From f945116e4e191cd543ecd56d9f13e6331494847c Mon Sep 17 00:00:00 2001 From: Johannes Weiner Date: Thu, 24 Aug 2023 11:38:21 -0400 Subject: mm: page_alloc: remove stale CMA guard code In the past, movable allocations could be disallowed from CMA through PF_MEMALLOC_PIN. As CMA pages are funneled through the MOVABLE pcplist, this required filtering that cornercase during allocations, such that pinnable allocations wouldn't accidentally get a CMA page. However, since 8e3560d963d2 ("mm: honor PF_MEMALLOC_PIN for all movable pages"), PF_MEMALLOC_PIN automatically excludes __GFP_MOVABLE. Once again, MOVABLE implies CMA is allowed. Remove the stale filtering code. Also remove a stale comment that was introduced as part of the filtering code, because the filtering let order-0 pages fall through to the buddy allocator. See 1d91df85f399 ("mm/page_alloc: handle a missing case for memalloc_nocma_{save/restore} APIs") for context. The comment's been obsolete since the introduction of the explicit ALLOC_HIGHATOMIC flag in eb2e2b425c69 ("mm/page_alloc: explicitly record high-order atomic allocations in alloc_flags"). Link: https://lkml.kernel.org/r/20230824153821.243148-1-hannes@cmpxchg.org Signed-off-by: Johannes Weiner Acked-by: Mel Gorman Cc: David Hildenbrand Cc: Joonsoo Kim Cc: Miaohe Lin Cc: Pasha Tatashin Cc: Vlastimil Babka Signed-off-by: Andrew Morton --- mm/page_alloc.c | 21 ++++----------------- 1 file changed, 4 insertions(+), 17 deletions(-) (limited to 'mm') diff --git a/mm/page_alloc.c b/mm/page_alloc.c index 452459836b71..0c5be12f9336 100644 --- a/mm/page_alloc.c +++ b/mm/page_alloc.c @@ -2641,12 +2641,6 @@ struct page *rmqueue_buddy(struct zone *preferred_zone, struct zone *zone, do { page = NULL; spin_lock_irqsave(&zone->lock, flags); - /* - * order-0 request can reach here when the pcplist is skipped - * due to non-CMA allocation context. HIGHATOMIC area is - * reserved for high-order atomic allocation, so order-0 - * request should skip it. - */ if (alloc_flags & ALLOC_HIGHATOMIC) page = __rmqueue_smallest(zone, order, MIGRATE_HIGHATOMIC); if (!page) { @@ -2780,17 +2774,10 @@ struct page *rmqueue(struct zone *preferred_zone, WARN_ON_ONCE((gfp_flags & __GFP_NOFAIL) && (order > 1)); if (likely(pcp_allowed_order(order))) { - /* - * MIGRATE_MOVABLE pcplist could have the pages on CMA area and - * we need to skip it when CMA area isn't allowed. - */ - if (!IS_ENABLED(CONFIG_CMA) || alloc_flags & ALLOC_CMA || - migratetype != MIGRATE_MOVABLE) { - page = rmqueue_pcplist(preferred_zone, zone, order, - migratetype, alloc_flags); - if (likely(page)) - goto out; - } + page = rmqueue_pcplist(preferred_zone, zone, order, + migratetype, alloc_flags); + if (likely(page)) + goto out; } page = rmqueue_buddy(preferred_zone, zone, order, alloc_flags, -- cgit v1.2.3