[PATCH 1/2] Have set_try_to_free_routine return the previous routine
- From
Johannes Sixt <j6t@kdbg.org>
- Date
- May 8, 2010, 15:13 UTC
- Message-ID
- <201005081713.49937.j6t@kdbg.org>
- In-Reply-To
- <4BDDDA21.4090304@kdbg.org>
This effectively requires from the callers of set_try_to_free_routine to treat the try-to-free-routines as a stack.
We will need this for the next patch where the only current caller cannot depend on that the previously set routine was the default routine.
Signed-off-by: Johannes Sixt <j6t@kdbg.org> --- On Sonntag, 2. Mai 2010, Johannes Sixt wrote:
Show 12 quoted lines
> Am 02.05.2010 18:12, schrieb Junio C Hamano: > > * np/malloc-threading (2010-04-08) 2 commits > > > > * js/async-thread (2010-03-09) 7 commits > > 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.
Here is a 2-patch series that implements this idea. I wrote it on top of np/malloc-threading, because it implements the infrastructure that is necessary for this.
builtin-pack-objects.c | 6 ++++-- git-compat-util.h | 3 ++- wrapper.c | 6 ++++-- 3 files changed, 10 insertions(+), 5 deletions(-)
diff --git a/builtin-pack-objects.c b/builtin-pack-objects.c index 26fc7cd..5279cd9 100644 --- a/builtin-pack-objects.c +++ b/builtin-pack-objects.c @@ -1556,6 +1556,8 @@ 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 @@ -1590,12 +1592,12 @@ 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 1c171db..828aada 100644 --- a/git-compat-util.h +++ b/git-compat-util.h @@ -346,7 +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)); +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/wrapper.c b/wrapper.c index 62edb57..8aa9df9 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)
-- 1.7.1.64.ga1799.dirty