The patch titled
Subject: mm: page_alloc: remove stale CMA guard code
has been added to the -mm mm-unstable branch. Its filename is
mm-page_alloc-remove-stale-cma-guard-code.patch
This patch will shortly appear at
https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/mm-page_alloc-remove-stale-cma-guard-code.patch
This patch will later appear in the mm-unstable branch at
git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
Before you just go and hit "reply", please:
a) Consider who else should be cc'ed
b) Prefer to cc a suitable mailing list as well
c) Ideally: find the original patch on the mailing list and do a
reply-to-all to that, adding suitable additional cc's
*** Remember to use Documentation/process/submit-checklist.rst when testing your code ***
The -mm tree is included into linux-next via the mm-everything
branch at git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
and is updated there every 2-3 working days
------------------------------------------------------
From: Johannes Weiner <hannes@xxxxxxxxxxx>
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@xxxxxxxxxxx
Signed-off-by: Johannes Weiner <hannes@xxxxxxxxxxx>
Cc: David Hildenbrand <david@xxxxxxxxxx>
Cc: Joonsoo Kim <iamjoonsoo.kim@xxxxxxx>
Cc: Mel Gorman <mgorman@xxxxxxxxxxxxxxxxxxx>
Cc: Miaohe Lin <linmiaohe@xxxxxxxxxx>
Cc: Pasha Tatashin <pasha.tatashin@xxxxxxxxxx>
Cc: Vlastimil Babka <vbabka@xxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
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
@@ -2671,12 +2671,6 @@ 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) {
@@ -2810,17 +2804,10 @@ 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@xxxxxxxxxxx are
mm-page_alloc-remove-stale-cma-guard-code.patch
