bianbu-linux-6.6/include/linux/sched
Linus Torvalds 005b2a9dc8 tif-task_work.arch-2020-12-14
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Merge tag 'tif-task_work.arch-2020-12-14' of git://git.kernel.dk/linux-block

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
  ...
2020-12-16 12:33:35 -08:00
..
autogroup.h
clock.h
coredump.h mm, oom_adj: don't loop through tasks in __set_oom_adj when not necessary 2020-10-13 18:38:35 -07:00
cpufreq.h
cputime.h
deadline.h
debug.h treewide: Convert macro and uses of __section(foo) to __section("foo") 2020-10-25 14:51:49 -07:00
hotplug.h sched/hotplug: Consolidate task migration on CPU unplug 2020-11-10 18:38:58 +01:00
idle.h
init.h
isolation.h isolcpus: Affine unbound kernel threads to housekeeping cpus 2020-06-15 14:10:03 +02:00
jobctl.h signal: kill JOBCTL_TASK_WORK 2020-12-12 09:17:38 -07:00
loadavg.h sched: nohz: stop passing around unused "ticks" parameter. 2020-07-22 10:22:04 +02:00
mm.h Merge branch 'akpm' (patches from Andrew) 2020-12-15 12:53:37 -08:00
nohz.h
numa_balancing.h
prio.h
rt.h
sd_flags.h sched/topology: Mark SD_NUMA as SDF_NEEDS_GROUPS 2020-08-19 10:49:50 +02:00
signal.h tif-task_work.arch-2020-12-14 2020-12-16 12:33:35 -08:00
smt.h
stat.h
sysctl.h sched/uclamp: Add a new sysctl to control RT default boost value 2020-07-29 13:51:47 +02:00
task.h sched: Un-hide lockdep_tasklist_lock_is_held() for !LOCKDEP 2020-11-02 17:09:59 -08:00
task_stack.h
topology.h sched/topology,schedutil: Wrap sched domains rebuild 2020-11-19 11:25:47 +01:00
types.h
user.h watch_queue: Limit the number of watches a user can hold 2020-08-17 09:39:18 -07:00
wake_q.h
xacct.h