+ mm-page_alloc-remove-pcpu_spin_-wrappers.patch added to mm-new branch

+ mm-page_alloc-remove-pcpu_spin_-wrappers.patch added to mm-new branch

[Andrew Morton]

The patch titled
     Subject: mm/page_alloc: remove pcpu_spin_* wrappers
has been added to the -mm mm-new branch.  Its filename is
     mm-page_alloc-remove-pcpu_spin_-wrappers.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-remove-pcpu_spin_-wrappers.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
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fixup patches in mm-new.

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------------------------------------------------------
From: Vlastimil Babka <vbabka@kernel.org>
Subject: mm/page_alloc: remove pcpu_spin_* wrappers
Date: Fri, 27 Feb 2026 18:08:00 +0100

We only ever use pcpu_spin_trylock()/unlock() with struct per_cpu_pages so
refactor the helpers to remove the generic layer.

No functional change intended.

Link: https://lkml.kernel.org/r/20260227-b4-pcp-locking-cleanup-v1-3-f7e22e603447@kernel.org
Signed-off-by: Vlastimil Babka (SUSE) <vbabka@kernel.org>
Suggested-by: Matthew Wilcox <willy@infradead.org>
Cc: Brendan Jackman <jackmanb@google.com>
Cc: David Hildenbrand (Arm) <david@kernel.org>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Mel Gorman <mgorman@techsingularity.net>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Zi Yan <ziy@nvidia.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---

 mm/page_alloc.c |   24 +++++++++---------------
 1 file changed, 9 insertions(+), 15 deletions(-)

--- a/mm/page_alloc.c~mm-page_alloc-remove-pcpu_spin_-wrappers
+++ a/mm/page_alloc.c
@@ -112,35 +112,29 @@ static DEFINE_MUTEX(pcp_batch_high_lock)
 #endif
 
 /*
- * Generic helper to lookup and a per-cpu variable with an embedded spinlock.
- * Return value should be used with equivalent unlock helper.
+ * A helper to lookup and trylock pcp with embedded spinlock.
+ * The return value should be used with the unlock helper.
+ * NULL return value means the trylock failed.
  */
-#define pcpu_spin_trylock(type, member, ptr)				\
+#ifdef CONFIG_SMP
+#define pcp_spin_trylock(ptr)						\
 ({									\
-	type *_ret;							\
+	struct per_cpu_pages *_ret;					\
 	pcpu_task_pin();						\
 	_ret = this_cpu_ptr(ptr);					\
-	if (!spin_trylock(&_ret->member)) {				\
+	if (!spin_trylock(&_ret->lock)) {				\
 		pcpu_task_unpin();					\
 		_ret = NULL;						\
 	}								\
 	_ret;								\
 })
 
-#define pcpu_spin_unlock(member, ptr)					\
+#define pcp_spin_unlock(ptr)						\
 ({									\
-	spin_unlock(&ptr->member);					\
+	spin_unlock(&ptr->lock);					\
 	pcpu_task_unpin();						\
 })
 
-/* struct per_cpu_pages specific helpers.*/
-#ifdef CONFIG_SMP
-#define pcp_spin_trylock(ptr)						\
-		pcpu_spin_trylock(struct per_cpu_pages, lock, ptr)
-
-#define pcp_spin_unlock(ptr)						\
-		pcpu_spin_unlock(lock, ptr)
-
 /*
  * On CONFIG_SMP=n the UP implementation of spin_trylock() never fails and thus
  * is not compatible with our locking scheme. However we do not need pcp for
_

Patches currently in -mm which might be from vbabka@kernel.org are

mm-page_alloc-effectively-disable-pcp-with-config_smp=n.patch
mm-page_alloc-remove-irq-saving-restoring-from-pcp-locking.patch
mm-page_alloc-remove-pcpu_spin_-wrappers.patch