Peter Zijlstra a écrit :
On Thu, 2008-11-27 at 00:32 +0100, Eric Dumazet wrote:
Avoids cache line ping pongs between cpus and prepare next patch,
because updates of nr_inodes metric dont need inode_lock anymore.
(socket8 bench result : 25s to 20.5s)
Signed-off-by: Eric Dumazet <dada1@xxxxxxxxxxxxx>
---
@@ -96,9 +96,40 @@ static DEFINE_MUTEX(iprune_mutex);
* Statistics gathering..
*/
struct inodes_stat_t inodes_stat;
+static DEFINE_PER_CPU(int, nr_inodes);
static struct kmem_cache * inode_cachep __read_mostly;
+int get_nr_inodes(void)
+{
+ int cpu;
+ int counter = 0;
+
+ for_each_possible_cpu(cpu)
+ counter += per_cpu(nr_inodes, cpu);
+ if (counter < 0)
+ counter = 0;
+ return counter;
+}
It would be good to get a cpu hotplug handler here and move to
for_each_online_cpu(). People are wanting distro's to be build with
NR_CPUS=4096.
Hum, I guess we can use regular percpu_counter for this...
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