[merged mm-stable] mm-page_alloc-remove-stale-cma-guard-code.patch removed from -mm tree

[merged mm-stable] mm-page_alloc-remove-stale-cma-guard-code.patch removed from -mm tree

[Andrew Morton]

The quilt patch titled
     Subject: mm: page_alloc: remove stale CMA guard code
has been removed from the -mm tree.  Its filename was
     mm-page_alloc-remove-stale-cma-guard-code.patch

This patch was dropped because it was merged into the mm-stable branch
of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm

------------------------------------------------------
From: Johannes Weiner <hannes@cmpxchg.org>
Subject: mm: page_alloc: remove stale CMA guard code
Date: Thu, 24 Aug 2023 11:38:21 -0400

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 <hannes@cmpxchg.org>
Acked-by: Mel Gorman <mgorman@techsingularity.net>
Cc: David Hildenbrand <david@redhat.com>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: Miaohe Lin <linmiaohe@huawei.com>
Cc: Pasha Tatashin <pasha.tatashin@soleen.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---

 mm/page_alloc.c |   21 ++++-----------------
 1 file changed, 4 insertions(+), 17 deletions(-)

--- a/mm/page_alloc.c~mm-page_alloc-remove-stale-cma-guard-code
+++ a/mm/page_alloc.c
@@ -2641,12 +2641,6 @@ struct page *rmqueue_buddy(struct 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 *prefer
 	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,
_

Patches currently in -mm which might be from hannes@cmpxchg.org are

memcontrol-ensure-memcg-acquired-by-id-is-properly-set-up.patch