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authorPaul Jackson <pj@sgi.com>2006-03-24 03:16:07 -0800
committerLinus Torvalds <torvalds@g5.osdl.org>2006-03-24 07:33:23 -0800
commit101a50019ae5e370d73984ee05d56dd3b08f330a (patch)
treef5628837d4bb68a4109dfb8d6601f95b630848c3 /include/linux/slab.h
parentfffb60f93ce5880aade88e01d7133b52a4879710 (diff)
[PATCH] cpuset memory spread slab cache implementation
Provide the slab cache infrastructure to support cpuset memory spreading. See the previous patches, cpuset_mem_spread, for an explanation of cpuset memory spreading. This patch provides a slab cache SLAB_MEM_SPREAD flag. If set in the kmem_cache_create() call defining a slab cache, then any task marked with the process state flag PF_MEMSPREAD will spread memory page allocations for that cache over all the allowed nodes, instead of preferring the local (faulting) node. On systems not configured with CONFIG_NUMA, this results in no change to the page allocation code path for slab caches. On systems with cpusets configured in the kernel, but the "memory_spread" cpuset option not enabled for the current tasks cpuset, this adds a call to a cpuset routine and failed bit test of the processor state flag PF_SPREAD_SLAB. For tasks so marked, a second inline test is done for the slab cache flag SLAB_MEM_SPREAD, and if that is set and if the allocation is not in_interrupt(), this adds a call to to a cpuset routine that computes which of the tasks mems_allowed nodes should be preferred for this allocation. ==> This patch adds another hook into the performance critical code path to allocating objects from the slab cache, in the ____cache_alloc() chunk, below. The next patch optimizes this hook, reducing the impact of the combined mempolicy plus memory spreading hooks on this critical code path to a single check against the tasks task_struct flags word. This patch provides the generic slab flags and logic needed to apply memory spreading to a particular slab. A subsequent patch will mark a few specific slab caches for this placement policy. Signed-off-by: Paul Jackson <pj@sgi.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Diffstat (limited to 'include/linux/slab.h')
-rw-r--r--include/linux/slab.h1
1 files changed, 1 insertions, 0 deletions
diff --git a/include/linux/slab.h b/include/linux/slab.h
index 2b28c849d75a..e2ee5b268797 100644
--- a/include/linux/slab.h
+++ b/include/linux/slab.h
@@ -46,6 +46,7 @@ typedef struct kmem_cache kmem_cache_t;
what is reclaimable later*/
#define SLAB_PANIC 0x00040000UL /* panic if kmem_cache_create() fails */
#define SLAB_DESTROY_BY_RCU 0x00080000UL /* defer freeing pages to RCU */
+#define SLAB_MEM_SPREAD 0x00100000UL /* Spread some memory over cpuset */
/* flags passed to a constructor func */
#define SLAB_CTOR_CONSTRUCTOR 0x001UL /* if not set, then deconstructor */