Re: [PATCH] io_uring: don't free request to slab

在 2021/8/25 下午9:28, Pavel Begunkov 写道:

On 8/25/21 12:40 PM, Hao Xu wrote:

quoted

It's not neccessary to free the request back to slab when we fail to
get sqe, just update state->free_reqs pointer.

It's a bit hackish because depends on the request being drawn
from the array in a particular way. How about returning it

It seems a req is always allocated from state->reqs, so it should be
ok? I actually didn't understand 'hackish' here, do you mean
io_submit_sqes() shouldn't move state->free_reqs which is req caches'
internal implementation?

into state->free_list. That thing is as cold as it can get,
only buggy apps can hit it.