Re: meminfo Committed_AS underflows

From: Balbir Singh
Date: Tue Apr 14 2009 - 23:35:47 EST


* KOSAKI Motohiro <kosaki.motohiro@xxxxxxxxxxxxxx> [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?

> 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()?


--
Balbir
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