diff options
| author | Eric Dumazet <dada1@cosmosbay.com> | 2009-01-06 14:41:04 -0800 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2009-01-06 15:59:13 -0800 |
| commit | 179f7ebff6be45738c6e2fa68c8d2cc5c2c6308e (patch) | |
| tree | 3d48b5f825cfa29f5b39656503c5157872454e9f /fs/ext4 | |
| parent | e3d5a27d5862b6425d0879272e24abecf7245105 (diff) | |
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 'fs/ext4')
| -rw-r--r-- | fs/ext4/ext4.h | 6 | ||||
| -rw-r--r-- | fs/ext4/inode.c | 2 |
2 files changed, 4 insertions, 4 deletions
diff --git a/fs/ext4/ext4.h b/fs/ext4/ext4.h index b0537c827024..6c46c648430d 100644 --- a/fs/ext4/ext4.h +++ b/fs/ext4/ext4.h @@ -1225,11 +1225,11 @@ do { \ } while (0) #ifdef CONFIG_SMP -/* Each CPU can accumulate FBC_BATCH blocks in their local +/* Each CPU can accumulate percpu_counter_batch blocks in their local * counters. So we need to make sure we have free blocks more - * than FBC_BATCH * nr_cpu_ids. Also add a window of 4 times. + * than percpu_counter_batch * nr_cpu_ids. Also add a window of 4 times. */ -#define EXT4_FREEBLOCKS_WATERMARK (4 * (FBC_BATCH * nr_cpu_ids)) +#define EXT4_FREEBLOCKS_WATERMARK (4 * (percpu_counter_batch * nr_cpu_ids)) #else #define EXT4_FREEBLOCKS_WATERMARK 0 #endif diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c index 6702a49992a6..98d3fe7057ef 100644 --- a/fs/ext4/inode.c +++ b/fs/ext4/inode.c @@ -2498,7 +2498,7 @@ static int ext4_nonda_switch(struct super_block *sb) /* * switch to non delalloc mode if we are running low * on free block. The free block accounting via percpu - * counters can get slightly wrong with FBC_BATCH getting + * counters can get slightly wrong with percpu_counter_batch getting * accumulated on each CPU without updating global counters * Delalloc need an accurate free block accounting. So switch * to non delalloc when we are near to error range. |