diff options
| author | Thadeu Lima de Souza Cascardo <cascardo@igalia.com> | 2025-08-14 14:22:45 -0300 |
|---|---|---|
| committer | Andrew Morton <akpm@linux-foundation.org> | 2025-09-13 16:55:01 -0700 |
| commit | 6a204d4b14c99232e05d35305c27ebce1c009840 (patch) | |
| tree | d1da4ded52c742684e7e19fcd5e9488cbd09083f /mm/page_alloc.c | |
| parent | 668208b161a0b679427e7d0f34c0a65fd7d23979 (diff) | |
mm/page_alloc: only set ALLOC_HIGHATOMIC for __GPF_HIGH allocations
Commit 524c48072e56 ("mm/page_alloc: rename ALLOC_HIGH to
ALLOC_MIN_RESERVE") is the start of a series that explains how __GFP_HIGH,
which implies ALLOC_MIN_RESERVE, is going to be used instead of
__GFP_ATOMIC for high atomic reserves.
Commit eb2e2b425c69 ("mm/page_alloc: explicitly record high-order atomic
allocations in alloc_flags") introduced ALLOC_HIGHATOMIC for such
allocations of order higher than 0. It still used __GFP_ATOMIC, though.
Then, commit 1ebbb21811b7 ("mm/page_alloc: explicitly define how
__GFP_HIGH non-blocking allocations accesses reserves") just turned that
check for !__GFP_DIRECT_RECLAIM, ignoring that high atomic reserves were
expected to test for __GFP_HIGH.
This leads to high atomic reserves being added for high-order GFP_NOWAIT
allocations and others that clear __GFP_DIRECT_RECLAIM, which is
unexpected. Later, those reserves lead to 0-order allocations going to
the slow path and starting reclaim.
From /proc/pagetypeinfo, without the patch:
Node 0, zone DMA, type HighAtomic 0 0 0 0 0 0 0 0 0 0 0
Node 0, zone DMA32, type HighAtomic 1 8 10 9 7 3 0 0 0 0 0
Node 0, zone Normal, type HighAtomic 64 20 12 5 0 0 0 0 0 0 0
With the patch:
Node 0, zone DMA, type HighAtomic 0 0 0 0 0 0 0 0 0 0 0
Node 0, zone DMA32, type HighAtomic 0 0 0 0 0 0 0 0 0 0 0
Node 0, zone Normal, type HighAtomic 0 0 0 0 0 0 0 0 0 0 0
Link: https://lkml.kernel.org/r/20250814172245.1259625-1-cascardo@igalia.com
Fixes: 1ebbb21811b7 ("mm/page_alloc: explicitly define how __GFP_HIGH non-blocking allocations accesses reserves")
Signed-off-by: Thadeu Lima de Souza Cascardo <cascardo@igalia.com>
Tested-by: Helen Koike <koike@igalia.com>
Reviewed-by: Vlastimil Babka <vbabka@suse.cz>
Tested-by: Sergey Senozhatsky <senozhatsky@chromium.org>
Acked-by: Michal Hocko <mhocko@suse.com>
Cc: Mel Gorman <mgorman@techsingularity.net>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: NeilBrown <neilb@suse.de>
Cc: Thierry Reding <thierry.reding@gmail.com>
Cc: Brendan Jackman <jackmanb@google.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Zi Yan <ziy@nvidia.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Diffstat (limited to 'mm/page_alloc.c')
| -rw-r--r-- | mm/page_alloc.c | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/mm/page_alloc.c b/mm/page_alloc.c index d1d037f97c5f..09241bb7663e 100644 --- a/mm/page_alloc.c +++ b/mm/page_alloc.c @@ -4408,7 +4408,7 @@ gfp_to_alloc_flags(gfp_t gfp_mask, unsigned int order) if (!(gfp_mask & __GFP_NOMEMALLOC)) { alloc_flags |= ALLOC_NON_BLOCK; - if (order > 0) + if (order > 0 && (alloc_flags & ALLOC_MIN_RESERVE)) alloc_flags |= ALLOC_HIGHATOMIC; } |