From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail138.messagelabs.com (mail138.messagelabs.com [216.82.249.35]) by kanga.kvack.org (Postfix) with SMTP id C54966B004D for ; Tue, 19 May 2009 00:48:19 -0400 (EDT) Date: Tue, 19 May 2009 12:48:32 +0800 From: Wu Fengguang Subject: Re: [PATCH 2/3] vmscan: make mapped executable pages the first class citizen Message-ID: <20090519044832.GA8769@localhost> References: <20090519032759.GA7608@localhost> <20090519133422.4ECC.A69D9226@jp.fujitsu.com> <20090519134253.4ECF.A69D9226@jp.fujitsu.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20090519134253.4ECF.A69D9226@jp.fujitsu.com> Sender: owner-linux-mm@kvack.org To: KOSAKI Motohiro Cc: Christoph Lameter , Andrew Morton , LKML , Elladan , Nick Piggin , Johannes Weiner , Peter Zijlstra , Rik van Riel , "tytso@mit.edu" , "linux-mm@kvack.org" , "minchan.kim@gmail.com" List-ID: On Tue, May 19, 2009 at 12:44:19PM +0800, KOSAKI Motohiro wrote: > > > begin: 2479 2344 9659 210 0 579643 > > > end: 284 232010 234142 260 772776 20917184 > > > restore: 379 232159 234371 301 774888 20967849 > > > > > > The numbers show that > > > > > > - The startup pgmajfault of 2.6.30-rc4-mm is merely 1/3 that of 2.6.29. > > > I'd attribute that improvement to the mmap readahead improvements :-) > > > > > > - The pgmajfault increment during the file copy is 633-630=3 vs 260-210=50. > > > That's a huge improvement - which means with the VM_EXEC protection logic, > > > active mmap pages is pretty safe even under partially cache hot streaming IO. > > > > > > - when active:inactive file lru size reaches 1:1, their scan rates is 1:20.8 > > > under 10% cache hot IO. (computed with formula Dpgdeactivate:Dpgfree) > > > That roughly means the active mmap pages get 20.8 more chances to get > > > re-referenced to stay in memory. > > > > > > - The absolute nr_mapped drops considerably to 1/9 during the big IO, and the > > > dropped pages are mostly inactive ones. The patch has almost no impact in > > > this aspect, that means it won't unnecessarily increase memory pressure. > > > (In contrast, your 20% mmap protection ratio will keep them all, and > > > therefore eliminate the extra 41 major faults to restore working set > > > of zsh etc.) > > > > I'm surprised this. > > Why your patch don't protect mapped page from streaming io? > > I guess you use initlevel=5 and use only terminal, right? > if so, dropping some graphics component makes sense. No, it's in pure console mode, no X running at all. > > > > > I strongly hope reproduce myself, please teach me reproduce way. > > > -- 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