Commit Graph

1177 Commits

Author SHA1 Message Date
Linus Torvalds 1b3618b60a Except for the preempt notifiers fix, these are all small bugfixes
that could have been waited for -rc2.  Sending them now since I
 was taking care of Peter's patch anyway.
 -----BEGIN PGP SIGNATURE-----
 Version: GnuPG v2.0.22 (GNU/Linux)
 
 iQEcBAABAgAGBQJVmB5pAAoJEL/70l94x66DpLAH/A0p2HICsG5Qw3gnI3NxAmK4
 YUvtMx0d67mFXPg0kuYRMO7C2Is6XHKtnmsX8oqkg3JTRFfn7XYqlwvrrK3Be08U
 tGvhigneJTGDXwU74jyik+D6VLmyJP3CxEvXM3d9AFyy7Ro9Grxx0Ja8c9cmKGQE
 esCwNAEJOcqaQMtNIix3WtXifOVFr40NZlbAawsMyxVw8LZK/K5maXyUTRDI57Qn
 B1wbTN1KD847/0rLrit+8VlsGEZBorUgCFhueeYGy/7EdiY0bNkzhLWb4erlWnRq
 ZlKzsLdfXmEg2CEepaHCm5jlLfIurgbLfoV1tzQ5jAuj/SHmUxq+k3lZZYTYA3w=
 =vDKM
 -----END PGP SIGNATURE-----

Merge tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm

Pull kvm fixes from Paolo Bonzini:
 "Except for the preempt notifiers fix, these are all small bugfixes
  that could have been waited for -rc2.  Sending them now since I was
  taking care of Peter's patch anyway"

* tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm:
  kvm: add hyper-v crash msrs values
  KVM: x86: remove data variable from kvm_get_msr_common
  KVM: s390: virtio-ccw: don't overwrite config space values
  KVM: x86: keep track of LVT0 changes under APICv
  KVM: x86: properly restore LVT0
  KVM: x86: make vapics_in_nmi_mode atomic
  sched, preempt_notifier: separate notifier registration from static_key inc/dec
2015-07-04 11:29:59 -07:00
Linus Torvalds 22a093b2fb Merge branch 'sched-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull scheduler fixes from Ingo Molnar:
 "Debug info and other statistics fixes and related enhancements"

* 'sched-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  sched/numa: Fix numa balancing stats in /proc/pid/sched
  sched/numa: Show numa_group ID in /proc/sched_debug task listings
  sched/debug: Move print_cfs_rq() declaration to kernel/sched/sched.h
  sched/stat: Expose /proc/pid/schedstat if CONFIG_SCHED_INFO=y
  sched/stat: Simplify the sched_info accounting dependency
2015-07-04 08:56:53 -07:00
Srikar Dronamraju 397f2378f1 sched/numa: Fix numa balancing stats in /proc/pid/sched
Commit 44dba3d5d6 ("sched: Refactor task_struct to use
numa_faults instead of numa_* pointers") modified the way
tsk->numa_faults stats are accounted.

However that commit never touched show_numa_stats() that is displayed
in /proc/pid/sched and thus the numbers displayed in /proc/pid/sched
don't match the actual numbers.

Fix it by making sure that /proc/pid/sched reflects the task
fault numbers. Also add group fault stats too.

Also couple of more modifications are added here:

1. Format changes:

  - Previously we would list two entries per node, one for private
    and one for shared. Also the home node info was listed in each entry.

  - Now preferred node, total_faults and current node are
    displayed separately.

  - Now there is one entry per node, that lists private,shared task and
    group faults.

2. Unit changes:

  - p->numa_pages_migrated was getting reset after every read of
    /proc/pid/sched. It's more useful to have absolute numbers since
    differential migrations between two accesses can be more easily
    calculated.

Signed-off-by: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
Acked-by: Rik van Riel <riel@redhat.com>
Cc: Iulia Manda <iulia.manda21@gmail.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/1435252903-1081-4-git-send-email-srikar@linux.vnet.ibm.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2015-07-04 10:04:33 +02:00
Srikar Dronamraju e3d24d0a60 sched/numa: Show numa_group ID in /proc/sched_debug task listings
Having the numa group ID in /proc/sched_debug helps to see how
the numa groups have spread across the system.

Signed-off-by: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
Acked-by: Rik van Riel <riel@redhat.com>
Cc: Iulia Manda <iulia.manda21@gmail.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/1435252903-1081-3-git-send-email-srikar@linux.vnet.ibm.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2015-07-04 10:04:32 +02:00
Srikar Dronamraju 6b55c9654f sched/debug: Move print_cfs_rq() declaration to kernel/sched/sched.h
Currently print_cfs_rq() is declared in include/linux/sched.h.
However it's not used outside kernel/sched. Hence move the
declaration to kernel/sched/sched.h

Also some functions are only available for CONFIG_SCHED_DEBUG=y.
Hence move the declarations to within the #ifdef.

Signed-off-by: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
Acked-by: Rik van Riel <riel@redhat.com>
Cc: Iulia Manda <iulia.manda21@gmail.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/1435252903-1081-2-git-send-email-srikar@linux.vnet.ibm.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2015-07-04 10:04:31 +02:00
Naveen N. Rao f6db834799 sched/stat: Simplify the sched_info accounting dependency
Both CONFIG_SCHEDSTATS=y and CONFIG_TASK_DELAY_ACCT=y track task
sched_info, which results in ugly #if clauses.

Simplify the code by introducing a synthethic CONFIG_SCHED_INFO
switch, selected by both.

Signed-off-by: Naveen N. Rao <naveen.n.rao@linux.vnet.ibm.com>
Cc: Balbir Singh <bsingharora@gmail.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: a.p.zijlstra@chello.nl
Cc: ricklind@us.ibm.com
Link: http://lkml.kernel.org/r/8d19eef800811a94b0f91bcbeb27430a884d7433.1435255405.git.naveen.n.rao@linux.vnet.ibm.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2015-07-04 10:04:30 +02:00
Peter Zijlstra 2ecd9d29ab sched, preempt_notifier: separate notifier registration from static_key inc/dec
Commit 1cde2930e1 ("sched/preempt: Add static_key() to preempt_notifiers")
had two problems.  First, the preempt-notifier API needs to sleep with the
addition of the static_key, we do however need to hold off preemption
while modifying the preempt notifier list, otherwise a preemption could
observe an inconsistent list state.  KVM correctly registers and
unregisters preempt notifiers with preemption disabled, so the sleep
caused dmesg splats.

Second, KVM registers and unregisters preemption notifiers very often
(in vcpu_load/vcpu_put).  With a single uniprocessor guest the static key
would move between 0 and 1 continuously, hitting the slow path on every
userspace exit.

To fix this, wrap the static_key inc/dec in a new API, and call it from
KVM.

Fixes: 1cde2930e1 ("sched/preempt: Add static_key() to preempt_notifiers")
Reported-by: Pontus Fuchs <pontus.fuchs@gmail.com>
Reported-by: Takashi Iwai <tiwai@suse.de>
Tested-by: Takashi Iwai <tiwai@suse.de>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2015-07-03 18:55:00 +02:00
Linus Torvalds 98ec21a018 Merge branch 'sched-hrtimers-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull scheduler updates from Thomas Gleixner:
 "This series of scheduler updates depends on sched/core and timers/core
  branches, which are already in your tree:

   - Scheduler balancing overhaul to plug a hard to trigger race which
     causes an oops in the balancer (Peter Zijlstra)

   - Lockdep updates which are related to the balancing updates (Peter
     Zijlstra)"

* 'sched-hrtimers-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  sched,lockdep: Employ lock pinning
  lockdep: Implement lock pinning
  lockdep: Simplify lock_release()
  sched: Streamline the task migration locking a little
  sched: Move code around
  sched,dl: Fix sched class hopping CBS hole
  sched, dl: Convert switched_{from, to}_dl() / prio_changed_dl() to balance callbacks
  sched,dl: Remove return value from pull_dl_task()
  sched, rt: Convert switched_{from, to}_rt() / prio_changed_rt() to balance callbacks
  sched,rt: Remove return value from pull_rt_task()
  sched: Allow balance callbacks for check_class_changed()
  sched: Use replace normalize_task() with __sched_setscheduler()
  sched: Replace post_schedule with a balance callback list
2015-06-24 15:09:40 -07:00
Linus Torvalds 43c9fad942 Power management and ACPI material for v4.2-rc1
- ACPICA update to upstream revision 20150515 including basic
    support for ACPI 6 features: new ACPI tables introduced by
    ACPI 6 (STAO, XENV, WPBT, NFIT, IORT), changes related to the
    other tables (DTRM, FADT, LPIT, MADT), new predefined names
    (_BTH, _CR3, _DSD, _LPI, _MTL, _PRR, _RDI, _RST, _TFP, _TSN),
    fixes and cleanups (Bob Moore, Lv Zheng).
 
  - ACPI device power management core code update to follow ACPI 6
    which reflects the ACPI device power management implementation
    in Windows (Rafael J Wysocki).
 
  - Rework of the backlight interface selection logic to reduce the
    number of kernel command line options and improve the handling
    of DMI quirks that may be involved in that and to make the
    code generally more straightforward (Hans de Goede).
 
  - Fixes for the ACPI Embedded Controller (EC) driver related to
    the handling of EC transactions (Lv Zheng).
 
  - Fix for a regression related to the ACPI resources management
    and resulting from a recent change of ACPI initialization code
    ordering (Rafael J Wysocki).
 
  - Fix for a system initialization regression related to ACPI
    introduced during the 3.14 cycle and caused by running the
    code that switches the platform over to the ACPI mode too
    early in the initialization sequence (Rafael J Wysocki).
 
  - Support for the ACPI _CCA device configuration object related
    to DMA cache coherence (Suravee Suthikulpanit).
 
  - ACPI/APEI fixes and cleanups (Jiri Kosina, Borislav Petkov).
 
  - ACPI battery driver cleanups (Luis Henriques, Mathias Krause).
 
  - ACPI processor driver cleanups (Hanjun Guo).
 
  - Cleanups and documentation update related to the ACPI device
    properties interface based on _DSD (Rafael J Wysocki).
 
  - ACPI device power management fixes (Rafael J Wysocki).
 
  - Assorted cleanups related to ACPI (Dominik Brodowski. Fabian
    Frederick, Lorenzo Pieralisi, Mathias Krause, Rafael J Wysocki).
 
  - Fix for a long-standing issue causing General Protection Faults
    to be generated occasionally on return to user space after resume
    from ACPI-based suspend-to-RAM on 32-bit x86 (Ingo Molnar).
 
  - Fix to make the suspend core code return -EBUSY consistently in
    all cases when system suspend is aborted due to wakeup detection
    (Ruchi Kandoi).
 
  - Support for automated device wakeup IRQ handling allowing drivers
    to make their PM support more starightforward (Tony Lindgren).
 
  - New tracepoints for suspend-to-idle tracing and rework of the
    prepare/complete callbacks tracing in the PM core (Todd E Brandt,
    Rafael J Wysocki).
 
  - Wakeup sources framework enhancements (Jin Qian).
 
  - New macro for noirq system PM callbacks (Grygorii Strashko).
 
  - Assorted cleanups related to system suspend (Rafael J Wysocki).
 
  - cpuidle core cleanups to make the code more efficient (Rafael J
    Wysocki).
 
  - powernv/pseries cpuidle driver update (Shilpasri G Bhat).
 
  - cpufreq core fixes related to CPU online/offline that should
    reduce the overhead of these operations quite a bit, unless the
    CPU in question is physically going away (Viresh Kumar, Saravana
    Kannan).
 
  - Serialization of cpufreq governor callbacks to avoid race
    conditions in some cases (Viresh Kumar).
 
  - intel_pstate driver fixes and cleanups (Doug Smythies, Prarit
    Bhargava, Joe Konno).
 
  - cpufreq driver (arm_big_little, cpufreq-dt, qoriq) updates (Sudeep
    Holla, Felipe Balbi, Tang Yuantian).
 
  - Assorted cleanups in cpufreq drivers and core (Shailendra Verma,
    Fabian Frederick, Wang Long).
 
  - New Device Tree bindings for representing Operating Performance
    Points (Viresh Kumar).
 
  - Updates for the common clock operations support code in the PM
    core (Rajendra Nayak, Geert Uytterhoeven).
 
  - PM domains core code update (Geert Uytterhoeven).
 
  - Intel Knights Landing support for the RAPL (Running Average Power
    Limit) power capping driver (Dasaratharaman Chandramouli).
 
  - Fixes related to the floor frequency setting on Atom SoCs in the
    RAPL power capping driver (Ajay Thomas).
 
  - Runtime PM framework documentation update (Ben Dooks).
 
  - cpupower tool fix (Herton R Krzesinski).
 
 /
 -----BEGIN PGP SIGNATURE-----
 Version: GnuPG v2.0.22 (GNU/Linux)
 
 iQIcBAABCAAGBQJViJdWAAoJEILEb/54YlRx/9gP/3gHoFevNRycvn0VpKqdufCI
 Mxy2LBBLlfyW2uD3+NvqvA2WWSo0Cs/LgXa04eAVxPdU7k48s8w+54U23wSouzjW
 gfwAmuHxzDR8v0h8X3h6BxNzmkIQHtmDcQlA/cZdHejY/UUw01yxRGNUUZDNbxlm
 WXn2nmlBLmGqXTYq0fpBV+3jicUghJqHHsBCqa3VR2yQioHMJG01F4UZMqYTZunN
 OIvDUghxByKz6alzdCqlLl1Y0exV6vwWUAzBsl1qHqmHu/bWFSZn3ujNNVrjqHhw
 Kl7/8dC2pQkv3Zo3gEVvfQ0onotwWZxGHzPQRdvmxvRnBunQVCi/wynx90yABX/r
 PPb/iBNV0mZskbF0zb0GZT3ZZWGA8Z0p3o5JQv2jV4m62qTzx8w50Y5kbn9N1WT+
 5bre7AVbVAlGonWszcS9iE+6TOboRz9OD1CCwPFXHItFutlBkau+1hHfFoLM0o9n
 LhpGuyszT/EUa1BHkLzuCckFqO2DpbF3N2CKmuTekw0CdgdsvRL2pRByuerk3j7R
 WQhlcvBq5YH6j43AuoEZKp8r1iN8oG/iqlrMYQaYWrW9hJaoQOoU8dGJxp/e7gKN
 r/qeYjETI+tIsjCbtH5WQzzxDI3gPISAYAtfqs7G34EEo+Lwp6kyRUAF4kDot2V3
 ZIyuKMmTu4cdwDETr/O+
 =7jTj
 -----END PGP SIGNATURE-----

Merge tag 'pm+acpi-4.2-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm

Pull power management and ACPI updates from Rafael Wysocki:
 "The rework of backlight interface selection API from Hans de Goede
  stands out from the number of commits and the number of affected
  places perspective.  The cpufreq core fixes from Viresh Kumar are
  quite significant too as far as the number of commits goes and because
  they should reduce CPU online/offline overhead quite a bit in the
  majority of cases.

  From the new featues point of view, the ACPICA update (to upstream
  revision 20150515) adding support for new ACPI 6 material to ACPICA is
  the one that matters the most as some new significant features will be
  based on it going forward.  Also included is an update of the ACPI
  device power management core to follow ACPI 6 (which in turn reflects
  the Windows' device PM implementation), a PM core extension to support
  wakeup interrupts in a more generic way and support for the ACPI _CCA
  device configuration object.

  The rest is mostly fixes and cleanups all over and some documentation
  updates, including new DT bindings for Operating Performance Points.

  There is one fix for a regression introduced in the 4.1 cycle, but it
  adds quite a number of lines of code, it wasn't really ready before
  Thursday and you were on vacation, so I refrained from pushing it on
  the last minute for 4.1.

  Specifics:

   - ACPICA update to upstream revision 20150515 including basic support
     for ACPI 6 features: new ACPI tables introduced by ACPI 6 (STAO,
     XENV, WPBT, NFIT, IORT), changes related to the other tables (DTRM,
     FADT, LPIT, MADT), new predefined names (_BTH, _CR3, _DSD, _LPI,
     _MTL, _PRR, _RDI, _RST, _TFP, _TSN), fixes and cleanups (Bob Moore,
     Lv Zheng).

   - ACPI device power management core code update to follow ACPI 6
     which reflects the ACPI device power management implementation in
     Windows (Rafael J Wysocki).

   - rework of the backlight interface selection logic to reduce the
     number of kernel command line options and improve the handling of
     DMI quirks that may be involved in that and to make the code
     generally more straightforward (Hans de Goede).

   - fixes for the ACPI Embedded Controller (EC) driver related to the
     handling of EC transactions (Lv Zheng).

   - fix for a regression related to the ACPI resources management and
     resulting from a recent change of ACPI initialization code ordering
     (Rafael J Wysocki).

   - fix for a system initialization regression related to ACPI
     introduced during the 3.14 cycle and caused by running the code
     that switches the platform over to the ACPI mode too early in the
     initialization sequence (Rafael J Wysocki).

   - support for the ACPI _CCA device configuration object related to
     DMA cache coherence (Suravee Suthikulpanit).

   - ACPI/APEI fixes and cleanups (Jiri Kosina, Borislav Petkov).

   - ACPI battery driver cleanups (Luis Henriques, Mathias Krause).

   - ACPI processor driver cleanups (Hanjun Guo).

   - cleanups and documentation update related to the ACPI device
     properties interface based on _DSD (Rafael J Wysocki).

   - ACPI device power management fixes (Rafael J Wysocki).

   - assorted cleanups related to ACPI (Dominik Brodowski, Fabian
     Frederick, Lorenzo Pieralisi, Mathias Krause, Rafael J Wysocki).

   - fix for a long-standing issue causing General Protection Faults to
     be generated occasionally on return to user space after resume from
     ACPI-based suspend-to-RAM on 32-bit x86 (Ingo Molnar).

   - fix to make the suspend core code return -EBUSY consistently in all
     cases when system suspend is aborted due to wakeup detection (Ruchi
     Kandoi).

   - support for automated device wakeup IRQ handling allowing drivers
     to make their PM support more starightforward (Tony Lindgren).

   - new tracepoints for suspend-to-idle tracing and rework of the
     prepare/complete callbacks tracing in the PM core (Todd E Brandt,
     Rafael J Wysocki).

   - wakeup sources framework enhancements (Jin Qian).

   - new macro for noirq system PM callbacks (Grygorii Strashko).

   - assorted cleanups related to system suspend (Rafael J Wysocki).

   - cpuidle core cleanups to make the code more efficient (Rafael J
     Wysocki).

   - powernv/pseries cpuidle driver update (Shilpasri G Bhat).

   - cpufreq core fixes related to CPU online/offline that should reduce
     the overhead of these operations quite a bit, unless the CPU in
     question is physically going away (Viresh Kumar, Saravana Kannan).

   - serialization of cpufreq governor callbacks to avoid race
     conditions in some cases (Viresh Kumar).

   - intel_pstate driver fixes and cleanups (Doug Smythies, Prarit
     Bhargava, Joe Konno).

   - cpufreq driver (arm_big_little, cpufreq-dt, qoriq) updates (Sudeep
     Holla, Felipe Balbi, Tang Yuantian).

   - assorted cleanups in cpufreq drivers and core (Shailendra Verma,
     Fabian Frederick, Wang Long).

   - new Device Tree bindings for representing Operating Performance
     Points (Viresh Kumar).

   - updates for the common clock operations support code in the PM core
     (Rajendra Nayak, Geert Uytterhoeven).

   - PM domains core code update (Geert Uytterhoeven).

   - Intel Knights Landing support for the RAPL (Running Average Power
     Limit) power capping driver (Dasaratharaman Chandramouli).

   - fixes related to the floor frequency setting on Atom SoCs in the
     RAPL power capping driver (Ajay Thomas).

   - runtime PM framework documentation update (Ben Dooks).

   - cpupower tool fix (Herton R Krzesinski)"

* tag 'pm+acpi-4.2-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm: (194 commits)
  cpuidle: powernv/pseries: Auto-promotion of snooze to deeper idle state
  x86: Load __USER_DS into DS/ES after resume
  PM / OPP: Add binding for 'opp-suspend'
  PM / OPP: Allow multiple OPP tables to be passed via DT
  PM / OPP: Add new bindings to address shortcomings of existing bindings
  ACPI: Constify ACPI device IDs in documentation
  ACPI / enumeration: Document the rules regarding the PRP0001 device ID
  ACPI / video: Make acpi_video_unregister_backlight() private
  acpi-video-detect: Remove old API
  toshiba-acpi: Port to new backlight interface selection API
  thinkpad-acpi: Port to new backlight interface selection API
  sony-laptop: Port to new backlight interface selection API
  samsung-laptop: Port to new backlight interface selection API
  msi-wmi: Port to new backlight interface selection API
  msi-laptop: Port to new backlight interface selection API
  intel-oaktrail: Port to new backlight interface selection API
  ideapad-laptop: Port to new backlight interface selection API
  fujitsu-laptop: Port to new backlight interface selection API
  eeepc-laptop: Port to new backlight interface selection API
  dell-wmi: Port to new backlight interface selection API
  ...
2015-06-23 14:18:07 -07:00
Linus Torvalds 3a95398f54 Merge branch 'timers-nohz-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull NOHZ updates from Thomas Gleixner:
 "A few updates to the nohz infrastructure:

   - recursion protection for context tracking

   - make the TIF_NOHZ inheritance smarter

   - isolate cpus which belong to the NOHZ full set"

* 'timers-nohz-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  nohz: Set isolcpus when nohz_full is set
  nohz: Add tick_nohz_full_add_cpus_to() API
  context_tracking: Inherit TIF_NOHZ through forks instead of context switches
  context_tracking: Protect against recursion
2015-06-22 19:20:04 -07:00
Linus Torvalds 43224b96af Merge branch 'timers-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull timer updates from Thomas Gleixner:
 "A rather largish update for everything time and timer related:

   - Cache footprint optimizations for both hrtimers and timer wheel

   - Lower the NOHZ impact on systems which have NOHZ or timer migration
     disabled at runtime.

   - Optimize run time overhead of hrtimer interrupt by making the clock
     offset updates smarter

   - hrtimer cleanups and removal of restrictions to tackle some
     problems in sched/perf

   - Some more leap second tweaks

   - Another round of changes addressing the 2038 problem

   - First step to change the internals of clock event devices by
     introducing the necessary infrastructure

   - Allow constant folding for usecs/msecs_to_jiffies()

   - The usual pile of clockevent/clocksource driver updates

  The hrtimer changes contain updates to sched, perf and x86 as they
  depend on them plus changes all over the tree to cleanup API changes
  and redundant code, which got copied all over the place.  The y2038
  changes touch s390 to remove the last non 2038 safe code related to
  boot/persistant clock"

* 'timers-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (114 commits)
  clocksource: Increase dependencies of timer-stm32 to limit build wreckage
  timer: Minimize nohz off overhead
  timer: Reduce timer migration overhead if disabled
  timer: Stats: Simplify the flags handling
  timer: Replace timer base by a cpu index
  timer: Use hlist for the timer wheel hash buckets
  timer: Remove FIFO "guarantee"
  timers: Sanitize catchup_timer_jiffies() usage
  hrtimer: Allow hrtimer::function() to free the timer
  seqcount: Introduce raw_write_seqcount_barrier()
  seqcount: Rename write_seqcount_barrier()
  hrtimer: Fix hrtimer_is_queued() hole
  hrtimer: Remove HRTIMER_STATE_MIGRATE
  selftest: Timers: Avoid signal deadlock in leap-a-day
  timekeeping: Copy the shadow-timekeeper over the real timekeeper last
  clockevents: Check state instead of mode in suspend/resume path
  selftests: timers: Add leap-second timer edge testing to leap-a-day.c
  ntp: Do leapsecond adjustment in adjtimex read path
  time: Prevent early expiry of hrtimers[CLOCK_REALTIME] at the leap second edge
  ntp: Introduce and use SECS_PER_DAY macro instead of 86400
  ...
2015-06-22 18:57:44 -07:00
Linus Torvalds 23b7776290 Merge branch 'sched-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull scheduler updates from Ingo Molnar:
 "The main changes are:

   - lockless wakeup support for futexes and IPC message queues
     (Davidlohr Bueso, Peter Zijlstra)

   - Replace spinlocks with atomics in thread_group_cputimer(), to
     improve scalability (Jason Low)

   - NUMA balancing improvements (Rik van Riel)

   - SCHED_DEADLINE improvements (Wanpeng Li)

   - clean up and reorganize preemption helpers (Frederic Weisbecker)

   - decouple page fault disabling machinery from the preemption
     counter, to improve debuggability and robustness (David
     Hildenbrand)

   - SCHED_DEADLINE documentation updates (Luca Abeni)

   - topology CPU masks cleanups (Bartosz Golaszewski)

   - /proc/sched_debug improvements (Srikar Dronamraju)"

* 'sched-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (79 commits)
  sched/deadline: Remove needless parameter in dl_runtime_exceeded()
  sched: Remove superfluous resetting of the p->dl_throttled flag
  sched/deadline: Drop duplicate init_sched_dl_class() declaration
  sched/deadline: Reduce rq lock contention by eliminating locking of non-feasible target
  sched/deadline: Make init_sched_dl_class() __init
  sched/deadline: Optimize pull_dl_task()
  sched/preempt: Add static_key() to preempt_notifiers
  sched/preempt: Fix preempt notifiers documentation about hlist_del() within unsafe iteration
  sched/stop_machine: Fix deadlock between multiple stop_two_cpus()
  sched/debug: Add sum_sleep_runtime to /proc/<pid>/sched
  sched/debug: Replace vruntime with wait_sum in /proc/sched_debug
  sched/debug: Properly format runnable tasks in /proc/sched_debug
  sched/numa: Only consider less busy nodes as numa balancing destinations
  Revert 095bebf61a ("sched/numa: Do not move past the balance point if unbalanced")
  sched/fair: Prevent throttling in early pick_next_task_fair()
  preempt: Reorganize the notrace definitions a bit
  preempt: Use preempt_schedule_context() as the official tracing preemption point
  sched: Make preempt_schedule_context() function-tracing safe
  x86: Remove cpu_sibling_mask() and cpu_core_mask()
  x86: Replace cpu_**_mask() with topology_**_cpumask()
  ...
2015-06-22 15:52:04 -07:00
Linus Torvalds c58267e9fa Merge branch 'perf-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull perf updates from Ingo Molnar:
 "Kernel side changes mostly consist of work on x86 PMU drivers:

   - x86 Intel PT (hardware CPU tracer) improvements (Alexander
     Shishkin)

   - x86 Intel CQM (cache quality monitoring) improvements (Thomas
     Gleixner)

   - x86 Intel PEBSv3 support (Peter Zijlstra)

   - x86 Intel PEBS interrupt batching support for lower overhead
     sampling (Zheng Yan, Kan Liang)

   - x86 PMU scheduler fixes and improvements (Peter Zijlstra)

  There's too many tooling improvements to list them all - here are a
  few select highlights:

  'perf bench':

      - Introduce new 'perf bench futex' benchmark: 'wake-parallel', to
        measure parallel waker threads generating contention for kernel
        locks (hb->lock). (Davidlohr Bueso)

  'perf top', 'perf report':

      - Allow disabling/enabling events dynamicaly in 'perf top':
        a 'perf top' session can instantly become a 'perf report'
        one, i.e. going from dynamic analysis to a static one,
        returning to a dynamic one is possible, to toogle the
        modes, just press 'f' to 'freeze/unfreeze' the sampling. (Arnaldo Carvalho de Melo)

      - Make Ctrl-C stop processing on TUI, allowing interrupting the load of big
        perf.data files (Namhyung Kim)

  'perf probe': (Masami Hiramatsu)

      - Support glob wildcards for function name
      - Support $params special probe argument: Collect all function arguments
      - Make --line checks validate C-style function name.
      - Add --no-inlines option to avoid searching inline functions
      - Greatly speed up 'perf probe --list' by caching debuginfo.
      - Improve --filter support for 'perf probe', allowing using its arguments
        on other commands, as --add, --del, etc.

  'perf sched':

      - Add option in 'perf sched' to merge like comms to lat output (Josef Bacik)

  Plus tons of infrastructure work - in particular preparation for
  upcoming threaded perf report support, but also lots of other work -
  and fixes and other improvements.  See (much) more details in the
  shortlog and in the git log"

* 'perf-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (305 commits)
  perf tools: Configurable per thread proc map processing time out
  perf tools: Add time out to force stop proc map processing
  perf report: Fix sort__sym_cmp to also compare end of symbol
  perf hists browser: React to unassigned hotkey pressing
  perf top: Tell the user how to unfreeze events after pressing 'f'
  perf hists browser: Honour the help line provided by builtin-{top,report}.c
  perf hists browser: Do not exit when 'f' is pressed in 'report' mode
  perf top: Replace CTRL+z with 'f' as hotkey for enable/disable events
  perf annotate: Rename source_line_percent to source_line_samples
  perf annotate: Display total number of samples with --show-total-period
  perf tools: Ensure thread-stack is flushed
  perf top: Allow disabling/enabling events dynamicly
  perf evlist: Add toggle_enable() method
  perf trace: Fix race condition at the end of started workloads
  perf probe: Speed up perf probe --list by caching debuginfo
  perf probe: Show usage even if the last event is skipped
  perf tools: Move libtraceevent dynamic list to separated LDFLAGS variable
  perf tools: Fix a problem when opening old perf.data with different byte order
  perf tools: Ignore .config-detected in .gitignore
  perf probe: Fix to return error if no probe is added
  ...
2015-06-22 15:19:21 -07:00
Linus Torvalds 1bf7067c6e Merge branch 'locking-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull locking updates from Ingo Molnar:
 "The main changes are:

   - 'qspinlock' support, enabled on x86: queued spinlocks - these are
     now the spinlock variant used by x86 as they outperform ticket
     spinlocks in every category.  (Waiman Long)

   - 'pvqspinlock' support on x86: paravirtualized variant of queued
     spinlocks.  (Waiman Long, Peter Zijlstra)

   - 'qrwlock' support, enabled on x86: queued rwlocks.  Similar to
     queued spinlocks, they are now the variant used by x86:

       CONFIG_ARCH_USE_QUEUED_SPINLOCKS=y
       CONFIG_QUEUED_SPINLOCKS=y
       CONFIG_ARCH_USE_QUEUED_RWLOCKS=y
       CONFIG_QUEUED_RWLOCKS=y

   - various lockdep fixlets

   - various locking primitives cleanups, further WRITE_ONCE()
     propagation"

* 'locking-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (24 commits)
  locking/lockdep: Remove hard coded array size dependency
  locking/qrwlock: Don't contend with readers when setting _QW_WAITING
  lockdep: Do not break user-visible string
  locking/arch: Rename set_mb() to smp_store_mb()
  locking/arch: Add WRITE_ONCE() to set_mb()
  rtmutex: Warn if trylock is called from hard/softirq context
  arch: Remove __ARCH_HAVE_CMPXCHG
  locking/rtmutex: Drop usage of __HAVE_ARCH_CMPXCHG
  locking/qrwlock: Rename QUEUE_RWLOCK to QUEUED_RWLOCKS
  locking/pvqspinlock: Rename QUEUED_SPINLOCK to QUEUED_SPINLOCKS
  locking/pvqspinlock: Replace xchg() by the more descriptive set_mb()
  locking/pvqspinlock, x86: Enable PV qspinlock for Xen
  locking/pvqspinlock, x86: Enable PV qspinlock for KVM
  locking/pvqspinlock, x86: Implement the paravirt qspinlock call patching
  locking/pvqspinlock: Implement simple paravirt support for the qspinlock
  locking/qspinlock: Revert to test-and-set on hypervisors
  locking/qspinlock: Use a simple write to grab the lock
  locking/qspinlock: Optimize for smaller NR_CPUS
  locking/qspinlock: Extract out code snippets for the next patch
  locking/qspinlock: Add pending bit
  ...
2015-06-22 14:54:22 -07:00
Thomas Gleixner bc7a34b8b9 timer: Reduce timer migration overhead if disabled
Eric reported that the timer_migration sysctl is not really nice
performance wise as it needs to check at every timer insertion whether
the feature is enabled or not. Further the check does not live in the
timer code, so we have an extra function call which checks an extra
cache line to figure out that it is disabled.

We can do better and store that information in the per cpu (hr)timer
bases. I pondered to use a static key, but that's a nightmare to
update from the nohz code and the timer base cache line is hot anyway
when we select a timer base.

The old logic enabled the timer migration unconditionally if
CONFIG_NO_HZ was set even if nohz was disabled on the kernel command
line.

With this modification, we start off with migration disabled. The user
visible sysctl is still set to enabled. If the kernel switches to NOHZ
migration is enabled, if the user did not disable it via the sysctl
prior to the switch. If nohz=off is on the kernel command line,
migration stays disabled no matter what.

Before:
  47.76%  hog       [.] main
  14.84%  [kernel]  [k] _raw_spin_lock_irqsave
   9.55%  [kernel]  [k] _raw_spin_unlock_irqrestore
   6.71%  [kernel]  [k] mod_timer
   6.24%  [kernel]  [k] lock_timer_base.isra.38
   3.76%  [kernel]  [k] detach_if_pending
   3.71%  [kernel]  [k] del_timer
   2.50%  [kernel]  [k] internal_add_timer
   1.51%  [kernel]  [k] get_nohz_timer_target
   1.28%  [kernel]  [k] __internal_add_timer
   0.78%  [kernel]  [k] timerfn
   0.48%  [kernel]  [k] wake_up_nohz_cpu

After:
  48.10%  hog       [.] main
  15.25%  [kernel]  [k] _raw_spin_lock_irqsave
   9.76%  [kernel]  [k] _raw_spin_unlock_irqrestore
   6.50%  [kernel]  [k] mod_timer
   6.44%  [kernel]  [k] lock_timer_base.isra.38
   3.87%  [kernel]  [k] detach_if_pending
   3.80%  [kernel]  [k] del_timer
   2.67%  [kernel]  [k] internal_add_timer
   1.33%  [kernel]  [k] __internal_add_timer
   0.73%  [kernel]  [k] timerfn
   0.54%  [kernel]  [k] wake_up_nohz_cpu


Reported-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Paul McKenney <paulmck@linux.vnet.ibm.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Viresh Kumar <viresh.kumar@linaro.org>
Cc: John Stultz <john.stultz@linaro.org>
Cc: Joonwoo Park <joonwoop@codeaurora.org>
Cc: Wenbo Wang <wenbo.wang@memblaze.com>
Link: http://lkml.kernel.org/r/20150526224512.127050787@linutronix.de
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2015-06-19 15:18:28 +02:00
Zhiqiang Zhang 6fab541019 sched/deadline: Remove needless parameter in dl_runtime_exceeded()
Sine commit 269ad8015a ("sched/deadline: Avoid double-accounting in
case of missed deadlines), parameter 'rq' is no longer used, so
remove it.

Signed-off-by: Zhiqiang Zhang <zhangzhiqiang.zhang@huawei.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: <juri.lelli@gmail.com>
Cc: <luca.abeni@unitn.it>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/1434338120-43773-1-git-send-email-zhangzhiqiang.zhang@huawei.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2015-06-19 10:06:48 +02:00
Wanpeng Li 6713c3aa7f sched: Remove superfluous resetting of the p->dl_throttled flag
Resetting the p->dl_throttled flag in rt_mutex_setprio() (for a task that is going
to be boosted) is superfluous, as the natural place to do so is in
replenish_dl_entity().

If the task was on the runqueue and it is boosted by a DL task, it will be enqueued
back with ENQUEUE_REPLENISH flag set, which can guarantee that dl_throttled is
reset in replenish_dl_entity().

This patch drops the resetting of throttled status in function rt_mutex_setprio().

Signed-off-by: Wanpeng Li <wanpeng.li@linux.intel.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Juri Lelli <juri.lelli@arm.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/1431496867-4194-6-git-send-email-wanpeng.li@linux.intel.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2015-06-19 10:06:47 +02:00
Wanpeng Li 178a4d23e4 sched/deadline: Drop duplicate init_sched_dl_class() declaration
There are two init_sched_dl_class() declarations, this patch drops
the duplicate.

Signed-off-by: Wanpeng Li <wanpeng.li@linux.intel.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Juri Lelli <juri.lelli@arm.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/1431496867-4194-5-git-send-email-wanpeng.li@linux.intel.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2015-06-19 10:06:47 +02:00
Wanpeng Li 9d51426242 sched/deadline: Reduce rq lock contention by eliminating locking of non-feasible target
This patch adds a check that prevents futile attempts to move DL tasks
to a CPU with active tasks of equal or earlier deadline. The same
behavior as commit 80e3d87b2c ("sched/rt: Reduce rq lock contention
by eliminating locking of non-feasible target") for rt class.

Signed-off-by: Wanpeng Li <wanpeng.li@linux.intel.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Juri Lelli <juri.lelli@arm.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/1431496867-4194-3-git-send-email-wanpeng.li@linux.intel.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2015-06-19 10:06:46 +02:00
Wanpeng Li a6c0e746fb sched/deadline: Make init_sched_dl_class() __init
It's a bootstrap function, make init_sched_dl_class() __init.

Signed-off-by: Wanpeng Li <wanpeng.li@linux.intel.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Juri Lelli <juri.lelli@arm.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/1431496867-4194-2-git-send-email-wanpeng.li@linux.intel.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2015-06-19 10:06:46 +02:00
Wanpeng Li 8b5e770ed7 sched/deadline: Optimize pull_dl_task()
pull_dl_task() uses pick_next_earliest_dl_task() to select a migration
candidate; this is sub-optimal since the next earliest task -- as per
the regular runqueue -- might not be migratable at all. This could
result in iterating the entire runqueue looking for a task.

Instead iterate the pushable queue -- this queue only contains tasks
that have at least 2 cpus set in their cpus_allowed mask.

Signed-off-by: Wanpeng Li <wanpeng.li@linux.intel.com>
[ Improved the changelog. ]
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Juri Lelli <juri.lelli@arm.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/1431496867-4194-1-git-send-email-wanpeng.li@linux.intel.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2015-06-19 10:06:45 +02:00
Peter Zijlstra 1cde2930e1 sched/preempt: Add static_key() to preempt_notifiers
Avoid touching the curr->preempt_notifier cacheline when not needed.

Provides a small improvement on pipe-bench:

  taskset 01 perf stat --repeat 10 -- perf bench sched pipe

before:

 Performance counter stats for 'perf bench sched pipe' (10 runs):

      12385.016204      task-clock (msec)         #    1.001 CPUs utilized            ( +-  0.34% )
         2,000,023      context-switches          #    0.161 M/sec                    ( +-  0.00% )
                 0      cpu-migrations            #    0.000 K/sec
               175      page-faults               #    0.014 K/sec                    ( +-  0.26% )
    41,376,162,250      cycles                    #    3.341 GHz                      ( +-  0.11% )
    17,389,139,321      stalled-cycles-frontend   #   42.03% frontend cycles idle     ( +-  0.25% )
   <not supported>      stalled-cycles-backend
    68,788,588,003      instructions              #    1.66  insns per cycle
                                                  #    0.25  stalled cycles per insn  ( +-  0.02% )
    13,449,387,620      branches                  # 1085.940 M/sec                    ( +-  0.02% )
        20,880,690      branch-misses             #    0.16% of all branches          ( +-  0.98% )

      12.372646094 seconds time elapsed                                          ( +-  0.34% )

after:

 Performance counter stats for 'perf bench sched pipe' (10 runs):

      12180.936528      task-clock (msec)         #    1.001 CPUs utilized            ( +-  0.33% )
         2,000,077      context-switches          #    0.164 M/sec                    ( +-  0.00% )
                 0      cpu-migrations            #    0.000 K/sec
               174      page-faults               #    0.014 K/sec                    ( +-  0.27% )
    40,691,545,577      cycles                    #    3.341 GHz                      ( +-  0.06% )
    16,446,333,371      stalled-cycles-frontend   #   40.42% frontend cycles idle     ( +-  0.18% )
   <not supported>      stalled-cycles-backend
    68,570,100,387      instructions              #    1.69  insns per cycle
                                                  #    0.24  stalled cycles per insn  ( +-  0.01% )
    13,389,740,014      branches                  # 1099.237 M/sec                    ( +-  0.01% )
        20,175,440      branch-misses             #    0.15% of all branches          ( +-  0.52% )

      12.169253010 seconds time elapsed                                          ( +-  0.33% )

Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2015-06-19 10:06:45 +02:00
Mathieu Desnoyers d84525a845 sched/preempt: Fix preempt notifiers documentation about hlist_del() within unsafe iteration
preempt_notifier_unregister() documents:

  "This is safe to call from within a preemption notifier."

However, both fire_sched_in_preempt_notifiers() and
fire_sched_out_preempt_notifiers() are using hlist_for_each_entry(),
which is not safe against entry removal during iteration.

Inspection of the KVM code does not reveal any use of
preempt_notifier_unregister() within the preempt notifiers.

Therefore, fix the comment.

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/1431881590-1456-1-git-send-email-mathieu.desnoyers@efficios.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2015-06-19 10:06:44 +02:00
Srikar Dronamraju 82a0d27626 sched/debug: Add sum_sleep_runtime to /proc/<pid>/sched
When CONFIG_SCHEDSTATS is enabled, /proc/<pid>/sched prints almost all
sched statistics except sum_sleep_runtime. Since sum_sleep_runtime is
a good info to collect, add this it to /proc/<pid>/sched.

Signed-off-by: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/1433751041-11724-4-git-send-email-srikar@linux.vnet.ibm.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2015-06-19 10:03:11 +02:00
Srikar Dronamraju c5f3ab1c3b sched/debug: Replace vruntime with wait_sum in /proc/sched_debug
Within runnable tasks in /proc/sched_debug, vruntime is printed twice,
once as tree-key and again as exec-runtime.

Since exec-runtime isnt populated in !CONFIG_SCHEDSTATS, use this field
to print wait_sum.

Signed-off-by: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/1433751041-11724-3-git-send-email-srikar@linux.vnet.ibm.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2015-06-19 10:03:11 +02:00
Srikar Dronamraju 33d6176eb1 sched/debug: Properly format runnable tasks in /proc/sched_debug
With !CONFIG_SCHEDSTATS, runnable tasks in /proc/sched_debug has too
many columns than required. Fix this by printing appropriate columns.

While at this, print sum_exec_runtime, since this information is
available even in !CONFIG_SCHEDSTATS case.

Signed-off-by: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/1433751041-11724-2-git-send-email-srikar@linux.vnet.ibm.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2015-06-19 10:03:10 +02:00
Rafael J. Wysocki 4a3004e5e6 Merge branch 'pm-cpuidle'
* pm-cpuidle:
  cpuidle: Do not use CPUIDLE_DRIVER_STATE_START in cpuidle.c
  cpuidle: Select a different state on tick_broadcast_enter() failures
  sched / idle: Call default_idle_call() from cpuidle_enter_state()
  sched / idle: Call idle_set_state() from cpuidle_enter_state()
  cpuidle: Fix the kerneldoc comment for cpuidle_enter_state()
  sched / idle: Eliminate the "reflect" check from cpuidle_idle_call()
  cpuidle: Check the sign of index in cpuidle_reflect()
  sched / idle: Move the default idle call code to a separate function
2015-06-19 01:17:44 +02:00
Peter Zijlstra cbce1a6867 sched,lockdep: Employ lock pinning
Employ the new lockdep lock pinning annotation to ensure no
'accidental' lock-breaks happen with rq->lock.

Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: ktkhai@parallels.com
Cc: rostedt@goodmis.org
Cc: juri.lelli@gmail.com
Cc: pang.xunlei@linaro.org
Cc: oleg@redhat.com
Cc: wanpeng.li@linux.intel.com
Cc: umgwanakikbuti@gmail.com
Link: http://lkml.kernel.org/r/20150611124744.003233193@infradead.org
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2015-06-19 00:25:27 +02:00
Peter Zijlstra 5e16bbc2fb sched: Streamline the task migration locking a little
The whole migrate_task{,s}() locking seems a little shaky, there's a
lot of dropping an require happening. Pull the locking up into the
callers as far as possible to streamline the lot.

Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: ktkhai@parallels.com
Cc: rostedt@goodmis.org
Cc: juri.lelli@gmail.com
Cc: pang.xunlei@linaro.org
Cc: oleg@redhat.com
Cc: wanpeng.li@linux.intel.com
Cc: umgwanakikbuti@gmail.com
Link: http://lkml.kernel.org/r/20150611124743.755256708@infradead.org
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2015-06-19 00:25:27 +02:00
Peter Zijlstra 5cc389bcee sched: Move code around
In preparation to reworking set_cpus_allowed_ptr() move some code
around. This also removes some superfluous #ifdefs and adds comments
to some #endifs.

   text    data     bss     dec     hex filename
12211532        1738144 1081344 15031020         e55aec defconfig-build/vmlinux.pre
12211532        1738144 1081344 15031020         e55aec defconfig-build/vmlinux.post

Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: ktkhai@parallels.com
Cc: rostedt@goodmis.org
Cc: juri.lelli@gmail.com
Cc: pang.xunlei@linaro.org
Cc: oleg@redhat.com
Cc: wanpeng.li@linux.intel.com
Cc: umgwanakikbuti@gmail.com
Link: http://lkml.kernel.org/r/20150611124743.662086684@infradead.org
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2015-06-19 00:25:26 +02:00
Peter Zijlstra a649f237db sched,dl: Fix sched class hopping CBS hole
We still have a few pending issues with the deadline code, one of which
is that switching between scheduling classes can 'leak' CBS state.

Close the hole by retaining the current CBS state when leaving
SCHED_DEADLINE and unconditionally programming the deadline timer.
The timer will then reset the CBS state if the task is still
!SCHED_DEADLINE by the time it hits.

If the task left SCHED_DEADLINE it will not call task_dead_dl() and
we'll not cancel the hrtimer, leaving us a pending timer in free
space. Avoid this by giving the timer a task reference, this avoids
littering the task exit path for this rather uncommon case.

In order to do this, I had to move dl_task_offline_migration() below
the replenishment, such that the task_rq()->lock fully covers that.
While doing this, I noticed that it (was) buggy in assuming a task is
enqueued and or we need to enqueue the task now. Fixing this means
select_task_rq_dl() might encounter an offline rq -- look into that.

As a result this kills cancel_dl_timer() which included a rq->lock
break.

Fixes: 40767b0dc7 ("sched/deadline: Fix deadline parameter modification handling")
Cc: Wanpeng Li <wanpeng.li@linux.intel.com>
Cc: Luca Abeni <luca.abeni@unitn.it>
Cc: Juri Lelli <juri.lelli@arm.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: ktkhai@parallels.com
Cc: rostedt@goodmis.org
Cc: juri.lelli@gmail.com
Cc: pang.xunlei@linaro.org
Cc: oleg@redhat.com
Cc: wanpeng.li@linux.intel.com
Cc: Luca Abeni <luca.abeni@unitn.it>
Cc: Juri Lelli <juri.lelli@arm.com>
Cc: umgwanakikbuti@gmail.com
Link: http://lkml.kernel.org/r/20150611124743.574192138@infradead.org
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2015-06-19 00:25:26 +02:00
Peter Zijlstra 9916e21499 sched, dl: Convert switched_{from, to}_dl() / prio_changed_dl() to balance callbacks
Remove the direct {push,pull} balancing operations from
switched_{from,to}_dl() / prio_changed_dl() and use the balance
callback queue.

Again, err on the side of too many reschedules; since too few is a
hard bug while too many is just annoying.

Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: ktkhai@parallels.com
Cc: rostedt@goodmis.org
Cc: juri.lelli@gmail.com
Cc: pang.xunlei@linaro.org
Cc: oleg@redhat.com
Cc: wanpeng.li@linux.intel.com
Cc: umgwanakikbuti@gmail.com
Link: http://lkml.kernel.org/r/20150611124742.968262663@infradead.org
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2015-06-19 00:25:26 +02:00
Peter Zijlstra 0ea60c2054 sched,dl: Remove return value from pull_dl_task()
In order to be able to use pull_dl_task() from a callback, we need to
do away with the return value.

Since the return value indicates if we should reschedule, do this
inside the function. Since not all callers currently do this, this can
increase the number of reschedules due rt balancing.

Too many reschedules is not a correctness issues, too few are.

Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: ktkhai@parallels.com
Cc: rostedt@goodmis.org
Cc: juri.lelli@gmail.com
Cc: pang.xunlei@linaro.org
Cc: oleg@redhat.com
Cc: wanpeng.li@linux.intel.com
Cc: umgwanakikbuti@gmail.com
Link: http://lkml.kernel.org/r/20150611124742.859398977@infradead.org
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2015-06-19 00:25:26 +02:00
Peter Zijlstra fd7a4bed18 sched, rt: Convert switched_{from, to}_rt() / prio_changed_rt() to balance callbacks
Remove the direct {push,pull} balancing operations from
switched_{from,to}_rt() / prio_changed_rt() and use the balance
callback queue.

Again, err on the side of too many reschedules; since too few is a
hard bug while too many is just annoying.

Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: ktkhai@parallels.com
Cc: rostedt@goodmis.org
Cc: juri.lelli@gmail.com
Cc: pang.xunlei@linaro.org
Cc: oleg@redhat.com
Cc: wanpeng.li@linux.intel.com
Cc: umgwanakikbuti@gmail.com
Link: http://lkml.kernel.org/r/20150611124742.766832367@infradead.org
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2015-06-19 00:25:26 +02:00
Peter Zijlstra 8046d68062 sched,rt: Remove return value from pull_rt_task()
In order to be able to use pull_rt_task() from a callback, we need to
do away with the return value.

Since the return value indicates if we should reschedule, do this
inside the function. Since not all callers currently do this, this can
increase the number of reschedules due rt balancing.

Too many reschedules is not a correctness issues, too few are.

Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: ktkhai@parallels.com
Cc: rostedt@goodmis.org
Cc: juri.lelli@gmail.com
Cc: pang.xunlei@linaro.org
Cc: oleg@redhat.com
Cc: wanpeng.li@linux.intel.com
Cc: umgwanakikbuti@gmail.com
Link: http://lkml.kernel.org/r/20150611124742.679002000@infradead.org
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2015-06-19 00:25:26 +02:00
Peter Zijlstra 4c9a4bc89a sched: Allow balance callbacks for check_class_changed()
In order to remove dropping rq->lock from the
switched_{to,from}()/prio_changed() sched_class methods, run the
balance callbacks after it.

We need to remove dropping rq->lock because its buggy,
suppose using sched_setattr()/sched_setscheduler() to change a running
task from FIFO to OTHER.

By the time we get to switched_from_rt() the task is already enqueued
on the cfs runqueues. If switched_from_rt() does pull_rt_task() and
drops rq->lock, load-balancing can come in and move our task @p to
another rq.

The subsequent switched_to_fair() still assumes @p is on @rq and bad
things will happen.

By using balance callbacks we delay the load-balancing operations
{rt,dl}x{push,pull} until we've done all the important work and the
task is fully set up.

Furthermore, the balance callbacks do not know about @p, therefore
they cannot get confused like this.

Reported-by: Mike Galbraith <umgwanakikbuti@gmail.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: ktkhai@parallels.com
Cc: rostedt@goodmis.org
Cc: juri.lelli@gmail.com
Cc: pang.xunlei@linaro.org
Cc: oleg@redhat.com
Cc: wanpeng.li@linux.intel.com
Link: http://lkml.kernel.org/r/20150611124742.615343911@infradead.org
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2015-06-19 00:25:26 +02:00
Peter Zijlstra dbc7f069b9 sched: Use replace normalize_task() with __sched_setscheduler()
Reduce duplicate logic; normalize_task() is a simplified version of
__sched_setscheduler(). Parametrize the difference and collapse.

This reduces the amount of check_class_changed() sites.

Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: ktkhai@parallels.com
Cc: rostedt@goodmis.org
Cc: juri.lelli@gmail.com
Cc: pang.xunlei@linaro.org
Cc: oleg@redhat.com
Cc: wanpeng.li@linux.intel.com
Cc: umgwanakikbuti@gmail.com
Link: http://lkml.kernel.org/r/20150611124742.532642391@infradead.org
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2015-06-19 00:25:26 +02:00
Peter Zijlstra e3fca9e7cb sched: Replace post_schedule with a balance callback list
Generalize the post_schedule() stuff into a balance callback list.
This allows us to more easily use it outside of schedule() and cross
sched_class.

Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: ktkhai@parallels.com
Cc: rostedt@goodmis.org
Cc: juri.lelli@gmail.com
Cc: pang.xunlei@linaro.org
Cc: oleg@redhat.com
Cc: wanpeng.li@linux.intel.com
Cc: umgwanakikbuti@gmail.com
Link: http://lkml.kernel.org/r/20150611124742.424032725@infradead.org
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2015-06-19 00:25:26 +02:00
Thomas Gleixner 624bbdfac9 Merge branch 'timers/core' into sched/hrtimers
Merge sched/core and timers/core so we can apply the sched balancing
patch queue, which depends on both.
2015-06-19 00:17:47 +02:00
Mel Gorman 8e76d4eecf sched, numa: do not hint for NUMA balancing on VM_MIXEDMAP mappings
Jovi Zhangwei reported the following problem

  Below kernel vm bug can be triggered by tcpdump which mmaped a lot of pages
  with GFP_COMP flag.

  [Mon May 25 05:29:33 2015] page:ffffea0015414000 count:66 mapcount:1 mapping:          (null) index:0x0
  [Mon May 25 05:29:33 2015] flags: 0x20047580004000(head)
  [Mon May 25 05:29:33 2015] page dumped because: VM_BUG_ON_PAGE(compound_order(page) && !PageTransHuge(page))
  [Mon May 25 05:29:33 2015] ------------[ cut here ]------------
  [Mon May 25 05:29:33 2015] kernel BUG at mm/migrate.c:1661!
  [Mon May 25 05:29:33 2015] invalid opcode: 0000 [#1] SMP

In this case it was triggered by running tcpdump but it's not necessary
reproducible on all systems.

  sudo tcpdump -i bond0.100 'tcp port 4242' -c 100000000000 -w 4242.pcap

Compound pages cannot be migrated and it was not expected that such pages
be marked for NUMA balancing.  This did not take into account that drivers
such as net/packet/af_packet.c may insert compound pages into userspace
with vm_insert_page.  This patch tells the NUMA balancing protection
scanner to skip all VM_MIXEDMAP mappings which avoids the possibility that
compound pages are marked for migration.

Signed-off-by: Mel Gorman <mgorman@suse.de>
Reported-by: Jovi Zhangwei <jovi@cloudflare.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2015-06-10 16:43:43 -07:00
Rik van Riel 6f9aad0bc3 sched/numa: Only consider less busy nodes as numa balancing destinations
Changeset a43455a1d5 ("sched/numa: Ensure task_numa_migrate() checks
the preferred node") fixes an issue where workloads would never
converge on a fully loaded (or overloaded) system.

However, it introduces a regression on less than fully loaded systems,
where workloads converge on a few NUMA nodes, instead of properly
staying spread out across the whole system. This leads to a reduction
in available memory bandwidth, and usable CPU cache, with predictable
performance problems.

The root cause appears to be an interaction between the load balancer
and NUMA balancing, where the short term load represented by the load
balancer differs from the long term load the NUMA balancing code would
like to base its decisions on.

Simply reverting a43455a1d5 would re-introduce the non-convergence
of workloads on fully loaded systems, so that is not a good option. As
an aside, the check done before a43455a1d5 only applied to a task's
preferred node, not to other candidate nodes in the system, so the
converge-on-too-few-nodes problem still happens, just to a lesser
degree.

Instead, try to compensate for the impedance mismatch between the load
balancer and NUMA balancing by only ever considering a lesser loaded
node as a destination for NUMA balancing, regardless of whether the
task is trying to move to the preferred node, or to another node.

This patch also addresses the issue that a system with a single
runnable thread would never migrate that thread to near its memory,
introduced by 095bebf61a ("sched/numa: Do not move past the balance
point if unbalanced").

A test where the main thread creates a large memory area, and spawns a
worker thread to iterate over the memory (placed on another node by
select_task_rq_fair), after which the main thread goes to sleep and
waits for the worker thread to loop over all the memory now sees the
worker thread migrated to where the memory is, instead of having all
the memory migrated over like before.

Jirka has run a number of performance tests on several systems: single
instance SpecJBB 2005 performance is 7-15% higher on a 4 node system,
with higher gains on systems with more cores per socket.
Multi-instance SpecJBB 2005 (one per node), linpack, and stream see
little or no changes with the revert of 095bebf61a and this patch.

Reported-by: Artem Bityutski <dedekind1@gmail.com>
Reported-by: Jirka Hladky <jhladky@redhat.com>
Tested-by: Jirka Hladky <jhladky@redhat.com>
Tested-by: Artem Bityutskiy <dedekind1@gmail.com>
Signed-off-by: Rik van Riel <riel@redhat.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: Mel Gorman <mgorman@suse.de>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/20150528095249.3083ade0@annuminas.surriel.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2015-06-07 15:57:45 +02:00
Rik van Riel e4991b240c Revert 095bebf61a ("sched/numa: Do not move past the balance point if unbalanced")
Commit 095bebf61a ("sched/numa: Do not move past the balance point
if unbalanced") broke convergence of workloads with just one runnable
thread, by making it impossible for the one runnable thread on the
system to move from one NUMA node to another.

Instead, the thread would remain where it was, and pull all the memory
across to its location, which is much slower than just migrating the
thread to where the memory is.

The next patch has a better fix for the issue that 095bebf61a tried
to address.

Reported-by: Jirka Hladky <jhladky@redhat.com>
Signed-off-by: Rik van Riel <riel@redhat.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: dedekind1@gmail.com
Cc: mgorman@suse.de
Link: http://lkml.kernel.org/r/1432753468-7785-2-git-send-email-riel@redhat.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2015-06-07 15:57:44 +02:00
Ben Segall 54d27365ca sched/fair: Prevent throttling in early pick_next_task_fair()
The optimized task selection logic optimistically selects a new task
to run without first doing a full put_prev_task(). This is so that we
can avoid a put/set on the common ancestors of the old and new task.

Similarly, we should only call check_cfs_rq_runtime() to throttle
eligible groups if they're part of the common ancestry, otherwise it
is possible to end up with no eligible task in the simple task
selection.

Imagine:
		/root
	/prev		/next
	/A		/B

If our optimistic selection ends up throttling /next, we goto simple
and our put_prev_task() ends up throttling /prev, after which we're
going to bug out in set_next_entity() because there aren't any tasks
left.

Avoid this scenario by only throttling common ancestors.

Reported-by: Mohammed Naser <mnaser@vexxhost.com>
Reported-by: Konstantin Khlebnikov <khlebnikov@yandex-team.ru>
Signed-off-by: Ben Segall <bsegall@google.com>
[ munged Changelog ]
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Roman Gushchin <klamm@yandex-team.ru>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: pjt@google.com
Fixes: 678d5718d8 ("sched/fair: Optimize cgroup pick_next_task_fair()")
Link: http://lkml.kernel.org/r/xm26wq1oswoq.fsf@sword-of-the-dawn.mtv.corp.google.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2015-06-07 15:57:44 +02:00
Frederic Weisbecker 4eaca0a887 preempt: Use preempt_schedule_context() as the official tracing preemption point
preempt_schedule_context() is a tracing safe preemption point but it's
only used when CONFIG_CONTEXT_TRACKING=y. Other configs have tracing
recursion issues since commit:

  b30f0e3ffe ("sched/preempt: Optimize preemption operations on __schedule() callers")

introduced function based preemp_count_*() ops.

Lets make it available on all configs and give it a more appropriate
name for its new position.

Reported-by: Fengguang Wu <fengguang.wu@intel.com>
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/1433432349-1021-3-git-send-email-fweisbec@gmail.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2015-06-07 15:57:42 +02:00
Frederic Weisbecker be690035df sched: Make preempt_schedule_context() function-tracing safe
Since function tracing disables preemption, it needs a safe preemption
point to use when preemption is re-enabled without worrying about tracing
recursion. Ie: to avoid tracing recursion, that preemption point can't
be traced (use of notrace qualifier) and it can't call any traceable
function before that preemption point disables preemption itself, which
disarms the recursion.

preempt_schedule() was fine until commit:

  b30f0e3ffe ("sched/preempt: Optimize preemption operations on __schedule() callers")

because PREEMPT_ACTIVE (which has the property to disable preemption
and this disarm tracing preemption recursion) was set before calling
any further function.

But that commit introduced the use of preempt_count_add/sub() functions
to set PREEMPT_ACTIVE and because these functions are called before
preemption gets a chance to be disabled, we have a tracing recursion.

preempt_schedule_context() is one of the possible preemption functions
used by tracing. Its special purpose is to avoid tracing recursion
against context tracking. Lets enhance this function to become more
generally tracing safe by disabling preemption with raw accessors, such
that no function is called before preemption gets disabled and disarm
the tracing recursion.

This function is going to become the specific tracing-safe preemption
point in further commit.

Reported-by: Fengguang Wu <fengguang.wu@intel.com>
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/1433432349-1021-2-git-send-email-fweisbec@gmail.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2015-06-07 15:57:41 +02:00
Ingo Molnar f407a82586 Merge branch 'linus' into sched/core, to resolve conflict
Conflicts:
	arch/sparc/include/asm/topology_64.h

Signed-off-by: Ingo Molnar <mingo@kernel.org>
2015-06-02 08:05:42 +02:00
Ingo Molnar 8d12ded3dd Merge branch 'perf/urgent' into perf/core, before applying dependent patches
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2015-05-27 09:17:21 +02:00
Linus Torvalds 1c8df7bd48 Merge branch 'for-linus' of git://git.kernel.dk/linux-block
Pull block fixes from Jens Axboe:
 "Three small fixes that have been picked up the last few weeks.
  Specifically:

   - Fix a memory corruption issue in NVMe with malignant user
     constructed request.  From Christoph.

   - Kill (now) unused blk_queue_bio(), dm was changed to not need this
     anymore.  From Mike Snitzer.

   - Always use blk_schedule_flush_plug() from the io_schedule() path
     when flushing a plug, fixing a !TASK_RUNNING warning with md.  From
     Shaohua"

* 'for-linus' of git://git.kernel.dk/linux-block:
  sched: always use blk_schedule_flush_plug in io_schedule_out
  nvme: fix kernel memory corruption with short INQUIRY buffers
  block: remove export for blk_queue_bio
2015-05-22 15:15:30 -07:00
Thomas Gleixner c3b5d3cea5 Merge branch 'linus' into timers/core
Make sure the upstream fixes are applied before adding further
modifications.
2015-05-19 16:12:32 +02:00
Rik van Riel c1ceac6276 sched/numa: Reduce conflict between fbq_classify_rq() and migration
It is possible for fbq_classify_rq() to indicate that a CPU has tasks that
should be moved to another NUMA node, but for migrate_improves_locality
and migrate_degrades_locality to not identify those tasks.

This patch always gives preference to preferred node evaluations, and
only checks the number of faults when evaluating moves between two
non-preferred nodes on a larger NUMA system.

On a two node system, the number of faults is never evaluated. Either
a task is about to be pulled off its preferred node, or migrated onto
it.

Signed-off-by: Rik van Riel <riel@redhat.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: mgorman@suse.de
Link: http://lkml.kernel.org/r/20150514225936.35b91717@annuminas.surriel.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2015-05-19 08:39:19 +02:00