lib: percpu_counter variable batch

Because the current batch setup has an quadric error bound on the counter,
allow for an alternative setup.

Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 3 insertions, 3 deletions

diff --git a/lib/percpu_counter.c b/lib/percpu_counter.c
index 5f36ad79a24a..f736d67c64d7 100644
--- a/lib/percpu_counter.c
+++ b/lib/percpu_counter.c
@@ -14,7 +14,7 @@ static LIST_HEAD(percpu_counters);
 static DEFINE_MUTEX(percpu_counters_lock);
 #endif
 
-void percpu_counter_add(struct percpu_counter *fbc, s32 amount)
+void __percpu_counter_add(struct percpu_counter *fbc, s32 amount, s32 batch)
 {
         long count;
         s32 *pcount;
@@ -22,7 +22,7 @@ void percpu_counter_add(struct percpu_counter *fbc, s32 amount)
 
         pcount = per_cpu_ptr(fbc->counters, cpu);
         count = *pcount + amount;
-        if (count >= FBC_BATCH || count <= -FBC_BATCH) {
+        if (count >= batch || count <= -batch) {
                 spin_lock(&fbc->lock);
                 fbc->count += count;
                 *pcount = 0;
@@ -32,7 +32,7 @@ void percpu_counter_add(struct percpu_counter *fbc, s32 amount)
         }
         put_cpu();
 }
-EXPORT_SYMBOL(percpu_counter_add);
+EXPORT_SYMBOL(__percpu_counter_add);
 
 /*
  * Add up all the per-cpu counts, return the result.  This is a more accurate