+ mm-compaction-stop-recording-free-page-order-in-page-private.patch added to mm-new branch

+ mm-compaction-stop-recording-free-page-order-in-page-private.patch added to mm-new branch

[Andrew Morton]

The patch titled
     Subject: mm/compaction: stop recording free page order in page->private
has been added to the -mm mm-new branch.  Its filename is
     mm-compaction-stop-recording-free-page-order-in-page-private.patch

This patch will shortly appear at
     https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/mm-compaction-stop-recording-free-page-order-in-page-private.patch

This patch will later appear in the mm-new branch at
    git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm

Note, mm-new is a provisional staging ground for work-in-progress
patches, and acceptance into mm-new is a notification for others take
notice and to finish up reviews.  Please do not hesitate to respond to
review feedback and post updated versions to replace or incrementally
fixup patches in mm-new.

The mm-new branch of mm.git is not included in linux-next

If a few days of testing in mm-new is successful, the patch will me moved
into mm.git's mm-unstable branch, which is included in linux-next

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and is updated there most days

------------------------------------------------------
From: Zi Yan <ziy@nvidia.com>
Subject: mm/compaction: stop recording free page order in page->private
Date: Fri, 03 Jul 2026 09:47:47 -0400

Commit 733aea0b3a7bb ("mm/compaction: add support for >0 order folio
memory compaction.") stores isolated free pages in an array indexed by
free page orders, it is no longer needed to store the order in each page's
->private field.  And there is no code using the stored order.  Stop doing
that.

It also prepares for an upcoming change that ensures subpage->private is
zero at page free time and the removal of set_page_private(0) from
prep_compound_tail().

Link: https://lore.kernel.org/20260703-keep-subpage-private-zero-at-free-v2-2-2970fe777dd6@nvidia.com
Signed-off-by: Zi Yan <ziy@nvidia.com>
Reviewed-by: David Hildenbrand (Arm) <david@kernel.org>
Reviewed-by: Lance Yang <lance.yang@linux.dev>
Reviewed-by: Baolin Wang <baolin.wang@linux.alibaba.com>
Reviewed-by: Vlastimil Babka (SUSE) <vbabka@kernel.org>
Cc: Alistair Popple <apopple@nvidia.com>
Cc: Barry Song <baohua@kernel.org>
Cc: Brendan Jackman <jackmanb@google.com>
Cc: Dennis Zhou <dennis@kernel.org>
Cc: Dev Jain <dev.jain@arm.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Liam R. Howlett <liam@infradead.org>
Cc: Lorenzo Stoakes <ljs@kernel.org>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Mike Rapoport <rppt@kernel.org>
Cc: Nico Pache <npache@redhat.com>
Cc: Ryan Roberts <ryan.roberts@arm.com>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Tejun Heo <tj@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---

 mm/compaction.c |    3 ---
 1 file changed, 3 deletions(-)

--- a/mm/compaction.c~mm-compaction-stop-recording-free-page-order-in-page-private
+++ a/mm/compaction.c
@@ -645,7 +645,6 @@ static unsigned long isolate_freepages_b
 		isolated = __isolate_free_page(page, order);
 		if (!isolated)
 			break;
-		set_page_private(page, order);
 
 		nr_scanned += isolated - 1;
 		total_isolated += isolated;
@@ -1618,7 +1617,6 @@ static void fast_isolate_freepages(struc
 		/* Isolate the page if available */
 		if (page) {
 			if (__isolate_free_page(page, order)) {
-				set_page_private(page, order);
 				nr_isolated = 1 << order;
 				nr_scanned += nr_isolated - 1;
 				total_isolated += nr_isolated;
@@ -1847,7 +1845,6 @@ again:
 		size >>= 1;
 
 		list_add(&freepage[size].lru, &cc->freepages[start_order]);
-		set_page_private(&freepage[size], start_order);
 	}
 	dst = (struct folio *)freepage;
 
_

Patches currently in -mm which might be from ziy@nvidia.com are

mm-percpu-km-clear-page-private-before-free-them.patch
mm-compaction-stop-recording-free-page-order-in-page-private.patch
mm-huge_memory-add-page-private-check-back-in-__split_folio_to_order.patch
mm-page_alloc-make-sure-tail_page-private-is-zero-at-page-free-time.patch
mm-page_alloc-remove-set_page_private-in-prep_compound_tail.patch