* [PATCH] mm/debug: optimize once judgment with clang
@ 2026-03-09 15:34 Xie Yuanbin
2026-03-10 10:50 ` vbabka
0 siblings, 1 reply; 2+ messages in thread
From: Xie Yuanbin @ 2026-03-09 15:34 UTC (permalink / raw)
To: rppt, david.laight.linux, akpm, david, ljs, Liam.Howlett, vbabka,
surenb, mhocko, nathan, nick.desaulniers+lkml, morbo, justinstitt
Cc: linux-mm, linux-kernel, llvm, Xie Yuanbin
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 VM_WARN_ON_ONCE_PAGE(), VM_WARN_ON_ONCE_FOLIO(),
VM_WARN_ON_ONCE_MM() and VM_WARN_ON_ONCE_VMA().
Cc: Mike Rapoport <rppt@kernel.org>
Cc: David Laight <david.laight.linux@gmail.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Xie Yuanbin <qq570070308@gmail.com>
---
include/linux/mmdebug.h | 8 ++++----
1 file changed, 4 insertions(+), 4 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); \
--
2.53.0
^ permalink raw reply related [flat|nested] 2+ messages in thread
* Re: [PATCH] mm/debug: optimize once judgment with clang
2026-03-09 15:34 [PATCH] mm/debug: optimize once judgment with clang Xie Yuanbin
@ 2026-03-10 10:50 ` vbabka
0 siblings, 0 replies; 2+ messages in thread
From: vbabka @ 2026-03-10 10:50 UTC (permalink / raw)
To: Xie Yuanbin, rppt, david.laight.linux, akpm, david, ljs,
Liam.Howlett, surenb, mhocko, nathan, nick.desaulniers+lkml,
morbo, justinstitt
Cc: linux-mm, linux-kernel, llvm
On 3/9/26 16:34, Xie Yuanbin wrote:
> 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 VM_WARN_ON_ONCE_PAGE(), VM_WARN_ON_ONCE_FOLIO(),
> VM_WARN_ON_ONCE_MM() and VM_WARN_ON_ONCE_VMA().
>
> Cc: Mike Rapoport <rppt@kernel.org>
> Cc: David Laight <david.laight.linux@gmail.com>
> Cc: Andrew Morton <akpm@linux-foundation.org>
> Signed-off-by: Xie Yuanbin <qq570070308@gmail.com>
We don't need to make debug code (hence perf doesn't matter there) more ugly
just for clang's sake, I think.
> ---
> include/linux/mmdebug.h | 8 ++++----
> 1 file changed, 4 insertions(+), 4 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); \
^ permalink raw reply [flat|nested] 2+ messages in thread
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2026-03-10 10:50 ` vbabka
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