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author | Dmitry Stogov <dmitry@zend.com> | 2017-12-11 18:16:54 +0300 |
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committer | Dmitry Stogov <dmitry@zend.com> | 2017-12-11 18:16:54 +0300 |
commit | 9f1e9700580245088d43cd6eef50edce3bce7abc (patch) | |
tree | 10761556075ef497e3a94fd4d40502c4bfc22b3f /ext/opcache/zend_shared_alloc.c | |
parent | 16eb3873b0c85e1e71ecb89276cbdf03492ada78 (diff) | |
download | php-git-9f1e9700580245088d43cd6eef50edce3bce7abc.tar.gz |
Reduce number of hash collisions during dulicate address detection.
Diffstat (limited to 'ext/opcache/zend_shared_alloc.c')
-rw-r--r-- | ext/opcache/zend_shared_alloc.c | 17 |
1 files changed, 13 insertions, 4 deletions
diff --git a/ext/opcache/zend_shared_alloc.c b/ext/opcache/zend_shared_alloc.c index 91496b15df..1ba1ac463c 100644 --- a/ext/opcache/zend_shared_alloc.c +++ b/ext/opcache/zend_shared_alloc.c @@ -337,8 +337,10 @@ void *zend_shared_alloc(size_t size) int zend_shared_memdup_size(void *source, size_t size) { void *old_p; + zend_ulong key = (zend_ulong)source; - if ((old_p = zend_hash_index_find_ptr(&ZCG(xlat_table), (zend_ulong)source)) != NULL) { + key = (key >> 3) | (key << ((sizeof(key) * 8) - 3)); /* key = _rotr(key, 3);*/ + if ((old_p = zend_hash_index_find_ptr(&ZCG(xlat_table), key)) != NULL) { /* we already duplicated this pointer */ return 0; } @@ -349,8 +351,10 @@ int zend_shared_memdup_size(void *source, size_t size) void *_zend_shared_memdup(void *source, size_t size, zend_bool free_source) { void *old_p, *retval; + zend_ulong key = (zend_ulong)source; - if ((old_p = zend_hash_index_find_ptr(&ZCG(xlat_table), (zend_ulong)source)) != NULL) { + key = (key >> 3) | (key << ((sizeof(key) * 8) - 3)); /* key = _rotr(key, 3);*/ + if ((old_p = zend_hash_index_find_ptr(&ZCG(xlat_table), key)) != NULL) { /* we already duplicated this pointer */ return old_p; } @@ -443,14 +447,19 @@ void zend_shared_alloc_clear_xlat_table(void) void zend_shared_alloc_register_xlat_entry(const void *old, const void *new) { - zend_hash_index_add_new_ptr(&ZCG(xlat_table), (zend_ulong)old, (void*)new); + zend_ulong key = (zend_ulong)old; + + key = (key >> 3) | (key << ((sizeof(key) * 8) - 3)); /* key = _rotr(key, 3);*/ + zend_hash_index_add_new_ptr(&ZCG(xlat_table), key, (void*)new); } void *zend_shared_alloc_get_xlat_entry(const void *old) { void *retval; + zend_ulong key = (zend_ulong)old; - if ((retval = zend_hash_index_find_ptr(&ZCG(xlat_table), (zend_ulong)old)) == NULL) { + key = (key >> 3) | (key << ((sizeof(key) * 8) - 3)); /* key = _rotr(key, 3);*/ + if ((retval = zend_hash_index_find_ptr(&ZCG(xlat_table), key)) == NULL) { return NULL; } return retval; |