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From: Xie Yuanbin <qq570070308@gmail.com>
To: akpm@linux-foundation.org, david@kernel.org, ljs@kernel.org,
	Liam.Howlett@oracle.com, vbabka@kernel.org, rppt@kernel.org,
	surenb@google.com, mhocko@suse.com, nathan@kernel.org,
	nick.desaulniers+lkml@gmail.com, morbo@google.com,
	justinstitt@google.com
Cc: linux-mm@kvack.org, linux-kernel@vger.kernel.org,
	llvm@lists.linux.dev, Xie Yuanbin <qq570070308@gmail.com>
Subject: [PATCH] mm: optimize once judgment with clang
Date: Sat,  7 Mar 2026 14:54:04 +0800	[thread overview]
Message-ID: <20260307065405.37473-1-qq570070308@gmail.com> (raw)

commit 242b872239f6a7deacbc ("include/linux/once_lite.h: fix judgment in
WARN_ONCE with clang") helps optimize performance and size under the
clang compiler, but the modification is not complete.

Port the modification to WARN_ON_ONCE_GFP(), VM_WARN_ON_ONCE_PAGE(),
VM_WARN_ON_ONCE_FOLIO(), VM_WARN_ON_ONCE_MM() and VM_WARN_ON_ONCE_VMA().

Cc: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Xie Yuanbin <qq570070308@gmail.com>
---
 include/linux/mmdebug.h | 8 ++++----
 mm/internal.h           | 3 ++-
 2 files changed, 6 insertions(+), 5 deletions(-)

diff --git a/include/linux/mmdebug.h b/include/linux/mmdebug.h
index ab60ffba08f5..a167c5aa525e 100644
--- a/include/linux/mmdebug.h
+++ b/include/linux/mmdebug.h
@@ -60,7 +60,7 @@ void vma_iter_dump_tree(const struct vma_iterator *vmi);
 	static bool __section(".data..once") __warned;			\
 	int __ret_warn_once = !!(cond);					\
 									\
-	if (unlikely(__ret_warn_once && !__warned)) {			\
+	if (unlikely(__ret_warn_once) && unlikely(!__warned)) {		\
 		dump_page(page, "VM_WARN_ON_ONCE_PAGE(" __stringify(cond)")");\
 		__warned = true;					\
 		WARN_ON(1);						\
@@ -80,7 +80,7 @@ void vma_iter_dump_tree(const struct vma_iterator *vmi);
 	static bool __section(".data..once") __warned;			\
 	int __ret_warn_once = !!(cond);					\
 									\
-	if (unlikely(__ret_warn_once && !__warned)) {			\
+	if (unlikely(__ret_warn_once) && unlikely(!__warned)) {		\
 		dump_page(&folio->page, "VM_WARN_ON_ONCE_FOLIO(" __stringify(cond)")");\
 		__warned = true;					\
 		WARN_ON(1);						\
@@ -91,7 +91,7 @@ void vma_iter_dump_tree(const struct vma_iterator *vmi);
 	static bool __section(".data..once") __warned;			\
 	int __ret_warn_once = !!(cond);					\
 									\
-	if (unlikely(__ret_warn_once && !__warned)) {			\
+	if (unlikely(__ret_warn_once) && unlikely(!__warned)) {		\
 		dump_mm(mm);						\
 		__warned = true;					\
 		WARN_ON(1);						\
@@ -102,7 +102,7 @@ void vma_iter_dump_tree(const struct vma_iterator *vmi);
 	static bool __section(".data..once") __warned;			\
 	int __ret_warn_once = !!(cond);					\
 									\
-	if (unlikely(__ret_warn_once && !__warned)) {			\
+	if (unlikely(__ret_warn_once) && unlikely(!__warned)) {		\
 		dump_vma(vma);						\
 		__warned = true;					\
 		WARN_ON(1);						\
diff --git a/mm/internal.h b/mm/internal.h
index 6e1162e13289..52367f52d623 100644
--- a/mm/internal.h
+++ b/mm/internal.h
@@ -93,7 +93,8 @@ struct pagetable_move_control {
 	static bool __section(".data..once") __warned;			\
 	int __ret_warn_once = !!(cond);					\
 									\
-	if (unlikely(!(gfp & __GFP_NOWARN) && __ret_warn_once && !__warned)) { \
+	if (unlikely(__ret_warn_once) && !(gfp & __GFP_NOWARN) &&	\
+	    unlikely(!__warned)) {					\
 		__warned = true;					\
 		WARN_ON(1);						\
 	}								\
-- 
2.51.0



             reply	other threads:[~2026-03-07  6:54 UTC|newest]

Thread overview: 2+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2026-03-07  6:54 Xie Yuanbin [this message]
2026-03-07  8:12 ` Mike Rapoport

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