Re: aio: questions with ioctx_alloc() and large num_possible_cpus()

From: Mauricio Faria de Oliveira
Date: Wed Oct 05 2016 - 13:58:27 EST

Hi Benjamin,

On 10/05/2016 02:41 PM, Benjamin LaHaise wrote:
I'd suggest increasing the default limit by changing how it is calculated.
The current number came about 13 years ago when machines had orders of
magnitude less RAM than they do today.

Thanks for the suggestion.

Does the default also have implications other than memory usage?
For example, concurrency/performance of as much aio contexts running,
or if userspace could try to exploit some point with a larger number?

Wondering about it because it can be set based on num_possible_cpus(),
but that might be really large on high-end systems.


Mauricio Faria de Oliveira
IBM Linux Technology Center