Messages in this thread | | | Date | Sat, 16 Apr 2016 16:31:36 -0400 | From | Michal Hocko <> | Subject | Re: [PATCH 17/19] dm: get rid of superfluous gfp flags |
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On Fri 15-04-16 14:41:29, Mikulas Patocka wrote: > > > On Fri, 15 Apr 2016, Michal Hocko wrote: > > > On Fri 15-04-16 08:29:28, Mikulas Patocka wrote: > > > > > > > > > On Mon, 11 Apr 2016, Michal Hocko wrote: > > > > > > > From: Michal Hocko <mhocko@suse.com> > > > > > > > > copy_params seems to be little bit confused about which allocation flags > > > > to use. It enforces GFP_NOIO even though it uses > > > > memalloc_noio_{save,restore} which enforces GFP_NOIO at the page > > > > > > memalloc_noio_{save,restore} is used because __vmalloc is flawed and > > > doesn't respect GFP_NOIO properly (it doesn't use gfp flags when > > > allocating pagetables). > > > > Yes and there are no plans to change __vmalloc to properly propagate gfp > > flags through the whole call chain and that is why we have > > memalloc_noio thingy. If that ever changes later the GFP_NOIO can be > > added in favor of memalloc_noio API. Both are clearly redundant. > > -- > > Michal Hocko > > SUSE Labs > > You could move memalloc_noio_{save,restore} to __vmalloc. Something like > > if (!(gfp_mask & __GFP_IO)) > noio_flag = memalloc_noio_save(); > ... > if (!(gfp_mask & __GFP_IO)) > memalloc_noio_restore(noio_flag); > > That would be better than repeating this hack in every __vmalloc caller > that need GFP_NOIO.
It is not my intention to change __vmalloc behavior. If you strongly oppose the GFP_NOIO change I can drop it from the patch. It is __GFP_REPEAT which I am after.
-- Michal Hocko SUSE Labs
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