reply-To: <20090508041700.GC8892@localhost> References: <20090430181340.6f07421d.akpm@linux-foundation.org> <20090430195439.e02edc26.akpm@linux-foundation.org> <49FB01C1.6050204@redhat.com> <20090501123541.7983a8ae.akpm@linux-foundation.org> <20090503031539.GC5702@localhost> <1241432635.7620.4732.camel@twins> <20090507121101.GB20934@localhost> <20090507151039.GA2413@cmpxchg.org> <1241709466.11251.164.camel@twins> <20090508041700.GC8892@localhost> Date: Fri, 8 May 2009 21:09:24 +0900 Message-ID: <28c262360905080509q333ec8acv2d2be69d99e1dfa3@mail.gmail.com> Subject: Re: [RFC][PATCH] vmscan: report vm_flags in page_referenced() From: Minchan Kim To: Wu Fengguang Cc: Peter Zijlstra , Johannes Weiner , Andrew Morton , Rik van Riel , "linux-kernel@vger.kernel.org" , "tytso@mit.edu" , "linux-mm@kvack.org" , Elladan , Nick Piggin , Christoph Lameter , KOSAKI Motohiro Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8BIT Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, May 8, 2009 at 1:17 PM, Wu Fengguang wrote: > On Thu, May 07, 2009 at 11:17:46PM +0800, Peter Zijlstra wrote: >> On Thu, 2009-05-07 at 17:10 +0200, Johannes Weiner wrote: >> >> > > @@ -1269,8 +1270,15 @@ static void shrink_active_list(unsigned >> > > >> > >           /* page_referenced clears PageReferenced */ >> > >           if (page_mapping_inuse(page) && >> > > -             page_referenced(page, 0, sc->mem_cgroup)) >> > > +             page_referenced(page, 0, sc->mem_cgroup)) { >> > > +                 struct address_space *mapping = page_mapping(page); >> > > + >> > >                   pgmoved++; >> > > +                 if (mapping && test_bit(AS_EXEC, &mapping->flags)) { >> > > +                         list_add(&page->lru, &l_active); >> > > +                         continue; >> > > +                 } >> > > +         } >> > >> > Since we walk the VMAs in page_referenced anyway, wouldn't it be >> > better to check if one of them is executable?  This would even work >> > for executable anon pages.  After all, there are applications that cow >> > executable mappings (sbcl and other language environments that use an >> > executable, run-time modified core image come to mind). >> >> Hmm, like provide a vm_flags mask along to page_referenced() to only >> account matching vmas... seems like a sensible idea. > > Here is a quick patch for your opinions. Compile tested. > > With the added vm_flags reporting, the mlock=>unevictable logic can > possibly be made more straightforward. > > Thanks, > Fengguang > --- > vmscan: report vm_flags in page_referenced() > > This enables more informed reclaim heuristics, eg. to protect executable > file pages more aggressively. > > Signed-off-by: Wu Fengguang > --- >  include/linux/rmap.h |    5 +++-- >  mm/rmap.c            |   30 +++++++++++++++++++++--------- >  mm/vmscan.c          |    7 +++++-- >  3 files changed, 29 insertions(+), 13 deletions(-) > > --- linux.orig/include/linux/rmap.h > +++ linux/include/linux/rmap.h > @@ -83,7 +83,8 @@ static inline void page_dup_rmap(struct >  /* >  * Called from mm/vmscan.c to handle paging out >  */ > -int page_referenced(struct page *, int is_locked, struct mem_cgroup *cnt); > +int page_referenced(struct page *, int is_locked, > +                       struct mem_cgroup *cnt, unsigned long *vm_flags); >  int try_to_unmap(struct page *, int ignore_refs); > >  /* > @@ -128,7 +129,7 @@ int page_wrprotect(struct page *page, in >  #define anon_vma_prepare(vma)  (0) >  #define anon_vma_link(vma)     do {} while (0) > > -#define page_referenced(page,l,cnt) TestClearPageReferenced(page) > +#define page_referenced(page, locked, cnt, flags) TestClearPageReferenced(page) >  #define try_to_unmap(page, refs) SWAP_FAIL > >  static inline int page_mkclean(struct page *page) > --- linux.orig/mm/rmap.c > +++ linux/mm/rmap.c > @@ -333,7 +333,8 @@ static int page_mapped_in_vma(struct pag >  * repeatedly from either page_referenced_anon or page_referenced_file. >  */ >  static int page_referenced_one(struct page *page, > -       struct vm_area_struct *vma, unsigned int *mapcount) > +                              struct vm_area_struct *vma, > +                              unsigned int *mapcount) >  { >        struct mm_struct *mm = vma->vm_mm; >        unsigned long address; > @@ -385,7 +386,8 @@ out: >  } > >  static int page_referenced_anon(struct page *page, > -                               struct mem_cgroup *mem_cont) > +                               struct mem_cgroup *mem_cont, > +                               unsigned long *vm_flags) >  { >        unsigned int mapcount; >        struct anon_vma *anon_vma; > @@ -406,6 +408,7 @@ static int page_referenced_anon(struct p >                if (mem_cont && !mm_match_cgroup(vma->vm_mm, mem_cont)) >                        continue; >                referenced += page_referenced_one(page, vma, &mapcount); > +               *vm_flags |= vma->vm_flags; Sometime this vma don't contain the anon page. That's why we need page_check_address. For such a case, wrong *vm_flag cause be harmful to reclaim. It can be happen in your first class citizen patch, I think. -- Kinds regards, Minchan Kim