The patch titled
Subject: mm/page_alloc: add some detailed comments in can_steal_fallback
has been added to the -mm mm-unstable branch. Its filename is
mm-page_alloc-add-some-detailed-comments-in-can_steal_fallback.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-add-some-detailed-comments-in-can_steal_fallback.patch
This patch will later appear in the mm-unstable branch at
git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
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------------------------------------------------------
From: gaoxiang17 <gaoxiang17@xxxxxxxxxx>
Subject: mm/page_alloc: add some detailed comments in can_steal_fallback
Date: Fri, 20 Sep 2024 20:20:30 +0800
Link: https://lkml.kernel.org/r/20240920122030.159751-1-gxxa03070307@xxxxxxxxx
Signed-off-by: gaoxiang17 <gaoxiang17@xxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
mm/page_alloc.c | 7 +++++++
1 file changed, 7 insertions(+)
--- a/mm/page_alloc.c~mm-page_alloc-add-some-detailed-comments-in-can_steal_fallback
+++ a/mm/page_alloc.c
@@ -1853,6 +1853,13 @@ static bool can_steal_fallback(unsigned
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 compact may occur to form large contiguous
+ * pages, and the next movable allocation may not need to steal. Unmovable and reclaimable
+ * allocation need to actually steal pages.
+ */
if (order >= pageblock_order / 2 ||
start_mt == MIGRATE_RECLAIMABLE ||
start_mt == MIGRATE_UNMOVABLE ||
_
Patches currently in -mm which might be from gaoxiang17@xxxxxxxxxx are
mm-page_alloc-add-some-detailed-comments-in-can_steal_fallback.patch
