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authorEric Dumazet <dada1@cosmosbay.com>2006-03-24 03:18:10 -0800
committerLinus Torvalds <torvalds@g5.osdl.org>2006-03-24 07:33:26 -0800
commit8a14342683b1e3adcf5f78660a42fcbd95b44a35 (patch)
tree332265cb9fe8b1e107864cdb380bf5f6b4bfb840
parent2ecb9e633c5057d1203a59ef3e5c3aaea37c402e (diff)
[PATCH] HOTPLUG_CPU: avoid hitting too many cachelines in recalc_bh_state()
Instead of using for_each_cpu(i), we can use for_each_online_cpu(i). When a CPU goes offline (ie removed from online map), it might have a non null bh_accounting.nr, so this patch adds a transfer of this counter to an online CPU counter. We already have a hotcpu_notifier, (function buffer_cpu_notify()), where we can do this bh_accounting. Signed-off-by: Eric Dumazet <dada1@cosmosbay.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
-rw-r--r--fs/buffer.c5
1 files changed, 4 insertions, 1 deletions
diff --git a/fs/buffer.c b/fs/buffer.c
index 36c7253bea7..11ca6eb46a3 100644
--- a/fs/buffer.c
+++ b/fs/buffer.c
@@ -3078,7 +3078,7 @@ static void recalc_bh_state(void)
if (__get_cpu_var(bh_accounting).ratelimit++ < 4096)
return;
__get_cpu_var(bh_accounting).ratelimit = 0;
- for_each_cpu(i)
+ for_each_online_cpu(i)
tot += per_cpu(bh_accounting, i).nr;
buffer_heads_over_limit = (tot > max_buffer_heads);
}
@@ -3127,6 +3127,9 @@ static void buffer_exit_cpu(int cpu)
brelse(b->bhs[i]);
b->bhs[i] = NULL;
}
+ get_cpu_var(bh_accounting).nr += per_cpu(bh_accounting, cpu).nr;
+ per_cpu(bh_accounting, cpu).nr = 0;
+ put_cpu_var(bh_accounting);
}
static int buffer_cpu_notify(struct notifier_block *self,