diff options
| -rw-r--r-- | libglusterfs/src/glusterfs/mem-pool.h | 5 | ||||
| -rw-r--r-- | libglusterfs/src/mem-pool.c | 57 |
2 files changed, 35 insertions, 27 deletions
diff --git a/libglusterfs/src/glusterfs/mem-pool.h b/libglusterfs/src/glusterfs/mem-pool.h index 004aa179b19..e0441756be7 100644 --- a/libglusterfs/src/glusterfs/mem-pool.h +++ b/libglusterfs/src/glusterfs/mem-pool.h @@ -230,7 +230,10 @@ typedef struct pooled_obj_hdr { struct mem_pool *pool; } pooled_obj_hdr_t; -#define AVAILABLE_SIZE(p2) (1 << (p2)) +/* Each memory block inside a pool has a fixed size that is a power of two. + * However each object will have a header that will reduce the available + * space. */ +#define AVAILABLE_SIZE(p2) ((1UL << (p2)) - sizeof(pooled_obj_hdr_t)) typedef struct per_thread_pool { /* the pool that was used to request this allocation */ diff --git a/libglusterfs/src/mem-pool.c b/libglusterfs/src/mem-pool.c index b4bd350b738..d0f8a64d2f7 100644 --- a/libglusterfs/src/mem-pool.c +++ b/libglusterfs/src/mem-pool.c @@ -627,6 +627,7 @@ struct mem_pool * mem_pool_new_fn(glusterfs_ctx_t *ctx, unsigned long sizeof_type, unsigned long count, char *name) { + unsigned long extra_size, size; unsigned int power; struct mem_pool *new = NULL; struct mem_pool_shared *pool = NULL; @@ -637,10 +638,25 @@ mem_pool_new_fn(glusterfs_ctx_t *ctx, unsigned long sizeof_type, return NULL; } - /* We ensure sizeof_type > 1 and the next power of two will be, at least, - * 2^POOL_SMALLEST */ - sizeof_type |= (1 << POOL_SMALLEST) - 1; - power = sizeof(sizeof_type) * 8 - __builtin_clzl(sizeof_type - 1) + 1; + /* This is the overhead we'll have because of memory accounting for each + * memory block. */ + extra_size = sizeof(pooled_obj_hdr_t); + + /* We need to compute the total space needed to hold the data type and + * the header. Given that the smallest block size we have in the pools + * is 2^POOL_SMALLEST, we need to take the MAX(size, 2^POOL_SMALLEST). + * However, since this value is only needed to compute its rounded + * logarithm in base 2, and this only depends on the highest bit set, + * we can simply do a bitwise or with the minimum size. We need to + * subtract 1 for correct handling of sizes that are exactly a power + * of 2. */ + size = (sizeof_type + extra_size - 1UL) | ((1UL << POOL_SMALLEST) - 1UL); + + /* We compute the logarithm in base 2 rounded up of the resulting size. + * This value will identify which pool we need to use from the pools of + * powers of 2. This is equivalent to finding the position of the highest + * bit set. */ + power = sizeof(size) * 8 - __builtin_clzl(size); if (power > POOL_LARGEST) { gf_msg_callingfn("mem-pool", GF_LOG_ERROR, EINVAL, LG_MSG_INVALID_ARG, "invalid argument"); @@ -732,8 +748,8 @@ mem_get_pool_list(void) return pool_list; } -pooled_obj_hdr_t * -mem_get_from_pool(struct mem_pool *mem_pool, struct mem_pool_shared *pool) +static pooled_obj_hdr_t * +mem_get_from_pool(struct mem_pool *mem_pool) { per_thread_pool_list_t *pool_list; per_thread_pool_t *pt_pool; @@ -747,12 +763,7 @@ mem_get_from_pool(struct mem_pool *mem_pool, struct mem_pool_shared *pool) return NULL; } - if (mem_pool) { - pt_pool = &pool_list - ->pools[mem_pool->pool->power_of_two - POOL_SMALLEST]; - } else { - pt_pool = &pool_list->pools[pool->power_of_two - POOL_SMALLEST]; - } + pt_pool = &pool_list->pools[mem_pool->pool->power_of_two - POOL_SMALLEST]; (void)pthread_spin_lock(&pool_list->lock); @@ -770,8 +781,7 @@ mem_get_from_pool(struct mem_pool *mem_pool, struct mem_pool_shared *pool) } else { (void)pthread_spin_unlock(&pool_list->lock); GF_ATOMIC_INC(pt_pool->parent->allocs_stdc); - retval = malloc((1 << pt_pool->parent->power_of_two) + - sizeof(pooled_obj_hdr_t)); + retval = malloc(1 << pt_pool->parent->power_of_two); #ifdef DEBUG hit = _gf_false; #endif @@ -779,19 +789,14 @@ mem_get_from_pool(struct mem_pool *mem_pool, struct mem_pool_shared *pool) } if (retval != NULL) { - if (mem_pool) { - retval->pool = mem_pool; - retval->power_of_two = mem_pool->pool->power_of_two; + retval->pool = mem_pool; + retval->power_of_two = mem_pool->pool->power_of_two; #ifdef DEBUG - if (hit == _gf_true) - GF_ATOMIC_INC(mem_pool->hit); - else - GF_ATOMIC_INC(mem_pool->miss); + if (hit == _gf_true) + GF_ATOMIC_INC(mem_pool->hit); + else + GF_ATOMIC_INC(mem_pool->miss); #endif - } else { - retval->power_of_two = pool->power_of_two; - retval->pool = NULL; - } retval->magic = GF_MEM_HEADER_MAGIC; retval->pool_list = pool_list; } @@ -811,7 +816,7 @@ mem_get(struct mem_pool *mem_pool) #if defined(GF_DISABLE_MEMPOOL) return GF_MALLOC(mem_pool->sizeof_type, gf_common_mt_mem_pool); #else - pooled_obj_hdr_t *retval = mem_get_from_pool(mem_pool, NULL); + pooled_obj_hdr_t *retval = mem_get_from_pool(mem_pool); if (!retval) { return NULL; } |