[PATCH 1/2] mm/slub: remove a redundant assignment in ___slab_alloc()

[PATCH 1/2] mm/slub: remove a redundant assignment in ___slab_alloc()

[Wei Yang]

When the code comes to this point, there are two cases:
1. cpu_slab is deactivated
2. cpu_slab is empty

In both cased, cpu_slab->freelist is NULL at this moment.

This patch removes the redundant assignment of cpu_slab->freelist.

Signed-off-by: Wei Yang <richard.weiyang@gmail.com>
---
 mm/slub.c | 1 -
 1 file changed, 1 deletion(-)

diff --git a/mm/slub.c b/mm/slub.c
index 795112b65c61..83332f19d226 100644
--- a/mm/slub.c
+++ b/mm/slub.c
@@ -2572,7 +2572,6 @@ static void *___slab_alloc(struct kmem_cache *s, gfp_t gfpflags, int node,
 		page = c->page = slub_percpu_partial(c);
 		slub_set_percpu_partial(c, page);
 		stat(s, CPU_PARTIAL_ALLOC);
-		c->freelist = NULL;
 		goto redo;
 	}
 
-- 
2.11.0

--
To unsubscribe, send a message with 'unsubscribe linux-mm' in
the body to majordomo@kvack.org.  For more info on Linux MM,
see: http://www.linux-mm.org/ .
Don't email: <a href=mailto:"dont@kvack.org"> email@kvack.org </a>

[PATCH 2/2] mm/slub: reset cpu_slab's pointer in deactivate_slab()

[Wei Yang]

Each time a slab is deactivated, the page and freelist pointer should be
reset.

This patch just merges these two options into deactivate_slab().

Signed-off-by: Wei Yang <richard.weiyang@gmail.com>
---
 mm/slub.c | 21 ++++++++-------------
 1 file changed, 8 insertions(+), 13 deletions(-)

diff --git a/mm/slub.c b/mm/slub.c
index 83332f19d226..9e4e682243a1 100644
--- a/mm/slub.c
+++ b/mm/slub.c
@@ -1993,7 +1993,7 @@ static void init_kmem_cache_cpus(struct kmem_cache *s)
  * Remove the cpu slab
  */
 static void deactivate_slab(struct kmem_cache *s, struct page *page,
-				void *freelist)
+				void *freelist, struct kmem_cache_cpu *c)
 {
 	enum slab_modes { M_NONE, M_PARTIAL, M_FULL, M_FREE };
 	struct kmem_cache_node *n = get_node(s, page_to_nid(page));
@@ -2132,6 +2132,9 @@ static void deactivate_slab(struct kmem_cache *s, struct page *page,
 		discard_slab(s, page);
 		stat(s, FREE_SLAB);
 	}
+
+	c->page = NULL;
+	c->freelist = NULL;
 }
 
 /*
@@ -2266,11 +2269,9 @@ static void put_cpu_partial(struct kmem_cache *s, struct page *page, int drain)
 static inline void flush_slab(struct kmem_cache *s, struct kmem_cache_cpu *c)
 {
 	stat(s, CPUSLAB_FLUSH);
-	deactivate_slab(s, c->page, c->freelist);
+	deactivate_slab(s, c->page, c->freelist, c);
 
 	c->tid = next_tid(c->tid);
-	c->page = NULL;
-	c->freelist = NULL;
 }
 
 /*
@@ -2521,9 +2522,7 @@ static void *___slab_alloc(struct kmem_cache *s, gfp_t gfpflags, int node,
 
 		if (unlikely(!node_match(page, searchnode))) {
 			stat(s, ALLOC_NODE_MISMATCH);
-			deactivate_slab(s, page, c->freelist);
-			c->page = NULL;
-			c->freelist = NULL;
+			deactivate_slab(s, page, c->freelist, c);
 			goto new_slab;
 		}
 	}
@@ -2534,9 +2533,7 @@ static void *___slab_alloc(struct kmem_cache *s, gfp_t gfpflags, int node,
 	 * information when the page leaves the per-cpu allocator
 	 */
 	if (unlikely(!pfmemalloc_match(page, gfpflags))) {
-		deactivate_slab(s, page, c->freelist);
-		c->page = NULL;
-		c->freelist = NULL;
+		deactivate_slab(s, page, c->freelist, c);
 		goto new_slab;
 	}
 
@@ -2591,9 +2588,7 @@ static void *___slab_alloc(struct kmem_cache *s, gfp_t gfpflags, int node,
 			!alloc_debug_processing(s, page, freelist, addr))
 		goto new_slab;	/* Slab failed checks. Next slab needed */
 
-	deactivate_slab(s, page, get_freepointer(s, freelist));
-	c->page = NULL;
-	c->freelist = NULL;
+	deactivate_slab(s, page, get_freepointer(s, freelist), c);
 	return freelist;
 }
 
-- 
2.11.0

--
To unsubscribe, send a message with 'unsubscribe linux-mm' in
the body to majordomo@kvack.org.  For more info on Linux MM,
see: http://www.linux-mm.org/ .
Don't email: <a href=mailto:"dont@kvack.org"> email@kvack.org </a>