From: Jens Axboe <[email protected]>
To: Pavel Begunkov <[email protected]>, [email protected]
Cc: [email protected], [email protected],
[email protected]
Subject: Re: [PATCH 12/12] io_uring: support true async buffered reads, if file provides it
Date: Tue, 26 May 2020 07:47:21 -0600 [thread overview]
Message-ID: <[email protected]> (raw)
In-Reply-To: <[email protected]>
On 5/26/20 1:38 AM, Pavel Begunkov wrote:
> On 23/05/2020 21:57, Jens Axboe wrote:
>> If the file is flagged with FMODE_BUF_RASYNC, then we don't have to punt
>> the buffered read to an io-wq worker. Instead we can rely on page
>> unlocking callbacks to support retry based async IO. This is a lot more
>> efficient than doing async thread offload.
>>
>> The retry is done similarly to how we handle poll based retry. From
>> the unlock callback, we simply queue the retry to a task_work based
>> handler.
>>
>> Signed-off-by: Jens Axboe <[email protected]>
>> ---
>> fs/io_uring.c | 99 +++++++++++++++++++++++++++++++++++++++++++++++++++
>> 1 file changed, 99 insertions(+)
>>
>> diff --git a/fs/io_uring.c b/fs/io_uring.c
>> index e95481c552ff..dd532d2634c2 100644
>> --- a/fs/io_uring.c
>> +++ b/fs/io_uring.c
>> @@ -498,6 +498,8 @@ struct io_async_rw {
>> struct iovec *iov;
>> ssize_t nr_segs;
>> ssize_t size;
>> + struct wait_page_queue wpq;
>> + struct callback_head task_work;
>> };
>>
>> struct io_async_ctx {
>> @@ -2568,6 +2570,99 @@ static int io_read_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe,
>> return 0;
>> }
>>
>> +static void io_async_buf_cancel(struct callback_head *cb)
>> +{
>> + struct io_async_rw *rw;
>> + struct io_ring_ctx *ctx;
>> + struct io_kiocb *req;
>> +
>> + rw = container_of(cb, struct io_async_rw, task_work);
>> + req = rw->wpq.wait.private;
>> + ctx = req->ctx;
>> +
>> + spin_lock_irq(&ctx->completion_lock);
>> + io_cqring_fill_event(req, -ECANCELED);
>
> It seems like it should go through kiocb_done()/io_complete_rw_common().
> My concern is missing io_put_kbuf().
Yeah, I noticed that too after sending it out. If you look at the
current one that I updated yesterday, it does add that (and also
renames the iter read helper):
https://git.kernel.dk/cgit/linux-block/commit/?h=async-buffered.5&id=6f4e3a4066d0db3e3478e58cc250afb16d8d4d91
--
Jens Axboe
next prev parent reply other threads:[~2020-05-26 13:47 UTC|newest]
Thread overview: 29+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-05-23 18:57 [PATCHSET v2 0/12] Add support for async buffered reads Jens Axboe
2020-05-23 18:57 ` [PATCH 01/12] block: read-ahead submission should imply no-wait as well Jens Axboe
2020-05-23 18:57 ` [PATCH 02/12] mm: allow read-ahead with IOCB_NOWAIT set Jens Axboe
2020-05-23 18:57 ` [PATCH 03/12] mm: abstract out wake_page_match() from wake_page_function() Jens Axboe
2020-05-23 18:57 ` [PATCH 04/12] mm: add support for async page locking Jens Axboe
2020-05-23 18:57 ` [PATCH 05/12] mm: support async buffered reads in generic_file_buffered_read() Jens Axboe
2020-05-24 14:05 ` Trond Myklebust
2020-05-24 16:30 ` Jens Axboe
2020-05-24 16:40 ` Jens Axboe
2020-05-24 17:11 ` Trond Myklebust
2020-05-24 17:12 ` Jens Axboe
2020-05-23 18:57 ` [PATCH 06/12] fs: add FMODE_BUF_RASYNC Jens Axboe
2020-05-23 18:57 ` [PATCH 07/12] ext4: flag as supporting buffered async reads Jens Axboe
2020-05-23 18:57 ` [PATCH 08/12] block: flag block devices as supporting IOCB_WAITQ Jens Axboe
2020-05-23 18:57 ` [PATCH 09/12] xfs: flag files as supporting buffered async reads Jens Axboe
2020-05-23 18:57 ` [PATCH 10/12] btrfs: " Jens Axboe
2020-05-23 18:57 ` [PATCH 11/12] mm: add kiocb_wait_page_queue_init() helper Jens Axboe
2020-05-23 18:57 ` [PATCH 12/12] io_uring: support true async buffered reads, if file provides it Jens Axboe
2020-05-25 7:29 ` Pavel Begunkov
2020-05-25 19:59 ` Jens Axboe
2020-05-26 7:44 ` Pavel Begunkov
2020-05-26 13:50 ` Jens Axboe
2020-05-26 7:38 ` Pavel Begunkov
2020-05-26 13:47 ` Jens Axboe [this message]
2020-05-23 19:20 ` [PATCHSET v2 0/12] Add support for async buffered reads Jens Axboe
2020-05-24 9:46 ` Chris Panayis
2020-05-24 19:24 ` Jens Axboe
-- strict thread matches above, loose matches on Subject: below --
2020-05-24 19:21 [PATCHSET v4 " Jens Axboe
2020-05-24 19:22 ` [PATCH 12/12] io_uring: support true async buffered reads, if file provides it Jens Axboe
2020-05-26 19:51 [PATCHSET v5 0/12] Add support for async buffered reads Jens Axboe
2020-05-26 19:51 ` [PATCH 12/12] io_uring: support true async buffered reads, if file provides it Jens Axboe
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