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| author | Eric Dumazet <dada1@cosmosbay.com> | 2009-01-07 01:41:04 +0300 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2009-01-07 02:59:13 +0300 |
| commit | 179f7ebff6be45738c6e2fa68c8d2cc5c2c6308e (patch) | |
| tree | 3d48b5f825cfa29f5b39656503c5157872454e9f /include/linux/percpu_counter.h | |
| parent | e3d5a27d5862b6425d0879272e24abecf7245105 (diff) | |
| download | linux-179f7ebff6be45738c6e2fa68c8d2cc5c2c6308e.tar.xz | |
percpu_counter: FBC_BATCH should be a variable
For NR_CPUS >= 16 values, FBC_BATCH is 2*NR_CPUS
Considering more and more distros are using high NR_CPUS values, it makes
sense to use a more sensible value for FBC_BATCH, and get rid of NR_CPUS.
A sensible value is 2*num_online_cpus(), with a minimum value of 32 (This
minimum value helps branch prediction in __percpu_counter_add())
We already have a hotcpu notifier, so we can adjust FBC_BATCH dynamically.
We rename FBC_BATCH to percpu_counter_batch since its not a constant
anymore.
Signed-off-by: Eric Dumazet <dada1@cosmosbay.com>
Acked-by: David S. Miller <davem@davemloft.net>
Acked-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>
Diffstat (limited to 'include/linux/percpu_counter.h')
| -rw-r--r-- | include/linux/percpu_counter.h | 8 |
1 files changed, 2 insertions, 6 deletions
diff --git a/include/linux/percpu_counter.h b/include/linux/percpu_counter.h index 9007ccdfc112..99de7a31bab8 100644 --- a/include/linux/percpu_counter.h +++ b/include/linux/percpu_counter.h @@ -24,11 +24,7 @@ struct percpu_counter { s32 *counters; }; -#if NR_CPUS >= 16 -#define FBC_BATCH (NR_CPUS*2) -#else -#define FBC_BATCH (NR_CPUS*4) -#endif +extern int percpu_counter_batch; int percpu_counter_init(struct percpu_counter *fbc, s64 amount); int percpu_counter_init_irq(struct percpu_counter *fbc, s64 amount); @@ -39,7 +35,7 @@ s64 __percpu_counter_sum(struct percpu_counter *fbc); static inline void percpu_counter_add(struct percpu_counter *fbc, s64 amount) { - __percpu_counter_add(fbc, amount, FBC_BATCH); + __percpu_counter_add(fbc, amount, percpu_counter_batch); } static inline s64 percpu_counter_sum_positive(struct percpu_counter *fbc) |