lkml.org 
[lkml]   [2018]   [Jun]   [7]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
    /
    From
    Subject[PATCH v9 0/7] Centralize and unify usage of preempt/irq
    Date
    From: "Joel Fernandes (Google)" <joel@joelfernandes.org>

    This is the next (hopefully close to final) revision of preempt/irq tracepoint
    centralization and unified usage across the kernel. This revision mostly has
    minor style corrections, reviewed-by tag additions and an improvement to the
    test module. All patches now have a Reviewed-by tag except for the kselftest
    script (patch 7/7). I have also now split out the softirq fix which really
    should go into an -rc cycle and is independent of this series (see [1]).

    The preempt/irq tracepoints exist but not everything in the kernel is using it
    whenever they need to be notified that a preempt disable/enable or an irq
    disable enable has occurred. This makes things not work simultaneously (for
    example, only either lockdep or irqsoff trace-events can be used at a time).

    This is particular painful to deal with, since turning on lockdep breaks
    tracers that install probes on IRQ events, such as the BCC atomic critical
    section tracer [2]. This constraint also makes it not possible to use synthetic
    events to trace irqsoff sections with lockdep simulataneously turned on.

    This series solves that, and also results in a nice clean up of relevant parts
    of the kernel. Several ifdefs are simpler, and the design is more unified and
    better. Also as a result of this, we also speeded performance all rcuidle
    tracepoints since their handling is simpler.

    [1] https://lkml.org/lkml/2018/6/7/1135
    [2] https://github.com/iovisor/bcc/pull/1801/

    v8->v9:
    - Small style changes to tracepoint code (Mathieu)
    - Minor style fix to use PTR_ERR_OR_ZERO (0-day bot)
    - Minor fix to test_atomic_sections to use unsigned long.
    - Added Namhyung's, Mathieu's Reviewed-by to some patches.

    v7->v8:
    - Refactored irqsoff tracer probe defines (Namhyung)

    v6->v7:
    - Added a module to simulate an atomic section, a kselftest to load and
    and trigger it which verifies the preempt-tracer and this series.

    - Fixed a new warning after I rebased in early boot, this is because
    early_boot_irqs_disabled was set too early, I moved it after the lockdep
    initialization.

    - added back the softirq fix since it appears it wasn't picked up.

    - Ran Ingo's locking API selftest suite which are passing with this
    series.

    - Mathieu suggested ifdef'ing the tracepoint_synchronize_unregister
    function incase tracepoints aren't enabled, did that.

    Joel Fernandes (Google) (6):
    srcu: Add notrace variant of srcu_dereference
    trace/irqsoff: Split reset into separate functions
    tracepoint: Make rcuidle tracepoint callers use SRCU
    tracing: Centralize preemptirq tracepoints and unify their usage
    lib: Add module to simulate atomic sections for testing preemptoff
    tracers
    kselftests: Add tests for the preemptoff and irqsoff tracers

    Paul McKenney (1):
    srcu: Add notrace variants of srcu_read_{lock,unlock}

    include/linux/ftrace.h | 11 +-
    include/linux/irqflags.h | 11 +-
    include/linux/lockdep.h | 8 +-
    include/linux/preempt.h | 2 +-
    include/linux/srcu.h | 22 ++
    include/linux/tracepoint.h | 49 +++-
    include/trace/events/preemptirq.h | 23 +-
    init/main.c | 5 +-
    kernel/locking/lockdep.c | 35 +--
    kernel/sched/core.c | 2 +-
    kernel/trace/Kconfig | 22 +-
    kernel/trace/Makefile | 2 +-
    kernel/trace/trace_irqsoff.c | 253 ++++++------------
    kernel/trace/trace_preemptirq.c | 71 +++++
    kernel/tracepoint.c | 16 +-
    lib/Kconfig.debug | 8 +
    lib/Makefile | 1 +
    lib/test_atomic_sections.c | 77 ++++++
    tools/testing/selftests/ftrace/config | 3 +
    .../test.d/preemptirq/irqsoff_tracer.tc | 74 +++++
    20 files changed, 454 insertions(+), 241 deletions(-)
    create mode 100644 kernel/trace/trace_preemptirq.c
    create mode 100644 lib/test_atomic_sections.c
    create mode 100644 tools/testing/selftests/ftrace/test.d/preemptirq/irqsoff_tracer.tc

    --
    2.17.1.1185.g55be947832-goog

    \
     
     \ /
      Last update: 2018-06-07 22:39    [W:2.158 / U:0.048 seconds]
    ©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site