Messages in this thread | | | Date | Thu, 27 Nov 2008 11:01:14 +0100 | From | Eric Dumazet <> | Subject | Re: [PATCH 4/6] fs: Introduce a per_cpu nr_inodes |
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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@cosmosbay.com> >> --- > >> @@ -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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