Messages in this thread | | | Date | Thu, 25 Jun 2015 21:08:00 +0200 | From | Peter Zijlstra <> | Subject | Re: [RFC][PATCH 05/13] percpu-rwsem: Optimize readers and reduce global impact |
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On Tue, Jun 23, 2015 at 09:28:11AM +0200, Nicholas Mc Guire wrote: > > A bit off-topic probably > but maybe this should not be in kernel/locking/percpu-rwsem.c but in a > generic percpu location as this construct is present in the core a few times > atleast in: > kernel/irq/irqdesc.c:kstat_irqs
> kernel/fork.c:nr_processes
That has an odd unsigned long vs int fail, but yes.
> mm/memcontrol.c:mem_cgroup_read_events > mm/memcontrol.c:mem_cgroup_read_stat
Those seem to be hotplug challenged. I'm thinking dropping that nocpu_base.count[] crap and just iterating all possible CPUs would've been much easier.
> > +#define per_cpu_sum(var) \ > > +({ \ > > + typeof(var) __sum = 0; \ > > + int cpu; \ > > + for_each_possible_cpu(cpu) \ > > + __sum += per_cpu(var, cpu); \ > > + __sum; \ > > +}) > > + > > so maybe put it into include/linux/percpu.h ?
Yes I can do that.
We can try and use it more after that, there seems to be loads of places that could use this fs/namespace.c fs/inode.c etc..
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