io_uring: reduce/pack size of io_ring_ctx

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With the recent flurry of additions and changes to io_uring, the
layout of io_ring_ctx has become a bit stale. We're right now at
704 bytes in size on my x86-64 build, or 11 cachelines. This
patch does two things:

- We have to completion structs embedded, that we only use for
  quiesce of the ctx (or shutdown) and for sqthread init cases.
  That 2x32 bytes right there, let's dynamically allocate them.

- Reorder the struct a bit with an eye on cachelines, use cases,
  and holes.

With this patch, we're down to 512 bytes, or 8 cachelines.

Reviewed-by: Jackie Liu <liuyun01@kylinos.cn>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

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This commit is contained in:

Jens Axboe 2019-11-07 18:27:42 -07:00

parent 5f8fd2d3e0

commit 206aefde4f

1 changed files with 38 additions and 31 deletions

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fs/io_uring.c

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