Am 02.05.2010 18:12, schrieb Junio C Hamano:
> * np/malloc-threading (2010-04-08) 2 commits
> (merged to 'next' on 2010-04-10 at e1730fb)
> + Thread-safe xmalloc and xrealloc needs a recursive mutex
> + Make xmalloc and xrealloc thread-safe
>
> The fix should eventually go to 'maint' and 'master'. This queues the one
> from J6t for Windows compatibility.
>
> * js/async-thread (2010-03-09) 7 commits
> (merged to 'next' on 2010-04-22 at ee8874e)
> + Enable threaded async procedures whenever pthreads is available
> (merged to 'next' on 2010-03-20 at 9939243)
> + Dying in an async procedure should only exit the thread, not the process.
> + Reimplement async procedures using pthreads
> + Windows: more pthreads functions
> + Fix signature of fcntl() compatibility dummy
> + Make report() from usage.c public as vreportf() and use it.
> + Modernize t5530-upload-pack-error.
>
> As the malloc-threading topic has been cooking for a while, the tip one
> may not be so bad to unleash to 'next' users, especially because we are in
> the pre-release feature freeze.
Note that np/malloc-threading does not help the potential xmalloc race
condition in js/async-thread topic at all. :-( np/malloc-threading is only
about a race that is internal in pack-objects.
Now that you force me to think about the problem, I suggest something along
these lines: Disable try_to_free_routine when GIT_TRACE is set, and require
callers of set_try_to_free_routine to restore the previous routine.
diff --git a/builtin/pack-objects.c b/builtin/pack-objects.c
index 214d7ef..0e81673 100644
--- a/builtin/pack-objects.c
+++ b/builtin/pack-objects.c
@@ -1529,6 +1529,8 @@ static void try_to_free_from_threads(size_t size)
read_unlock();
}
+try_to_free_t old_try_to_free_routine;
+
/*
* 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
@@ -1563,12 +1565,12 @@ 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);
+ old_try_to_free_routine = set_try_to_free_routine(try_to_free_from_threads);
}
static void cleanup_threaded_search(void)
{
- set_try_to_free_routine(NULL);
+ set_try_to_free_routine(old_try_to_free_routine);
pthread_cond_destroy(&progress_cond);
pthread_mutex_destroy(&read_mutex);
pthread_mutex_destroy(&cache_mutex);
diff --git a/git-compat-util.h b/git-compat-util.h
index 4a508c1..51d2a01 100644
--- a/git-compat-util.h
+++ b/git-compat-util.h
@@ -357,7 +357,8 @@ static inline void *gitmempcpy(void *dest, const void *src, size_t n)
extern void release_pack_memory(size_t, int);
-extern void set_try_to_free_routine(void (*routine)(size_t));
+typedef void (*try_to_free_t)(size_t);
+extern try_to_free_t set_try_to_free_routine(try_to_free_t);
extern char *xstrdup(const char *str);
extern void *xmalloc(size_t size);
diff --git a/trace.c b/trace.c
index 4229ae1..9816a8b 100644
--- a/trace.c
+++ b/trace.c
@@ -72,6 +72,7 @@ void trace_printf(const char *fmt, ...)
if (!fd)
return;
+ set_try_to_free_routine(NULL);
strbuf_init(&buf, 64);
va_start(ap, fmt);
len = vsnprintf(buf.buf, strbuf_avail(&buf), fmt, ap);
@@ -103,6 +104,7 @@ void trace_argv_printf(const char **argv, const char *fmt, ...)
if (!fd)
return;
+ set_try_to_free_routine(NULL);
strbuf_init(&buf, 64);
va_start(ap, fmt);
len = vsnprintf(buf.buf, strbuf_avail(&buf), fmt, ap);
diff --git a/wrapper.c b/wrapper.c
index 62edb57..02da613 100644
--- a/wrapper.c
+++ b/wrapper.c
@@ -10,9 +10,11 @@ static void try_to_free_builtin(size_t size)
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_t set_try_to_free_routine(try_to_free_t routine)
{
- try_to_free_routine = (routine) ? routine : try_to_free_builtin;
+ try_to_free_t old = try_to_free_routine;
+ try_to_free_routine = routine;
+ return old;
}
char *xstrdup(const char *str)
@@ -33,8 +35,10 @@ void *xmalloc(size_t size)
if (!ret && !size)
ret = malloc(1);
if (!ret) {
- try_to_free_routine(size);
- ret = malloc(size);
+ if (try_to_free_routine) {
+ try_to_free_routine(size);
+ ret = malloc(size);
+ }
if (!ret && !size)
ret = malloc(1);
if (!ret)
--
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