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Date: Tue, 2 May 2017 22:45:33 +0800
From: Wei Yang <richard.weiyang@...il.com>
To: cl@...ux.com, penberg@...nel.org, rientjes@...gle.com,
iamjoonsoo.kim@....com, akpm@...ux-foundation.org,
willy@...radead.org
Cc: linux-mm@...ck.org, linux-kernel@...r.kernel.org,
Wei Yang <richard.weiyang@...il.com>
Subject: [PATCH V2 3/3] mm/slub: wrap kmem_cache->cpu_partial in config CONFIG_SLUB_CPU_PARTIAL
kmem_cache->cpu_partial is just used when CONFIG_SLUB_CPU_PARTIAL is set,
so wrap it with config CONFIG_SLUB_CPU_PARTIAL will save some space
on 32bit arch.
This patch wrap kmem_cache->cpu_partial in config CONFIG_SLUB_CPU_PARTIAL
and wrap its sysfs too.
Signed-off-by: Wei Yang <richard.weiyang@...il.com>
---
v2: define slub_cpu_partial() to make code more elegant
---
include/linux/slub_def.h | 13 +++++++++
mm/slub.c | 69 ++++++++++++++++++++++++++----------------------
2 files changed, 51 insertions(+), 31 deletions(-)
diff --git a/include/linux/slub_def.h b/include/linux/slub_def.h
index f882a34bb9aa..d808e8e6293b 100644
--- a/include/linux/slub_def.h
+++ b/include/linux/slub_def.h
@@ -86,7 +86,9 @@ struct kmem_cache {
int size; /* The size of an object including meta data */
int object_size; /* The size of an object without meta data */
int offset; /* Free pointer offset. */
+#ifdef CONFIG_SLUB_CPU_PARTIAL
int cpu_partial; /* Number of per cpu partial objects to keep around */
+#endif
struct kmem_cache_order_objects oo;
/* Allocation and freeing of slabs */
@@ -130,6 +132,17 @@ struct kmem_cache {
struct kmem_cache_node *node[MAX_NUMNODES];
};
+#ifdef CONFIG_SLUB_CPU_PARTIAL
+#define slub_cpu_partial(s) ((s)->cpu_partial)
+#define slub_set_cpu_partial(s, n) \
+({ \
+ slub_cpu_partial(s) = (n); \
+})
+#else
+#define slub_cpu_partial(s) (0)
+#define slub_set_cpu_partial(s, n)
+#endif // CONFIG_SLUB_CPU_PARTIAL
+
#ifdef CONFIG_SYSFS
#define SLAB_SUPPORTS_SYSFS
void sysfs_slab_release(struct kmem_cache *);
diff --git a/mm/slub.c b/mm/slub.c
index ae6166533261..795112b65c61 100644
--- a/mm/slub.c
+++ b/mm/slub.c
@@ -1829,7 +1829,7 @@ static void *get_partial_node(struct kmem_cache *s, struct kmem_cache_node *n,
stat(s, CPU_PARTIAL_NODE);
}
if (!kmem_cache_has_cpu_partial(s)
- || available > s->cpu_partial / 2)
+ || available > slub_cpu_partial(s) / 2)
break;
}
@@ -3410,6 +3410,39 @@ static void set_min_partial(struct kmem_cache *s, unsigned long min)
s->min_partial = min;
}
+static void set_cpu_partial(struct kmem_cache *s)
+{
+#ifdef CONFIG_SLUB_CPU_PARTIAL
+ /*
+ * cpu_partial determined the maximum number of objects kept in the
+ * per cpu partial lists of a processor.
+ *
+ * Per cpu partial lists mainly contain slabs that just have one
+ * object freed. If they are used for allocation then they can be
+ * filled up again with minimal effort. The slab will never hit the
+ * per node partial lists and therefore no locking will be required.
+ *
+ * This setting also determines
+ *
+ * A) The number of objects from per cpu partial slabs dumped to the
+ * per node list when we reach the limit.
+ * B) The number of objects in cpu partial slabs to extract from the
+ * per node list when we run out of per cpu objects. We only fetch
+ * 50% to keep some capacity around for frees.
+ */
+ if (!kmem_cache_has_cpu_partial(s))
+ s->cpu_partial = 0;
+ else if (s->size >= PAGE_SIZE)
+ s->cpu_partial = 2;
+ else if (s->size >= 1024)
+ s->cpu_partial = 6;
+ else if (s->size >= 256)
+ s->cpu_partial = 13;
+ else
+ s->cpu_partial = 30;
+#endif
+}
+
/*
* calculate_sizes() determines the order and the distribution of data within
* a slab object.
@@ -3568,33 +3601,7 @@ static int kmem_cache_open(struct kmem_cache *s, unsigned long flags)
*/
set_min_partial(s, ilog2(s->size) / 2);
- /*
- * cpu_partial determined the maximum number of objects kept in the
- * per cpu partial lists of a processor.
- *
- * Per cpu partial lists mainly contain slabs that just have one
- * object freed. If they are used for allocation then they can be
- * filled up again with minimal effort. The slab will never hit the
- * per node partial lists and therefore no locking will be required.
- *
- * This setting also determines
- *
- * A) The number of objects from per cpu partial slabs dumped to the
- * per node list when we reach the limit.
- * B) The number of objects in cpu partial slabs to extract from the
- * per node list when we run out of per cpu objects. We only fetch
- * 50% to keep some capacity around for frees.
- */
- if (!kmem_cache_has_cpu_partial(s))
- s->cpu_partial = 0;
- else if (s->size >= PAGE_SIZE)
- s->cpu_partial = 2;
- else if (s->size >= 1024)
- s->cpu_partial = 6;
- else if (s->size >= 256)
- s->cpu_partial = 13;
- else
- s->cpu_partial = 30;
+ set_cpu_partial(s);
#ifdef CONFIG_NUMA
s->remote_node_defrag_ratio = 1000;
@@ -3981,7 +3988,7 @@ void __kmemcg_cache_deactivate(struct kmem_cache *s)
* Disable empty slabs caching. Used to avoid pinning offline
* memory cgroups by kmem pages that can be freed.
*/
- s->cpu_partial = 0;
+ slub_set_cpu_partial(s, 0);
s->min_partial = 0;
/*
@@ -4921,7 +4928,7 @@ SLAB_ATTR(min_partial);
static ssize_t cpu_partial_show(struct kmem_cache *s, char *buf)
{
- return sprintf(buf, "%u\n", s->cpu_partial);
+ return sprintf(buf, "%u\n", slub_cpu_partial(s));
}
static ssize_t cpu_partial_store(struct kmem_cache *s, const char *buf,
@@ -4936,7 +4943,7 @@ static ssize_t cpu_partial_store(struct kmem_cache *s, const char *buf,
if (objects && !kmem_cache_has_cpu_partial(s))
return -EINVAL;
- s->cpu_partial = objects;
+ slub_set_cpu_partial(s, objects);
flush_all(s);
return length;
}
--
2.11.0
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