Re: [PATCH v2 0/4] open/accept directly into io_uring fixed file table

On 8/15/21 9:05 AM, Jens Axboe wrote:

On 8/14/21 9:42 PM, Josh Triplett wrote:

quoted

On Sat, Aug 14, 2021 at 05:03:44PM -0600, Jens Axboe wrote:

quoted

What's the plan in terms of limiting the amount of direct descriptors
(for lack of a better word)? That seems like an important aspect that
should get sorted out upfront.

[...]

quoted

Maybe we have a way to size the direct table, which will consume entries
from the same pool that the regular file table does? That would then
work both ways, and could potentially just be done dynamically similarly
to how we expand the regular file table when we exceed its current size.

I think we'll want a way to size the direct table regardless, so that
it's pre-allocated and doesn't need to be resized when an index is used.

But how do you size it then? I can see this being used into the hundreds
of thousands of fds easily, and right now the table is just an array
(though split into segments, avoiding huge allocs).

I guess that will just naturally follow by registering the empty set of
a given size initially. So should not actually be a problem...

-- 
Jens Axboe