[PATCH] Cpuset: memory_spread_slab drop useless PF_SPREAD_PAGE check

[Paul Jackson]

From: Paul Jackson <pj@xxxxxxx>

The hook in the slab cache allocation path to handle cpuset
memory spreading for tasks in cpusets with 'memory_spread_slab'
enabled has a modest performance bug.  The hook calls into
the memory spreading handler alternate_node_alloc() if either of
'memory_spread_slab' or 'memory_spread_page' is enabled, even
though the handler does nothing (albeit harmlessly) for the page
case

Fix - drop PF_SPREAD_PAGE from the set of flag bits that are
used to trigger a call to alternate_node_alloc().

The page case is handled by separate hooks -- see the calls
conditioned on cpuset_do_page_mem_spread() in mm/filemap.c

Signed-off-by: Paul Jackson <pj@xxxxxxx>

---

 mm/slab.c |    5 ++---
 1 files changed, 2 insertions(+), 3 deletions(-)

--- 2.6.16-rc6-mm2.orig/mm/slab.c	2006-03-18 17:30:15.254950360 -0800
+++ 2.6.16-rc6-mm2/mm/slab.c	2006-03-18 21:40:42.465283732 -0800
@@ -2835,8 +2835,7 @@ static inline void *____cache_alloc(stru
 	struct array_cache *ac;
 
 #ifdef CONFIG_NUMA
-	if (unlikely(current->flags & (PF_SPREAD_PAGE | PF_SPREAD_SLAB |
-							PF_MEMPOLICY))) {
+	if (unlikely(current->flags & (PF_SPREAD_SLAB | PF_MEMPOLICY))) {
 		objp = alternate_node_alloc(cachep, flags);
 		if (objp != NULL)
 			return objp;
@@ -2875,7 +2874,7 @@ static __always_inline void *__cache_all
 
 #ifdef CONFIG_NUMA
 /*
- * Try allocating on another node if PF_SPREAD_PAGE|PF_SPREAD_SLAB|PF_MEMPOLICY.
+ * Try allocating on another node if PF_SPREAD_SLAB|PF_MEMPOLICY.
  *
  * If we are in_interrupt, then process context, including cpusets and
  * mempolicy, may not apply and should not be used for allocation policy.

-- 
                          I won't rest till it's the best ...
                          Programmer, Linux Scalability
                          Paul Jackson <pj@xxxxxxx> 1.650.933.1373
-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/