diff options
Diffstat (limited to 'mm/slab.h')
| -rw-r--r-- | mm/slab.h | 53 |
1 files changed, 46 insertions, 7 deletions
diff --git a/mm/slab.h b/mm/slab.h index f01ac256a8f5..bc36edd5ba4f 100644 --- a/mm/slab.h +++ b/mm/slab.h @@ -6,6 +6,38 @@ */ void __init kmem_cache_init(void); +#ifdef CONFIG_64BIT +# ifdef system_has_cmpxchg128 +# define system_has_freelist_aba() system_has_cmpxchg128() +# define try_cmpxchg_freelist try_cmpxchg128 +# endif +#define this_cpu_try_cmpxchg_freelist this_cpu_try_cmpxchg128 +typedef u128 freelist_full_t; +#else /* CONFIG_64BIT */ +# ifdef system_has_cmpxchg64 +# define system_has_freelist_aba() system_has_cmpxchg64() +# define try_cmpxchg_freelist try_cmpxchg64 +# endif +#define this_cpu_try_cmpxchg_freelist this_cpu_try_cmpxchg64 +typedef u64 freelist_full_t; +#endif /* CONFIG_64BIT */ + +#if defined(system_has_freelist_aba) && !defined(CONFIG_HAVE_ALIGNED_STRUCT_PAGE) +#undef system_has_freelist_aba +#endif + +/* + * Freelist pointer and counter to cmpxchg together, avoids the typical ABA + * problems with cmpxchg of just a pointer. + */ +typedef union { + struct { + void *freelist; + unsigned long counter; + }; + freelist_full_t full; +} freelist_aba_t; + /* Reuses the bits in struct page */ struct slab { unsigned long __page_flags; @@ -38,14 +70,21 @@ struct slab { #endif }; /* Double-word boundary */ - void *freelist; /* first free object */ union { - unsigned long counters; struct { - unsigned inuse:16; - unsigned objects:15; - unsigned frozen:1; + void *freelist; /* first free object */ + union { + unsigned long counters; + struct { + unsigned inuse:16; + unsigned objects:15; + unsigned frozen:1; + }; + }; }; +#ifdef system_has_freelist_aba + freelist_aba_t freelist_counter; +#endif }; }; struct rcu_head rcu_head; @@ -72,8 +111,8 @@ SLAB_MATCH(memcg_data, memcg_data); #endif #undef SLAB_MATCH static_assert(sizeof(struct slab) <= sizeof(struct page)); -#if defined(CONFIG_HAVE_CMPXCHG_DOUBLE) && defined(CONFIG_SLUB) -static_assert(IS_ALIGNED(offsetof(struct slab, freelist), 2*sizeof(void *))); +#if defined(system_has_freelist_aba) && defined(CONFIG_SLUB) +static_assert(IS_ALIGNED(offsetof(struct slab, freelist), sizeof(freelist_aba_t))); #endif /** |