Swapped memory limited to about 500MB for a process ?

Lowell Gilbert freebsd-questions-local at be-well.ilk.org
Wed Sep 12 14:03:10 UTC 2012

Mickaël Canévet <canevet at embl.fr> writes:

> On Tue, 2012-09-11 at 13:05 -0400, Lowell Gilbert wrote:
>> Mickaël Canévet <canevet at embl.fr> writes:
>> > I was impacted by a memory leak that has been fixed by this patch:
>> > http://people.freebsd.org/~rmacklem/namei-leak.patch
>> >
>> > What I noticed when the server was paging is that it seems that only
>> > about 500MB of my 4GB swap partition was used before crashing. I was
>> > wondering why it didn't take the whole 4GB up to the crash of the server
>> > because of lake of memory (that would let me more time to react).
>> >
>> > Is there such king of setting that prevent a process to put more then
>> > 500MB of data in swap ?
>> limits(1)?
> Thank you for your answer.
> Here is the result of limits:
> limits
> Resource limits (current):
>   cputime              infinity secs
>   filesize             infinity kB
>   datasize             33554432 kB
>   stacksize              524288 kB
>   coredumpsize         infinity kB
>   memoryuse            infinity kB
>   memorylocked         infinity kB
>   maxprocesses             5547
>   openfiles               11095
>   sbsize               infinity bytes
>   vmemoryuse           infinity kB
>   pseudo-terminals     infinity
>   swapuse              infinity kB
> swapuse is set to unlimited, but stacksize is set to 512MB.
> Is it the stacksize setting that prevent my kernel to swap more then
> 512MB ?

No, I don't think so. datasize was the parameter I was most
suspecting; and it assumes that a particular process was causing the
crash (which is unlikely; the OS is supposed to protect you against

Most likely, the crash was not directly caused by a shortage of virtual
memory. You would have to diagnose through crash dumps, but it could be
that some more specific resource was exhausted. Or perhaps the memory
leak left dangling references in a vnode.

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