linux-toradex.git/include/linux/kernel.h, branch v5.12-rc5

sched: Harden PREEMPT_DYNAMIC

2021-02-17T13:12:42+00:00

Use the new EXPORT_STATIC_CALL_TRAMP() / static_call_mod() to unexport
the static_call_key for the PREEMPT_DYNAMIC calls such that modules
can no longer update these calls.

Having modules change/hi-jack the preemption calls would be horrible.

Signed-off-by: Peter Zijlstra (Intel) 
Signed-off-by: Ingo Molnar

preempt/dynamic: Provide cond_resched() and might_resched() static calls

2021-02-17T13:12:42+00:00

Provide static calls to control cond_resched() (called in !CONFIG_PREEMPT)
and might_resched() (called in CONFIG_PREEMPT_VOLUNTARY) to that we
can override their behaviour when preempt= is overriden.

Since the default behaviour is full preemption, both their calls are
ignored when preempt= isn't passed.

  [fweisbec: branch might_resched() directly to __cond_resched(), only
             define static calls when PREEMPT_DYNAMIC]

Signed-off-by: Peter Zijlstra (Intel) 
Signed-off-by: Frederic Weisbecker 
Signed-off-by: Peter Zijlstra (Intel) 
Signed-off-by: Ingo Molnar 
Link: https://lkml.kernel.org/r/20210118141223.123667-6-frederic@kernel.org

kernel.h: split out mathematical helpers

2020-12-16T06:46:15+00:00

kernel.h is being used as a dump for all kinds of stuff for a long time.
Here is the attempt to start cleaning it up by splitting out
mathematical helpers.

At the same time convert users in header and lib folder to use new
header.  Though for time being include new header back to kernel.h to
avoid twisted indirected includes for existing users.

[sfr@canb.auug.org.au: fix powerpc build]
  Link: https://lkml.kernel.org/r/20201029150809.13059608@canb.auug.org.au

Link: https://lkml.kernel.org/r/20201028173212.41768-1-andriy.shevchenko@linux.intel.com
Signed-off-by: Andy Shevchenko 
Cc: "Paul E. McKenney" 
Cc: Trond Myklebust 
Cc: Jeff Layton 
Cc: Rasmus Villemoes 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

Merge tag 'sched-core-2020-12-14' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

2020-12-15T02:29:11+00:00

Pull scheduler updates from Thomas Gleixner:

 - migrate_disable/enable() support which originates from the RT tree
   and is now a prerequisite for the new preemptible kmap_local() API
   which aims to replace kmap_atomic().

 - A fair amount of topology and NUMA related improvements

 - Improvements for the frequency invariant calculations

 - Enhanced robustness for the global CPU priority tracking and decision
   making

 - The usual small fixes and enhancements all over the place

* tag 'sched-core-2020-12-14' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (61 commits)
  sched/fair: Trivial correction of the newidle_balance() comment
  sched/fair: Clear SMT siblings after determining the core is not idle
  sched: Fix kernel-doc markup
  x86: Print ratio freq_max/freq_base used in frequency invariance calculations
  x86, sched: Use midpoint of max_boost and max_P for frequency invariance on AMD EPYC
  x86, sched: Calculate frequency invariance for AMD systems
  irq_work: Optimize irq_work_single()
  smp: Cleanup smp_call_function*()
  irq_work: Cleanup
  sched: Limit the amount of NUMA imbalance that can exist at fork time
  sched/numa: Allow a floating imbalance between NUMA nodes
  sched: Avoid unnecessary calculation of load imbalance at clone time
  sched/numa: Rename nr_running and break out the magic number
  sched: Make migrate_disable/enable() independent of RT
  sched/topology: Condition EAS enablement on FIE support
  arm64: Rebuild sched domains on invariance status changes
  sched/topology,schedutil: Wrap sched domains rebuild
  sched/uclamp: Allow to reset a task uclamp constraint value
  sched/core: Fix typos in comments
  Documentation: scheduler: fix information on arch SD flags, sched_domain and sched_debug
  ...

sched: Make migrate_disable/enable() independent of RT

2020-11-24T10:25:44+00:00

Now that the scheduler can deal with migrate disable properly, there is no
real compelling reason to make it only available for RT.

There are quite some code pathes which needlessly disable preemption in
order to prevent migration and some constructs like kmap_atomic() enforce
it implicitly.

Making it available independent of RT allows to provide a preemptible
variant of kmap_atomic() and makes the code more consistent in general.

Signed-off-by: Thomas Gleixner 
Grudgingly-Acked-by: Peter Zijlstra (Intel) 
Link: https://lore.kernel.org/r/20201118204007.269943012@linutronix.de

rcu: Panic after fixed number of stalls

2020-11-20T03:37:16+00:00

Some stalls are transient, so that system fully recovers.  This commit
therefore allows users to configure the number of stalls that must happen
in order to trigger kernel panic.

Signed-off-by: chao 
Signed-off-by: Paul E. McKenney

treewide: Convert macro and uses of section(foo) to section("foo")

2020-10-25T21:51:49+00:00

Use a more generic form for __section that requires quotes to avoid
complications with clang and gcc differences.

Remove the quote operator # from compiler_attributes.h __section macro.

Convert all unquoted __section(foo) uses to quoted __section("foo").
Also convert __attribute__((section("foo"))) uses to __section("foo")
even if the __attribute__ has multiple list entry forms.

Conversion done using the script at:

    https://lore.kernel.org/lkml/75393e5ddc272dc7403de74d645e6c6e0f4e70eb.camel@perches.com/2-convert_section.pl

Signed-off-by: Joe Perches 
Reviewed-by: Nick Desaulniers 
Reviewed-by: Miguel Ojeda 
Signed-off-by: Linus Torvalds

kernel.h: split out min()/max() et al. helpers

2020-10-16T18:11:19+00:00

kernel.h is being used as a dump for all kinds of stuff for a long time.
Here is the attempt to start cleaning it up by splitting out min()/max()
et al.  helpers.

At the same time convert users in header and lib folder to use new header.
Though for time being include new header back to kernel.h to avoid
twisted indirected includes for other existing users.

Signed-off-by: Andy Shevchenko 
Signed-off-by: Andrew Morton 
Cc: "Rafael J. Wysocki" 
Cc: Steven Rostedt 
Cc: Rasmus Villemoes 
Cc: Joe Perches 
Cc: Linus Torvalds 
Link: https://lkml.kernel.org/r/20200910164152.GA1891694@smile.fi.intel.com
Signed-off-by: Linus Torvalds

Merge tag 'printk-for-5.10' of git://git.kernel.org/pub/scm/linux/kernel/git/printk/linux

2020-10-13T22:58:10+00:00

Pull printk updates from Petr Mladek:
"The big new thing is the fully lockless ringbuffer implementation,
including the support for continuous lines. It will allow to store and
read messages in any situation wihtout the risk of deadlocks and
without the need of temporary per-CPU buffers.

The access is still serialized by logbuf_lock. It synchronizes few
more operations, for example, temporary buffer for formatting the
message, syslog and kmsg_dump operations. The lock removal is being
discussed and should be ready for the next release.

The continuous lines are handled exactly the same way as before to
avoid regressions in user space. It means that they are appended to
the last message when the caller is the same. Only the last message
can be extended.

The data ring includes plain text of the messages. Except for an
integer at the beginning of each message that points back to the
descriptor ring with other metadata.

The dictionary has to stay. journalctl uses it to filter the log. It
allows to show messages related to a given device. The dictionary
values are stored in the descriptor ring with the other metadata.

This is the first part of the printk rework as discussed at Plumbers
2019, see https://lore.kernel.org/r/87k1acz5rx.fsf@linutronix.de. The
next big step will be handling consoles by kthreads during the normal
system operation. It will require special handling of situations when
the kthreads could not get scheduled, for example, early boot,
suspend, panic.

Other changes:

- Add John Ogness as a reviewer for printk subsystem. He is author of
the rework and is familiar with the code and history.

- Fix locking in serial8250_do_startup() to prevent lockdep report.

- Few code cleanups"

* tag 'printk-for-5.10' of git://git.kernel.org/pub/scm/linux/kernel/git/printk/linux: (27 commits)
printk: Use fallthrough pseudo-keyword
printk: reduce setup_text_buf size to LOG_LINE_MAX
printk: avoid and/or handle record truncation
printk: remove dict ring
printk: move dictionary keys to dev_printk_info
printk: move printk_info into separate array
printk: reimplement log_cont using record extension
printk: ringbuffer: add finalization/extension support
printk: ringbuffer: change representation of states
printk: ringbuffer: clear initial reserved fields
printk: ringbuffer: add BLK_DATALESS() macro
printk: ringbuffer: relocate get_data()
printk: ringbuffer: avoid memcpy() on state_var
printk: ringbuffer: fix setting state in desc_read()
kernel.h: Move oops_in_progress to printk.h
scripts/gdb: update for lockless printk ringbuffer
scripts/gdb: add utils.read_ulong()
docs: vmcoreinfo: add lockless printk ringbuffer vmcoreinfo
printk: reduce LOG_BUF_SHIFT range for H8300
printk: ringbuffer: support dataless records
...

kernel.h: Move oops_in_progress to printk.h

2020-09-15T11:51:08+00:00

The oops_in_progress is defined in printk.c, so it's logical
to move oops_in_progress to printk.h.

Signed-off-by: Andy Shevchenko 
Acked-by: Sergey Senozhatsky 
Signed-off-by: Petr Mladek 
Link: https://lore.kernel.org/r/20200911170202.8565-1-andriy.shevchenko@linux.intel.com