[lkml]   [2016]   [Oct]   [10]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
Messages in this thread
SubjectRe: [RFC PATCH] mm, compaction: allow compaction for GFP_NOFS requests
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.

 \ /
  Last update: 2016-10-10 08:45    [W:0.081 / U:0.180 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site