The node field is always page_to_nid(c->page). So its rather easy to
replace. Note that there maybe slightly more overhead in various hot paths
due to the need to shift the bits from page->flags. However, that is mostly
compensated for by a smaller footprint of the kmem_cache_cpu structure (this
patch reduces that to 3 words per cache) which allows better caching.
Signed-off-by: Christoph Lameter <cl@xxxxxxxxx>
---
include/linux/slub_def.h | 1 -
mm/slub.c | 35 ++++++++++++++++-------------------
2 files changed, 16 insertions(+), 20 deletions(-)
Index: linux-2.6/mm/slub.c
===================================================================
--- linux-2.6.orig/mm/slub.c 2012-01-20 07:30:03.810312824 -0600
+++ linux-2.6/mm/slub.c 2012-01-20 08:15:54.066255837 -0600
@@ -1555,7 +1555,6 @@ static void *get_partial_node(struct kme
if (!object) {
c->page = page;
- c->node = page_to_nid(page);
stat(s, ALLOC_FROM_PARTIAL);
object = t;
available = page->objects - page->inuse;
@@ -2032,7 +2031,7 @@ static void flush_all(struct kmem_cache
static inline int node_match(struct kmem_cache_cpu *c, int node)
{
#ifdef CONFIG_NUMA
- if (node != NUMA_NO_NODE && c->node != node)
+ if (node != NUMA_NO_NODE && page_to_nid(c->page) != node)
return 0;
#endif
return 1;
@@ -2127,7 +2126,6 @@ static inline void *new_slab_objects(str
page->freelist = NULL;
stat(s, ALLOC_SLAB);
- c->node = page_to_nid(page);
c->page = page;
*pc = c;
} else
@@ -2244,7 +2242,6 @@ new_slab:
if (c->partial) {
c->page = c->partial;
c->partial = c->page->next;
- c->node = page_to_nid(c->page);
stat(s, CPU_PARTIAL_ALLOC);
c->freelist = NULL;
goto redo;
@@ -2269,7 +2266,6 @@ new_slab:
c->freelist = get_freepointer(s, freelist);
deactivate_slab(s, c);
- c->node = NUMA_NO_NODE;
local_irq_restore(flags);
return freelist;
}
@@ -4474,30 +4470,31 @@ static ssize_t show_slab_objects(struct
for_each_possible_cpu(cpu) {
struct kmem_cache_cpu *c = per_cpu_ptr(s->cpu_slab, cpu);
- int node = ACCESS_ONCE(c->node);
+ int node;
struct page *page;
- if (node < 0)
- continue;
page = ACCESS_ONCE(c->page);
- if (page) {
- if (flags & SO_TOTAL)
- x = page->objects;
- else if (flags & SO_OBJECTS)
- x = page->inuse;
- else
- x = 1;
+ if (!page)
+ continue;
- total += x;
- nodes[node] += x;
- }
- page = c->partial;
+ node = page_to_nid(page);
+ if (flags & SO_TOTAL)
+ x = page->objects;
+ else if (flags & SO_OBJECTS)
+ x = page->inuse;
+ else
+ x = 1;
+ total += x;
+ nodes[node] += x;
+
+ page = ACCESS_ONCE(c->partial);
if (page) {
x = page->pobjects;
total += x;
nodes[node] += x;
}
+
per_cpu[node]++;
}
}
Index: linux-2.6/include/linux/slub_def.h
===================================================================
--- linux-2.6.orig/include/linux/slub_def.h 2012-01-20 05:06:45.478490987 -0600
+++ linux-2.6/include/linux/slub_def.h 2012-01-20 08:15:54.066255837 -0600
@@ -45,7 +45,6 @@ struct kmem_cache_cpu {
unsigned long tid; /* Globally unique transaction id */
struct page *page; /* The slab from which we are allocating */
struct page *partial; /* Partially allocated frozen slabs */
- int node; /* The node of the page (or -1 for debug) */
#ifdef CONFIG_SLUB_STATS
unsigned stat[NR_SLUB_STAT_ITEMS];
#endif
--
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