kernel_optimize_test/kernel/sched
Linus Torvalds 6a965666b7 Pipework for general notification queue
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Merge tag 'notifications-pipe-prep-20191115' of git://git.kernel.org/pub/scm/linux/kernel/git/dhowells/linux-fs

Pull pipe rework from David Howells:
 "This is my set of preparatory patches for building a general
  notification queue on top of pipes. It makes a number of significant
  changes:

   - It removes the nr_exclusive argument from __wake_up_sync_key() as
     this is always 1. This prepares for the next step:

   - Adds wake_up_interruptible_sync_poll_locked() so that poll can be
     woken up from a function that's holding the poll waitqueue
     spinlock.

   - Change the pipe buffer ring to be managed in terms of unbounded
     head and tail indices rather than bounded index and length. This
     means that reading the pipe only needs to modify one index, not
     two.

   - A selection of helper functions are provided to query the state of
     the pipe buffer, plus a couple to apply updates to the pipe
     indices.

   - The pipe ring is allowed to have kernel-reserved slots. This allows
     many notification messages to be spliced in by the kernel without
     allowing userspace to pin too many pages if it writes to the same
     pipe.

   - Advance the head and tail indices inside the pipe waitqueue lock
     and use wake_up_interruptible_sync_poll_locked() to poke poll
     without having to take the lock twice.

   - Rearrange pipe_write() to preallocate the buffer it is going to
     write into and then drop the spinlock. This allows kernel
     notifications to then be added the ring whilst it is filling the
     buffer it allocated. The read side is stalled because the pipe
     mutex is still held.

   - Don't wake up readers on a pipe if there was already data in it
     when we added more.

   - Don't wake up writers on a pipe if the ring wasn't full before we
     removed a buffer"

* tag 'notifications-pipe-prep-20191115' of git://git.kernel.org/pub/scm/linux/kernel/git/dhowells/linux-fs:
  pipe: Remove sync on wake_ups
  pipe: Increase the writer-wakeup threshold to reduce context-switch count
  pipe: Check for ring full inside of the spinlock in pipe_write()
  pipe: Remove redundant wakeup from pipe_write()
  pipe: Rearrange sequence in pipe_write() to preallocate slot
  pipe: Conditionalise wakeup in pipe_read()
  pipe: Advance tail pointer inside of wait spinlock in pipe_read()
  pipe: Allow pipes to have kernel-reserved slots
  pipe: Use head and tail pointers for the ring, not cursor and length
  Add wake_up_interruptible_sync_poll_locked()
  Remove the nr_exclusive argument from __wake_up_sync_key()
  pipe: Reduce #inclusion of pipe_fs_i.h
2019-11-30 14:12:13 -08:00
..
autogroup.c sched/autogroup: Make autogroup_path() always available 2019-06-24 19:23:40 +02:00
autogroup.h
clock.c treewide: Add SPDX license identifier for missed files 2019-05-21 10:50:45 +02:00
completion.c sched/Documentation: Update wake_up() & co. memory-barrier guarantees 2018-07-17 09:30:34 +02:00
core.c Merge branch 'locking-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2019-11-26 16:02:40 -08:00
cpuacct.c
cpudeadline.c Linux 5.2-rc5 2019-06-17 12:12:27 +02:00
cpudeadline.h
cpufreq_schedutil.c Power management updates for 5.4-rc1 2019-09-17 19:15:14 -07:00
cpufreq.c sched/cpufreq: Annotate cpufreq_update_util_data pointer with __rcu 2019-04-03 12:34:31 +02:00
cpupri.c Linux 5.2-rc5 2019-06-17 12:12:27 +02:00
cpupri.h
cputime.c sched/vtime: Bring up complete kcpustat accessor 2019-11-21 07:33:24 +01:00
deadline.c sched/core: Further clarify sched_class::set_next_task() 2019-11-11 08:35:21 +01:00
debug.c Linux 5.2-rc6 2019-06-24 19:19:53 +02:00
fair.c sched/cpufreq: Move the cfs_rq_util_change() call to cpufreq_update_util() 2019-11-18 14:42:26 +01:00
features.h sched/fair/util_est: Implement faster ramp-up EWMA on utilization increases 2019-10-29 10:01:07 +01:00
idle.c Power management updates for 5.5-rc1 2019-11-26 19:06:44 -08:00
isolation.c sched/isolation: Prefer housekeeping CPU in local node 2019-07-25 15:51:55 +02:00
loadavg.c sched: loadavg: make calc_load_n() public 2018-10-26 16:26:32 -07:00
Makefile psi: pressure stall information for CPU, memory, and IO 2018-10-26 16:26:32 -07:00
membarrier.c membarrier: Fix RCU locking bug caused by faulty merge 2019-10-01 21:27:50 +02:00
pelt.c sched/debug: Add new tracepoint to track PELT at se level 2019-06-24 19:23:42 +02:00
pelt.h sched/topology: Remove unused 'sd' parameter from arch_scale_cpu_capacity() 2019-06-24 19:23:39 +02:00
psi.c Merge branch 'sched-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2019-09-16 17:25:49 -07:00
rt.c sched/core: Further clarify sched_class::set_next_task() 2019-11-11 08:35:21 +01:00
sched-pelt.h sched/fair: Fix "runnable_avg_yN_inv" not used warnings 2019-06-17 12:15:58 +02:00
sched.h sched/uclamp: Fix overzealous type replacement 2019-11-17 10:46:05 +01:00
stats.c
stats.h sched/stats: Fix unlikely() use of sched_info_on() 2019-07-25 15:51:55 +02:00
stop_task.c sched/core: Further clarify sched_class::set_next_task() 2019-11-11 08:35:21 +01:00
swait.c kernel/sched/: remove caller signal_pending branch predictions 2019-01-04 13:13:48 -08:00
topology.c Linux 5.4-rc7 2019-11-11 08:34:59 +01:00
wait_bit.c treewide: Add SPDX license identifier for missed files 2019-05-21 10:50:45 +02:00
wait.c Add wake_up_interruptible_sync_poll_locked() 2019-10-31 15:12:23 +00:00