[Beowulf] [OOM killer/scheduler] disabling swap on cluster nodes?

Andrew Shewmaker agshew at gmail.com
Tue Feb 10 08:54:56 PST 2015


On Mon, Feb 9, 2015 at 11:12 PM, Mark Hahn <hahn at mcmaster.ca> wrote:

> overcommitment from happening. Available pages are checked on malloc, but
>> if a process never touches a page it mallocs, then it isn't subtracted out
>> of the available pages. So, if you want to be sure not to overcommit, make
>> sure apps use calloc, mlock, or walk over their pages as soon as possible.
>> Please correct me if I'm wrong on that.
>>
>
> pretty much just the opposite, I'm afraid.  vm.overcommit_memory=2
> means that VM allocations will be counted at at brk/mmap time
> against /proc/meminfo:CommitLimit.  this is good, because it means your
> allocation will fail, rather than some later time when you touch pages
> within it.
>
> in other words, the accounting is via VSZ, rather than RSS.
>

​Good. I'm glad I was wrong.​​

​Do you know if remote swap is working well now? I remember it working not
so good because it's a difficult problem, but I haven't tested it lately.​


-- 
Andrew Shewmaker
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