Messages in this thread | | | Date | Sun, 01 Jan 2012 18:50:18 +0200 | From | Avi Kivity <> | Subject | Re: [PATCH v4 4/5] slub: Only IPI CPUs that have per cpu obj to flush |
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On 01/01/2012 06:12 PM, Gilad Ben-Yossef wrote: > > > > 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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