Messages in this thread Patch in this message | | | Date | Sat, 19 Jul 2008 15:30:09 +0300 (EEST) | From | Pekka J Enberg <> | Subject | [PATCH 1/8] slub: Add defrag_ratio field and sysfs support. |
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From: Christoph Lameter <clameter@sgi.com>
The defrag_ratio is used to set the threshold at which defragmentation should be attempted on a slab page.
The allocation ratio is measured by the percentage of the available slots allocated.
Add a defrag ratio field and set it to 30% by default. A limit of 30% specified that less than 3 out of 10 available slots for objects are in use before slab defragmeentation runs.
Reviewed-by: Rik van Riel <riel@redhat.com> Signed-off-by: Christoph Lameter <clameter@sgi.com> Signed-off-by: Pekka Enberg <penberg@cs.helsinki.fi> --- include/linux/slub_def.h | 7 +++++++ mm/slub.c | 23 +++++++++++++++++++++++ 2 files changed, 30 insertions(+), 0 deletions(-)
diff --git a/include/linux/slub_def.h b/include/linux/slub_def.h index d117ea2..6f8d25f 100644 --- a/include/linux/slub_def.h +++ b/include/linux/slub_def.h @@ -88,6 +88,13 @@ struct kmem_cache { void (*ctor)(struct kmem_cache *, void *); int inuse; /* Offset to metadata */ int align; /* Alignment */ + int defrag_ratio; /* + * Ratio used to check the percentage of + * objects allocate in a slab page. + * If less than this ratio is allocated + * then reclaim attempts are made. + */ + const char *name; /* Name (only for display!) */ struct list_head list; /* List of slab caches */ #ifdef CONFIG_SLUB_DEBUG diff --git a/mm/slub.c b/mm/slub.c index 35ab38a..1b910ab 100644 --- a/mm/slub.c +++ b/mm/slub.c @@ -2338,6 +2338,7 @@ static int kmem_cache_open(struct kmem_cache *s, gfp_t gfpflags, goto error; s->refcount = 1; + s->defrag_ratio = 30; #ifdef CONFIG_NUMA s->remote_node_defrag_ratio = 100; #endif @@ -4071,6 +4072,27 @@ static ssize_t free_calls_show(struct kmem_cache *s, char *buf) } SLAB_ATTR_RO(free_calls); +static ssize_t defrag_ratio_show(struct kmem_cache *s, char *buf) +{ + return sprintf(buf, "%d\n", s->defrag_ratio); +} + +static ssize_t defrag_ratio_store(struct kmem_cache *s, + const char *buf, size_t length) +{ + unsigned long ratio; + int err; + + err = strict_strtoul(buf, 10, &ratio); + if (err) + return err; + + if (ratio < 100) + s->defrag_ratio = ratio; + return length; +} +SLAB_ATTR(defrag_ratio); + #ifdef CONFIG_NUMA static ssize_t remote_node_defrag_ratio_show(struct kmem_cache *s, char *buf) { @@ -4178,6 +4200,7 @@ static struct attribute *slab_attrs[] = { &shrink_attr.attr, &alloc_calls_attr.attr, &free_calls_attr.attr, + &defrag_ratio_attr.attr, #ifdef CONFIG_ZONE_DMA &cache_dma_attr.attr, #endif -- 1.5.4.3
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