Messages in this thread | | | From | KOSAKI Motohiro <> | Subject | Re: [PATCH v3] mm: make expand_downwards symmetrical to expand_upwards | Date | Wed, 20 Apr 2011 16:15:23 +0900 (JST) |
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> On Wed, Apr 20, 2011 at 4:23 AM, KOSAKI Motohiro > <kosaki.motohiro@jp.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
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