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From: Christoph Hellwig <hch@lst.de>
To: viro@zeniv.linux.org.uk
Cc: Avi Kivity <avi@scylladb.com>,
	linux-aio@kvack.org, linux-fsdevel@vger.kernel.org,
	netdev@vger.kernel.org, linux-api@vger.kernel.org,
	linux-kernel@vger.kernel.org
Subject: aio poll and a new in-kernel poll API V13
Date: Wed, 23 May 2018 21:19:49 +0200	[thread overview]
Message-ID: <20180523192022.1703-1-hch@lst.de> (raw)

Hi all,

this series adds support for the IOCB_CMD_POLL operation to poll for the
readyness of file descriptors using the aio subsystem.  The API is based
on patches that existed in RHAS2.1 and RHEL3, which means it already is
supported by libaio.  To implement the poll support efficiently new
methods to poll are introduced in struct file_operations:  get_poll_head
and poll_mask.  The first one returns a wait_queue_head to wait on
(lifetime is bound by the file), and the second does a non-blocking
check for the POLL* events.  This allows aio poll to work without
any additional context switches, unlike epoll.

This series sits on top of the aio-fsync series that also includes
support for io_pgetevents.

The changes were sponsored by Scylladb, and improve performance
of the seastar framework up to 10%, while also removing the need
for a privileged SCHED_FIFO epoll listener thread.

    git://git.infradead.org/users/hch/vfs.git aio-poll.13

Gitweb:

    http://git.infradead.org/users/hch/vfs.git/shortlog/refs/heads/aio-poll.13

Libaio changes:

    https://pagure.io/libaio.git io-poll

Seastar changes (not updated for the new io_pgetevens ABI yet):

    https://github.com/avikivity/seastar/commits/aio

Changes since v12:
 - remove iocb from ki_list only after ki_cancel has completed
 - fix __poll_t annotations
 - turn __poll_t sparse checkin on by default
 - call fput after aio_complete
 - only add the iocb to active_reqs if we wait for it

Changes since v11:
 - simplify cancellation by completion poll requests from a workqueue
   if we can't take the ctx_lock

Changes since v10:
 - fixed a mismerge that let a sock_rps_record_flow sneak into
   tcp_poll_mask
 - remove the now unused struct proto_ops get_poll_head method

Changes since v9:
 - add to the delayed_cancel_reqs earlier to avoid a race
 - get rid of POLL_TO_PTR magic

Changes since v8:
 - make delayed cancellation conditional again
 - add a cancel_kiocb file operation to split delayed vs normal cancel

Changes since v7:
 - make delayed cancellation safe and unconditional

Changes since v6:
 - reworked cancellation

Changes since v5:
 - small changelog updates
 - rebased on top of the aio-fsync changes

Changes since v4:
 - rebased ontop of Linux 4.16-rc4

Changes since v3:
 - remove the pre-sleep ->poll_mask call in vfs_poll,
   allow ->get_poll_head to return POLL* values.

Changes since v2:
 - removed a double initialization
 - new vfs_get_poll_head helper
 - document that ->get_poll_head can return NULL
 - call ->poll_mask before sleeping
 - various ACKs
 - add conversion of random to ->poll_mask
 - add conversion of af_alg to ->poll_mask
 - lacking ->poll_mask support now returns -EINVAL for IOCB_CMD_POLL
 - reshuffled the series so that prep patches and everything not
   requiring the new in-kernel poll API is in the beginning

Changes since v1:
 - handle the NULL ->poll case in vfs_poll
 - dropped the file argument to the ->poll_mask socket operation
 - replace the ->pre_poll socket operation with ->get_poll_head as
   in the file operations

             reply	other threads:[~2018-05-23 19:19 UTC|newest]

Thread overview: 72+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-05-23 19:19 Christoph Hellwig [this message]
2018-05-23 19:19 ` [PATCH 01/33] fix io_destroy()/aio_complete() race Christoph Hellwig
2018-05-23 19:19 ` [PATCH 02/33] uapi: turn __poll_t sparse checkin on by default Christoph Hellwig
2018-05-23 19:19 ` [PATCH 03/33] fs: unexport poll_schedule_timeout Christoph Hellwig
2018-05-23 19:19 ` [PATCH 04/33] fs: cleanup do_pollfd Christoph Hellwig
2018-05-23 19:19 ` [PATCH 05/33] fs: update documentation to mention __poll_t and match the code Christoph Hellwig
2018-05-23 19:19 ` [PATCH 06/33] fs: add new vfs_poll and file_can_poll helpers Christoph Hellwig
2018-05-23 19:19 ` [PATCH 07/33] fs: introduce new ->get_poll_head and ->poll_mask methods Christoph Hellwig
2018-05-23 19:19 ` [PATCH 08/33] aio: simplify KIOCB_KEY handling Christoph Hellwig
2018-05-23 19:19 ` [PATCH 09/33] aio: simplify cancellation Christoph Hellwig
2018-05-23 19:19 ` [PATCH 10/33] aio: implement IOCB_CMD_POLL Christoph Hellwig
2018-05-23 19:20 ` [PATCH 11/33] aio: try to complete poll iocbs without context switch Christoph Hellwig
2018-05-23 19:20 ` [PATCH 12/33] net: refactor socket_poll Christoph Hellwig
2018-05-23 19:20 ` [PATCH 13/33] net: add support for ->poll_mask in proto_ops Christoph Hellwig
2018-05-23 19:20 ` [PATCH 14/33] net: remove sock_no_poll Christoph Hellwig
2018-05-23 19:20 ` [PATCH 15/33] net/tcp: convert to ->poll_mask Christoph Hellwig
2018-05-23 19:20 ` [PATCH 16/33] net/unix: " Christoph Hellwig
2018-05-23 19:20 ` [PATCH 17/33] net: convert datagram_poll users tp ->poll_mask Christoph Hellwig
2018-05-23 19:20 ` [PATCH 18/33] net/dccp: convert to ->poll_mask Christoph Hellwig
2018-05-23 19:20 ` [PATCH 19/33] net/atm: " Christoph Hellwig
2018-05-23 19:20 ` [PATCH 20/33] net/vmw_vsock: " Christoph Hellwig
2018-05-23 19:20 ` [PATCH 21/33] net/tipc: " Christoph Hellwig
2018-05-23 19:20 ` [PATCH 22/33] net/sctp: " Christoph Hellwig
2018-05-23 19:20 ` [PATCH 23/33] net/bluetooth: " Christoph Hellwig
2018-05-23 19:20 ` [PATCH 24/33] net/caif: " Christoph Hellwig
2018-05-23 19:20 ` [PATCH 25/33] net/nfc: " Christoph Hellwig
2018-05-23 19:20 ` [PATCH 26/33] net/phonet: " Christoph Hellwig
2018-05-23 19:20 ` [PATCH 27/33] net/iucv: " Christoph Hellwig
2018-05-23 19:20 ` [PATCH 28/33] net/rxrpc: " Christoph Hellwig
2018-05-23 19:20 ` [PATCH 29/33] crypto: af_alg: " Christoph Hellwig
2018-05-23 19:20 ` [PATCH 30/33] pipe: " Christoph Hellwig
2018-05-23 19:20 ` [PATCH 31/33] eventfd: switch " Christoph Hellwig
2018-05-23 19:20 ` [PATCH 32/33] timerfd: convert " Christoph Hellwig
2018-05-23 19:20 ` [PATCH 33/33] random: " Christoph Hellwig
2018-05-26  0:11 ` aio poll and a new in-kernel poll API V13 Al Viro
2018-05-26  7:09   ` Al Viro
2018-05-26  7:23     ` Christoph Hellwig
2018-05-27 22:27       ` Al Viro
2018-05-27 22:28         ` [PATCH 1/4] aio: all callers of aio_{read,write,fsync,poll} treat 0 and -EIOCBQUEUED the same way Al Viro
2018-05-27 22:28           ` [PATCH 2/4] aio_read_events_ring(): make a bit more readable Al Viro
2018-05-27 22:28           ` [PATCH 3/4] aio: shift copyin of iocb into io_submit_one() Al Viro
2018-05-28  5:16             ` Christoph Hellwig
2018-05-27 22:28           ` [PATCH 4/4] aio: fold do_io_submit() into callers Al Viro
2018-05-27 23:14             ` Al Viro
2018-05-28  5:24               ` Christoph Hellwig
2018-05-28  5:15           ` [PATCH 1/4] aio: all callers of aio_{read,write,fsync,poll} treat 0 and -EIOCBQUEUED the same way Christoph Hellwig
2018-05-28 14:04             ` Al Viro
2018-05-28 17:54               ` Al Viro
2018-05-28 17:57                 ` [PATCH v2 1/6] aio: take list removal to (some) callers of aio_complete() Al Viro
2018-05-28 17:57                   ` [PATCH v2 2/6] aio: all callers of aio_{read,write,fsync,poll} treat 0 and -EIOCBQUEUED the same way Al Viro
2018-05-29  6:08                     ` Christoph Hellwig
2018-05-28 17:57                   ` [PATCH v2 3/6] aio_read_events_ring(): make a bit more readable Al Viro
2018-05-28 17:57                   ` [PATCH v2 4/6] aio: shift copyin of iocb into io_submit_one() Al Viro
2018-05-28 17:57                   ` [PATCH v2 5/6] aio: fold do_io_submit() into callers Al Viro
2018-05-29  6:10                     ` Christoph Hellwig
2018-05-28 17:57                   ` [PATCH v2 6/6] aio: sanitize the limit checking in io_submit(2) Al Viro
2018-05-29  6:10                     ` Christoph Hellwig
2018-05-29  6:08                   ` [PATCH v2 1/6] aio: take list removal to (some) callers of aio_complete() Christoph Hellwig
2018-05-28 22:20                 ` [PATCH 1/4] vmsplice: lift import_iovec() into do_vmsplice() Al Viro
2018-05-28 22:20                   ` [PATCH 2/4] vmsplice(): lift importing iovec into vmsplice(2) and compat counterpart Al Viro
2018-05-28 22:20                   ` [PATCH 3/4] signalfd: lift sigmask copyin and size checks to callers of do_signalfd4() Al Viro
2018-05-28 22:20                   ` [PATCH 4/4] orangefs: simplify compat ioctl handling Al Viro
2018-05-31 11:11                     ` kbuild test robot
2018-05-31 20:54                     ` Mike Marshall
2018-05-31 21:03                       ` Al Viro
2018-06-01 21:13                         ` Mike Marshall
2018-06-06 22:57                   ` [1/4] vmsplice: lift import_iovec() into do_vmsplice() Andrei Vagin
2018-06-07 17:56                     ` Andrei Vagin
2018-06-11 20:14                       ` Cyrill Gorcunov
2018-06-11 20:16                         ` Al Viro
2018-06-11 20:18                           ` Cyrill Gorcunov
2018-06-14 22:22                           ` Andrey Vagin

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