rtree: add rtree_szind_slab_read_fast

For a free fastpath, we want something that will not make additional
calls.  Assume most free() calls will hit the L1 cache, and use
a custom rtree function for this.

Additionally, roll the ptr=NULL check in to the rtree cache check.
This commit is contained in:
Dave Watson 2018-10-18 12:51:54 -07:00
parent a4c6b9ae01
commit 5e795297b3

View File

@ -452,6 +452,42 @@ rtree_extent_szind_read(tsdn_t *tsdn, rtree_t *rtree, rtree_ctx_t *rtree_ctx,
return false;
}
/*
* Try to read szind_slab from the L1 cache. Returns true on a hit,
* and fills in r_szind and r_slab. Otherwise returns false.
*
* Key is allowed to be NULL in order to save an extra branch on the
* fastpath. returns false in this case.
*/
JEMALLOC_ALWAYS_INLINE bool
rtree_szind_slab_read_fast(tsdn_t *tsdn, rtree_t *rtree, rtree_ctx_t *rtree_ctx,
uintptr_t key, szind_t *r_szind, bool *r_slab) {
rtree_leaf_elm_t *elm;
size_t slot = rtree_cache_direct_map(key);
uintptr_t leafkey = rtree_leafkey(key);
assert(leafkey != RTREE_LEAFKEY_INVALID);
if (likely(rtree_ctx->cache[slot].leafkey == leafkey)) {
rtree_leaf_elm_t *leaf = rtree_ctx->cache[slot].leaf;
assert(leaf != NULL);
uintptr_t subkey = rtree_subkey(key, RTREE_HEIGHT-1);
elm = &leaf[subkey];
#ifdef RTREE_LEAF_COMPACT
uintptr_t bits = rtree_leaf_elm_bits_read(tsdn, rtree,
elm, true);
*r_szind = rtree_leaf_elm_bits_szind_get(bits);
*r_slab = rtree_leaf_elm_bits_slab_get(bits);
#else
*r_szind = rtree_leaf_elm_szind_read(tsdn, rtree, elm, true);
*r_slab = rtree_leaf_elm_slab_read(tsdn, rtree, elm, true);
#endif
return true;
} else {
return false;
}
}
JEMALLOC_ALWAYS_INLINE bool
rtree_szind_slab_read(tsdn_t *tsdn, rtree_t *rtree, rtree_ctx_t *rtree_ctx,
uintptr_t key, bool dependent, szind_t *r_szind, bool *r_slab) {