[PATCH] malloc: destroy thread cache on thread exit

[Joern Engel]

I don't think this matters much - current glibc malloc actually leaks
memory every time a thread exits.  But for correctness sake.

JIRA: PURE-27597
---
 tpc/malloc2.13/arena.h  |  2 +-
 tpc/malloc2.13/malloc.c |  1 +
 tpc/malloc2.13/tcache.h | 15 +++++++++++++++
 3 files changed, 17 insertions(+), 1 deletion(-)

diff --git a/tpc/malloc2.13/arena.h b/tpc/malloc2.13/arena.h
index 599774ea1300..9236a3231f07 100644
--- a/tpc/malloc2.13/arena.h
+++ b/tpc/malloc2.13/arena.h
@@ -363,7 +363,7 @@ static void ptmalloc_init(void)
 	}
 
 	mutex_init(&list_lock);
-	tsd_key_create(&cache_key, NULL);
+	tsd_key_create(&cache_key, tcache_destroy);
 	tsd_key_create(&arena_key, NULL);
 	tsd_setspecific(arena_key, (Void_t *) & main_arena);
 	thread_atfork(ptmalloc_lock_all, ptmalloc_unlock_all, ptmalloc_unlock_all2);
diff --git a/tpc/malloc2.13/malloc.c b/tpc/malloc2.13/malloc.c
index 022b9a4ce712..94b7e223ec6f 100644
--- a/tpc/malloc2.13/malloc.c
+++ b/tpc/malloc2.13/malloc.c
@@ -2209,6 +2209,7 @@ static Void_t*  sYSMALLOc(INTERNAL_SIZE_T, struct malloc_state *);
 static int      sYSTRIm(size_t, struct malloc_state *);
 static void     malloc_consolidate(struct malloc_state *);
 static Void_t** iALLOc(struct malloc_state *, size_t, size_t*, int, Void_t**);
+static void tcache_destroy(void *_cache);
 
 
 /* -------------- Early definitions for debugging hooks ---------------- */
diff --git a/tpc/malloc2.13/tcache.h b/tpc/malloc2.13/tcache.h
index 1d324526194f..628dbc00256a 100644
--- a/tpc/malloc2.13/tcache.h
+++ b/tpc/malloc2.13/tcache.h
@@ -202,6 +202,21 @@ static void tcache_gc(struct thread_cache *cache)
 	}
 }
 
+static void tcache_destroy(void *_cache)
+{
+	struct thread_cache *cache = _cache;
+
+	/*
+	 * tcache_gc almost does what we want.  It tries hard to only
+	 * free part of the cache, but call it often enough and it
+	 * will free everything.  Probably slightly slower than having
+	 * a specialized copy of the same code, but also much simpler.
+	 */
+	while (cache->tc_count)
+		tcache_gc(cache);
+	public_fREe(cache);
+}
+
 static void add_to_bin(struct malloc_chunk **bin, struct malloc_chunk *p)
 {
 	struct malloc_chunk *old;
-- 
2.7.0.rc3