Messages in this thread | | | From | KOSAKI Motohiro <> | Subject | Re: meminfo Committed_AS underflows | Date | Wed, 15 Apr 2009 13:10:06 +0900 (JST) |
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> * KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> [2009-04-15 11:04:59]: > > > committed = atomic_long_read(&vm_committed_space); > > + if (committed < 0) > > + committed = 0; > > Isn't this like pushing the problem under the rug?
global_page_state() already has same logic. IOW almost meminfo filed has this one (except Commited_AS).
> > allowed = ((totalram_pages - hugetlb_total_pages()) > > * sysctl_overcommit_ratio / 100) + total_swap_pages; > > > > Index: b/mm/swap.c > > =================================================================== > > --- a/mm/swap.c > > +++ b/mm/swap.c > > @@ -519,7 +519,7 @@ EXPORT_SYMBOL(pagevec_lookup_tag); > > * We tolerate a little inaccuracy to avoid ping-ponging the counter between > > * CPUs > > */ > > -#define ACCT_THRESHOLD max(16, NR_CPUS * 2) > > +#define ACCT_THRESHOLD max_t(long, 16, num_online_cpus() * 2) > > > > Hmm.. this is a one time expansion, free of CPU hotplug. > > Should we use nr_cpu_ids or num_possible_cpus()?
#define num_online_cpus() cpumask_weight(cpu_online_mask) #define num_possible_cpus() cpumask_weight(cpu_possible_mask)
num_possible_cpus() have the same calculation cost. nr_cpu_ids isn't proper value. it point to valid cpu-id range, no related number of online nor possible cpus.
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