Re: [PATCH v3 4/4] slub: Force on no_hash_pointers when slub_debug is enabled
From: Stephen Boyd <hidden>
Date: 2021-06-02 01:03:14
Also in:
lkml, oe-kbuild-all
Quoting Andrew Morton (2021-06-01 17:26:59)
On Wed, 2 Jun 2021 06:45:55 +0800 kernel test robot [off-list ref] wrote:quoted
quoted
quoted
mm/slub.c:4464:30: error: use of undeclared identifier 'slub_debug_enabled'if (static_branch_unlikely(&slub_debug_enabled)) ^quoted
quoted
mm/slub.c:4464:30: error: use of undeclared identifier 'slub_debug_enabled' mm/slub.c:4464:30: error: use of undeclared identifier 'slub_debug_enabled' mm/slub.c:4464:30: error: use of undeclared identifier 'slub_debug_enabled' mm/slub.c:4464:6: error: invalid argument type 'void' to unary expressionif (static_branch_unlikely(&slub_debug_enabled)) ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~Thanks. Stephen, how about this?
Looks good to me. Thanks for the quick fix!
quoted hunk ↗ jump to hunk
--- a/mm/slub.c~slub-force-on-no_hash_pointers-when-slub_debug-is-enabled-fix +++ a/mm/slub.c@@ -117,12 +117,26 @@ */ #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 -#endif + +static inline bool __slub_debug_enabled(void) +{ + return static_branch_unlikely(&slub_debug_enabled);
To make this even better it could be return static_branch_maybe(CONFIG_SLUB_DEBUG_ON, &slub_debug_enabled);
quoted hunk ↗ jump to hunk
+} + +#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) {@@ -4493,7 +4507,7 @@ void __init kmem_cache_init(void) slub_max_order = 0; /* Print slub debugging pointers without hashing */ - if (static_branch_unlikely(&slub_debug_enabled)) + if (__slub_debug_enabled())
It would be super cool if static branches could be optimized out when they're never changed by any code, nor exported to code, just tested in conditions. I've no idea if that is the case though.
no_hash_pointers_enable(NULL);
kmem_cache_node = &boot_kmem_cache_node;