linux.git/arch/openrisc/kernel, branch v5.12 Linux kernel source tree Merge tag 'io_uring-worker.v3-2021-02-25' of git://git.kernel.dk/linux-block 2021-02-27T16:29:02+00:00 Linus Torvalds torvalds@linux-foundation.org 2021-02-27T16:29:02+00:00 5695e51619745d4fe3ec2506a2f0cd982c5e27a4 Pull io_uring thread rewrite from Jens Axboe: "This converts the io-wq workers to be forked off the tasks in question instead of being kernel threads that assume various bits of the original task identity. This kills > 400 lines of code from io_uring/io-wq, and it's the worst part of the code. We've had several bugs in this area, and the worry is always that we could be missing some pieces for file types doing unusual things (recent /dev/tty example comes to mind, userfaultfd reads installing file descriptors is another fun one... - both of which need special handling, and I bet it's not the last weird oddity we'll find). With these identical workers, we can have full confidence that we're never missing anything. That, in itself, is a huge win. Outside of that, it's also more efficient since we're not wasting space and code on tracking state, or switching between different states. I'm sure we're going to find little things to patch up after this series, but testing has been pretty thorough, from the usual regression suite to production. Any issue that may crop up should be manageable. There's also a nice series of further reductions we can do on top of this, but I wanted to get the meat of it out sooner rather than later. The general worry here isn't that it's fundamentally broken. Most of the little issues we've found over the last week have been related to just changes in how thread startup/exit is done, since that's the main difference between using kthreads and these kinds of threads. In fact, if all goes according to plan, I want to get this into the 5.10 and 5.11 stable branches as well. That said, the changes outside of io_uring/io-wq are: - arch setup, simple one-liner to each arch copy_thread() implementation. - Removal of net and proc restrictions for io_uring, they are no longer needed or useful" * tag 'io_uring-worker.v3-2021-02-25' of git://git.kernel.dk/linux-block: (30 commits) io-wq: remove now unused IO_WQ_BIT_ERROR io_uring: fix SQPOLL thread handling over exec io-wq: improve manager/worker handling over exec io_uring: ensure SQPOLL startup is triggered before error shutdown io-wq: make buffered file write hashed work map per-ctx io-wq: fix race around io_worker grabbing io-wq: fix races around manager/worker creation and task exit io_uring: ensure io-wq context is always destroyed for tasks arch: ensure parisc/powerpc handle PF_IO_WORKER in copy_thread() io_uring: cleanup ->user usage io-wq: remove nr_process accounting io_uring: flag new native workers with IORING_FEAT_NATIVE_WORKERS net: remove cmsg restriction from io_uring based send/recvmsg calls Revert "proc: don't allow async path resolution of /proc/self components" Revert "proc: don't allow async path resolution of /proc/thread-self components" io_uring: move SQPOLL thread io-wq forked worker io-wq: make io_wq_fork_thread() available to other users io-wq: only remove worker from free_list, if it was there io_uring: remove io_identity io_uring: remove any grabbing of context ... 
Pull io_uring thread rewrite from Jens Axboe:
 "This converts the io-wq workers to be forked off the tasks in question
  instead of being kernel threads that assume various bits of the
  original task identity.

  This kills > 400 lines of code from io_uring/io-wq, and it's the worst
  part of the code. We've had several bugs in this area, and the worry
  is always that we could be missing some pieces for file types doing
  unusual things (recent /dev/tty example comes to mind, userfaultfd
  reads installing file descriptors is another fun one... - both of
  which need special handling, and I bet it's not the last weird oddity
  we'll find).

  With these identical workers, we can have full confidence that we're
  never missing anything. That, in itself, is a huge win. Outside of
  that, it's also more efficient since we're not wasting space and code
  on tracking state, or switching between different states.

  I'm sure we're going to find little things to patch up after this
  series, but testing has been pretty thorough, from the usual
  regression suite to production. Any issue that may crop up should be
  manageable.

  There's also a nice series of further reductions we can do on top of
  this, but I wanted to get the meat of it out sooner rather than later.
  The general worry here isn't that it's fundamentally broken. Most of
  the little issues we've found over the last week have been related to
  just changes in how thread startup/exit is done, since that's the main
  difference between using kthreads and these kinds of threads. In fact,
  if all goes according to plan, I want to get this into the 5.10 and
  5.11 stable branches as well.

  That said, the changes outside of io_uring/io-wq are:

   - arch setup, simple one-liner to each arch copy_thread()
     implementation.

   - Removal of net and proc restrictions for io_uring, they are no
     longer needed or useful"

* tag 'io_uring-worker.v3-2021-02-25' of git://git.kernel.dk/linux-block: (30 commits)
  io-wq: remove now unused IO_WQ_BIT_ERROR
  io_uring: fix SQPOLL thread handling over exec
  io-wq: improve manager/worker handling over exec
  io_uring: ensure SQPOLL startup is triggered before error shutdown
  io-wq: make buffered file write hashed work map per-ctx
  io-wq: fix race around io_worker grabbing
  io-wq: fix races around manager/worker creation and task exit
  io_uring: ensure io-wq context is always destroyed for tasks
  arch: ensure parisc/powerpc handle PF_IO_WORKER in copy_thread()
  io_uring: cleanup ->user usage
  io-wq: remove nr_process accounting
  io_uring: flag new native workers with IORING_FEAT_NATIVE_WORKERS
  net: remove cmsg restriction from io_uring based send/recvmsg calls
  Revert "proc: don't allow async path resolution of /proc/self components"
  Revert "proc: don't allow async path resolution of /proc/thread-self components"
  io_uring: move SQPOLL thread io-wq forked worker
  io-wq: make io_wq_fork_thread() available to other users
  io-wq: only remove worker from free_list, if it was there
  io_uring: remove io_identity
  io_uring: remove any grabbing of context
  ...
arch: setup PF_IO_WORKER threads like PF_KTHREAD 2021-02-22T00:25:22+00:00 Jens Axboe axboe@kernel.dk 2021-02-17T15:48:00+00:00 4727dc20e0422211a0e0c72b1ace4ed6096df8a6 PF_IO_WORKER are kernel threads too, but they aren't PF_KTHREAD in the sense that we don't assign ->set_child_tid with our own structure. Just ensure that every arch sets up the PF_IO_WORKER threads like kthreads in the arch implementation of copy_thread(). Signed-off-by: Jens Axboe <axboe@kernel.dk> 
PF_IO_WORKER are kernel threads too, but they aren't PF_KTHREAD in the
sense that we don't assign ->set_child_tid with our own structure. Just
ensure that every arch sets up the PF_IO_WORKER threads like kthreads
in the arch implementation of copy_thread().

Signed-off-by: Jens Axboe <axboe@kernel.dk>
openrisc: Use devicetree to determine present cpus 2021-02-08T20:38:50+00:00 Jan Henrik Weinstock jan.weinstock@rwth-aachen.de 2021-02-08T14:27:16+00:00 8f722f67452f4b28cd8d7acf1658daa5796437c2 Use the device tree to determine the present cpus instead of assuming all CONFIG_NRCPUS are actually present in the system. Signed-off-by: Jan Henrik Weinstock <jan.weinstock@rwth-aachen.de> [shorne: Squashed 2 email commits and added summary from email] Cc: Geert Uytterhoeven <geert@linux-m68k.org> Signed-off-by: Stafford Horne <shorne@gmail.com> 
Use the device tree to determine the present cpus instead of assuming
all CONFIG_NRCPUS are actually present in the system.

Signed-off-by: Jan Henrik Weinstock <jan.weinstock@rwth-aachen.de>
[shorne: Squashed 2 email commits and added summary from email]
Cc: Geert Uytterhoeven <geert@linux-m68k.org>
Signed-off-by: Stafford Horne <shorne@gmail.com>
openrisc: restart: Call common handlers before hanging 2021-01-01T06:00:08+00:00 Joel Stanley joel@jms.id.au 2020-12-27T09:14:46+00:00 131172a4a8ce3fccfd4a9f0f8b3c0d0e59222f1d Currently openrisc will print a message and then hang in an infinite loop when rebooting. This patch adopts some code from ARM, which calls the common restart infrastructure and hangs after a small delay if the restart infra doesn't do anything. Signed-off-by: Joel Stanley <joel@jms.id.au> Signed-off-by: Stafford Horne <shorne@gmail.com> 
Currently openrisc will print a message and then hang in an infinite
loop when rebooting.

This patch adopts some code from ARM, which calls the common restart
infrastructure and hangs after a small delay if the restart infra
doesn't do anything.

Signed-off-by: Joel Stanley <joel@jms.id.au>
Signed-off-by: Stafford Horne <shorne@gmail.com>
Merge tag 'for-linus' of git://github.com/openrisc/linux 2020-12-17T21:41:27+00:00 Linus Torvalds torvalds@linux-foundation.org 2020-12-17T21:41:27+00:00 0c6c887835b59c10602add88057c9c06f265effe Pull OpenRISC updates from Stafford Horne: - New drivers and OpenRISC support for the LiteX platform - A bug fix to support userspace gdb debugging - Fixes one compile issue with blk-iocost * tag 'for-linus' of git://github.com/openrisc/linux: openrisc: add local64.h to fix blk-iocost build openrisc: fix trap for debugger breakpoint signalling openrisc: add support for LiteX drivers/tty/serial: add LiteUART driver dt-bindings: serial: document LiteUART bindings drivers/soc/litex: add LiteX SoC Controller driver dt-bindings: soc: document LiteX SoC Controller bindings dt-bindings: vendor: add vendor prefix for LiteX 
Pull OpenRISC updates from Stafford Horne:

 - New drivers and OpenRISC support for the LiteX platform

 - A bug fix to support userspace gdb debugging

 - Fixes one compile issue with blk-iocost

* tag 'for-linus' of git://github.com/openrisc/linux:
  openrisc: add local64.h to fix blk-iocost build
  openrisc: fix trap for debugger breakpoint signalling
  openrisc: add support for LiteX
  drivers/tty/serial: add LiteUART driver
  dt-bindings: serial: document LiteUART bindings
  drivers/soc/litex: add LiteX SoC Controller driver
  dt-bindings: soc: document LiteX SoC Controller bindings
  dt-bindings: vendor: add vendor prefix for LiteX
Merge tag 'tif-task_work.arch-2020-12-14' of git://git.kernel.dk/linux-block 2020-12-16T20:33:35+00:00 Linus Torvalds torvalds@linux-foundation.org 2020-12-16T20:33:35+00:00 005b2a9dc819a1265a8c765595f8f6d88d6173d9 Pull TIF_NOTIFY_SIGNAL updates from Jens Axboe: "This sits on top of of the core entry/exit and x86 entry branch from the tip tree, which contains the generic and x86 parts of this work. Here we convert the rest of the archs to support TIF_NOTIFY_SIGNAL. With that done, we can get rid of JOBCTL_TASK_WORK from task_work and signal.c, and also remove a deadlock work-around in io_uring around knowing that signal based task_work waking is invoked with the sighand wait queue head lock. The motivation for this work is to decouple signal notify based task_work, of which io_uring is a heavy user of, from sighand. The sighand lock becomes a huge contention point, particularly for threaded workloads where it's shared between threads. Even outside of threaded applications it's slower than it needs to be. Roman Gershman <romger@amazon.com> reported that his networked workload dropped from 1.6M QPS at 80% CPU to 1.0M QPS at 100% CPU after io_uring was changed to use TIF_NOTIFY_SIGNAL. The time was all spent hammering on the sighand lock, showing 57% of the CPU time there [1]. There are further cleanups possible on top of this. One example is TIF_PATCH_PENDING, where a patch already exists to use TIF_NOTIFY_SIGNAL instead. Hopefully this will also lead to more consolidation, but the work stands on its own as well" [1] https://github.com/axboe/liburing/issues/215 * tag 'tif-task_work.arch-2020-12-14' of git://git.kernel.dk/linux-block: (28 commits) io_uring: remove 'twa_signal_ok' deadlock work-around kernel: remove checking for TIF_NOTIFY_SIGNAL signal: kill JOBCTL_TASK_WORK io_uring: JOBCTL_TASK_WORK is no longer used by task_work task_work: remove legacy TWA_SIGNAL path sparc: add support for TIF_NOTIFY_SIGNAL riscv: add support for TIF_NOTIFY_SIGNAL nds32: add support for TIF_NOTIFY_SIGNAL ia64: add support for TIF_NOTIFY_SIGNAL h8300: add support for TIF_NOTIFY_SIGNAL c6x: add support for TIF_NOTIFY_SIGNAL alpha: add support for TIF_NOTIFY_SIGNAL xtensa: add support for TIF_NOTIFY_SIGNAL arm: add support for TIF_NOTIFY_SIGNAL microblaze: add support for TIF_NOTIFY_SIGNAL hexagon: add support for TIF_NOTIFY_SIGNAL csky: add support for TIF_NOTIFY_SIGNAL openrisc: add support for TIF_NOTIFY_SIGNAL sh: add support for TIF_NOTIFY_SIGNAL um: add support for TIF_NOTIFY_SIGNAL ... 
Pull TIF_NOTIFY_SIGNAL updates from Jens Axboe:
 "This sits on top of of the core entry/exit and x86 entry branch from
  the tip tree, which contains the generic and x86 parts of this work.

  Here we convert the rest of the archs to support TIF_NOTIFY_SIGNAL.

  With that done, we can get rid of JOBCTL_TASK_WORK from task_work and
  signal.c, and also remove a deadlock work-around in io_uring around
  knowing that signal based task_work waking is invoked with the sighand
  wait queue head lock.

  The motivation for this work is to decouple signal notify based
  task_work, of which io_uring is a heavy user of, from sighand. The
  sighand lock becomes a huge contention point, particularly for
  threaded workloads where it's shared between threads. Even outside of
  threaded applications it's slower than it needs to be.

  Roman Gershman <romger@amazon.com> reported that his networked
  workload dropped from 1.6M QPS at 80% CPU to 1.0M QPS at 100% CPU
  after io_uring was changed to use TIF_NOTIFY_SIGNAL. The time was all
  spent hammering on the sighand lock, showing 57% of the CPU time there
  [1].

  There are further cleanups possible on top of this. One example is
  TIF_PATCH_PENDING, where a patch already exists to use
  TIF_NOTIFY_SIGNAL instead. Hopefully this will also lead to more
  consolidation, but the work stands on its own as well"

[1] https://github.com/axboe/liburing/issues/215

* tag 'tif-task_work.arch-2020-12-14' of git://git.kernel.dk/linux-block: (28 commits)
  io_uring: remove 'twa_signal_ok' deadlock work-around
  kernel: remove checking for TIF_NOTIFY_SIGNAL
  signal: kill JOBCTL_TASK_WORK
  io_uring: JOBCTL_TASK_WORK is no longer used by task_work
  task_work: remove legacy TWA_SIGNAL path
  sparc: add support for TIF_NOTIFY_SIGNAL
  riscv: add support for TIF_NOTIFY_SIGNAL
  nds32: add support for TIF_NOTIFY_SIGNAL
  ia64: add support for TIF_NOTIFY_SIGNAL
  h8300: add support for TIF_NOTIFY_SIGNAL
  c6x: add support for TIF_NOTIFY_SIGNAL
  alpha: add support for TIF_NOTIFY_SIGNAL
  xtensa: add support for TIF_NOTIFY_SIGNAL
  arm: add support for TIF_NOTIFY_SIGNAL
  microblaze: add support for TIF_NOTIFY_SIGNAL
  hexagon: add support for TIF_NOTIFY_SIGNAL
  csky: add support for TIF_NOTIFY_SIGNAL
  openrisc: add support for TIF_NOTIFY_SIGNAL
  sh: add support for TIF_NOTIFY_SIGNAL
  um: add support for TIF_NOTIFY_SIGNAL
  ...
sched/idle: Fix arch_cpu_idle() vs tracing 2020-11-24T15:47:35+00:00 Peter Zijlstra peterz@infradead.org 2020-11-20T10:50:35+00:00 58c644ba512cfbc2e39b758dd979edd1d6d00e27 We call arch_cpu_idle() with RCU disabled, but then use local_irq_{en,dis}able(), which invokes tracing, which relies on RCU. Switch all arch_cpu_idle() implementations to use raw_local_irq_{en,dis}able() and carefully manage the lockdep,rcu,tracing state like we do in entry. (XXX: we really should change arch_cpu_idle() to not return with interrupts enabled) Reported-by: Sven Schnelle <svens@linux.ibm.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Reviewed-by: Mark Rutland <mark.rutland@arm.com> Tested-by: Mark Rutland <mark.rutland@arm.com> Link: https://lkml.kernel.org/r/20201120114925.594122626@infradead.org 
We call arch_cpu_idle() with RCU disabled, but then use
local_irq_{en,dis}able(), which invokes tracing, which relies on RCU.

Switch all arch_cpu_idle() implementations to use
raw_local_irq_{en,dis}able() and carefully manage the
lockdep,rcu,tracing state like we do in entry.

(XXX: we really should change arch_cpu_idle() to not return with
interrupts enabled)

Reported-by: Sven Schnelle <svens@linux.ibm.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Mark Rutland <mark.rutland@arm.com>
Tested-by: Mark Rutland <mark.rutland@arm.com>
Link: https://lkml.kernel.org/r/20201120114925.594122626@infradead.org
openrisc: fix trap for debugger breakpoint signalling 2020-11-11T21:32:20+00:00 Stafford Horne shorne@gmail.com 2020-10-17T21:37:01+00:00 28b852b1dc351efc6525234c5adfd5bc2ad6d6e1 I have been working on getting native Linux GDB support working for the OpenRISC port. The trap signal handler here was wrong in a few ways. During trap handling address (from the EEAR register) is not set by the CPU, so it is not correct to use here. We want to use trap as a break-point so use TRAP_BRKPT. Adding 4 to the pc was incorrect and causing GDB to think the breakpoint was not hit. Fixing these allows GDB to work now. Signed-off-by: Stafford Horne <shorne@gmail.com> 
I have been working on getting native Linux GDB support working for the
OpenRISC port.  The trap signal handler here was wrong in a few ways.
During trap handling address (from the EEAR register) is not set by the
CPU, so it is not correct to use here.  We want to use trap as a
break-point so use TRAP_BRKPT.  Adding 4 to the pc was incorrect and
causing GDB to think the breakpoint was not hit.

Fixing these allows GDB to work now.

Signed-off-by: Stafford Horne <shorne@gmail.com>
openrisc: add support for TIF_NOTIFY_SIGNAL 2020-11-09T15:16:55+00:00 Jens Axboe axboe@kernel.dk 2020-10-09T21:24:46+00:00 e181c0aa2e532af2b17128fbde699f8578cc0562 Wire up TIF_NOTIFY_SIGNAL handling for openrisc. Cc: openrisc@lists.librecores.org Acked-by: Stafford Horne <shorne@gmail.com> Signed-off-by: Jens Axboe <axboe@kernel.dk> 
Wire up TIF_NOTIFY_SIGNAL handling for openrisc.

Cc: openrisc@lists.librecores.org
Acked-by: Stafford Horne <shorne@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
tracehook: clear TIF_NOTIFY_RESUME in tracehook_notify_resume() 2020-10-17T21:04:36+00:00 Jens Axboe axboe@kernel.dk 2020-10-03T16:49:22+00:00 3c532798ec96b6c2d77706f04ed1d8b566a805df All the callers currently do this, clean it up and move the clearing into tracehook_notify_resume() instead. Reviewed-by: Oleg Nesterov <oleg@redhat.com> Reviewed-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Jens Axboe <axboe@kernel.dk> 
All the callers currently do this, clean it up and move the clearing
into tracehook_notify_resume() instead.

Reviewed-by: Oleg Nesterov <oleg@redhat.com>
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>