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 for Android: free password hash cracker in your pocket

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

Message-ID: <84144f020905182339o5fb1e78eved95c4c20fd9ffa7@mail.gmail.com>
Date:	Tue, 19 May 2009 09:39:27 +0300
From:	Pekka Enberg <penberg@...helsinki.fi>
To:	Wu Fengguang <fengguang.wu@...el.com>
Cc:	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>,
	Christoph Lameter <cl@...ux-foundation.org>,
	KOSAKI Motohiro <kosaki.motohiro@...fujitsu.com>,
	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

Hi!

On Sat, May 16, 2009 at 12:00 PM, Wu Fengguang <fengguang.wu@...el.com> wrote:
> @@ -1272,28 +1273,40 @@ static void shrink_active_list(unsigned
>
>                /* page_referenced clears PageReferenced */
>                if (page_mapping_inuse(page) &&
> -                   page_referenced(page, 0, sc->mem_cgroup, &vm_flags))
> +                   page_referenced(page, 0, sc->mem_cgroup, &vm_flags)) {
>                        pgmoved++;
> +                       /*
> +                        * Identify referenced, file-backed active pages and
> +                        * give them one more trip around the active list. So
> +                        * that executable code get better chances to stay in
> +                        * memory under moderate memory pressure.  Anon pages
> +                        * are ignored, since JVM can create lots of anon
> +                        * VM_EXEC pages.
> +                        */
> +                       if ((vm_flags & VM_EXEC) && !PageAnon(page)) {
> +                               list_add(&page->lru, &l_active);
> +                               continue;
> +                       }

Why do we need to skip JIT'd code? There are plenty of desktop
applications that use Mono, for example, and it would be nice if we
gave them the same treatment as native applications. Likewise, I am
sure all browsers that use JIT for JavaScript need to be considered.

                                   Pekka
--
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/