[merged mm-stable] mm-percpu-make-cached-pages-lookup-explicit.patch removed from -mm tree

The quilt patch titled
     Subject: mm/percpu: make cached pages lookup explicit
has been removed from the -mm tree.  Its filename was
     mm-percpu-make-cached-pages-lookup-explicit.patch

This patch was dropped because it was merged into the mm-stable branch
of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm

------------------------------------------------------
From: Kaitao Cheng <[email protected]>
Subject: mm/percpu: make cached pages lookup explicit
Date: Thu, 18 Jun 2026 21:04:13 +0800

pcpu_depopulate_chunk() only needs the temporary pages array that was
already allocated by an earlier successful population attempt.  Passing
GFP_KERNEL to pcpu_get_pages() in this path is misleading because the
depopulation path is not expected to allocate the array.

Teach pcpu_get_pages() to treat a zero gfp mask as a cached-only lookup
and add pcpu_get_pages_cached() for that use case.  This keeps allocation
on the populate path tied to the caller supplied GFP mask while making the
depopulate path's dependency on the cached array explicit.

Link: https://lore.kernel.org/[email protected]
Signed-off-by: Kaitao Cheng <[email protected]>
Suggested-by: Dennis Zhou <[email protected]>
Acked-by: Michal Hocko <[email protected]>
Cc: Christoph Lameter <[email protected]>
Cc: Pedro Falcato <[email protected]>
Cc: Shivam Kalra <[email protected]>
Cc: Tejun Heo <[email protected]>
Cc: Uladzislau Rezki (Sony) <[email protected]>
Cc: Vlastimil Babka <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
---

 mm/percpu-vm.c |   12 +++++++++---
 1 file changed, 9 insertions(+), 3 deletions(-)

--- a/mm/percpu-vm.c~mm-percpu-make-cached-pages-lookup-explicit
+++ a/mm/percpu-vm.c
@@ -21,7 +21,8 @@ static struct page *pcpu_chunk_page(stru
 
 /**
  * pcpu_get_pages - get temp pages array
- * @gfp: allocation flags passed to the underlying allocator
+ * @gfp: allocation flags passed to the underlying allocator, 0 to only
+ *	 return the cached array
  *
  * Returns pointer to array of pointers to struct page which can be indexed
  * with pcpu_page_idx().  Note that there is only one array and accesses
@@ -37,11 +38,16 @@ static struct page **pcpu_get_pages(gfp_
 
 	lockdep_assert_held(&pcpu_alloc_mutex);
 
-	if (!pages)
+	if (!pages && gfp)
 		pages = pcpu_mem_zalloc(pages_size, gfp);
 	return pages;
 }
 
+static struct page **pcpu_get_pages_cached(void)
+{
+	return pcpu_get_pages(0);
+}
+
 /**
  * pcpu_free_pages - free pages which were allocated for @chunk
  * @chunk: chunk pages were allocated for
@@ -333,7 +339,7 @@ static void pcpu_depopulate_chunk(struct
 	 * successful population attempt so the temp pages array must
 	 * be available now.
 	 */
-	pages = pcpu_get_pages(GFP_KERNEL);
+	pages = pcpu_get_pages_cached();
 	BUG_ON(!pages);
 
 	/* unmap and free */
_

Patches currently in -mm which might be from [email protected] are

mm-kconfig-drop-redundant-memory-hotplug-dependencies.patch
mm-kconfig-drop-redundant-dependency-wrappers.patch