linux-stable.git/include/linux/types.h, branch v6.15.2

Merge tag 'mm-nonmm-stable-2025-03-30-18-23' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm

2025-04-01T17:06:52+00:00

Pull non-MM updates from Andrew Morton:

 - The series "powerpc/crash: use generic crashkernel reservation" from
   Sourabh Jain changes powerpc's kexec code to use more of the generic
   layers.

 - The series "get_maintainer: report subsystem status separately" from
   Vlastimil Babka makes some long-requested improvements to the
   get_maintainer output.

 - The series "ucount: Simplify refcounting with rcuref_t" from
   Sebastian Siewior cleans up and optimizing the refcounting in the
   ucount code.

 - The series "reboot: support runtime configuration of emergency
   hw_protection action" from Ahmad Fatoum improves the ability for a
   driver to perform an emergency system shutdown or reboot.

 - The series "Converge on using secs_to_jiffies() part two" from Easwar
   Hariharan performs further migrations from msecs_to_jiffies() to
   secs_to_jiffies().

 - The series "lib/interval_tree: add some test cases and cleanup" from
   Wei Yang permits more userspace testing of kernel library code, adds
   some more tests and performs some cleanups.

 - The series "hung_task: Dump the blocking task stacktrace" from Masami
   Hiramatsu arranges for the hung_task detector to dump the stack of
   the blocking task and not just that of the blocked task.

 - The series "resource: Split and use DEFINE_RES*() macros" from Andy
   Shevchenko provides some cleanups to the resource definition macros.

 - Plus the usual shower of singleton patches - please see the
   individual changelogs for details.

* tag 'mm-nonmm-stable-2025-03-30-18-23' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm: (77 commits)
  mailmap: consolidate email addresses of Alexander Sverdlin
  fs/procfs: fix the comment above proc_pid_wchan()
  relay: use kasprintf() instead of fixed buffer formatting
  resource: replace open coded variant of DEFINE_RES()
  resource: replace open coded variants of DEFINE_RES_*_NAMED()
  resource: replace open coded variant of DEFINE_RES_NAMED_DESC()
  resource: split DEFINE_RES_NAMED_DESC() out of DEFINE_RES_NAMED()
  samples: add hung_task detector mutex blocking sample
  hung_task: show the blocker task if the task is hung on mutex
  kexec_core: accept unaccepted kexec segments' destination addresses
  watchdog/perf: optimize bytes copied and remove manual NUL-termination
  lib/interval_tree: fix the comment of interval_tree_span_iter_next_gap()
  lib/interval_tree: skip the check before go to the right subtree
  lib/interval_tree: add test case for span iteration
  lib/interval_tree: add test case for interval_tree_iter_xxx() helpers
  lib/rbtree: add random seed
  lib/rbtree: split tests
  lib/rbtree: enable userland test suite for rbtree related data structure
  checkpatch: describe --min-conf-desc-length
  scripts/gdb/symbols: determine KASLR offset on s390
  ...

lib/rbtree: add random seed

2025-03-17T19:17:00+00:00

Current test use pseudo rand function with fixed seed, which means the
test data is the same pattern each time.

Add random seed parameter to randomize the test.

Link: https://lkml.kernel.org/r/20250310074938.26756-4-richard.weiyang@gmail.com
Signed-off-by: Wei Yang 
Cc: Matthew Wilcox 
Cc: Michel Lespinasse 
Cc: Jason Gunthorpe 
Signed-off-by: Andrew Morton

types: move struct rcuwait into types.h

2025-03-17T05:06:18+00:00

Move rcuwait struct definition into types.h so that rcuwait can be used
without including rcuwait.h which includes other headers.  Without this
change mm_types.h can't use rcuwait due to a the following circular
dependency:

mm_types.h -> rcuwait.h -> signal.h -> mm_types.h

Link: https://lkml.kernel.org/r/20250213224655.1680278-7-surenb@google.com
Suggested-by: Matthew Wilcox 
Signed-off-by: Suren Baghdasaryan 
Acked-by: Davidlohr Bueso 
Acked-by: Liam R. Howlett 
Acked-by: Lorenzo Stoakes 
Tested-by: Shivank Garg 
  Link: https://lkml.kernel.org/r/5e19ec93-8307-47c2-bb13-3ddf7150624e@amd.com
Cc: Christian Brauner 
Cc: David Hildenbrand 
Cc: David Howells 
Cc: Hugh Dickins 
Cc: Jann Horn 
Cc: Johannes Weiner 
Cc: Jonathan Corbet 
Cc: Klara Modin 
Cc: Lokesh Gidra 
Cc: Mateusz Guzik 
Cc: Mel Gorman 
Cc: Michal Hocko 
Cc: Minchan Kim 
Cc: Oleg Nesterov 
Cc: Pasha Tatashin 
Cc: "Paul E . McKenney" 
Cc: Peter Xu 
Cc: Peter Zijlstra (Intel) 
Cc: Shakeel Butt 
Cc: Sourav Panda 
Cc: Vlastimil Babka 
Cc: Wei Yang 
Cc: Will Deacon 
Cc: Heiko Carstens 
Cc: Stephen Rothwell 
Signed-off-by: Andrew Morton

include: update references to include/asm-

2025-01-13T04:20:59+00:00

"include/asm-" was replaced by "arch//include/asm" a long time
ago.

Link: https://lkml.kernel.org/r/541258219b0441fa1da890e2f8458a7ac18c2ef9.1733404444.git.geert+renesas@glider.be
Signed-off-by: Geert Uytterhoeven 
Cc: Andy Whitcroft 
Cc: Arnd Bergmann 
Cc: Dwaipayan Ray 
Cc: Joe Perches 
Cc: Lukas Bulwahn 
Cc: Masahiro Yamada 
Cc: Nathan Chancellor 
Cc: Nicolas Schier 
Cc: Oleg Nesterov 
Cc: Rasmus Villemoes 
Cc: Yury Norov 
Signed-off-by: Andrew Morton

types: Complement the aligned types with signed 64-bit one

2024-09-30T08:20:59+00:00

Some user may want to use aligned signed 64-bit type.
Provide it for them.

Signed-off-by: Andy Shevchenko 
Link: https://patch.msgid.link/20240903180218.3640501-2-andriy.shevchenko@linux.intel.com
Signed-off-by: Jonathan Cameron

ktime.h: move ktime_t to types.h

2023-12-21T00:26:30+00:00

ktime.h pulls in quite a few headers recursively (including printk.h) -
this is going to help with trimming sched.h dependencies.

Signed-off-by: Kent Overstreet

Merge tag 'mm-nonmm-stable-2023-06-24-19-23' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm

2023-06-28T17:59:38+00:00

Pull non-mm updates from Andrew Morton:

 - Arnd Bergmann has fixed a bunch of -Wmissing-prototypes in top-level
   directories

 - Douglas Anderson has added a new "buddy" mode to the hardlockup
   detector. It permits the detector to work on architectures which
   cannot provide the required interrupts, by having CPUs periodically
   perform checks on other CPUs

 - Zhen Lei has enhanced kexec's ability to support two crash regions

 - Petr Mladek has done a lot of cleanup on the hard lockup detector's
   Kconfig entries

 - And the usual bunch of singleton patches in various places

* tag 'mm-nonmm-stable-2023-06-24-19-23' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm: (72 commits)
  kernel/time/posix-stubs.c: remove duplicated include
  ocfs2: remove redundant assignment to variable bit_off
  watchdog/hardlockup: fix typo in config HARDLOCKUP_DETECTOR_PREFER_BUDDY
  powerpc: move arch_trigger_cpumask_backtrace from nmi.h to irq.h
  devres: show which resource was invalid in __devm_ioremap_resource()
  watchdog/hardlockup: define HARDLOCKUP_DETECTOR_ARCH
  watchdog/sparc64: define HARDLOCKUP_DETECTOR_SPARC64
  watchdog/hardlockup: make HAVE_NMI_WATCHDOG sparc64-specific
  watchdog/hardlockup: declare arch_touch_nmi_watchdog() only in linux/nmi.h
  watchdog/hardlockup: make the config checks more straightforward
  watchdog/hardlockup: sort hardlockup detector related config values a logical way
  watchdog/hardlockup: move SMP barriers from common code to buddy code
  watchdog/buddy: simplify the dependency for HARDLOCKUP_DETECTOR_PREFER_BUDDY
  watchdog/buddy: don't copy the cpumask in watchdog_next_cpu()
  watchdog/buddy: cleanup how watchdog_buddy_check_hardlockup() is called
  watchdog/hardlockup: remove softlockup comment in touch_nmi_watchdog()
  watchdog/hardlockup: in watchdog_hardlockup_check() use cpumask_copy()
  watchdog/hardlockup: don't use raw_cpu_ptr() in watchdog_hardlockup_kick()
  watchdog/hardlockup: HAVE_NMI_WATCHDOG must implement watchdog_hardlockup_probe()
  watchdog/hardlockup: keep kernel.nmi_watchdog sysctl as 0444 if probe fails
  ...

add intptr_t

2023-06-10T00:44:13+00:00

Add signed intptr_t given that a) it is standard type and b) uintptr_t is
in tree.

Link: https://lkml.kernel.org/r/ed66b9e4-1fb7-45be-9bb9-d4bc291c691f@p183
Signed-off-by: Alexey Dobriyan 
Signed-off-by: Andrew Morton

types: Introduce [us]128

2023-06-05T07:36:35+00:00

Introduce [us]128 (when available). Unlike [us]64, ensure they are
always naturally aligned.

This also enables 128bit wide atomics (which require natural
alignment) such as cmpxchg128().

Signed-off-by: Peter Zijlstra (Intel) 
Reviewed-by: Arnd Bergmann 
Reviewed-by: Mark Rutland 
Acked-by: Herbert Xu 
Tested-by: Mark Rutland 
Link: https://lore.kernel.org/r/20230531132323.385005581@infradead.org

atomics: Provide rcuref - scalable reference counting

2023-03-28T08:39:29+00:00

atomic_t based reference counting, including refcount_t, uses
atomic_inc_not_zero() for acquiring a reference. atomic_inc_not_zero() is
implemented with a atomic_try_cmpxchg() loop. High contention of the
reference count leads to retry loops and scales badly. There is nothing to
improve on this implementation as the semantics have to be preserved.

Provide rcuref as a scalable alternative solution which is suitable for RCU
managed objects. Similar to refcount_t it comes with overflow and underflow
detection and mitigation.

rcuref treats the underlying atomic_t as an unsigned integer and partitions
this space into zones:

  0x00000000 - 0x7FFFFFFF	valid zone (1 .. (INT_MAX + 1) references)
  0x80000000 - 0xBFFFFFFF	saturation zone
  0xC0000000 - 0xFFFFFFFE	dead zone
  0xFFFFFFFF   			no reference

rcuref_get() unconditionally increments the reference count with
atomic_add_negative_relaxed(). rcuref_put() unconditionally decrements the
reference count with atomic_add_negative_release().

This unconditional increment avoids the inc_not_zero() problem, but
requires a more complex implementation on the put() side when the count
drops from 0 to -1.

When this transition is detected then it is attempted to mark the reference
count dead, by setting it to the midpoint of the dead zone with a single
atomic_cmpxchg_release() operation. This operation can fail due to a
concurrent rcuref_get() elevating the reference count from -1 to 0 again.

If the unconditional increment in rcuref_get() hits a reference count which
is marked dead (or saturated) it will detect it after the fact and bring
back the reference count to the midpoint of the respective zone. The zones
provide enough tolerance which makes it practically impossible to escape
from a zone.

The racy implementation of rcuref_put() requires to protect rcuref_put()
against a grace period ending in order to prevent a subtle use after
free. As RCU is the only mechanism which allows to protect against that, it
is not possible to fully replace the atomic_inc_not_zero() based
implementation of refcount_t with this scheme.

The final drop is slightly more expensive than the atomic_dec_return()
counterpart, but that's not the case which this is optimized for. The
optimization is on the high frequeunt get()/put() pairs and their
scalability.

The performance of an uncontended rcuref_get()/put() pair where the put()
is not dropping the last reference is still on par with the plain atomic
operations, while at the same time providing overflow and underflow
detection and mitigation.

The performance of rcuref compared to plain atomic_inc_not_zero() and
atomic_dec_return() based reference counting under contention:

 -  Micro benchmark: All CPUs running a increment/decrement loop on an
    elevated reference count, which means the 0 to -1 transition never
    happens.

    The performance gain depends on microarchitecture and the number of
    CPUs and has been observed in the range of 1.3X to 4.7X

 - Conversion of dst_entry::__refcnt to rcuref and testing with the
    localhost memtier/memcached benchmark. That benchmark shows the
    reference count contention prominently.

    The performance gain depends on microarchitecture and the number of
    CPUs and has been observed in the range of 1.1X to 2.6X over the
    previous fix for the false sharing issue vs. struct
    dst_entry::__refcnt.

    When memtier is run over a real 1Gb network connection, there is a
    small gain on top of the false sharing fix. The two changes combined
    result in a 2%-5% total gain for that networked test.

Reported-by: Wangyang Guo 
Reported-by: Arjan Van De Ven 
Signed-off-by: Thomas Gleixner 
Signed-off-by: Peter Zijlstra (Intel) 
Link: https://lore.kernel.org/r/20230323102800.158429195@linutronix.de