+ percpu_counter-use-this_cpu_ptr-instead-of-per_cpu_ptr.patch added to -mm tree

+ percpu_counter-use-this_cpu_ptr-instead-of-per_cpu_ptr.patch added to -mm tree

[akpm]

The patch titled
     percpu_counter: use this_cpu_ptr() instead of per_cpu_ptr()
has been added to the -mm tree.  Its filename is
     percpu_counter-use-this_cpu_ptr-instead-of-per_cpu_ptr.patch

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------------------------------------------------------
Subject: percpu_counter: use this_cpu_ptr() instead of per_cpu_ptr()
From: Christoph Lameter <cl@linux.com>

this_cpu_ptr() avoids an array lookup and can use the percpu offset of the
local cpu directly.

Signed-off-by: Christoph Lameter <cl@linux.com>
Cc: Eric Dumazet <eric.dumazet@gmail.com>
Cc: Tejun Heo <tj@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---

 lib/percpu_counter.c |    6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff -puN lib/percpu_counter.c~percpu_counter-use-this_cpu_ptr-instead-of-per_cpu_ptr lib/percpu_counter.c
--- a/lib/percpu_counter.c~percpu_counter-use-this_cpu_ptr-instead-of-per_cpu_ptr
+++ a/lib/percpu_counter.c
@@ -73,9 +73,9 @@ void __percpu_counter_add(struct percpu_
 {
 	s64 count;
 	s32 *pcount;
-	int cpu = get_cpu();
 
-	pcount = per_cpu_ptr(fbc->counters, cpu);
+	preempt_disable();
+	pcount = this_cpu_ptr(fbc->counters);
 	count = *pcount + amount;
 	if (count >= batch || count <= -batch) {
 		spin_lock(&fbc->lock);
@@ -85,7 +85,7 @@ void __percpu_counter_add(struct percpu_
 	} else {
 		*pcount = count;
 	}
-	put_cpu();
+	preempt_enable();
 }
 EXPORT_SYMBOL(__percpu_counter_add);
 
_

Patches currently in -mm which might be from cl@linux.com are

linux-next.patch
mm-compaction-fix-compactpagefailed-counting.patch
mm-mempolicy-check-return-code-of-check_range.patch
percpu_counter-use-this_cpu_ptr-instead-of-per_cpu_ptr.patch