Re: [PATCH 22/33] aio: percpu reqs_available

[Theodore Ts'o]

On Thu, Mar 21, 2013 at 09:35:43AM -0700, Kent Overstreet wrote:
> See the previous patch ("aio: reqs_active -> reqs_available") for why we
> want to do this - this basically implements a per cpu allocator for
> reqs_available that doesn't actually allocate anything.
> 
> Note that we need to increase the size of the ringbuffer we allocate,
> since a single thread won't necessarily be able to use all the
> reqs_available slots - some (up to about half) might be on other per cpu
> lists, unavailable for the current thread.
> 
> We size the ringbuffer based on the nr_events userspace passed to
> io_setup(), so this is a slight behaviour change - but nr_events wasn't
> being used as a hard limit before, it was being rounded up to the next
> page before so this doesn't change the actual semantics.

Reviewed-by: "Theodore Ts'o" <tytso@xxxxxxx>

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