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.
First, this doesn't work for allocation fastpath. In the fastpath, original gfp_mask is used since current_gfp_context() is introduced in order to control reclaim and it is on slowpath. Second, clearing __GFP_MOVABLE has a side effect to exclude the memory on the ZONE_MOVABLE for allocation target.
To fix these problems, this patch changes the implementation to exclude cma area in page allocation. Main point of this change is using the alloc_flags. alloc_flags is mainly used to control allocation so it fits for excluding cma area in allocation.
Fixes: d7fefcc (mm/cma: add PF flag to force non cma alloc) Cc: stable@vger.kernel.org Signed-off-by: Joonsoo Kim iamjoonsoo.kim@lge.com --- include/linux/sched/mm.h | 4 ---- mm/page_alloc.c | 27 +++++++++++++++------------ 2 files changed, 15 insertions(+), 16 deletions(-)
diff --git a/include/linux/sched/mm.h b/include/linux/sched/mm.h index 44ad5b7..a73847a 100644 --- a/include/linux/sched/mm.h +++ b/include/linux/sched/mm.h @@ -191,10 +191,6 @@ static inline gfp_t current_gfp_context(gfp_t flags) flags &= ~(__GFP_IO | __GFP_FS); else if (pflags & PF_MEMALLOC_NOFS) flags &= ~__GFP_FS; -#ifdef CONFIG_CMA - if (pflags & PF_MEMALLOC_NOCMA) - flags &= ~__GFP_MOVABLE; -#endif } return flags; } 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 @@ -2791,7 +2791,7 @@ __rmqueue(struct zone *zone, unsigned int order, int migratetype, * allocating from CMA when over half of the zone's free memory * is in the CMA area. */ - if (migratetype == MIGRATE_MOVABLE && + if (alloc_flags & ALLOC_CMA && zone_page_state(zone, NR_FREE_CMA_PAGES) > zone_page_state(zone, NR_FREE_PAGES) / 2) { page = __rmqueue_cma_fallback(zone, order); @@ -2802,7 +2802,7 @@ __rmqueue(struct zone *zone, unsigned int order, int migratetype, retry: page = __rmqueue_smallest(zone, order, migratetype); if (unlikely(!page)) { - if (migratetype == MIGRATE_MOVABLE) + if (alloc_flags & ALLOC_CMA) page = __rmqueue_cma_fallback(zone, order);
if (!page && __rmqueue_fallback(zone, order, migratetype, @@ -3502,11 +3502,9 @@ static inline long __zone_watermark_unusable_free(struct zone *z, if (likely(!alloc_harder)) unusable_free += z->nr_reserved_highatomic;
-#ifdef CONFIG_CMA /* If allocation can't use CMA areas don't use free CMA pages */ - if (!(alloc_flags & ALLOC_CMA)) + if (IS_ENABLED(CONFIG_CMA) && !(alloc_flags & ALLOC_CMA)) unusable_free += zone_page_state(z, NR_FREE_CMA_PAGES); -#endif
return unusable_free; } @@ -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; +} + /* * get_page_from_freelist goes through the zonelist trying to allocate * a page. @@ -3706,6 +3714,8 @@ get_page_from_freelist(gfp_t gfp_mask, unsigned int order, int alloc_flags, struct pglist_data *last_pgdat_dirty_limit = NULL; bool no_fallback;
+ current_alloc_flags(gfp_mask, &alloc_flags); + retry: /* * Scan zonelist, looking for a zone with enough free. @@ -4339,10 +4349,6 @@ gfp_to_alloc_flags(gfp_t gfp_mask) } else if (unlikely(rt_task(current)) && !in_interrupt()) alloc_flags |= ALLOC_HARDER;
-#ifdef CONFIG_CMA - if (gfp_migratetype(gfp_mask) == MIGRATE_MOVABLE) - alloc_flags |= ALLOC_CMA; -#endif return alloc_flags; }
@@ -4808,9 +4814,6 @@ static inline bool prepare_alloc_pages(gfp_t gfp_mask, unsigned int order, if (should_fail_alloc_page(gfp_mask, order)) return false;
- if (IS_ENABLED(CONFIG_CMA) && ac->migratetype == MIGRATE_MOVABLE) - *alloc_flags |= ALLOC_CMA; - return true; }