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authorKees Cook <keescook@chromium.org>2021-04-01 16:23:43 -0700
committerThomas Gleixner <tglx@linutronix.de>2021-04-08 14:05:19 +0200
commit51cba1ebc60df9c4ce034a9f5441169c0d0956c0 (patch)
tree9f3f79596f1922730ac3d2a90a47ad493484c75d /mm/slab.h
parent0d66ccc1627013c95f1e7ef10b95b8451cd7834e (diff)
downloadlinux-51cba1ebc60df9c4ce034a9f5441169c0d0956c0.tar.bz2
init_on_alloc: Optimize static branches
The state of CONFIG_INIT_ON_ALLOC_DEFAULT_ON (and ...ON_FREE...) did not change the assembly ordering of the static branches: they were always out of line. Use the new jump_label macros to check the CONFIG settings to default to the "expected" state, which slightly optimizes the resulting assembly code. Signed-off-by: Kees Cook <keescook@chromium.org> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Reviewed-by: Alexander Potapenko <glider@google.com> Acked-by: Vlastimil Babka <vbabka@suse.cz> Link: https://lore.kernel.org/r/20210401232347.2791257-3-keescook@chromium.org
Diffstat (limited to 'mm/slab.h')
-rw-r--r--mm/slab.h6
1 files changed, 4 insertions, 2 deletions
diff --git a/mm/slab.h b/mm/slab.h
index 076582f58f68..774c7221efdc 100644
--- a/mm/slab.h
+++ b/mm/slab.h
@@ -601,7 +601,8 @@ static inline void cache_random_seq_destroy(struct kmem_cache *cachep) { }
static inline bool slab_want_init_on_alloc(gfp_t flags, struct kmem_cache *c)
{
- if (static_branch_unlikely(&init_on_alloc)) {
+ if (static_branch_maybe(CONFIG_INIT_ON_ALLOC_DEFAULT_ON,
+ &init_on_alloc)) {
if (c->ctor)
return false;
if (c->flags & (SLAB_TYPESAFE_BY_RCU | SLAB_POISON))
@@ -613,7 +614,8 @@ static inline bool slab_want_init_on_alloc(gfp_t flags, struct kmem_cache *c)
static inline bool slab_want_init_on_free(struct kmem_cache *c)
{
- if (static_branch_unlikely(&init_on_free))
+ if (static_branch_maybe(CONFIG_INIT_ON_FREE_DEFAULT_ON,
+ &init_on_free))
return !(c->ctor ||
(c->flags & (SLAB_TYPESAFE_BY_RCU | SLAB_POISON)));
return false;