diff mbox series

[v5,1/2] mm: introduce helper to check slub_debug_enabled

Message ID 20210705024101.1567-2-yee.lee@mediatek.com (mailing list archive)
State New
Headers show
Series [v5,1/2] mm: introduce helper to check slub_debug_enabled | expand

Commit Message

Yee Lee (李建誼) July 5, 2021, 2:40 a.m. UTC 
From: Marco Elver <elver@google.com>

Introduce a helper to check slub_debug_enabled, so that we can confine
the use of #ifdef to the definition of the slub_debug_enabled_unlikely()
helper.

Signed-off-by: Marco Elver <elver@google.com>
Signed-off-by: Yee Lee <yee.lee@mediatek.com>
---
 mm/slab.h | 15 +++++++++++----
 1 file changed, 11 insertions(+), 4 deletions(-)

Comments

Matthew Wilcox July 5, 2021, 3:20 a.m. UTC | #1 
On Mon, Jul 05, 2021 at 10:40:57AM +0800, yee.lee@mediatek.com wrote:
> From: Marco Elver <elver@google.com>
> 
> Introduce a helper to check slub_debug_enabled, so that we can confine
> the use of #ifdef to the definition of the slub_debug_enabled_unlikely()
> helper.

We don't usually embed '_unlikely' in function names; we
just do:

static inline bool slub_debug_enabled(void)
{
	return static_branch_unlikely(&slub_debug_enabled);
}

eg:

static inline bool cpusets_enabled(void)
{
        return static_branch_unlikely(&cpusets_enabled_key);
}

#define cgroup_bpf_enabled(type) static_branch_unlikely(&cgroup_bpf_enabled_key[type])

static inline int ip_tunnel_collect_metadata(void)
{
        return static_branch_unlikely(&ip_tunnel_metadata_cnt);
}

static inline bool frontswap_enabled(void)
{
        return static_branch_unlikely(&frontswap_enabled_key);
}
Marco Elver July 5, 2021, 6:51 a.m. UTC | #2 
On Mon, Jul 05, 2021 at 04:20AM +0100, Matthew Wilcox wrote:
> On Mon, Jul 05, 2021 at 10:40:57AM +0800, yee.lee@mediatek.com wrote:
> > From: Marco Elver <elver@google.com>
> > 
> > Introduce a helper to check slub_debug_enabled, so that we can confine
> > the use of #ifdef to the definition of the slub_debug_enabled_unlikely()
> > helper.
> 
> We don't usually embed '_unlikely' in function names; we
> just do:
> 
> static inline bool slub_debug_enabled(void)
> {
> 	return static_branch_unlikely(&slub_debug_enabled);
> }

The names are identical, this obviously won't work:

In file included from mm/slub.c:21:
mm/slab.h:219:20: error: ‘slub_debug_enabled’ redeclared as different kind of symbol
  219 | static inline bool slub_debug_enabled(void)

But it seems that someone had the same idea, and this merge window got a
__slub_debug_enabled() with 792702911f58.

Yee, can you replace this patch with the below:

From: Marco Elver <elver@google.com>
Date: Wed, 30 Jun 2021 20:56:57 +0200
Subject: [PATCH] mm: move helper to check slub_debug_enabled

Move the helper to check slub_debug_enabled, so that we can confine
the use of #ifdef outside slub.c as well.

Signed-off-by: Marco Elver <elver@google.com>
---
v6:
* Move helper instead of introducing a new one.
---
 mm/slab.h | 15 +++++++++++----
 mm/slub.c | 14 --------------
 2 files changed, 11 insertions(+), 18 deletions(-)

diff --git a/mm/slab.h b/mm/slab.h
index 67e06637ff2e..f997fd5e42c8 100644
--- a/mm/slab.h
+++ b/mm/slab.h
@@ -216,10 +216,18 @@ DECLARE_STATIC_KEY_FALSE(slub_debug_enabled);
 #endif
 extern void print_tracking(struct kmem_cache *s, void *object);
 long validate_slab_cache(struct kmem_cache *s);
+static inline bool __slub_debug_enabled(void)
+{
+	return static_branch_unlikely(&slub_debug_enabled);
+}
 #else
 static inline void print_tracking(struct kmem_cache *s, void *object)
 {
 }
+static inline bool __slub_debug_enabled(void)
+{
+	return false;
+}
 #endif
 
 /*
@@ -229,11 +237,10 @@ static inline void print_tracking(struct kmem_cache *s, void *object)
  */
 static inline bool kmem_cache_debug_flags(struct kmem_cache *s, slab_flags_t flags)
 {
-#ifdef CONFIG_SLUB_DEBUG
-	VM_WARN_ON_ONCE(!(flags & SLAB_DEBUG_FLAGS));
-	if (static_branch_unlikely(&slub_debug_enabled))
+	if (IS_ENABLED(CONFIG_SLUB_DEBUG))
+		VM_WARN_ON_ONCE(!(flags & SLAB_DEBUG_FLAGS));
+	if (__slub_debug_enabled())
 		return s->flags & flags;
-#endif
 	return false;
 }
 
diff --git a/mm/slub.c b/mm/slub.c
index 2ee43ff667a5..090fa14628f9 100644
--- a/mm/slub.c
+++ b/mm/slub.c
@@ -119,25 +119,11 @@
  */
 
 #ifdef CONFIG_SLUB_DEBUG
-
 #ifdef CONFIG_SLUB_DEBUG_ON
 DEFINE_STATIC_KEY_TRUE(slub_debug_enabled);
 #else
 DEFINE_STATIC_KEY_FALSE(slub_debug_enabled);
 #endif
-
-static inline bool __slub_debug_enabled(void)
-{
-	return static_branch_unlikely(&slub_debug_enabled);
-}
-
-#else		/* CONFIG_SLUB_DEBUG */
-
-static inline bool __slub_debug_enabled(void)
-{
-	return false;
-}
-
 #endif		/* CONFIG_SLUB_DEBUG */
 
 static inline bool kmem_cache_debug(struct kmem_cache *s)
diff mbox series

Patch

diff --git a/mm/slab.h b/mm/slab.h
index 7b60ef2f32c3..a11126afe24c 100644
--- a/mm/slab.h
+++ b/mm/slab.h
@@ -216,10 +216,18 @@  DECLARE_STATIC_KEY_FALSE(slub_debug_enabled);
 #endif
 extern void print_tracking(struct kmem_cache *s, void *object);
 long validate_slab_cache(struct kmem_cache *s);
+static inline bool slub_debug_enabled_unlikely(void)
+{
+	return static_branch_unlikely(&slub_debug_enabled);
+}
 #else
 static inline void print_tracking(struct kmem_cache *s, void *object)
 {
 }
+static inline bool slub_debug_enabled_unlikely(void)
+{
+	return false;
+}
 #endif
 
 /*
@@ -229,11 +237,10 @@  static inline void print_tracking(struct kmem_cache *s, void *object)
  */
 static inline bool kmem_cache_debug_flags(struct kmem_cache *s, slab_flags_t flags)
 {
-#ifdef CONFIG_SLUB_DEBUG
-	VM_WARN_ON_ONCE(!(flags & SLAB_DEBUG_FLAGS));
-	if (static_branch_unlikely(&slub_debug_enabled))
+	if (IS_ENABLED(CONFIG_SLUB_DEBUG))
+		VM_WARN_ON_ONCE(!(flags & SLAB_DEBUG_FLAGS));
+	if (slub_debug_enabled_unlikely())
 		return s->flags & flags;
-#endif
 	return false;
 }