[PATCH 2/7] mm/page_alloc: Treat RT tasks similar to __GFP_HIGH

Mel Gorman
2023-01-09T15:19:05Z

RT tasks are allowed to dip below the min reserve but ALLOC_HARDER is
typically combined with ALLOC_MIN_RESERVE so RT tasks are a little
unusual. While there is some justification for allowing RT tasks
access to memory reserves, there is a strong chance that a RT task
that is also under memory pressure is at risk of missing deadlines
anyway. Relax how much reserves an RT task can access by treating
it the same as __GFP_HIGH allocations.

Signed-off-by: Mel Gorman <mgorman@techsingularity.net>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
---
mm/page_alloc.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index 244c1e675dc8..0040b4e00913 100644
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -4847,7 +4847,7 @@ gfp_to_alloc_flags(gfp_t gfp_mask)
*/
alloc_flags &= ~ALLOC_CPUSET;
} else if (unlikely(rt_task(current)) && in_task())
- alloc_flags |= ALLOC_HARDER;
+ alloc_flags |= ALLOC_MIN_RESERVE;

alloc_flags = gfp_to_alloc_flags_cma(gfp_mask, alloc_flags);

--
2.35.3