Skip to content

Commit

Permalink
Split pcre cache into permanent and per-request caches
Browse files Browse the repository at this point in the history 
In addition to the permanent pcre cache, maintain a separate per-request
cache so that we can use string identity comparisons instead of having
to do full zend_string_equal_content() on every cache fetch -- this can
be quite costly if the regular expression is large.
  • Loading branch information
@cscott
cscott committed Mar 28, 2019
1 parent 0585548 commit a5214d5
Show file tree
Hide file tree
Showing 3 changed files with 74 additions and 41 deletions.
8 changes: 2 additions & 6 deletions ext/opcache/ZendAccelerator.c
View file
Expand Up @@ -2261,15 +2261,11 @@ static void accel_reset_pcre_cache(void)
{
Bucket *p;

if (PCRE_G(per_request_cache)) {
return;
}

ZEND_HASH_FOREACH_BUCKET(&PCRE_G(pcre_cache), p) {
ZEND_HASH_FOREACH_BUCKET(&PCRE_G(pcre_permanent_cache), p) {
/* Remove PCRE cache entries with inconsistent keys */
if (zend_accel_in_shm(p->key)) {
p->key = NULL;
zend_hash_del_bucket(&PCRE_G(pcre_cache), p);
zend_hash_del_bucket(&PCRE_G(pcre_permanent_cache), p);
}
} ZEND_HASH_FOREACH_END();
}
Expand Down
103 changes: 70 additions & 33 deletions ext/pcre/php_pcre.c
View file
Expand Up @@ -140,12 +140,20 @@ static void pcre_handle_exec_error(int pcre_code) /* {{{ */
}
/* }}} */

static void php_free_pcre_cache(zval *data) /* {{{ */
static void php_free_pcre_permanent_cache(zval *data) /* {{{ */
{
pcre_cache_entry *pce = (pcre_cache_entry *) Z_PTR_P(data);
if (!pce) return;
pcre2_code_free(pce->re);
pefree(pce, !PCRE_G(per_request_cache));
pefree(pce, 1);
}
/* }}} */

static void php_free_pcre_request_cache(zval *data) /* {{{ */
{
pcre_cache_entry *pce = (pcre_cache_entry *) Z_PTR_P(data);
if (!pce) return;
php_pcre_pce_decref(pce);
}
/* }}} */

Expand Down Expand Up @@ -254,12 +262,8 @@ static PHP_GINIT_FUNCTION(pcre) /* {{{ */
{
php_pcre_mutex_alloc();

/* If we're on the CLI SAPI, there will only be one request, so we don't need the
* cache to survive after RSHUTDOWN. */
pcre_globals->per_request_cache = strcmp(sapi_module.name, "cli") == 0;
if (!pcre_globals->per_request_cache) {
zend_hash_init(&pcre_globals->pcre_cache, 0, NULL, php_free_pcre_cache, 1);
}
/* Persistent pcre cache */
zend_hash_init(&pcre_globals->pcre_permanent_cache, 0, NULL, php_free_pcre_permanent_cache, 1);

pcre_globals->backtrack_limit = 0;
pcre_globals->recursion_limit = 0;
Expand All @@ -279,9 +283,7 @@ static PHP_GINIT_FUNCTION(pcre) /* {{{ */

static PHP_GSHUTDOWN_FUNCTION(pcre) /* {{{ */
{
if (!pcre_globals->per_request_cache) {
zend_hash_destroy(&pcre_globals->pcre_cache);
}
zend_hash_destroy(&pcre_globals->pcre_permanent_cache);

php_pcre_shutdown_pcre2();
#if HAVE_SETLOCALE
Expand Down Expand Up @@ -465,19 +467,15 @@ static PHP_RINIT_FUNCTION(pcre)
mdata_used = 0;
#endif

if (PCRE_G(per_request_cache)) {
zend_hash_init(&PCRE_G(pcre_cache), 0, NULL, php_free_pcre_cache, 0);
}
zend_hash_init(&PCRE_G(pcre_request_cache), 0, NULL, php_free_pcre_request_cache, 0);

return SUCCESS;
}
/* }}} */

static PHP_RSHUTDOWN_FUNCTION(pcre)
{
if (PCRE_G(per_request_cache)) {
zend_hash_destroy(&PCRE_G(pcre_cache));
}
zend_hash_destroy(&PCRE_G(pcre_request_cache));

zval_ptr_dtor(&PCRE_G(unmatched_null_pair));
zval_ptr_dtor(&PCRE_G(unmatched_empty_pair));
Expand All @@ -486,8 +484,23 @@ static PHP_RSHUTDOWN_FUNCTION(pcre)
return SUCCESS;
}

/* {{{ static pcre_clean_cache */
static int pcre_clean_cache(zval *data, void *arg)
/* {{{ static pcre_clean_request_cache */
static int pcre_clean_request_cache(zval *data, void *arg)
{
pcre_cache_entry *pce = (pcre_cache_entry *) Z_PTR_P(data);
int *num_clean = (int *)arg;

if (*num_clean > 0 && pce->refcount <= 1) {
(*num_clean)--;
return ZEND_HASH_APPLY_REMOVE;
} else {
return ZEND_HASH_APPLY_KEEP;
}
}
/* }}} */

/* {{{ static pcre_clean_permanent_cache */
static int pcre_clean_permanent_cache(zval *data, void *arg)
{
pcre_cache_entry *pce = (pcre_cache_entry *) Z_PTR_P(data);
int *num_clean = (int *)arg;
Expand Down Expand Up @@ -599,16 +612,28 @@ PHPAPI pcre_cache_entry* pcre_get_compiled_regex_cache(zend_string *regex)
key = regex;
}

/* Try to lookup the cached regex entry, and if successful, just pass
back the compiled pattern, otherwise go on and compile it. */
zv = zend_hash_find(&PCRE_G(pcre_cache), key);
if (zv) {
/* First try to look up the cached regex entry in the per-request cache,
* and if successful just pass back the compiled pattern.
*/
ret = (pcre_cache_entry*) zend_hash_find_ptr(&PCRE_G(pcre_request_cache), key);
if (ret) {
#if HAVE_SETLOCALE
if (key != regex) {
zend_string_release_ex(key, 0);
}
#endif
return (pcre_cache_entry*)Z_PTR_P(zv);
return ret;
}

/* Now try to lookup the cached regex entry in the permanent cache. */
zv = zend_hash_find(&PCRE_G(pcre_permanent_cache), key);
if (zv) {
/* Copy this over to the per-request cache, but with our local
* key string. This ensures that string constants which didn't
* manage to get interned into IS_PERMANENT still get to use
* identity key comparisons. */
ret = (pcre_cache_entry*)Z_PTR_P(zv);
goto out;
}

p = ZSTR_VAL(regex);
Expand Down Expand Up @@ -832,9 +857,13 @@ PHPAPI pcre_cache_entry* pcre_get_compiled_regex_cache(zend_string *regex)
* these are supposedly the oldest ones (but not necessarily the least used
* ones).
*/
if (zend_hash_num_elements(&PCRE_G(pcre_cache)) == PCRE_CACHE_SIZE) {
if (zend_hash_num_elements(&PCRE_G(pcre_request_cache)) >= PCRE_CACHE_SIZE) {
int num_clean = PCRE_CACHE_SIZE / 8;
zend_hash_apply_with_argument(&PCRE_G(pcre_cache), pcre_clean_cache, &num_clean);
zend_hash_apply_with_argument(&PCRE_G(pcre_request_cache), pcre_clean_request_cache, &num_clean);
}
if (zend_hash_num_elements(&PCRE_G(pcre_permanent_cache)) >= PCRE_CACHE_SIZE) {
int num_clean = PCRE_CACHE_SIZE / 8;
zend_hash_apply_with_argument(&PCRE_G(pcre_permanent_cache), pcre_clean_permanent_cache, &num_clean);
}

/* Store the compiled pattern and extra info in the cache. */
Expand Down Expand Up @@ -871,21 +900,29 @@ PHPAPI pcre_cache_entry* pcre_get_compiled_regex_cache(zend_string *regex)
/*
* Interned strings are not duplicated when stored in HashTable,
* but all the interned strings created during HTTP request are removed
* at end of request. However PCRE_G(pcre_cache) must be consistent
* on the next request as well. So we disable usage of interned strings
* as hash keys especually for this table.
* See bug #63180
* at end of request. However PCRE_G(pcre_permanent_cache) must be
* consistent on the next request as well. So we disable usage of interned
* strings as hash keys for this table.
*/
if (!(GC_FLAGS(key) & IS_STR_PERMANENT) && !PCRE_G(per_request_cache)) {
if (!(GC_FLAGS(key) & IS_STR_PERMANENT)) {
zend_string *str = zend_string_init(ZSTR_VAL(key), ZSTR_LEN(key), 1);
GC_MAKE_PERSISTENT_LOCAL(str);

ret = zend_hash_add_new_mem(&PCRE_G(pcre_cache), str, &new_entry, sizeof(pcre_cache_entry));
ret = zend_hash_add_new_mem(&PCRE_G(pcre_permanent_cache), str, &new_entry, sizeof(pcre_cache_entry));
zend_string_release(str);
} else {
ret = zend_hash_add_new_mem(&PCRE_G(pcre_cache), key, &new_entry, sizeof(pcre_cache_entry));
ret = zend_hash_add_new_mem(&PCRE_G(pcre_permanent_cache), key, &new_entry, sizeof(pcre_cache_entry));
}

out:
/**
* Store a local reference to this cache entry in our request cache,
* keyed by the local string value (which could be a non-permanent interned
* string).
*/
php_pcre_pce_incref(ret);
zend_hash_add_ptr(&PCRE_G(pcre_request_cache), key, ret);

#if HAVE_SETLOCALE
if (key != regex) {
zend_string_release_ex(key, 0);
Expand Down
4 changes: 2 additions & 2 deletions ext/pcre/php_pcre.h
View file
Expand Up @@ -66,13 +66,13 @@ PHPAPI pcre2_match_data *php_pcre_create_match_data(uint32_t, pcre2_code *);
PHPAPI void php_pcre_free_match_data(pcre2_match_data *);

ZEND_BEGIN_MODULE_GLOBALS(pcre)
HashTable pcre_cache;
HashTable pcre_permanent_cache;
HashTable pcre_request_cache;
zend_long backtrack_limit;
zend_long recursion_limit;
#ifdef HAVE_PCRE_JIT_SUPPORT
zend_bool jit;
#endif
zend_bool per_request_cache;
int error_code;
/* Used for unmatched subpatterns in OFFSET_CAPTURE mode */
zval unmatched_null_pair;
Expand Down

0 comments on commit a5214d5

Please sign in to comment.