Signed-off-by: Nicolas Pitre <nico@xxxxxxx>
---
On Mon, 10 Sep 2007, Nicolas Pitre wrote:
> On Mon, 10 Sep 2007, Martin Koegler wrote:
>
> > I noticed some other (potential) problem:
> > delta_cache_size is not protected by locks, although it is modified by
> > concurrent threads, eg:
> > delta_cache_size -= trg_entry->delta_size
>
> Yeah I know. I was worried about the performance hit of additional
> locks initially, and it is not critical for the delta_cache_size
> variable to be perfectly accurate. Locking doesn't appear to be the
> issue anymore, so it might be a good thing to do for delta_cache_size
> too.
So here it is.
diff --git a/builtin-pack-objects.c b/builtin-pack-objects.c
index 42698d2..7b6671f 100644
--- a/builtin-pack-objects.c
+++ b/builtin-pack-objects.c
@@ -1301,6 +1301,10 @@ static pthread_mutex_t read_mutex = PTHREAD_MUTEX_INITIALIZER;
#define read_lock() pthread_mutex_lock(&read_mutex)
#define read_unlock() pthread_mutex_unlock(&read_mutex)
+static pthread_mutex_t cache_mutex = PTHREAD_MUTEX_INITIALIZER;
+#define cache_lock() pthread_mutex_lock(&cache_mutex)
+#define cache_unlock() pthread_mutex_unlock(&cache_mutex)
+
static pthread_mutex_t progress_mutex = PTHREAD_MUTEX_INITIALIZER;
#define progress_lock() pthread_mutex_lock(&progress_mutex)
#define progress_unlock() pthread_mutex_unlock(&progress_mutex)
@@ -1309,6 +1313,8 @@ static pthread_mutex_t progress_mutex = PTHREAD_MUTEX_INITIALIZER;
#define read_lock() 0
#define read_unlock() 0
+#define cache_lock() 0
+#define cache_unlock() 0
#define progress_lock() 0
#define progress_unlock() 0
@@ -1423,17 +1429,27 @@ static int try_delta(struct unpacked *trg, struct unpacked *src,
trg_entry->delta_size = delta_size;
trg->depth = src->depth + 1;
+ /*
+ * Handle memory allocation outside of the cache
+ * accounting lock. Compiler will optimize the strangeness
+ * away when THREADED_DELTA_SEARCH is not defined.
+ */
+ if (trg_entry->delta_data)
+ free(trg_entry->delta_data);
+ cache_lock();
if (trg_entry->delta_data) {
delta_cache_size -= trg_entry->delta_size;
- free(trg_entry->delta_data);
trg_entry->delta_data = NULL;
}
-
if (delta_cacheable(src_size, trg_size, delta_size)) {
- trg_entry->delta_data = xrealloc(delta_buf, delta_size);
delta_cache_size += trg_entry->delta_size;
- } else
+ cache_unlock();
+ trg_entry->delta_data = xrealloc(delta_buf, delta_size);
+ } else {
+ cache_unlock();
free(delta_buf);
+ }
+
return 1;
}
-
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