linux-kernel - Re: [PATCH 5/5] proc: export more page flags in /proc/kpageflags

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: <20090429080553.GA14838@localhost>
Date:	Wed, 29 Apr 2009 16:05:53 +0800
From:	Wu Fengguang <fengguang.wu@...el.com>
To:	Matt Mackall <mpm@...enic.com>
Cc:	Andrew Morton <akpm@...ux-foundation.org>,
	LKML <linux-kernel@...r.kernel.org>,
	KOSAKI Motohiro <kosaki.motohiro@...fujitsu.com>,
	Andi Kleen <andi@...stfloor.org>,
	Alexey Dobriyan <adobriyan@...il.com>,
	"linux-mm@...ck.org" <linux-mm@...ck.org>
Subject: Re: [PATCH 5/5] proc: export more page flags in /proc/kpageflags

On Wed, Apr 29, 2009 at 01:49:21AM +0800, Matt Mackall wrote:
> On Tue, 2009-04-28 at 09:09 +0800, Wu Fengguang wrote:
> > plain text document attachment (kpageflags-extending.patch)
> > Export 9 page flags in /proc/kpageflags, and 8 more for kernel developers.
> 
> My only concern with this patch is it knows a bit too much about SLUB
> internals (and perhaps not enough about SLOB, which also overloads
> flags). 

Yup. PG_private=PG_slob_free is not masked because SLOB actually does
not set PG_slab at all. I wonder if it's safe to do this change:

        /* SLOB */
-       PG_slob_page = PG_active,
+       PG_slob_page = PG_slab,
        PG_slob_free = PG_private,


In the page-types output:

         flags  page-count       MB  symbolic-flags                     long-symbolic-flags
0x000800000040        7113       27  ______A_________________P____      active,private
0x000000000040          66        0  ______A______________________      active

The above two lines are obviously for SLOB pages.  It indicates lots of
free SLOB pages. So my question is:

- Do you have other means to get the nr_free_slobs info? (I found none in the code)
or
- Will exporting the SL*B overloaded flags going to help?

Thanks,
Fengguang
--
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/