[Mesa-dev] [PATCH 3/7] util/slab: Add function to flush allocations from a child pool

[Ian Romanick]

From: Ian Romanick <ian.d.romanick at intel.com>

Ralloc has a feature that all allocations from a temporary memory
context can be whisked away in a single call without fear of leaks.  As
the slab allocator is designed for use in multhreaded scenarios with a
child pool per CPU, it lacks this feature.  However, many users will be
single threaded with a single child pool.  For these users, we can have
our cake and eat it too.

Signed-off-by: Ian Romanick <ian.d.romanick at intel.com>
Cc: Nicolai Hähnle <nicolai.haehnle at amd.com>
---
 src/util/slab.c | 21 +++++++++++++++++++++
 src/util/slab.h |  1 +
 2 files changed, 22 insertions(+)

diff --git a/src/util/slab.c b/src/util/slab.c
index 5f048666b56..1bcc1db6e09 100644
--- a/src/util/slab.c
+++ b/src/util/slab.c
@@ -172,6 +172,27 @@ void slab_destroy_child(struct slab_child_pool *pool)
    pool->parent = NULL;
 }
 
+/**
+ * Flush all allocations from a pool.  Single-threaded (no mutex).
+ */
+void
+slab_flush_st(struct slab_mempool *parent)
+{
+   struct slab_child_pool *const pool = &parent->child;
+
+   assert(pool->migrated == NULL);
+   assert(pool->parent == parent);
+
+   while (pool->pages) {
+      struct slab_page_header *page = pool->pages;
+      pool->pages = page->u.next;
+
+      free(page);
+   }
+
+   pool->free = NULL;
+}
+
 static bool
 slab_add_new_page(struct slab_child_pool *pool)
 {
diff --git a/src/util/slab.h b/src/util/slab.h
index e83f8ec1a0e..a4279d8e65b 100644
--- a/src/util/slab.h
+++ b/src/util/slab.h
@@ -90,5 +90,6 @@ void slab_create(struct slab_mempool *pool,
 void slab_destroy(struct slab_mempool *pool);
 void *slab_alloc_st(struct slab_mempool *pool);
 void slab_free_st(struct slab_mempool *pool, void *ptr);
+void slab_flush_st(struct slab_mempool *parent);
 
 #endif
-- 
2.14.4