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    Subject[PATCH v2 5/8] perf: Add pmu callbacks to track event mapping and unmapping
    Date
    Signed-off-by: Andy Lutomirski <luto@amacapital.net>
    ---
    include/linux/perf_event.h | 7 +++++++
    kernel/events/core.c | 9 +++++++++
    2 files changed, 16 insertions(+)

    diff --git a/include/linux/perf_event.h b/include/linux/perf_event.h
    index 893a0d07986f..c93aff25a459 100644
    --- a/include/linux/perf_event.h
    +++ b/include/linux/perf_event.h
    @@ -207,6 +207,13 @@ struct pmu {
    */
    int (*event_init) (struct perf_event *event);

    + /*
    + * Notification that the event was mapped or unmapped. Called
    + * in the context of the mapping task.
    + */
    + void (*event_mapped) (struct perf_event *event); /*optional*/
    + void (*event_unmapped) (struct perf_event *event); /*optional*/
    +
    #define PERF_EF_START 0x01 /* start the counter when adding */
    #define PERF_EF_RELOAD 0x02 /* reload the counter when starting */
    #define PERF_EF_UPDATE 0x04 /* update the counter when stopping */
    diff --git a/kernel/events/core.c b/kernel/events/core.c
    index 2b02c9fda790..3b1ec69d189f 100644
    --- a/kernel/events/core.c
    +++ b/kernel/events/core.c
    @@ -4139,6 +4139,9 @@ static void perf_mmap_open(struct vm_area_struct *vma)

    atomic_inc(&event->mmap_count);
    atomic_inc(&event->rb->mmap_count);
    +
    + if (event->pmu->event_mapped)
    + event->pmu->event_mapped(event);
    }

    /*
    @@ -4158,6 +4161,9 @@ static void perf_mmap_close(struct vm_area_struct *vma)
    int mmap_locked = rb->mmap_locked;
    unsigned long size = perf_data_size(rb);

    + if (event->pmu->event_unmapped)
    + event->pmu->event_unmapped(event);
    +
    atomic_dec(&rb->mmap_count);

    if (!atomic_dec_and_mutex_lock(&event->mmap_count, &event->mmap_mutex))
    @@ -4359,6 +4365,9 @@ unlock:
    vma->vm_flags |= VM_DONTCOPY | VM_DONTEXPAND | VM_DONTDUMP;
    vma->vm_ops = &perf_mmap_vmops;

    + if (event->pmu->event_mapped)
    + event->pmu->event_mapped(event);
    +
    return ret;
    }

    --
    1.9.3


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