Some people have mentioned having problems where idle PHP processes hang
around without freeing their memory (in a FastCGI or Apache module modes).
As I have found, it's not really a memory fragmentation problem.
The core of the problem is the fact, that free() doesn't return memory
to the OS immediately. So, if we have memory hungry PHP scripts and use
PHP in a FastCGI or Apache module environment, then large amount of
memory could still remain allocated for a process while it's waiting for
the next HTTP request.
Attached is a patch which resolves this problem by forcing the memory
allocator to return free pages to the operating system at the end of the
request. Especially in instances where some of your PHP scripts use a
lot of memory, this maybe be quite useful in reducing the machine's
overall memory consumption at a given time.
I think it's probably best for this explicit memory collector mode not
to be used in the multithreaded environment (for performance reasons),
but the patch works properly if ZTS is enabled.
Two new configuration variables could be set in a php.ini:
memory_trim_limit (default is 1M) - is a minimum memory grow per request
limit until malloc_trim mechanism will be invoked. "0" value disables it.
memory_grow_limit (default is 128M) - is a memory grow limit. If process
reaches it, then force_exit SAPI global is turned on and could be used
in SAPI modules to force process exit. This is for the case when we have
persistent objects on the top of memory or memory leaks in external
libraries. "0" value disables it.
Patch also includes processing of force_exit SAPI global for CGI SAPI
module (for FastCGI mode), Apache SAPI module and Apache 2.0 Handler
SAPI module (for prefork Apache2 mode).
Please review it, try it and send me feedback.
With best regards,
Alexander Veremyev.
Index: php-src/Zend/zend_alloc.c
===================================================================
RCS file: /repository/ZendEngine2/zend_alloc.c,v
retrieving revision 1.144
diff -u -r1.144 zend_alloc.c
--- php-src/Zend/zend_alloc.c 3 Aug 2005 13:30:47 -0000 1.144
+++ php-src/Zend/zend_alloc.c 9 Aug 2005 23:18:58 -0000
@@ -23,6 +23,7 @@
#include "zend_alloc.h"
#include "zend_globals.h"
#include "zend_fast_cache.h"
+#include "SAPI.h"
#ifdef HAVE_SIGNAL_H
# include <signal.h>
#endif
@@ -455,6 +456,52 @@
}
+ZEND_API int zend_set_memory_trim_limit(unsigned int memory_trim_limit)
+{
+ TSRMLS_FETCH();
+
+ AG(memory_trim_limit) = memory_trim_limit;
+ return SUCCESS;
+}
+
+
+ZEND_API int zend_set_memory_grow_limit(unsigned int memory_grow_limit)
+{
+ TSRMLS_FETCH();
+
+ AG(memory_grow_limit) = memory_grow_limit;
+ return SUCCESS;
+}
+
+
+#if defined(ZEND_WIN32)
+static inline unsigned int HeapCommittedSize( HANDLE memory_heap )
+{
+ PROCESS_HEAP_ENTRY heap_entry;
+ unsigned int mem_size;
+ int cnt;
+
+ cnt=0;
+
+ mem_size = 0;
+ memset(&heap_entry,0,sizeof(heap_entry));
+ heap_entry.wFlags = PROCESS_HEAP_REGION;
+
+ while( HeapWalk(memory_heap,&heap_entry) ) {
+ if( heap_entry.wFlags & PROCESS_HEAP_REGION ) {
+ mem_size += heap_entry.Region.dwCommittedSize;
+ }
+ }
+
+ if( GetLastError() != ERROR_NO_MORE_ITEMS ) {
+ fprintf(stderr, "HeapCommittedSize: Heap is corrupted\n" );
+ return 0;
+ }
+ return mem_size;
+}
+#endif
+
+
ZEND_API void start_memory_manager(TSRMLS_D)
{
AG(head) = NULL;
@@ -483,6 +530,15 @@
memset(AG(cache_stats), 0, sizeof(AG(cache_stats)));
memset(AG(fast_cache_stats), 0, sizeof(AG(fast_cache_stats)));
#endif
+
+#ifdef ZEND_WIN32
+ /* Heap is just created, so it costs us nothing to get heap size */
+ AG(startup_memory) = AG(request_start_memory) = HeapCommittedSize(
AG(memory_heap) );
+#elif HAVE_SBRK
+ AG(startup_memory) = AG(request_start_memory) = (unsigned int)sbrk(0);
+#else
+ AG(startup_memory) = AG(request_start_memory) = 0;
+#endif
}
@@ -648,6 +704,39 @@
return;
}
#endif
+
+ if ( !full_shutdown && (AG(memory_trim_limit) != 0 ||
AG(memory_grow_limit) != 0) ) {
+ unsigned int process_memory;
+#ifdef ZEND_WIN32
+ process_memory = HeapCommittedSize( AG(memory_heap) );
+ if( AG(memory_trim_limit) &&
+ (int)(process_memory - AG(request_start_memory)) >
AG(memory_trim_limit) ) {
+ HeapCompact( AG(memory_heap), HEAP_NO_SERIALIZE );
+ process_memory = HeapCommittedSize( AG(memory_heap) );
+ }
+#elif HAVE_SBRK
+ process_memory = (unsigned int)sbrk(0);
+ #if HAVE_MALLOC_TRIM
+ if( AG(memory_trim_limit) &&
+ (int)(process_memory - AG(request_start_memory)) >
AG(memory_trim_limit) ) {
+ malloc_trim(0);
+ process_memory = (unsigned int)sbrk(0);
+ }
+ #endif
+#else
+ process_memory = 0;
+#endif
+
+ if( AG(memory_grow_limit) &&
+ (int)(process_memory - AG(startup_memory)) >
AG(memory_grow_limit) ) {
+ SG(force_exit) = 1;
+ }
+
+ /* Current process memory size should be used as
request_start_memory
+ * for next request
+ */
+ AG(request_start_memory) = process_memory;
+ }
}
Index: php-src/Zend/zend_alloc.h
===================================================================
RCS file: /repository/ZendEngine2/zend_alloc.h,v
retrieving revision 1.63
diff -u -r1.63 zend_alloc.h
--- php-src/Zend/zend_alloc.h 3 Aug 2005 13:30:47 -0000 1.63
+++ php-src/Zend/zend_alloc.h 9 Aug 2005 23:18:58 -0000
@@ -172,6 +172,9 @@
ZEND_API int zend_set_memory_limit(unsigned int memory_limit);
+ZEND_API int zend_set_memory_trim_limit(unsigned int memory_trim_limit);
+ZEND_API int zend_set_memory_grow_limit(unsigned int memory_grow_limit);
+
ZEND_API void start_memory_manager(TSRMLS_D);
ZEND_API void shutdown_memory_manager(int silent, int full_shutdown TSRMLS_DC);
Index: php-src/Zend/zend_globals.h
===================================================================
RCS file: /repository/ZendEngine2/zend_globals.h,v
retrieving revision 1.141
diff -u -r1.141 zend_globals.h
--- php-src/Zend/zend_globals.h 3 Aug 2005 13:30:52 -0000 1.141
+++ php-src/Zend/zend_globals.h 9 Aug 2005 23:18:58 -0000
@@ -261,6 +261,10 @@
#ifdef ZEND_MM
zend_mm_heap mm_heap;
#endif
+ unsigned int memory_trim_limit;
+ unsigned int memory_grow_limit;
+ unsigned int startup_memory;
+ unsigned int request_start_memory;
};
struct _zend_scanner_globals {
Index: php-src/Zend/Zend.m4
===================================================================
RCS file: /repository/ZendEngine2/Zend.m4,v
retrieving revision 1.58
diff -u -r1.58 Zend.m4
--- php-src/Zend/Zend.m4 14 Jun 2005 12:23:26 -0000 1.58
+++ php-src/Zend/Zend.m4 9 Aug 2005 23:18:58 -0000
@@ -313,3 +313,6 @@
])
+
+AC_CHECK_FUNC(sbrk,[AC_DEFINE(HAVE_SBRK, 1,[ ])])
+AC_CHECK_FUNC(malloc_trim,[AC_DEFINE(HAVE_MALLOC_TRIM, 1,[ ])])
Index: php-src/main/SAPI.h
===================================================================
RCS file: /repository/php-src/main/SAPI.h,v
retrieving revision 1.114
diff -u -r1.114 SAPI.h
--- php-src/main/SAPI.h 3 Aug 2005 14:08:28 -0000 1.114
+++ php-src/main/SAPI.h 9 Aug 2005 23:18:59 -0000
@@ -129,6 +129,7 @@
zend_bool sapi_started;
time_t global_request_time;
HashTable known_post_content_types;
+ int force_exit;
} sapi_globals_struct;
Index: php-src/main/php_globals.h
===================================================================
RCS file: /repository/php-src/main/php_globals.h,v
retrieving revision 1.98
diff -u -r1.98 php_globals.h
--- php-src/main/php_globals.h 3 Aug 2005 14:08:33 -0000 1.98
+++ php-src/main/php_globals.h 9 Aug 2005 23:18:59 -0000
@@ -76,6 +76,9 @@
long memory_limit;
long max_input_time;
+ long memory_trim_limit;
+ long memory_grow_limit;
+
zend_bool track_errors;
zend_bool display_errors;
zend_bool display_startup_errors;
Index: php-src/main/main.c
===================================================================
RCS file: /repository/php-src/main/main.c,v
retrieving revision 1.639
diff -u -r1.639 main.c
--- php-src/main/main.c 3 Aug 2005 14:08:30 -0000 1.639
+++ php-src/main/main.c 9 Aug 2005 23:18:59 -0000
@@ -119,6 +119,31 @@
/* }}} */
#endif
+/* {{{ PHP_INI_MH
+ */
+static PHP_INI_MH(OnChangeMemoryTrimLimit)
+{
+ if (new_value) {
+ PG(memory_trim_limit) = zend_atoi(new_value, new_value_length);
+ } else {
+ PG(memory_trim_limit) = 1024*1024;
+ }
+ return zend_set_memory_trim_limit(PG(memory_trim_limit));
+}
+/* }}} */
+
+/* {{{ PHP_INI_MH
+ */
+static PHP_INI_MH(OnChangeMemoryGrowLimit)
+{
+ if (new_value) {
+ PG(memory_grow_limit) = zend_atoi(new_value, new_value_length);
+ } else {
+ PG(memory_grow_limit) = 128*1024*1024;
+ }
+ return zend_set_memory_grow_limit(PG(memory_grow_limit));
+}
+/* }}} */
/* {{{ php_disable_functions
*/
@@ -313,6 +338,8 @@
#if MEMORY_LIMIT
PHP_INI_ENTRY("memory_limit", "8M",
PHP_INI_ALL, OnChangeMemoryLimit)
#endif
+ PHP_INI_ENTRY("memory_trim_limit", "1M",
PHP_INI_ALL, OnChangeMemoryTrimLimit)
+ PHP_INI_ENTRY("memory_grow_limit", "128M",
PHP_INI_ALL, OnChangeMemoryGrowLimit)
PHP_INI_ENTRY("precision", "14",
PHP_INI_ALL, OnSetPrecision)
PHP_INI_ENTRY("sendmail_from", NULL,
PHP_INI_ALL, NULL)
PHP_INI_ENTRY("sendmail_path", DEFAULT_SENDMAIL_PATH, PHP_INI_SYSTEM,
NULL)
Index: php-src/sapi/cgi/cgi_main.c
===================================================================
RCS file: /repository/php-src/sapi/cgi/cgi_main.c,v
retrieving revision 1.267
diff -u -r1.267 cgi_main.c
--- php-src/sapi/cgi/cgi_main.c 3 Aug 2005 11:12:17 -0000 1.267
+++ php-src/sapi/cgi/cgi_main.c 9 Aug 2005 23:18:59 -0000
@@ -1644,7 +1644,7 @@
if (!fastcgi) break;
/* only fastcgi will get here */
requests++;
- if (max_requests && (requests == max_requests)) {
+ if ( SG(force_exit) || (max_requests && (requests ==
max_requests)) ) {
FCGX_Finish_r(&request);
#ifndef PHP_WIN32
if (bindpath) {
Index: php-src/sapi/apache/sapi_apache.c
===================================================================
RCS file: /repository/php-src/sapi/apache/sapi_apache.c,v
retrieving revision 1.47
diff -u -r1.47 sapi_apache.c
--- php-src/sapi/apache/sapi_apache.c 3 Aug 2005 14:08:46 -0000 1.47
+++ php-src/sapi/apache/sapi_apache.c 9 Aug 2005 23:19:00 -0000
@@ -58,6 +58,10 @@
zend_try {
php_request_shutdown(NULL);
} zend_end_try();
+
+ if( SG(force_exit) ) {
+ ap_child_terminate( ((request_rec *)SG(server_context)) );
+ }
return retval;
}
Index: php-src/sapi/apache2handler/sapi_apache2.c
===================================================================
RCS file: /repository/php-src/sapi/apache2handler/sapi_apache2.c,v
retrieving revision 1.57
diff -u -r1.57 sapi_apache2.c
--- php-src/sapi/apache2handler/sapi_apache2.c 3 Aug 2005 14:08:48 -0000
1.57
+++ php-src/sapi/apache2handler/sapi_apache2.c 9 Aug 2005 23:19:00 -0000
@@ -592,6 +592,12 @@
ctx->r = parent_req;
}
+#ifndef ZTS
+ if (SG(force_exit)) {
+ exit(0);
+ }
+#endif
+
return OK;
}
--
PHP Internals - PHP Runtime Development Mailing List
To unsubscribe, visit: http://www.php.net/unsub.php
