On Tue, 2011-08-23 at 23:25 +0800, Christoph Lameter wrote:
> On Tue, 23 Aug 2011, Shaohua Li wrote:
>
> > Adding slab to partial list head/tail is sensentive to performance.
> > So adding a type to document it to avoid we get it wrong.
>
> I think that if you want to make it more descriptive then using the stats
> values (DEACTIVATE_TO_TAIL/HEAD) would avoid having to introduce an
> additional enum and it would also avoid the if statement in the stat call.
ok, that's better.
Subject: slub: explicitly document position of inserting slab to partial list
Adding slab to partial list head/tail is sensitive to performance.
So explicitly uses DEACTIVATE_TO_TAIL/DEACTIVATE_TO_HEAD to document
it to avoid we get it wrong.
Signed-off-by: Shaohua Li <shli@xxxxxxxxxx>
Signed-off-by: Shaohua Li <shaohua.li@xxxxxxxxx>
---
mm/slub.c | 12 ++++++------
1 file changed, 6 insertions(+), 6 deletions(-)
Index: linux/mm/slub.c
===================================================================
--- linux.orig/mm/slub.c 2011-08-24 08:46:27.000000000 +0800
+++ linux/mm/slub.c 2011-08-24 08:49:41.000000000 +0800
@@ -1534,7 +1534,7 @@ static inline void add_partial(struct km
struct page *page, int tail)
{
n->nr_partial++;
- if (tail)
+ if (tail == DEACTIVATE_TO_TAIL)
list_add_tail(&page->lru, &n->partial);
else
list_add(&page->lru, &n->partial);
@@ -1781,13 +1781,13 @@ static void deactivate_slab(struct kmem_
enum slab_modes l = M_NONE, m = M_NONE;
void *freelist;
void *nextfree;
- int tail = 0;
+ int tail = DEACTIVATE_TO_HEAD;
struct page new;
struct page old;
if (page->freelist) {
stat(s, DEACTIVATE_REMOTE_FREES);
- tail = 1;
+ tail = DEACTIVATE_TO_TAIL;
}
c->tid = next_tid(c->tid);
@@ -1893,7 +1893,7 @@ redo:
if (m == M_PARTIAL) {
add_partial(n, page, tail);
- stat(s, tail ? DEACTIVATE_TO_TAIL : DEACTIVATE_TO_HEAD);
+ stat(s, tail);
} else if (m == M_FULL) {
@@ -2377,7 +2377,7 @@ static void __slab_free(struct kmem_cach
*/
if (unlikely(!prior)) {
remove_full(s, page);
- add_partial(n, page, 1);
+ add_partial(n, page, DEACTIVATE_TO_TAIL);
stat(s, FREE_ADD_PARTIAL);
}
}
@@ -2695,7 +2695,7 @@ static void early_kmem_cache_node_alloc(
init_kmem_cache_node(n, kmem_cache_node);
inc_slabs_node(kmem_cache_node, node, page->objects);
- add_partial(n, page, 0);
+ add_partial(n, page, DEACTIVATE_TO_HEAD);
}
static void free_kmem_cache_nodes(struct kmem_cache *s)
--
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