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| author |   gaoxiang17 <gaoxiang17@xiaomi.com> | 2024-09-20 20:20:30 +0800 |
|---|---|---|
| committer |   Andrew Morton <akpm@linux-foundation.org> | 2025-01-13 22:40:42 -0800 |
| commit | 6025ea5abbe5d813d6a41c78e6ea14259fb503f4 (patch) | |
| tree | c76126484bee25051c14548b1463383608fece21 | |
| parent | mm:kasan: fix sparse warnings: Should it be static? (diff) | |
| download | wireguard-linux-6025ea5abbe5d813d6a41c78e6ea14259fb503f4.tar.xz wireguard-linux-6025ea5abbe5d813d6a41c78e6ea14259fb503f4.zip | |
mm/page_alloc: add some detailed comments in can_steal_fallback
[akpm@linux-foundation.org: tweak grammar, fit to 80 cols]
Link: https://lkml.kernel.org/r/20240920122030.159751-1-gxxa03070307@gmail.com
Signed-off-by: gaoxiang17 <gaoxiang17@xiaomi.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
| -rw-r--r-- | mm/page_alloc.c | 8 |
1 files changed, 8 insertions, 0 deletions
diff --git a/mm/page_alloc.c b/mm/page_alloc.c index 7a2853b7967d..a887ba2cc91d 100644 --- a/mm/page_alloc.c +++ b/mm/page_alloc.c @@ -1855,6 +1855,14 @@ static bool can_steal_fallback(unsigned int order, int start_mt) if (order >= pageblock_order) return true; + /* + * Movable pages won't cause permanent fragmentation, so when you alloc + * small pages, you just need to temporarily steal unmovable or + * reclaimable pages that are closest to the request size. After a + * while, memory compaction may occur to form large contiguous pages, + * and the next movable allocation may not need to steal. Unmovable and + * reclaimable allocations need to actually steal pages. + */ if (order >= pageblock_order / 2 || start_mt == MIGRATE_RECLAIMABLE || start_mt == MIGRATE_UNMOVABLE || |