linux-kernel - Re: [PATCH v3] mm: make expand_downwards symmetrical to expand

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: <20110420161615.462D.A69D9226@jp.fujitsu.com>
Date:	Wed, 20 Apr 2011 16:15:23 +0900 (JST)
From:	KOSAKI Motohiro <kosaki.motohiro@...fujitsu.com>
To:	Pekka Enberg <penberg@...nel.org>
Cc:	kosaki.motohiro@...fujitsu.com, Christoph Lameter <cl@...ux.com>,
	James Bottomley <James.Bottomley@...senpartnership.com>,
	Michal Hocko <mhocko@...e.cz>,
	Andrew Morton <akpm@...ux-foundation.org>,
	Hugh Dickins <hughd@...gle.com>, linux-mm@...ck.org,
	LKML <linux-kernel@...r.kernel.org>,
	linux-parisc@...r.kernel.org, David Rientjes <rientjes@...gle.com>
Subject: Re: [PATCH v3] mm: make expand_downwards symmetrical to expand_upwards

> On Wed, Apr 20, 2011 at 4:23 AM, KOSAKI Motohiro
> <kosaki.motohiro@...fujitsu.com> wrote:
> > I'm worry about this patch. A lot of mm code assume !NUMA systems
> > only have node 0. Not only SLUB.
> 
> So is that a valid assumption or not? Christoph seems to think it is
> and James seems to think it's not. Which way should we aim to fix it?
> Would be nice if other people chimed in as we already know what James
> and Christoph think.

I'm sorry. I don't know it really. The fact was gone into historical myst. ;-)

Now, CONFIG_NUMA has mainly five meanings.

1) system may has !0 node id.
2) compile mm/mempolicy.c (ie enable mempolicy APIs)
3) Allocator (kmalloc, vmalloc, alloc_page, et al) awake NUMA topology.
4) enable zone-reclaim feature
5) scheduler makes per-node load balancing scheduler domain

Anyway, we have to fix this issue.  I'm digging which fixing way has least risk.


btw, x86 don't have an issue. Probably it's a reason why this issue was neglected
long time.

arch/x86/Kconfig
-------------------------------------
config ARCH_DISCONTIGMEM_ENABLE
        def_bool y
        depends on NUMA && X86_32



--
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/