Re: warn-maybe-out-of-memory

[Dmitry Antipov]

On 07/15/2014 07:45 AM, Stefan Monnier wrote:

> Freeing space from the cache is a trivial action.

AFAICS on Linux, this is not true - in my tests, huge allocations
may be 20% slower when the kernel should reclaim cache space first.
This may be even slower if an OS has to increase swap space
(according to Eli, this may happen on MS-Windows).

> The OS wants to keep as much stuff in the cache as it can, thus
> minimizing the "free" space, since "free" here basically means "wasted".

This depends on usage patterns. If you interleave I/O and relatively
large allocations, it's fairly unreasonable to fill almost all memory
with cached data just to throw it away very soon.

> If your "free" includes "free in RAM + free in swap" then it's
> marginally more useful ("free in RAM" will usually be close to 0,
> whereas "free in swap" should usually be fairly large), but I still
> can't think of a frequent enough configuration and situation where this
> would be useful enough to justify wasting code on it.

This is not expected to be frequent.

Dmitry