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Filename Latest commit message Latest commit date
Sebastian Andrzej Siewior 619bd4a718 sched/rt: Add a missing rescheduling point
Since the change in commit:

  fd7a4bed18 ("sched, rt: Convert switched_{from, to}_rt() / prio_changed_rt() to balance callbacks")

... we don't reschedule a task under certain circumstances:

Lets say task-A, SCHED_OTHER, is running on CPU0 (and it may run only on
CPU0) and holds a PI lock. This task is removed from the CPU because it
used up its time slice and another SCHED_OTHER task is running. Task-B on
CPU1 runs at RT priority and asks for the lock owned by task-A. This
results in a priority boost for task-A. Task-B goes to sleep until the
lock has been made available. Task-A is already runnable (but not active),
so it receives no wake up.

The reality now is that task-A gets on the CPU once the scheduler decides
to remove the current task despite the fact that a high priority task is
enqueued and waiting. This may take a long time.

The desired behaviour is that CPU0 immediately reschedules after the
priority boost which made task-A the task with the lowest priority.

Suggested-by: Peter Zijlstra <peterz@infradead.org>
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Thomas Gleixner <tglx@linutronix.de>
Fixes: fd7a4bed18 ("sched, rt: Convert switched_{from, to}_rt() prio_changed_rt() to balance callbacks")
Link: http://lkml.kernel.org/r/20170124144006.29821-1-bigeasy@linutronix.de
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2017-01-30 11:46:37 +01:00
arch sched/clock: Fix hotplug crash 2017-01-20 02:38:46 +01:00
block Merge branch 'for-linus' of git://git.kernel.dk/linux-block 2017-01-04 09:03:37 -08:00
certs
crypto crypto: testmgr - Use heap buffer for acomp test input 2016-12-27 17:32:11 +08:00
Documentation sched/Documentation/sched-rt-group: Fix incorrect example 2017-01-22 10:34:17 +01:00
drivers VFIO fixes for v4.10-rc4 2017-01-13 17:35:43 -08:00
firmware
fs fs/jbd2, locking/mutex, sched/wait: Use mutex_lock_io() for journal->j_checkpoint_mutex 2017-01-14 11:30:06 +01:00
include sched/clock: Fix hotplug crash 2017-01-20 02:38:46 +01:00
init sched/clock: Delay switching sched_clock to stable 2017-01-14 11:29:59 +01:00
ipc ipc/sem.c: fix incorrect sem_lock pairing 2017-01-10 18:31:55 -08:00
kernel sched/rt: Add a missing rescheduling point 2017-01-30 11:46:37 +01:00
lib lib/Kconfig.debug: fix frv build failure 2017-01-10 18:31:55 -08:00
mm mm/hugetlb.c: fix reservation race when freeing surplus pages 2017-01-10 18:31:55 -08:00
net Merge branch 'akpm' (patches from Andrew) 2017-01-11 11:15:15 -08:00
samples vfio-mdev: remove some dead code 2017-01-11 12:12:37 -07:00
scripts gcc-plugins: update gcc-common.h for gcc-7 2017-01-03 12:08:59 -08:00
security
sound ASoC: Fixes for v4.10 2017-01-11 19:49:27 +01:00
tools Merge branch 'akpm' (patches from Andrew) 2017-01-11 11:15:15 -08:00
usr kbuild: initramfs cleanup, set target from Kconfig 2017-01-05 09:40:16 -08:00
virt KVM: eventfd: fix NULL deref irqbypass consumer 2017-01-12 14:42:34 +01:00
.cocciconfig
.get_maintainer.ignore
.gitattributes
.gitignore
.mailmap mailmap: add codeaurora.org names for nameless email commits 2017-01-10 18:31:55 -08:00
COPYING
CREDITS
Kbuild
Kconfig
MAINTAINERS MAINTAINERS: remove duplicate bug filling description 2017-01-10 18:31:54 -08:00
Makefile Linux 4.10-rc3 2017-01-08 14:18:17 -08:00
README

Linux kernel
============

This file was moved to Documentation/admin-guide/README.rst

Please notice that there are several guides for kernel developers and users.
These guides can be rendered in a number of formats, like HTML and PDF.

In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``.

There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.
See Documentation/00-INDEX for a list of what is contained in each file.

Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.