Messages in this thread |  | | Subject | Re: [RFC PATCH] mm, compaction: allow compaction for GFP_NOFS requests | From | Vlastimil Babka <> | Date | Mon, 10 Oct 2016 08:44:33 +0200 |
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On 10/07/2016 11:21 AM, Michal Hocko wrote: > On Fri 07-10-16 10:15:07, Vlastimil Babka wrote: >> On 10/07/2016 08:50 AM, Michal Hocko wrote: >>> On Fri 07-10-16 07:27:37, Vlastimil Babka wrote: > [...] >>>> But make sure you don't break kcompactd and manual compaction from /proc, as >>>> they don't currently set cc->gfp_mask. Looks like until now it was only used >>>> to determine direct compactor's migratetype which is irrelevant in those >>>> contexts. >>> >>> OK, I see. This is really subtle. One way to go would be to provide a >>> fake gfp_mask for them. How does the following look to you? >> >> Looks OK. I'll have to think about the kcompactd case, as gfp mask implying >> unmovable migratetype might restrict it without good reason. But that would >> be separate patch anyway, yours doesn't change that (empty gfp_mask also >> means unmovable migratetype) and that's good. > > OK, I see. A follow up patch would be really trivial AFAICS. Just add > __GFP_MOVABLE to the mask. But I am not familiar with all these details > enough to propose a patch with full description.
Hm, actually the migratetype only matters for async compaction, and kcompactd uses sync_light, so __GFP_MOVABLE will have no effect right now.
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