io_uring: optimise io_get_cqe()

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io_get_cqe() is expensive because of a bunch of loads, masking, etc.
However, most of the time we should have enough of entries in the CQ,
so we can cache two pointers representing a range of contiguous CQE
memory we can use. When the range is exhausted we'll go through a slower
path to set up a new range. When there are no CQEs avaliable, pointers
will naturally point to the same address.

Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Link: https://lore.kernel.org/r/487eeef00f3146537b3d9c1a9cef2fc0b9a86f81.1649771823.git.asml.silence@gmail.com
[axboe: santinel -> sentinel]
Signed-off-by: Jens Axboe <axboe@kernel.dk>

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Pavel Begunkov 2022-04-12 15:09:51 +01:00 • committed by Jens Axboe

parent 1cd15904b6

commit d8da428b7a

1 changed files with 35 additions and 11 deletions

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fs/io_uring.c

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