[PATCH] cpuset memory spread page cache implementation and hooks

Change the page cache allocation calls to support cpuset memory spreading.

See the previous patch, cpuset_mem_spread, for an explanation of cpuset memory
spreading.

On systems without cpusets configured in the kernel, this is no change.

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_PAGE.

On tasks in cpusets with "memory_spread" enabled, this adds a call to a cpuset
routine that computes which of the tasks mems_allowed nodes should be
preferred for this allocation.

If memory spreading applies to a particular allocation, then any other NUMA
mempolicy does not apply.

Signed-off-by: Paul Jackson <pj@sgi.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

1 files changed, 5 insertions, 0 deletions

diff --git a/include/linux/pagemap.h b/include/linux/pagemap.h
index ee700c6eb44..839f0b3c23a 100644
--- a/include/linux/pagemap.h
+++ b/include/linux/pagemap.h
@@ -51,6 +51,10 @@ static inline void mapping_set_gfp_mask(struct address_space *m, gfp_t mask)
 #define page_cache_release(page)        put_page(page)
 void release_pages(struct page **pages, int nr, int cold);
 
+#ifdef CONFIG_NUMA
+extern struct page *page_cache_alloc(struct address_space *x);
+extern struct page *page_cache_alloc_cold(struct address_space *x);
+#else
 static inline struct page *page_cache_alloc(struct address_space *x)
 {
         return alloc_pages(mapping_gfp_mask(x), 0);
@@ -60,6 +64,7 @@ static inline struct page *page_cache_alloc_cold(struct address_space *x)
 {
         return alloc_pages(mapping_gfp_mask(x)|__GFP_COLD, 0);
 }
+#endif
 
 typedef int filler_t(void *, struct page *);