Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757676Ab0KVWWF (ORCPT ); Mon, 22 Nov 2010 17:22:05 -0500 Received: from smtp1.linux-foundation.org ([140.211.169.13]:45411 "EHLO smtp1.linux-foundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755806Ab0KVWWD (ORCPT ); Mon, 22 Nov 2010 17:22:03 -0500 Date: Mon, 22 Nov 2010 14:21:09 -0800 From: Andrew Morton To: Minchan Kim Cc: 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: <20101122142109.2f3e168c.akpm@linux-foundation.org> In-Reply-To: <5d205f8a4df078b0da3681063bbf37382b02dd23.1290349672.git.minchan.kim@gmail.com> References: <5d205f8a4df078b0da3681063bbf37382b02dd23.1290349672.git.minchan.kim@gmail.com> X-Mailer: Sylpheed 2.4.8 (GTK+ 2.12.9; x86_64-pc-linux-gnu) Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1588 Lines: 38 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". It isn't a term which is presently used in Linux MM. Probably "activate" has a better-known meaning. And `activate' could be a bool if one is in the mood for that. -- 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/