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From: Jens Axboe <[email protected]>
To: [email protected]
Cc: [email protected], [email protected],
	[email protected]
Subject: [PATCHSET RFC 0/18] Remove kthread usage from io_uring
Date: Fri, 19 Feb 2021 10:09:52 -0700	[thread overview]
Message-ID: <[email protected]> (raw)

Hi,

tldr - instead of using kthreads that assume the identity of the original
tasks for work that needs offloading to a thread, setup these workers as
threads of the original task.

Here's a first cut of moving away from kthreads for io_uring. It passes
the test suite and various other testing I've done with it. It also
performs better, both for workloads actually using the async offload, but
also in general as we slim down structures and kill code from the hot path.

The series is roughly split into these parts:

- Patches 1-6, io_uring/io-wq prep patches
- Patches 7-8, Minor arch/kernel support
- Patches 9-15, switch from kthread to thread, remove state only needed
  for kthreads
- Patches 16-18, remove now dead/unneeded PF_IO_WORKER restrictions

Comments/suggestions welcome. I'm pretty happy with the series at this
point, and particularly with how we end up cutting a lot of code while
also unifying how sync vs async is presented.

If you prefer browsing this on cgit, find it here:

https://git.kernel.dk/cgit/linux-block/log/?h=io_uring-worker.v2

 arch/alpha/kernel/process.c      |   2 +-
 arch/arc/kernel/process.c        |   2 +-
 arch/arm/kernel/process.c        |   2 +-
 arch/arm64/kernel/process.c      |   2 +-
 arch/c6x/kernel/process.c        |   2 +-
 arch/csky/kernel/process.c       |   2 +-
 arch/h8300/kernel/process.c      |   2 +-
 arch/hexagon/kernel/process.c    |   2 +-
 arch/ia64/kernel/process.c       |   2 +-
 arch/m68k/kernel/process.c       |   2 +-
 arch/microblaze/kernel/process.c |   2 +-
 arch/mips/kernel/process.c       |   2 +-
 arch/nds32/kernel/process.c      |   2 +-
 arch/nios2/kernel/process.c      |   2 +-
 arch/openrisc/kernel/process.c   |   2 +-
 arch/riscv/kernel/process.c      |   2 +-
 arch/s390/kernel/process.c       |   2 +-
 arch/sh/kernel/process_32.c      |   2 +-
 arch/sparc/kernel/process_32.c   |   2 +-
 arch/sparc/kernel/process_64.c   |   2 +-
 arch/um/kernel/process.c         |   2 +-
 arch/x86/kernel/process.c        |   2 +-
 arch/xtensa/kernel/process.c     |   2 +-
 fs/io-wq.c                       | 393 +++++--------
 fs/io-wq.h                       |  14 +-
 fs/io_uring.c                    | 917 ++++++++++---------------------
 fs/proc/self.c                   |   7 -
 fs/proc/thread_self.c            |   7 -
 include/linux/io_uring.h         |  20 +-
 include/linux/sched.h            |   3 +
 kernel/ptrace.c                  |   2 +-
 kernel/signal.c                  |   4 +-
 net/socket.c                     |  10 -
 33 files changed, 451 insertions(+), 972 deletions(-)

-- 
Jens Axboe



             reply	other threads:[~2021-02-19 17:11 UTC|newest]

Thread overview: 49+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-02-19 17:09 Jens Axboe [this message]
2021-02-19 17:09 ` [PATCH 01/18] io_uring: remove the need for relying on an io-wq fallback worker Jens Axboe
2021-02-19 20:25   ` Eric W. Biederman
2021-02-19 20:37     ` Jens Axboe
2021-02-22 13:46   ` Pavel Begunkov
2021-02-19 17:09 ` [PATCH 02/18] io-wq: don't create any IO workers upfront Jens Axboe
2021-02-19 17:09 ` [PATCH 03/18] io_uring: disable io-wq attaching Jens Axboe
2021-02-19 17:09 ` [PATCH 04/18] io-wq: get rid of wq->use_refs Jens Axboe
2021-02-19 17:09 ` [PATCH 05/18] io_uring: tie async worker side to the task context Jens Axboe
2021-02-20  8:11   ` Hao Xu
2021-02-20 14:38     ` Jens Axboe
2021-02-21  9:16       ` Hao Xu
2021-02-19 17:09 ` [PATCH 06/18] io-wq: don't pass 'wqe' needlessly around Jens Axboe
2021-02-19 17:09 ` [PATCH 07/18] arch: setup PF_IO_WORKER threads like PF_KTHREAD Jens Axboe
2021-02-19 22:21   ` Eric W. Biederman
2021-02-19 23:26     ` Jens Axboe
2021-02-19 17:10 ` [PATCH 08/18] kernel: treat PF_IO_WORKER like PF_KTHREAD for ptrace/signals Jens Axboe
2021-02-19 17:10 ` [PATCH 09/18] io-wq: fork worker threads from original task Jens Axboe
2021-03-04 12:23   ` Stefan Metzmacher
2021-03-04 13:05     ` Jens Axboe
2021-03-04 13:19       ` Stefan Metzmacher
2021-03-04 16:13         ` Stefan Metzmacher
2021-03-04 16:42           ` Jens Axboe
2021-03-04 17:09             ` Stefan Metzmacher
2021-03-04 17:32               ` Jens Axboe
2021-03-04 18:19                 ` Jens Axboe
2021-03-04 18:56                   ` Linus Torvalds
2021-03-04 19:19                     ` Jens Axboe
2021-03-04 19:46                       ` Linus Torvalds
2021-03-04 19:54                         ` Jens Axboe
2021-03-04 20:00                           ` Jens Axboe
2021-03-04 20:23                             ` Jens Axboe
2021-03-04 20:50                           ` Linus Torvalds
2021-03-04 20:54                             ` Jens Axboe
2021-03-05 19:16           ` Eric W. Biederman
2021-03-05 19:00       ` Eric W. Biederman
2021-02-19 17:10 ` [PATCH 10/18] io-wq: worker idling always returns false Jens Axboe
2021-02-19 17:10 ` [PATCH 11/18] io_uring: remove any grabbing of context Jens Axboe
2021-02-19 17:10 ` [PATCH 12/18] io_uring: remove io_identity Jens Axboe
2021-02-19 17:10 ` [PATCH 13/18] io-wq: only remove worker from free_list, if it was there Jens Axboe
2021-02-19 17:10 ` [PATCH 14/18] io-wq: make io_wq_fork_thread() available to other users Jens Axboe
2021-02-19 17:10 ` [PATCH 15/18] io_uring: move SQPOLL thread io-wq forked worker Jens Axboe
2021-02-19 17:10 ` [PATCH 16/18] Revert "proc: don't allow async path resolution of /proc/thread-self components" Jens Axboe
2021-02-19 17:10 ` [PATCH 17/18] Revert "proc: don't allow async path resolution of /proc/self components" Jens Axboe
2021-02-19 17:10 ` [PATCH 18/18] net: remove cmsg restriction from io_uring based send/recvmsg calls Jens Axboe
2021-02-19 23:44 ` [PATCHSET RFC 0/18] Remove kthread usage from io_uring Stefan Metzmacher
2021-02-19 23:51   ` Jens Axboe
2021-02-21  5:04 ` Linus Torvalds
2021-02-21 21:22   ` Jens Axboe

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