linux-stable.git/kernel/sched, branch v6.3.13

sched/core: Avoid multiple calling update_rq_clock() in __cfsb_csd_unthrottle()

2023-07-11T17:39:26+00:00

[ Upstream commit ebb83d84e49b54369b0db67136a5fe1087124dcc ]

After commit 8ad075c2eb1f ("sched: Async unthrottling for cfs
bandwidth"), we may update the rq clock multiple times in the loop of
__cfsb_csd_unthrottle().

A prior (although less common) instance of this problem exists in
unthrottle_offline_cfs_rqs().

Cure both by ensuring update_rq_clock() is called before the loop and
setting RQCF_ACT_SKIP during the loop, to supress further updates.
The alternative would be pulling update_rq_clock() out of
unthrottle_cfs_rq(), but that gives an even bigger mess.

Fixes: 8ad075c2eb1f ("sched: Async unthrottling for cfs bandwidth")
Reviewed-By: Ben Segall 
Suggested-by: Vincent Guittot 
Signed-off-by: Hao Jia 
Signed-off-by: Peter Zijlstra (Intel) 
Reviewed-by: Vincent Guittot 
Link: https://lkml.kernel.org/r/20230613082012.49615-4-jiahao.os@bytedance.com
Signed-off-by: Sasha Levin

sched/clock: Fix local_clock() before sched_clock_init()

2023-05-11T14:17:29+00:00

[ Upstream commit f31dcb152a3d0816e2f1deab4e64572336da197d ]

Have local_clock() return sched_clock() if sched_clock_init() has not
yet run. sched_clock_cpu() has this check but it was not included in the
new noinstr implementation of local_clock().

The effect can be seen on x86 with CONFIG_PRINTK_TIME enabled, for
instance. scd->clock quickly reaches the value of TICK_NSEC and that
value is returned until sched_clock_init() runs.

dmesg without this patch:

    [    0.000000] kvm-clock: ...
    [    0.000002] kvm-clock: ...
    [    0.000672] clocksource: ...
    [    0.001000] tsc: ...
    [    0.001000] e820: ...
    [    0.001000] e820: ...
     ...
    [    0.001000] ..TIMER: ...
    [    0.001000] clocksource: ...
    [    0.378956] Calibrating delay loop ...
    [    0.379955] pid_max: ...

dmesg with this patch:

    [    0.000000] kvm-clock: ...
    [    0.000001] kvm-clock: ...
    [    0.000675] clocksource: ...
    [    0.002685] tsc: ...
    [    0.003331] e820: ...
    [    0.004190] e820: ...
     ...
    [    0.421939] ..TIMER: ...
    [    0.422842] clocksource: ...
    [    0.424582] Calibrating delay loop ...
    [    0.425580] pid_max: ...

Fixes: 776f22913b8e ("sched/clock: Make local_clock() noinstr")
Signed-off-by: Aaron Thompson 
Signed-off-by: Peter Zijlstra (Intel) 
Link: https://lkml.kernel.org/r/20230413175012.2201-1-dev@aaront.org
Signed-off-by: Sasha Levin

sched/rt: Fix bad task migration for rt tasks

2023-05-11T14:17:29+00:00

[ Upstream commit feffe5bb274dd3442080ef0e4053746091878799 ]

Commit 95158a89dd50 ("sched,rt: Use the full cpumask for balancing")
allows find_lock_lowest_rq() to pick a task with migration disabled.
The purpose of the commit is to push the current running task on the
CPU that has the migrate_disable() task away.

However, there is a race which allows a migrate_disable() task to be
migrated. Consider:

  CPU0                                    CPU1
  push_rt_task
    check is_migration_disabled(next_task)

                                          task not running and
                                          migration_disabled == 0

    find_lock_lowest_rq(next_task, rq);
      _double_lock_balance(this_rq, busiest);
        raw_spin_rq_unlock(this_rq);
        double_rq_lock(this_rq, busiest);
          <>
                                              
                                          task become running
                                          migrate_disable();
                                            
    deactivate_task(rq, next_task, 0);
    set_task_cpu(next_task, lowest_rq->cpu);
      WARN_ON_ONCE(is_migration_disabled(p));

Fixes: 95158a89dd50 ("sched,rt: Use the full cpumask for balancing")
Signed-off-by: Schspa Shi 
Signed-off-by: Peter Zijlstra (Intel) 
Reviewed-by: Steven Rostedt (Google) 
Reviewed-by: Dietmar Eggemann 
Reviewed-by: Valentin Schneider 
Tested-by: Dwaine Gonyier 
Signed-off-by: Sasha Levin

sched/fair: Fix inaccurate tally of ttwu_move_affine

2023-05-11T14:17:29+00:00

[ Upstream commit 39afe5d6fc59237ff7738bf3ede5a8856822d59d ]

There are scenarios where non-affine wakeups are incorrectly counted as
affine wakeups by schedstats.

When wake_affine_idle() returns prev_cpu which doesn't equal to
nr_cpumask_bits, it will slip through the check: target == nr_cpumask_bits
in wake_affine() and be counted as if target == this_cpu in schedstats.

Replace target == nr_cpumask_bits with target != this_cpu to make sure
affine wakeups are accurately tallied.

Fixes: 806486c377e33 (sched/fair: Do not migrate if the prev_cpu is idle)
Suggested-by: Daniel Jordan 
Signed-off-by: Libo Chen 
Signed-off-by: Peter Zijlstra (Intel) 
Reviewed-by: Gautham R. Shenoy 
Link: https://lore.kernel.org/r/20220810223313.386614-1-libo.chen@oracle.com
Signed-off-by: Sasha Levin

sched/fair: Fix imbalance overflow

2023-04-12T14:46:30+00:00

When local group is fully busy but its average load is above system load,
computing the imbalance will overflow and local group is not the best
target for pulling this load.

Fixes: 0b0695f2b34a ("sched/fair: Rework load_balance()")
Reported-by: Tingjia Cao 
Signed-off-by: Vincent Guittot 
Signed-off-by: Peter Zijlstra (Intel) 
Tested-by: Tingjia Cao 
Link: https://lore.kernel.org/lkml/CABcWv9_DAhVBOq2=W=2ypKE9dKM5s2DvoV8-U0+GDwwuKZ89jQ@mail.gmail.com/T/

sched/fair: Sanitize vruntime of entity being migrated

2023-03-21T13:43:04+00:00

Commit 829c1651e9c4 ("sched/fair: sanitize vruntime of entity being placed")
fixes an overflowing bug, but ignore a case that se->exec_start is reset
after a migration.

For fixing this case, we delay the reset of se->exec_start after
placing the entity which se->exec_start to detect long sleeping task.

In order to take into account a possible divergence between the clock_task
of 2 rqs, we increase the threshold to around 104 days.

Fixes: 829c1651e9c4 ("sched/fair: sanitize vruntime of entity being placed")
Originally-by: Zhang Qiao 
Signed-off-by: Vincent Guittot 
Signed-off-by: Peter Zijlstra (Intel) 
Tested-by: Zhang Qiao 
Link: https://lore.kernel.org/r/20230317160810.107988-1-vincent.guittot@linaro.org

sched_getaffinity: don't assume 'cpumask_size()' is fully initialized

2023-03-15T02:32:38+00:00

The getaffinity() system call uses 'cpumask_size()' to decide how big
the CPU mask is - so far so good.  It is indeed the allocation size of a
cpumask.

But the code also assumes that the whole allocation is initialized
without actually doing so itself.  That's wrong, because we might have
fixed-size allocations (making copying and clearing more efficient), but
not all of it is then necessarily used if 'nr_cpu_ids' is smaller.

Having checked other users of 'cpumask_size()', they all seem to be ok,
either using it purely for the allocation size, or explicitly zeroing
the cpumask before using the size in bytes to copy it.

See for example the ublk_ctrl_get_queue_affinity() function that uses
the proper 'zalloc_cpumask_var()' to make sure that the whole mask is
cleared, whether the storage is on the stack or if it was an external
allocation.

Fix this by just zeroing the allocation before using it.  Do the same
for the compat version of sched_getaffinity(), which had the same logic.

Also, for consistency, make sched_getaffinity() use 'cpumask_bits()' to
access the bits.  For a cpumask_var_t, it ends up being a pointer to the
same data either way, but it's just a good idea to treat it like you
would a 'cpumask_t'.  The compat case already did that.

Reported-by: Ryan Roberts 
Link: https://lore.kernel.org/lkml/7d026744-6bd6-6827-0471-b5e8eae0be3f@arm.com/
Cc: Yury Norov 
Signed-off-by: Linus Torvalds

Merge tag 'pm-6.3-rc1-2' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm

2023-03-03T18:30:58+00:00

Pull more power management updates from Rafael Wysocki:
 "These update power capping (new hardware support and cleanup) and
  cpufreq (bug fixes, cleanups and intel_pstate adjustment for a new
  platform).

  Specifics:

   - Fix error handling in the apple-soc cpufreq driver (Dan Carpenter)

   - Change the log level of a message in the amd-pstate cpufreq driver
     so it is more visible to users (Kai-Heng Feng)

   - Adjust the balance_performance EPP value for Sapphire Rapids in the
     intel_pstate cpufreq driver (Srinivas Pandruvada)

   - Remove MODULE_LICENSE from 3 pieces of non-modular code (Nick
     Alcock)

   - Make a read-only kobj_type structure in the schedutil cpufreq
     governor constant (Thomas Weißschuh)

   - Add Add Power Limit4 support for Meteor Lake SoC to the Intel RAPL
     power capping driver (Sumeet Pawnikar)"

* tag 'pm-6.3-rc1-2' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm:
  cpufreq: apple-soc: Fix an IS_ERR() vs NULL check
  powercap: remove MODULE_LICENSE in non-modules
  cpufreq: intel_pstate: remove MODULE_LICENSE in non-modules
  powercap: RAPL: Add Power Limit4 support for Meteor Lake SoC
  cpufreq: amd-pstate: remove MODULE_LICENSE in non-modules
  cpufreq: schedutil: make kobj_type structure constant
  cpufreq: amd-pstate: Let user know amd-pstate is disabled
  cpufreq: intel_pstate: Adjust balance_performance EPP for Sapphire Rapids

Merge tag 'mm-stable-2023-02-20-13-37' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm

2023-02-24T01:09:35+00:00

Pull MM updates from Andrew Morton:

 - Daniel Verkamp has contributed a memfd series ("mm/memfd: add
   F_SEAL_EXEC") which permits the setting of the memfd execute bit at
   memfd creation time, with the option of sealing the state of the X
   bit.

 - Peter Xu adds a patch series ("mm/hugetlb: Make huge_pte_offset()
   thread-safe for pmd unshare") which addresses a rare race condition
   related to PMD unsharing.

 - Several folioification patch serieses from Matthew Wilcox, Vishal
   Moola, Sidhartha Kumar and Lorenzo Stoakes

 - Johannes Weiner has a series ("mm: push down lock_page_memcg()")
   which does perform some memcg maintenance and cleanup work.

 - SeongJae Park has added DAMOS filtering to DAMON, with the series
   "mm/damon/core: implement damos filter".

   These filters provide users with finer-grained control over DAMOS's
   actions. SeongJae has also done some DAMON cleanup work.

 - Kairui Song adds a series ("Clean up and fixes for swap").

 - Vernon Yang contributed the series "Clean up and refinement for maple
   tree".

 - Yu Zhao has contributed the "mm: multi-gen LRU: memcg LRU" series. It
   adds to MGLRU an LRU of memcgs, to improve the scalability of global
   reclaim.

 - David Hildenbrand has added some userfaultfd cleanup work in the
   series "mm: uffd-wp + change_protection() cleanups".

 - Christoph Hellwig has removed the generic_writepages() library
   function in the series "remove generic_writepages".

 - Baolin Wang has performed some maintenance on the compaction code in
   his series "Some small improvements for compaction".

 - Sidhartha Kumar is doing some maintenance work on struct page in his
   series "Get rid of tail page fields".

 - David Hildenbrand contributed some cleanup, bugfixing and
   generalization of pte management and of pte debugging in his series
   "mm: support __HAVE_ARCH_PTE_SWP_EXCLUSIVE on all architectures with
   swap PTEs".

 - Mel Gorman and Neil Brown have removed the __GFP_ATOMIC allocation
   flag in the series "Discard __GFP_ATOMIC".

 - Sergey Senozhatsky has improved zsmalloc's memory utilization with
   his series "zsmalloc: make zspage chain size configurable".

 - Joey Gouly has added prctl() support for prohibiting the creation of
   writeable+executable mappings.

   The previous BPF-based approach had shortcomings. See "mm: In-kernel
   support for memory-deny-write-execute (MDWE)".

 - Waiman Long did some kmemleak cleanup and bugfixing in the series
   "mm/kmemleak: Simplify kmemleak_cond_resched() & fix UAF".

 - T.J. Alumbaugh has contributed some MGLRU cleanup work in his series
   "mm: multi-gen LRU: improve".

 - Jiaqi Yan has provided some enhancements to our memory error
   statistics reporting, mainly by presenting the statistics on a
   per-node basis. See the series "Introduce per NUMA node memory error
   statistics".

 - Mel Gorman has a second and hopefully final shot at fixing a CPU-hog
   regression in compaction via his series "Fix excessive CPU usage
   during compaction".

 - Christoph Hellwig does some vmalloc maintenance work in the series
   "cleanup vfree and vunmap".

 - Christoph Hellwig has removed block_device_operations.rw_page() in
   ths series "remove ->rw_page".

 - We get some maple_tree improvements and cleanups in Liam Howlett's
   series "VMA tree type safety and remove __vma_adjust()".

 - Suren Baghdasaryan has done some work on the maintainability of our
   vm_flags handling in the series "introduce vm_flags modifier
   functions".

 - Some pagemap cleanup and generalization work in Mike Rapoport's
   series "mm, arch: add generic implementation of pfn_valid() for
   FLATMEM" and "fixups for generic implementation of pfn_valid()"

 - Baoquan He has done some work to make /proc/vmallocinfo and
   /proc/kcore better represent the real state of things in his series
   "mm/vmalloc.c: allow vread() to read out vm_map_ram areas".

 - Jason Gunthorpe rationalized the GUP system's interface to the rest
   of the kernel in the series "Simplify the external interface for
   GUP".

 - SeongJae Park wishes to migrate people from DAMON's debugfs interface
   over to its sysfs interface. To support this, we'll temporarily be
   printing warnings when people use the debugfs interface. See the
   series "mm/damon: deprecate DAMON debugfs interface".

 - Andrey Konovalov provided the accurately named "lib/stackdepot: fixes
   and clean-ups" series.

 - Huang Ying has provided a dramatic reduction in migration's TLB flush
   IPI rates with the series "migrate_pages(): batch TLB flushing".

 - Arnd Bergmann has some objtool fixups in "objtool warning fixes".

* tag 'mm-stable-2023-02-20-13-37' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm: (505 commits)
  include/linux/migrate.h: remove unneeded externs
  mm/memory_hotplug: cleanup return value handing in do_migrate_range()
  mm/uffd: fix comment in handling pte markers
  mm: change to return bool for isolate_movable_page()
  mm: hugetlb: change to return bool for isolate_hugetlb()
  mm: change to return bool for isolate_lru_page()
  mm: change to return bool for folio_isolate_lru()
  objtool: add UACCESS exceptions for __tsan_volatile_read/write
  kmsan: disable ftrace in kmsan core code
  kasan: mark addr_has_metadata __always_inline
  mm: memcontrol: rename memcg_kmem_enabled()
  sh: initialize max_mapnr
  m68k/nommu: add missing definition of ARCH_PFN_OFFSET
  mm: percpu: fix incorrect size in pcpu_obj_full_size()
  maple_tree: reduce stack usage with gcc-9 and earlier
  mm: page_alloc: call panic() when memoryless node allocation fails
  mm: multi-gen LRU: avoid futile retries
  migrate_pages: move THP/hugetlb migration support check to simplify code
  migrate_pages: batch flushing TLB
  migrate_pages: share more code between _unmap and _move
  ...

cpufreq: schedutil: make kobj_type structure constant

2023-02-23T18:57:29+00:00

Since commit ee6d3dd4ed48 ("driver core: make kobj_type constant.")
the driver core allows the usage of const struct kobj_type.

Take advantage of this to constify the structure definition to prevent
modification at runtime.

Signed-off-by: Thomas Weißschuh 
Acked-by: Viresh Kumar 
Signed-off-by: Rafael J. Wysocki