undef/git-commit-vandalism
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Make xmalloc and xrealloc thread-safe

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By providing a hook for the routine responsible for trying to free some
memory on malloc failure, we can ensure that the  called routine is
protected by the appropriate locks when threads are in play.

The obvious offender here was pack-objects which was calling xmalloc()
within threads while release_pack_memory() is not thread safe.

Signed-off-by: Nicolas Pitre <nico@fluxnic.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
This commit is contained in:
Nicolas Pitre 2010-03-24 16:22:34 -04:00 committed by Junio C Hamano
parent 846b8f681a
commit a9a746364b
3 changed files with 27 additions and 4 deletions
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9
builtin-pack-objects.c
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@ -1549,6 +1549,13 @@ static void find_deltas(struct object_entry **list, unsigned *list_size,
#ifndef NO_PTHREADS
static void try_to_free_from_threads(size_t size)
{
read_lock();
release_pack_memory(size, -1);
read_unlock();
}
/*
* The main thread waits on the condition that (at least) one of the workers
* has stopped working (which is indicated in the .working member of
@ -1583,10 +1590,12 @@ static void init_threaded_search(void)
pthread_mutex_init(&cache_mutex, NULL);
pthread_mutex_init(&progress_mutex, NULL);
pthread_cond_init(&progress_cond, NULL);
set_try_to_free_routine(try_to_free_from_threads);
}
static void cleanup_threaded_search(void)
{
set_try_to_free_routine(NULL);
pthread_cond_destroy(&progress_cond);
pthread_mutex_destroy(&read_mutex);
pthread_mutex_destroy(&cache_mutex);

2
git-compat-util.h
View File

@ -346,6 +346,8 @@ static inline char *gitstrchrnul(const char *s, int c)
extern void release_pack_memory(size_t, int);
extern void set_try_to_free_routine(void (*routine)(size_t));
extern char *xstrdup(const char *str);
extern void *xmalloc(size_t size);
extern void *xmallocz(size_t size);

20
wrapper.c
View File

@ -3,11 +3,23 @@
*/
#include "cache.h"
static void try_to_free_builtin(size_t size)
{
release_pack_memory(size, -1);
}
static void (*try_to_free_routine)(size_t size) = try_to_free_builtin;
void set_try_to_free_routine(void (*routine)(size_t))
{
try_to_free_routine = (routine) ? routine : try_to_free_builtin;
}
char *xstrdup(const char *str)
{
char *ret = strdup(str);
if (!ret) {
release_pack_memory(strlen(str) + 1, -1);
try_to_free_routine(strlen(str) + 1);
ret = strdup(str);
if (!ret)
die("Out of memory, strdup failed");
@ -21,7 +33,7 @@ void *xmalloc(size_t size)
if (!ret && !size)
ret = malloc(1);
if (!ret) {
release_pack_memory(size, -1);
try_to_free_routine(size);
ret = malloc(size);
if (!ret && !size)
ret = malloc(1);
@ -67,7 +79,7 @@ void *xrealloc(void *ptr, size_t size)
if (!ret && !size)
ret = realloc(ptr, 1);
if (!ret) {
release_pack_memory(size, -1);
try_to_free_routine(size);
ret = realloc(ptr, size);
if (!ret && !size)
ret = realloc(ptr, 1);
@ -83,7 +95,7 @@ void *xcalloc(size_t nmemb, size_t size)
if (!ret && (!nmemb || !size))
ret = calloc(1, 1);
if (!ret) {
release_pack_memory(nmemb * size, -1);
try_to_free_routine(nmemb * size);
ret = calloc(nmemb, size);
if (!ret && (!nmemb || !size))
ret = calloc(1, 1);