Messages in this thread | | | Subject | Re: [PATCH v5 4/9] mm/migrate: clear __GFP_RECLAIM to make the migration callback consistent with regular THP allocations | From | Vlastimil Babka <> | Date | Mon, 13 Jul 2020 09:52:20 +0200 |
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On 7/13/20 8:41 AM, js1304@gmail.com wrote: > From: Joonsoo Kim <iamjoonsoo.kim@lge.com> > > new_page_nodemask is a migration callback and it tries to use a common > gfp flags for the target page allocation whether it is a base page or a > THP. The later only adds GFP_TRANSHUGE to the given mask. This results > in the allocation being slightly more aggressive than necessary because > the resulting gfp mask will contain also __GFP_RECLAIM_KSWAPD. THP > allocations usually exclude this flag to reduce over eager background > reclaim during a high THP allocation load which has been seen during > large mmaps initialization. There is no indication that this is a > problem for migration as well but theoretically the same might happen > when migrating large mappings to a different node. Make the migration > callback consistent with regular THP allocations. > > Signed-off-by: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Thanks!
Typo below (I assume Andrew will fix it)
> --- > mm/migrate.c | 5 +++++ > 1 file changed, 5 insertions(+) > > diff --git a/mm/migrate.c b/mm/migrate.c > index 3b3d918..1cfc965 100644 > --- a/mm/migrate.c > +++ b/mm/migrate.c > @@ -1547,6 +1547,11 @@ struct page *new_page_nodemask(struct page *page, > } > > if (PageTransHuge(page)) { > + /* > + * clear __GFP_RECALIM to make the migration callback
__GFP_RECLAIM
> + * consistent with regular THP allocations. > + */ > + gfp_mask &= ~__GFP_RECLAIM; > gfp_mask |= GFP_TRANSHUGE; > order = HPAGE_PMD_ORDER; > } >
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