lkml.org 
[lkml]   [2020]   [Jul]   [9]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
From
Date
SubjectRe: [PATCH v4 06/11] mm/migrate: make a standard migration target allocation function
2020년 7월 8일 (수) 오전 4:00, Michal Hocko <mhocko@kernel.org>님이 작성:
>
> On Tue 07-07-20 16:49:51, Vlastimil Babka wrote:
> > On 7/7/20 9:44 AM, js1304@gmail.com wrote:
> > > From: Joonsoo Kim <iamjoonsoo.kim@lge.com>
> > >
> > > There are some similar functions for migration target allocation. Since
> > > there is no fundamental difference, it's better to keep just one rather
> > > than keeping all variants. This patch implements base migration target
> > > allocation function. In the following patches, variants will be converted
> > > to use this function.
> > >
> > > Changes should be mechanical but there are some differences. First, Some
> > > callers' nodemask is assgined to NULL since NULL nodemask will be
> > > considered as all available nodes, that is, &node_states[N_MEMORY].
> > > Second, for hugetlb page allocation, gfp_mask is ORed since a user could
> > > provide a gfp_mask from now on.
> >
> > I think that's wrong. See how htlb_alloc_mask() determines between
> > GFP_HIGHUSER_MOVABLE and GFP_HIGHUSER, but then you OR it with __GFP_MOVABLE so
> > it's always GFP_HIGHUSER_MOVABLE.

Indeed.

> Right you are! Not that it would make any real difference because only
> migrateable hugetlb pages will get __GFP_MOVABLE and so we shouldn't
> really end up here for !movable pages in the first place (not sure about
> soft offlining at this moment). But yeah it would be simply better to
> override gfp mask for hugetlb which we have been doing anyway.

Override gfp mask doesn't work since some users will call this function with
__GFP_THISNODE. I will use hugepage_movable_supported() here and
clear __GFP_MOVABLE if needed.

Thanks.

Thanks.

\
 
 \ /
  Last update: 2020-07-09 09:15    [W:0.067 / U:3.092 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site