On 01/01/2012 06:12 PM, Gilad Ben-Yossef wrote:

quoted

Since this seems to be a common pattern, how about:

  zalloc_cpumask_var_or_all_online_cpus(&cpus, GFTP_ATOMIC);
  ...
  free_cpumask_var(cpus);

The long-named function at the top of the block either returns a newly
allocated zeroed cpumask, or a static cpumask with all online cpus set.
The code in the middle is only allowed to set bits in the cpumask
(should be the common usage).  free_cpumask_var() needs to check whether
the freed object is the static variable.

Thanks for the feedback and advice! I totally agree the repeating
pattern needs abstracting.

I ended up chosing to try a different abstraction though - basically a wrapper
on_each_cpu_cond that gets a predicate function to run per CPU to
build the mask
to send the IPI to. It seems cleaner to me not having to mess with
free_cpumask_var
and it abstracts more of the general pattern.

This converts the algorithm to O(NR_CPUS) from a potentially lower
complexity algorithm.  Also, the existing algorithm may not like to be
driven by cpu number.  Both are true for kvm.

-- 
error compiling committee.c: too many arguments to function

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