Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752941Ab0KWJvK (ORCPT ); Tue, 23 Nov 2010 04:51:10 -0500 Received: from gir.skynet.ie ([193.1.99.77]:55197 "EHLO gir.skynet.ie" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752535Ab0KWJvI (ORCPT ); Tue, 23 Nov 2010 04:51:08 -0500 Date: Tue, 23 Nov 2010 09:50:53 +0000 From: Mel Gorman To: Andrew Morton Cc: Minchan Kim , linux-mm , LKML , Rik van Riel , KOSAKI Motohiro , Johannes Weiner , Nick Piggin Subject: Re: [RFC 2/2] Prevent promotion of page in madvise_dontneed Message-ID: <20101123095053.GG19571@csn.ul.ie> References: <5d205f8a4df078b0da3681063bbf37382b02dd23.1290349672.git.minchan.kim@gmail.com> <20101122142109.2f3e168c.akpm@linux-foundation.org> MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-15 Content-Disposition: inline In-Reply-To: <20101122142109.2f3e168c.akpm@linux-foundation.org> User-Agent: Mutt/1.5.17+20080114 (2008-01-14) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1998 Lines: 46 On Mon, Nov 22, 2010 at 02:21:09PM -0800, Andrew Morton wrote: > On Sun, 21 Nov 2010 23:30:24 +0900 > Minchan Kim wrote: > > > Now zap_pte_range alwayas promotes pages which are pte_young && > > !VM_SequentialReadHint(vma). But in case of calling MADV_DONTNEED, > > it's unnecessary since the page wouldn't use any more. > > > > If the page is sharred by other processes and it's real working set > > This patch doesn't actually do anything. It passes variable `promote' > all the way down to unmap_vmas(), but unmap_vmas() doesn't use that new > variable. > > Have a comment fixlet: > > --- a/mm/memory.c~mm-prevent-promotion-of-page-in-madvise_dontneed-fix > +++ a/mm/memory.c > @@ -1075,7 +1075,7 @@ static unsigned long unmap_page_range(st > * @end_addr: virtual address at which to end unmapping > * @nr_accounted: Place number of unmapped pages in vm-accountable vma's here > * @details: details of nonlinear truncation or shared cache invalidation > - * @promote: whether pages inclued vma would be promoted or not > + * @promote: whether pages included in the vma should be promoted or not > * > * Returns the end address of the unmapping (restart addr if interrupted). > * > _ > > Also, I'd suggest that we avoid introducing the term "promote". Promote also has special meaning for huge pages. Demoting or promoting a page refers to changing its size. The same applies to the other patch - s/demote/deactive/ s/promote/activate/ . Currently this is no confusion within the VM but when Andrea's THP patches are merged, it'll become an issue. -- Mel Gorman Part-time Phd Student Linux Technology Center University of Limerick IBM Dublin Software Lab -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/