Messages in this thread | | | Date | Wed, 26 Oct 2011 00:10:26 -0700 (PDT) | From | David Rientjes <> | Subject | Re: [PATCH] mm: avoid livelock on !__GFP_FS allocations |
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On Tue, 25 Oct 2011, Colin Cross wrote:
> > gfp_allowed_mask is initialized to GFP_BOOT_MASK to start so that __GFP_FS > > is never allowed before the slab allocator is completely initialized, so > > you've now implicitly made all early boot allocations to be __GFP_NORETRY > > even though they may not pass it. > > Only before interrupts are enabled, and then isn't it vulnerable to > the same livelock? Interrupts are off, single cpu, kswapd can't run. > If an allocation ever failed, which seems unlikely, why would retrying > help? >
If you want to claim gfp_allowed_mask as a pm-only entity, then I see no problem with this approach. However, if gfp_allowed_mask would be allowed to temporarily change after init for another purpose then it would make sense to retry because another allocation with __GFP_FS on another cpu or kswapd could start making progress could allow for future memory freeing.
The suggestion to add a hook directly into a pm-interface was so that we could isolate it only to suspend and, to me, is the most maintainable solution.
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