Messages in this thread | | | Date | Thu, 11 Feb 2010 09:08:58 -0500 | From | Rik van Riel <> | Subject | Re: [patch 6/7 -mm] oom: avoid oom killer for lowmem allocations |
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On 02/11/2010 04:19 AM, David Rientjes wrote: > On Wed, 10 Feb 2010, Rik van Riel wrote: > >>> diff --git a/mm/page_alloc.c b/mm/page_alloc.c >>> --- a/mm/page_alloc.c >>> +++ b/mm/page_alloc.c >>> @@ -1914,6 +1914,9 @@ rebalance: >>> * running out of options and have to consider going OOM >>> */ >>> if (!did_some_progress) { >>> + /* The oom killer won't necessarily free lowmem */ >>> + if (high_zoneidx< ZONE_NORMAL) >>> + goto nopage; >>> if ((gfp_mask& __GFP_FS)&& !(gfp_mask& __GFP_NORETRY)) { >>> if (oom_killer_disabled) >>> goto nopage; >> >> Are there architectures that only have one memory zone? >> > > It actually ends up not to matter because of how gfp_zone() is implemented > (and you can do it with mem= on architectures with larger ZONE_DMA zones > such as ia64). ZONE_NORMAL is always guaranteed to be defined regardless > of architecture or configuration because it's the default zone for memory > allocation unless specified by a bit in GFP_ZONEMASK, it doesn't matter > whether it actually has memory or not. high_zoneidx in this case is just > gfp_zone(gfp_flags) which always defaults to ZONE_NORMAL when one of the > GFP_ZONEMASK bits is not set. Thus, the only way to for the conditional > in this patch to be true is when __GFP_DMA, or __GFP_DMA32 for x86_64, is > passed to the page allocator and CONFIG_ZONE_DMA or CONFIG_ZONE_DMA32 is > enabled, respectively.
Fair enough.
Acked-by: Rik van Riel <riel@redhat.com>
-- All rights reversed.
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