Messages in this thread Patch in this message | | | From | Zhiguo Jiang <> | Subject | [PATCH v2 1/1] mm: ALLOC_HIGHATOMIC flag allocation issue | Date | Thu, 9 Nov 2023 15:31:33 +0800 |
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Add a new bool* argument to pass return flag instead of *alloc_flags and add the related comments.
Signed-off-by: Zhiguo Jiang <justinjiang@vivo.com> ---
Changelog: v1->v2: 1. Delete ALLOC_PCPLIST macro. 2. In rmqueue() add a new bool* argument to pass return flag instead of alloc_flags. 3. Add comments for reader understanding.
mm/internal.h | 1 - mm/page_alloc.c | 41 ++++++++++++++++++++++++++++++----------- 2 files changed, 30 insertions(+), 12 deletions(-)
diff --git a/mm/internal.h b/mm/internal.h index 98c14b16ce81..1d67c141902d 100755 --- a/mm/internal.h +++ b/mm/internal.h @@ -905,7 +905,6 @@ unsigned int reclaim_clean_pages_from_list(struct zone *zone, #endif #define ALLOC_HIGHATOMIC 0x200 /* Allows access to MIGRATE_HIGHATOMIC */ #define ALLOC_KSWAPD 0x800 /* allow waking of kswapd, __GFP_KSWAPD_RECLAIM set */ -#define ALLOC_PCPLIST 0x1000 /* Allocations from pcplist */ /* Flags that allow allocations below the min watermark. */ #define ALLOC_RESERVES (ALLOC_NON_BLOCK|ALLOC_MIN_RESERVE|ALLOC_HIGHATOMIC|ALLOC_OOM) diff --git a/mm/page_alloc.c b/mm/page_alloc.c index 67cec88164b1..3c84c3e3eeb0 100755 --- a/mm/page_alloc.c +++ b/mm/page_alloc.c @@ -2854,6 +2854,11 @@ struct page *__rmqueue_pcplist(struct zone *zone, unsigned int order, int batch = nr_pcp_alloc(pcp, zone, order); int alloced; + /* + * If pcplist is empty and alloc_flags is with ALLOC_HIGHATOMIC, + * it should alloc from buddy highatomic migrate freelist firstly + * to ensure quick and successful allocation. + */ if (alloc_flags & ALLOC_HIGHATOMIC) goto out; @@ -2925,8 +2930,8 @@ __no_sanitize_memory static inline struct page *rmqueue(struct zone *preferred_zone, struct zone *zone, unsigned int order, - gfp_t gfp_flags, unsigned int *alloc_flags, - int migratetype) + gfp_t gfp_flags, unsigned int alloc_flags, + int migratetype, bool *highatomc_allocation) { struct page *page; @@ -2938,19 +2943,33 @@ struct page *rmqueue(struct zone *preferred_zone, if (likely(pcp_allowed_order(order))) { page = rmqueue_pcplist(preferred_zone, zone, order, - migratetype, *alloc_flags); - if (likely(page)) { - *alloc_flags |= ALLOC_PCPLIST; + migratetype, alloc_flags); + if (likely(page)) goto out; - } } - page = rmqueue_buddy(preferred_zone, zone, order, *alloc_flags, + page = rmqueue_buddy(preferred_zone, zone, order, alloc_flags, migratetype); + /* + * The high-order atomic allocation pageblock reserved conditions: + * + * If the high-order atomic allocation page is alloced from pcplist, + * the highatomic pageblock does not need to be reserved, which can + * void to migrate an increasing number of pages into buddy + * MIGRATE_HIGHATOMIC freelist and lead to an increasing risk of + * allocation failure on other buddy migrate freelists. + * + * If the high-order atomic allocation page is alloced from buddy + * highatomic migrate freelist, regardless of whether the allocation + * is successful or not, the highatomic pageblock can try to be + * reserved. + */ + if (unlikely(alloc_flags & ALLOC_HIGHATOMIC)) + *highatomc_allocation = true; out: /* Separate test+clear to avoid unnecessary atomics */ - if ((*alloc_flags & ALLOC_KSWAPD) && + if ((alloc_flags & ALLOC_KSWAPD) && unlikely(test_bit(ZONE_BOOSTED_WATERMARK, &zone->flags))) { clear_bit(ZONE_BOOSTED_WATERMARK, &zone->flags); wakeup_kswapd(zone, 0, 0, zone_idx(zone)); @@ -3218,6 +3237,7 @@ get_page_from_freelist(gfp_t gfp_mask, unsigned int order, int alloc_flags, struct pglist_data *last_pgdat = NULL; bool last_pgdat_dirty_ok = false; bool no_fallback; + bool highatomc_allocation = false; retry: /* @@ -3349,7 +3369,7 @@ get_page_from_freelist(gfp_t gfp_mask, unsigned int order, int alloc_flags, try_this_zone: page = rmqueue(ac->preferred_zoneref->zone, zone, order, - gfp_mask, &alloc_flags, ac->migratetype); + gfp_mask, alloc_flags, ac->migratetype, &highatomc_allocation); if (page) { prep_new_page(page, order, gfp_mask, alloc_flags); @@ -3357,8 +3377,7 @@ get_page_from_freelist(gfp_t gfp_mask, unsigned int order, int alloc_flags, * If this is a high-order atomic allocation then check * if the pageblock should be reserved for the future */ - if (unlikely(alloc_flags & ALLOC_HIGHATOMIC) && - unlikely(!(alloc_flags & ALLOC_PCPLIST))) + if (unlikely(highatomc_allocation)) reserve_highatomic_pageblock(page, zone); return page; -- 2.39.0
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