linux-kernel - Re: [PATCH 2/3] vmscan: make mapped executable pages the first class citizen

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-Id: <20090519134253.4ECF.A69D9226@jp.fujitsu.com>
Date:	Tue, 19 May 2009 13:44:19 +0900 (JST)
From:	KOSAKI Motohiro <kosaki.motohiro@...fujitsu.com>
To:	KOSAKI Motohiro <kosaki.motohiro@...fujitsu.com>
Cc:	kosaki.motohiro@...fujitsu.com,
	Wu Fengguang <fengguang.wu@...el.com>,
	Christoph Lameter <cl@...ux-foundation.org>,
	Andrew Morton <akpm@...ux-foundation.org>,
	LKML <linux-kernel@...r.kernel.org>,
	Elladan <elladan@...imo.com>, Nick Piggin <npiggin@...e.de>,
	Johannes Weiner <hannes@...xchg.org>,
	Peter Zijlstra <peterz@...radead.org>,
	Rik van Riel <riel@...hat.com>,
	"tytso@....edu" <tytso@....edu>,
	"linux-mm@...ck.org" <linux-mm@...ck.org>,
	"minchan.kim@...il.com" <minchan.kim@...il.com>
Subject: Re: [PATCH 2/3] vmscan: make mapped executable pages the first class citizen

> > 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.


> 
> I strongly hope reproduce myself, please teach me reproduce way.




--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/