The patch titled
SLUB: Define functions for cpu slab handling instead of using PageActive
has been removed from the -mm tree. Its filename was
slub-define-functions-for-cpu-slab-handling-instead-of-using.patch
This patch was dropped because it was merged into mainline or a subsystem tree
------------------------------------------------------
Subject: SLUB: Define functions for cpu slab handling instead of using PageActive
From: Christoph Lameter <clameter@xxxxxxx>
Use inline functions to access the per cpu bit. Intoduce the notion of
"freezing" a slab to make things more understandable.
Signed-off-by: Christoph Lameter <clameter@xxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
mm/slub.c | 57 ++++++++++++++++++++++++++++++++++------------------
1 file changed, 38 insertions(+), 19 deletions(-)
diff -puN mm/slub.c~slub-define-functions-for-cpu-slab-handling-instead-of-using mm/slub.c
--- a/mm/slub.c~slub-define-functions-for-cpu-slab-handling-instead-of-using
+++ a/mm/slub.c
@@ -78,10 +78,18 @@
*
* Overloading of page flags that are otherwise used for LRU management.
*
- * PageActive The slab is used as a cpu cache. Allocations
- * may be performed from the slab. The slab is not
- * on any slab list and cannot be moved onto one.
- * The cpu slab may be equipped with an additioanl
+ * PageActive The slab is frozen and exempt from list processing.
+ * This means that the slab is dedicated to a purpose
+ * such as satisfying allocations for a specific
+ * processor. Objects may be freed in the slab while
+ * it is frozen but slab_free will then skip the usual
+ * list operations. It is up to the processor holding
+ * the slab to integrate the slab into the slab lists
+ * when the slab is no longer needed.
+ *
+ * One use of this flag is to mark slabs that are
+ * used for allocations. Then such a slab becomes a cpu
+ * slab. The cpu slab may be equipped with an additional
* lockless_freelist that allows lockless access to
* free objects in addition to the regular freelist
* that requires the slab lock.
@@ -91,6 +99,21 @@
* the fast path and disables lockless freelists.
*/
+static inline int SlabFrozen(struct page *page)
+{
+ return PageActive(page);
+}
+
+static inline void SetSlabFrozen(struct page *page)
+{
+ SetPageActive(page);
+}
+
+static inline void ClearSlabFrozen(struct page *page)
+{
+ ClearPageActive(page);
+}
+
static inline int SlabDebug(struct page *page)
{
#ifdef CONFIG_SLUB_DEBUG
@@ -1135,11 +1158,12 @@ static void remove_partial(struct kmem_c
*
* Must hold list_lock.
*/
-static int lock_and_del_slab(struct kmem_cache_node *n, struct page *page)
+static inline int lock_and_freeze_slab(struct kmem_cache_node *n, struct page *page)
{
if (slab_trylock(page)) {
list_del(&page->lru);
n->nr_partial--;
+ SetSlabFrozen(page);
return 1;
}
return 0;
@@ -1163,7 +1187,7 @@ static struct page *get_partial_node(str
spin_lock(&n->list_lock);
list_for_each_entry(page, &n->partial, lru)
- if (lock_and_del_slab(n, page))
+ if (lock_and_freeze_slab(n, page))
goto out;
page = NULL;
out:
@@ -1242,10 +1266,11 @@ static struct page *get_partial(struct k
*
* On exit the slab lock will have been dropped.
*/
-static void putback_slab(struct kmem_cache *s, struct page *page)
+static void unfreeze_slab(struct kmem_cache *s, struct page *page)
{
struct kmem_cache_node *n = get_node(s, page_to_nid(page));
+ ClearSlabFrozen(page);
if (page->inuse) {
if (page->freelist)
@@ -1296,9 +1321,7 @@ static void deactivate_slab(struct kmem_
page->inuse--;
}
s->cpu_slab[cpu] = NULL;
- ClearPageActive(page);
-
- putback_slab(s, page);
+ unfreeze_slab(s, page);
}
static void flush_slab(struct kmem_cache *s, struct page *page, int cpu)
@@ -1389,9 +1412,7 @@ another_slab:
new_slab:
page = get_partial(s, gfpflags, node);
if (page) {
-have_slab:
s->cpu_slab[cpu] = page;
- SetPageActive(page);
goto load_freelist;
}
@@ -1421,7 +1442,9 @@ have_slab:
flush_slab(s, s->cpu_slab[cpu], cpu);
}
slab_lock(page);
- goto have_slab;
+ SetSlabFrozen(page);
+ s->cpu_slab[cpu] = page;
+ goto load_freelist;
}
return NULL;
debug:
@@ -1508,11 +1531,7 @@ checks_ok:
page->freelist = object;
page->inuse--;
- if (unlikely(PageActive(page)))
- /*
- * Cpu slabs are never on partial lists and are
- * never freed.
- */
+ if (unlikely(SlabFrozen(page)))
goto out_unlock;
if (unlikely(!page->inuse))
@@ -1544,7 +1563,7 @@ slab_empty:
debug:
if (!free_object_checks(s, page, x))
goto out_unlock;
- if (!PageActive(page) && !page->freelist)
+ if (!SlabFrozen(page) && !page->freelist)
remove_full(s, page);
if (s->flags & SLAB_STORE_USER)
set_track(s, x, TRACK_FREE, addr);
_
Patches currently in -mm which might be from clameter@xxxxxxx are
origin.patch
slub-another-slabinfo-fix.patch
git-ubi.patch
quicklist-support-for-x86_64.patch
change-zonelist-order-zonelist-order-selection-logic.patch
change-zonelist-order-zonelist-order-selection-logic-add-check_highest_zone-to-build_zonelists_in_zone_order.patch
change-zonelist-order-v6-zonelist-fix.patch
change-zonelist-order-auto-configuration.patch
change-zonelist-order-documentaion.patch
add-__gfp_movable-for-callers-to-flag-allocations-from-high-memory-that-may-be-migrated-mark-bio_alloc-allocations-correctly.patch
add-__gfp_movable-for-callers-to-flag-allocations-from-high-memory-that-may-be-migrated-rename-gfp_high_movable-to-gfp_highuser_movable.patch
add-__gfp_movable-for-callers-to-flag-allocations-from-high-memory-that-may-be-migrated-mark-page-cache-pages-as-__gfp_pagecache-instead-of-__gfp_movable.patch
group-short-lived-and-reclaimable-kernel-allocations-use-slab_account_reclaim-to-determine-when-__gfp_reclaimable-should-be-used.patch
group-short-lived-and-reclaimable-kernel-allocations-use-slab_account_reclaim-to-determine-when-__gfp_reclaimable-should-be-used-fix.patch
group-short-lived-and-reclaimable-kernel-allocations-do-not-annotate-shmem-allocations-explicitly.patch
group-short-lived-and-reclaimable-kernel-allocations-add-__gfp_temporary-to-identify-allocations-that-are-short-lived.patch
have-kswapd-keep-a-minimum-order-free-other-than-order-0.patch
have-kswapd-keep-a-minimum-order-free-other-than-order-0-fix.patch
only-check-absolute-watermarks-for-alloc_high-and-alloc_harder-allocations.patch
slub-mm-only-make-slub-the-default-slab-allocator.patch
slub-exploit-page-mobility-to-increase-allocation-order.patch
slub-reduce-antifrag-max-order.patch
slub-reduce-antifrag-max-order-use-antifrag-constant-instead-of-hardcoding-page-order.patch
mm-implement-swap-prefetching.patch
rename-gfp_high_movable-to-gfp_highuser_movable-prefetch.patch
revoke-core-code.patch
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