linux-kernel - Re: [PATCH] block: Fix LSF default inconsistency

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]

Date:	Fri, 12 Dec 2008 17:37:48 +0000 (GMT)
From:	Hugh Dickins <hugh@...itas.com>
To:	Rik van Riel <riel@...hat.com>
cc:	KOSAKI Motohiro <kosaki.motohiro@...fujitsu.com>,
	Jens Axboe <jens.axboe@...cle.com>,
	Jean Delvare <khali@...ux-fr.org>,
	Trond Myklebust <Trond.Myklebust@...app.com>,
	LKML <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH] block: Fix LSF default inconsistency

On Fri, 12 Dec 2008, Rik van Riel wrote:
> Hugh Dickins wrote:
> > On Sat, 13 Dec 2008, KOSAKI Motohiro wrote:
> >   
> > > To move mlocked file cache page to unevictable list is useful although
> > > swapless embedded device.
> >
> > Yes, I don't understand why Rik suggested CONFIG_SWAP for it either.
> On swapless systems (with CONFIG_SWAP=n), we never scan
> the anon lists, so we do not need to split out the mlocked pages from
> the anon pages.
> 
> On a system with swap, we want to split out the mlocked pages
> so that scan balancing always works right.  So whenever
> CONFIG_SWAP is on, we want CONFIG_UNEVICTABLE_LRU
> to be on as well.
> 
> That means we can replace CONFIG_UNEVICTABLE_LRU
> with CONFIG_SWAP throughout the code, and get a kernel
> with the desired behaviour either way.

Sorry, I'm still puzzled: I thought the unevictable lru was for
shared file pages as well as for anon pages?  Of course I agree
with you over the anons (and shm and tmpfs get counted along
with the anons in this context), but wouldn't we still need
an unevictable lru for mlocked shared file pages?

Hugh
--
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/