linux-toradex.git/kernel/time/sched_clock.c, branch v5.1-rc1

sched/clock: Remove license boilerplate

2018-11-23T10:51:22+00:00

The SPDX identifier defines the license of the file already. No need for
the boilerplate.

Signed-off-by: Thomas Gleixner 
Acked-by: Kees Cook 
Acked-by: Ingo Molnar 
Acked-by: John Stultz 
Acked-by: Corey Minyard 
Cc: Peter Zijlstra 
Cc: Kate Stewart 
Cc: Philippe Ombredanne 
Cc: Peter Anvin 
Cc: Russell King 
Cc: Richard Cochran 
Cc: "Paul E. McKenney" 
Cc: Nicolas Pitre 
Cc: David Riley 
Cc: Colin Cross 
Cc: Mark Brown 
Link: https://lkml.kernel.org/r/20181031182253.300140921@linutronix.de

time: Add SPDX license identifiers

2018-11-23T10:51:20+00:00

Update the time(r) core files files with the correct SPDX license
identifier based on the license text in the file itself. The SPDX
identifier is a legally binding shorthand, which can be used instead of the
full boiler plate text.

This work is based on a script and data from Philippe Ombredanne, Kate
Stewart and myself. The data has been created with two independent license
scanners and manual inspection.

The following files do not contain any direct license information and have
been omitted from the big initial SPDX changes:

  timeconst.bc: The .bc files were not touched
  time.c, timer.c, timekeeping.c: Licence was deduced from EXPORT_SYMBOL_GPL

As those files do not contain direct license references they fall under the
project license, i.e. GPL V2 only.

Signed-off-by: Thomas Gleixner 
Acked-by: Kees Cook 
Acked-by: Ingo Molnar 
Acked-by: John Stultz 
Acked-by: Corey Minyard 
Cc: Peter Zijlstra 
Cc: Kate Stewart 
Cc: Philippe Ombredanne 
Cc: Russell King 
Cc: Richard Cochran 
Cc: Nicolas Pitre 
Cc: David Riley 
Cc: Colin Cross 
Cc: Mark Brown 
Cc: H. Peter Anvin 
Cc: Paul E. McKenney 
Link: https://lkml.kernel.org/r/20181031182252.879109557@linutronix.de

time: Remove useless filenames in top level comments

2018-11-23T10:51:20+00:00

Remove the pointless filenames in the top level comments. They have no
value at all and just occupy space. While at it tidy up some of the
comments and remove a stale one.

Signed-off-by: Thomas Gleixner 
Acked-by: Nicolas Pitre 
Acked-by: Kees Cook 
Acked-by: Ingo Molnar 
Acked-by: John Stultz 
Acked-by: Corey Minyard 
Cc: Peter Zijlstra 
Cc: Kate Stewart 
Cc: Philippe Ombredanne 
Cc: Peter Anvin 
Cc: Russell King 
Cc: Richard Cochran 
Cc: "Paul E. McKenney" 
Cc: David Riley 
Cc: Colin Cross 
Cc: Mark Brown 
Link: https://lkml.kernel.org/r/20181031182252.794898238@linutronix.de

sched/clock: Move sched clock initialization and merge with generic clock

2018-07-19T22:02:43+00:00

sched_clock_postinit() initializes a generic clock on systems where no
other clock is provided. This function may be called only after
timekeeping_init().

Rename sched_clock_postinit to generic_clock_inti() and call it from
sched_clock_init(). Move the call for sched_clock_init() until after
time_init().

Suggested-by: Peter Zijlstra 
Signed-off-by: Pavel Tatashin 
Signed-off-by: Thomas Gleixner 
Cc: steven.sistare@oracle.com
Cc: daniel.m.jordan@oracle.com
Cc: linux@armlinux.org.uk
Cc: schwidefsky@de.ibm.com
Cc: heiko.carstens@de.ibm.com
Cc: john.stultz@linaro.org
Cc: sboyd@codeaurora.org
Cc: hpa@zytor.com
Cc: douly.fnst@cn.fujitsu.com
Cc: prarit@redhat.com
Cc: feng.tang@intel.com
Cc: pmladek@suse.com
Cc: gnomes@lxorguk.ukuu.org.uk
Cc: linux-s390@vger.kernel.org
Cc: boris.ostrovsky@oracle.com
Cc: jgross@suse.com
Cc: pbonzini@redhat.com
Link: https://lkml.kernel.org/r/20180719205545.16512-23-pasha.tatashin@oracle.com

timers, sched_clock: Update timeout for clock wrap

2017-03-23T19:30:27+00:00

The scheduler clock framework may not use the correct timeout for the clock
wrap. This happens when a new clock driver calls sched_clock_register()
after the kernel called sched_clock_postinit(). In this case the clock wrap
timeout is too long thus sched_clock_poll() is called too late and the clock
already wrapped.

On my ARM system the scheduler was no longer scheduling any other task than
the idle task because the sched_clock() wrapped.

Signed-off-by: David Engraf 
Signed-off-by: John Stultz

sched/headers: Prepare for new header dependencies before moving code to

2017-03-02T07:42:27+00:00

We are going to split  out of , which
will have to be picked up from other headers and .c files.

Create a trivial placeholder  file that just
maps to  to make this patch obviously correct and
bisectable.

Include the new header in the files that are going to need it.

Acked-by: Linus Torvalds 
Cc: Mike Galbraith 
Cc: Peter Zijlstra 
Cc: Thomas Gleixner 
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Ingo Molnar

timers, sched/clock: Clean up the code a bit

2015-03-27T07:34:01+00:00

Trivial cleanups, to improve the readability of the generic sched_clock() code:

 - Improve and standardize comments
 - Standardize the coding style
 - Use vertical spacing where appropriate
 - etc.

No code changed:

  md5:
    19a053b31e0c54feaeff1492012b019a  sched_clock.o.before.asm
    19a053b31e0c54feaeff1492012b019a  sched_clock.o.after.asm

Cc: Catalin Marinas 
Cc: Daniel Thompson 
Cc: John Stultz 
Cc: Peter Zijlstra (Intel) 
Cc: Peter Zijlstra 
Cc: Russell King 
Cc: Stephen Boyd 
Cc: Thomas Gleixner 
Cc: Will Deacon 
Signed-off-by: Ingo Molnar

timers, sched/clock: Avoid deadlock during read from NMI

2015-03-27T07:34:00+00:00

Currently it is possible for an NMI (or FIQ on ARM) to come in
and read sched_clock() whilst update_sched_clock() has locked
the seqcount for writing. This results in the NMI handler
locking up when it calls raw_read_seqcount_begin().

This patch fixes the NMI safety issues by providing banked clock
data. This is a similar approach to the one used in Thomas
Gleixner's 4396e058c52e("timekeeping: Provide fast and NMI safe
access to CLOCK_MONOTONIC").

Suggested-by: Stephen Boyd 
Signed-off-by: Daniel Thompson 
Signed-off-by: John Stultz 
Reviewed-by: Stephen Boyd 
Acked-by: Peter Zijlstra (Intel) 
Cc: Catalin Marinas 
Cc: Peter Zijlstra 
Cc: Russell King 
Cc: Thomas Gleixner 
Cc: Will Deacon 
Link: http://lkml.kernel.org/r/1427397806-20889-6-git-send-email-john.stultz@linaro.org
Signed-off-by: Ingo Molnar

timers, sched/clock: Remove redundant notrace from update function

2015-03-27T07:33:59+00:00

Currently update_sched_clock() is marked as notrace but this
function is not called by ftrace. This is trivially fixed by
removing the mark up.

Signed-off-by: Daniel Thompson 
Signed-off-by: John Stultz 
Reviewed-by: Stephen Boyd 
Acked-by: Peter Zijlstra (Intel) 
Cc: Catalin Marinas 
Cc: Peter Zijlstra 
Cc: Russell King 
Cc: Thomas Gleixner 
Cc: Will Deacon 
Link: http://lkml.kernel.org/r/1427397806-20889-5-git-send-email-john.stultz@linaro.org
Signed-off-by: Ingo Molnar

timers, sched/clock: Remove suspend from clock_read_data()

2015-03-27T07:33:58+00:00

Currently cd.read_data.suspended is read by the hotpath function
sched_clock(). This variable need not be accessed on the
hotpath. In fact, once it is removed, we can remove the
conditional branches from sched_clock() and install a dummy
read_sched_clock function to suspend the clock.

The new master copy of the function pointer
(actual_read_sched_clock) is introduced and is used for all
reads of the clock hardware except those within sched_clock
itself.

Suggested-by: Thomas Gleixner 
Signed-off-by: Daniel Thompson 
Signed-off-by: John Stultz 
Reviewed-by: Stephen Boyd 
Acked-by: Peter Zijlstra (Intel) 
Cc: Catalin Marinas 
Cc: Peter Zijlstra 
Cc: Russell King 
Cc: Will Deacon 
Link: http://lkml.kernel.org/r/1427397806-20889-4-git-send-email-john.stultz@linaro.org
Signed-off-by: Ingo Molnar