| From: |
| Olivier Langlois <olivier-AT-trillion01.com> |
| To: |
| Jens Axboe <axboe-AT-kernel.dk>, Pavel Begunkov <asml.silence-AT-gmail.com> |
| Subject: |
| [PATCH v3 0/2] io_uring: Add support for napi_busy_poll |
| Date: |
| Tue, 01 Mar 2022 08:38:29 -0500 |
| Message-ID: |
| <cover.1646141294.git.olivier@trillion01.com> |
| Cc: |
| Hao Xu <haoxu-AT-linux.alibaba.com>, io-uring <io-uring-AT-vger.kernel.org>, linux-kernel <linux-kernel-AT-vger.kernel.org> |
| Archive-link: |
| Article |
The sqpoll thread can be used for performing the napi busy poll in a
similar way that it does io polling for file systems supporting direct
access bypassing the page cache.
The other way that io_uring can be used for napi busy poll is by
calling io_uring_enter() to get events.
If the user specify a timeout value, it is distributed between polling
and sleeping by using the systemwide setting
/proc/sys/net/core/busy_poll.
v2:
* Evaluate list_empty(&ctx->napi_list) outside io_napi_busy_loop() to keep
__io_sq_thread() execution as fast as possible
* In io_cqring_wait(), move up the sig block to avoid needless computation
if the block exits the function
* In io_cqring_wait(), protect ctx->napi_list from race condition by
splicing it into a local list
* In io_cqring_wait(), allow busy polling when uts is missing
* Fix kernel test robot issues
v3:
* Fix do_div() type mismatch warning
* Reduce uring_lock contention by creating a spinlock for protecting
napi_list
* Support correctly MULTISHOT poll requests
Co-developed-by: Hao Xu <haoxu@linux.alibaba.com>
Signed-off-by: Hao Xu <haoxu@linux.alibaba.com>
Signed-off-by: Olivier Langlois <olivier@trillion01.com>
Olivier Langlois (2):
io_uring: minor io_cqring_wait() optimization
io_uring: Add support for napi_busy_poll
fs/io_uring.c | 246 ++++++++++++++++++++++++++++++++++++++++++++++++--
1 file changed, 237 insertions(+), 9 deletions(-)
base-commit: 719fce7539cd3e186598e2aed36325fe892150cf
--
2.35.1
