From: js1304@gmail.com
Sent: 15 July 2020 06:05 From: Joonsoo Kim iamjoonsoo.kim@lge.com
Currently, preventing cma area in page allocation is implemented by using current_gfp_context(). However, there are two problems of this implementation.
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diff --git a/mm/page_alloc.c b/mm/page_alloc.c index 6416d08..cd53894 100644 --- a/mm/page_alloc.c +++ b/mm/page_alloc.c
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@@ -3693,6 +3691,16 @@ alloc_flags_nofragment(struct zone *zone, gfp_t gfp_mask) return alloc_flags; }
+static inline void current_alloc_flags(gfp_t gfp_mask,
unsigned int *alloc_flags)+{
- unsigned int pflags = READ_ONCE(current->flags);
- if (!(pflags & PF_MEMALLOC_NOCMA) &&
gfp_migratetype(gfp_mask) == MIGRATE_MOVABLE)*alloc_flags |= ALLOC_CMA;+}
I'd guess this would be easier to understand and probably generate better code if renamed and used as: alloc_flags |= can_alloc_cma(gpf_mask);
Given it is a 'static inline' the compiler might end up generating the same code. If you needed to clear a flag doing: alloc_flags = current_alloc_flags(gpf_mask, alloc_flags); is much better for non-inlined function.
David
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