Messages in this thread | | | Date | Thu, 12 Sep 2013 15:51:38 +0900 | From | Joonsoo Kim <> | Subject | Re: [PATCH 01/16] slab: correct pfmemalloc check |
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On Wed, Sep 11, 2013 at 02:30:03PM +0000, Christoph Lameter wrote: > On Thu, 22 Aug 2013, Joonsoo Kim wrote: > > > And, therefore we should check pfmemalloc in page flag of first page, > > but current implementation don't do that. virt_to_head_page(obj) just > > return 'struct page' of that object, not one of first page, since the SLAB > > don't use __GFP_COMP when CONFIG_MMU. To get 'struct page' of first page, > > we first get a slab and try to get it via virt_to_head_page(slab->s_mem). > > Maybe using __GFP_COMP would make it consistent across all allocators and > avoid the issue? We then do only have to set the flags on the first page.
Yes, you are right. It can be solved by using __GFP_COMP. But I made this patch to clarify the problem in current code and to be merged seperately.
If I solve the problem with __GFP_COMP which is implemented in [09/16] of this patchset, it would also weaken the purpose of that patch.
Thanks.
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