| Message ID | 20220704150514.48816-3-elver@google.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | perf/hw_breakpoint: Optimize for thousands of tasks | expand |
On Mon, 4 Jul 2022 at 17:06, Marco Elver <elver@google.com> wrote: > > Provide hw_breakpoint_is_used() to check if breakpoints are in use on > the system. > > Use it in the KUnit test to verify the global state before and after a > test case. > > Signed-off-by: Marco Elver <elver@google.com> Reviewed-by: Dmitry Vyukov <dvyukov@google.com> > --- > v3: > * New patch. > --- > include/linux/hw_breakpoint.h | 3 +++ > kernel/events/hw_breakpoint.c | 29 +++++++++++++++++++++++++++++ > kernel/events/hw_breakpoint_test.c | 12 +++++++++++- > 3 files changed, 43 insertions(+), 1 deletion(-) > > diff --git a/include/linux/hw_breakpoint.h b/include/linux/hw_breakpoint.h > index 78dd7035d1e5..a3fb846705eb 100644 > --- a/include/linux/hw_breakpoint.h > +++ b/include/linux/hw_breakpoint.h > @@ -74,6 +74,7 @@ register_wide_hw_breakpoint(struct perf_event_attr *attr, > extern int register_perf_hw_breakpoint(struct perf_event *bp); > extern void unregister_hw_breakpoint(struct perf_event *bp); > extern void unregister_wide_hw_breakpoint(struct perf_event * __percpu *cpu_events); > +extern bool hw_breakpoint_is_used(void); > > extern int dbg_reserve_bp_slot(struct perf_event *bp); > extern int dbg_release_bp_slot(struct perf_event *bp); > @@ -121,6 +122,8 @@ register_perf_hw_breakpoint(struct perf_event *bp) { return -ENOSYS; } > static inline void unregister_hw_breakpoint(struct perf_event *bp) { } > static inline void > unregister_wide_hw_breakpoint(struct perf_event * __percpu *cpu_events) { } > +static inline bool hw_breakpoint_is_used(void) { return false; } > + > static inline int > reserve_bp_slot(struct perf_event *bp) {return -ENOSYS; } > static inline void release_bp_slot(struct perf_event *bp) { } > diff --git a/kernel/events/hw_breakpoint.c b/kernel/events/hw_breakpoint.c > index f32320ac02fd..fd5cd1f9e7fc 100644 > --- a/kernel/events/hw_breakpoint.c > +++ b/kernel/events/hw_breakpoint.c > @@ -604,6 +604,35 @@ void unregister_wide_hw_breakpoint(struct perf_event * __percpu *cpu_events) > } > EXPORT_SYMBOL_GPL(unregister_wide_hw_breakpoint); > > +/** > + * hw_breakpoint_is_used - check if breakpoints are currently used > + * > + * Returns: true if breakpoints are used, false otherwise. > + */ > +bool hw_breakpoint_is_used(void) > +{ > + int cpu; > + > + if (!constraints_initialized) > + return false; > + > + for_each_possible_cpu(cpu) { > + for (int type = 0; type < TYPE_MAX; ++type) { > + struct bp_cpuinfo *info = get_bp_info(cpu, type); > + > + if (info->cpu_pinned) > + return true; > + > + for (int slot = 0; slot < nr_slots[type]; ++slot) { > + if (info->tsk_pinned[slot]) > + return true; > + } > + } > + } > + > + return false; > +} > + > static struct notifier_block hw_breakpoint_exceptions_nb = { > .notifier_call = hw_breakpoint_exceptions_notify, > /* we need to be notified first */ > diff --git a/kernel/events/hw_breakpoint_test.c b/kernel/events/hw_breakpoint_test.c > index 433c5c45e2a5..5ced822df788 100644 > --- a/kernel/events/hw_breakpoint_test.c > +++ b/kernel/events/hw_breakpoint_test.c > @@ -294,7 +294,14 @@ static struct kunit_case hw_breakpoint_test_cases[] = { > static int test_init(struct kunit *test) > { > /* Most test cases want 2 distinct CPUs. */ > - return num_online_cpus() < 2 ? -EINVAL : 0; > + if (num_online_cpus() < 2) > + return -EINVAL; > + > + /* Want the system to not use breakpoints elsewhere. */ > + if (hw_breakpoint_is_used()) > + return -EBUSY; > + > + return 0; > } > > static void test_exit(struct kunit *test) > @@ -308,6 +315,9 @@ static void test_exit(struct kunit *test) > kthread_stop(__other_task); > __other_task = NULL; > } > + > + /* Verify that internal state agrees that no breakpoints are in use. */ > + KUNIT_EXPECT_FALSE(test, hw_breakpoint_is_used()); > } > > static struct kunit_suite hw_breakpoint_test_suite = { > -- > 2.37.0.rc0.161.g10f37bed90-goog >
On Mon, Jul 4, 2022 at 8:10 AM Dmitry Vyukov <dvyukov@google.com> wrote: > > On Mon, 4 Jul 2022 at 17:06, Marco Elver <elver@google.com> wrote: > > > > Provide hw_breakpoint_is_used() to check if breakpoints are in use on > > the system. > > > > Use it in the KUnit test to verify the global state before and after a > > test case. > > > > Signed-off-by: Marco Elver <elver@google.com> > > Reviewed-by: Dmitry Vyukov <dvyukov@google.com> Acked-by: Ian Rogers <irogers@google.com> Thanks, Ian > > --- > > v3: > > * New patch. > > --- > > include/linux/hw_breakpoint.h | 3 +++ > > kernel/events/hw_breakpoint.c | 29 +++++++++++++++++++++++++++++ > > kernel/events/hw_breakpoint_test.c | 12 +++++++++++- > > 3 files changed, 43 insertions(+), 1 deletion(-) > > > > diff --git a/include/linux/hw_breakpoint.h b/include/linux/hw_breakpoint.h > > index 78dd7035d1e5..a3fb846705eb 100644 > > --- a/include/linux/hw_breakpoint.h > > +++ b/include/linux/hw_breakpoint.h > > @@ -74,6 +74,7 @@ register_wide_hw_breakpoint(struct perf_event_attr *attr, > > extern int register_perf_hw_breakpoint(struct perf_event *bp); > > extern void unregister_hw_breakpoint(struct perf_event *bp); > > extern void unregister_wide_hw_breakpoint(struct perf_event * __percpu *cpu_events); > > +extern bool hw_breakpoint_is_used(void); > > > > extern int dbg_reserve_bp_slot(struct perf_event *bp); > > extern int dbg_release_bp_slot(struct perf_event *bp); > > @@ -121,6 +122,8 @@ register_perf_hw_breakpoint(struct perf_event *bp) { return -ENOSYS; } > > static inline void unregister_hw_breakpoint(struct perf_event *bp) { } > > static inline void > > unregister_wide_hw_breakpoint(struct perf_event * __percpu *cpu_events) { } > > +static inline bool hw_breakpoint_is_used(void) { return false; } > > + > > static inline int > > reserve_bp_slot(struct perf_event *bp) {return -ENOSYS; } > > static inline void release_bp_slot(struct perf_event *bp) { } > > diff --git a/kernel/events/hw_breakpoint.c b/kernel/events/hw_breakpoint.c > > index f32320ac02fd..fd5cd1f9e7fc 100644 > > --- a/kernel/events/hw_breakpoint.c > > +++ b/kernel/events/hw_breakpoint.c > > @@ -604,6 +604,35 @@ void unregister_wide_hw_breakpoint(struct perf_event * __percpu *cpu_events) > > } > > EXPORT_SYMBOL_GPL(unregister_wide_hw_breakpoint); > > > > +/** > > + * hw_breakpoint_is_used - check if breakpoints are currently used > > + * > > + * Returns: true if breakpoints are used, false otherwise. > > + */ > > +bool hw_breakpoint_is_used(void) > > +{ > > + int cpu; > > + > > + if (!constraints_initialized) > > + return false; > > + > > + for_each_possible_cpu(cpu) { > > + for (int type = 0; type < TYPE_MAX; ++type) { > > + struct bp_cpuinfo *info = get_bp_info(cpu, type); > > + > > + if (info->cpu_pinned) > > + return true; > > + > > + for (int slot = 0; slot < nr_slots[type]; ++slot) { > > + if (info->tsk_pinned[slot]) > > + return true; > > + } > > + } > > + } > > + > > + return false; > > +} > > + > > static struct notifier_block hw_breakpoint_exceptions_nb = { > > .notifier_call = hw_breakpoint_exceptions_notify, > > /* we need to be notified first */ > > diff --git a/kernel/events/hw_breakpoint_test.c b/kernel/events/hw_breakpoint_test.c > > index 433c5c45e2a5..5ced822df788 100644 > > --- a/kernel/events/hw_breakpoint_test.c > > +++ b/kernel/events/hw_breakpoint_test.c > > @@ -294,7 +294,14 @@ static struct kunit_case hw_breakpoint_test_cases[] = { > > static int test_init(struct kunit *test) > > { > > /* Most test cases want 2 distinct CPUs. */ > > - return num_online_cpus() < 2 ? -EINVAL : 0; > > + if (num_online_cpus() < 2) > > + return -EINVAL; > > + > > + /* Want the system to not use breakpoints elsewhere. */ > > + if (hw_breakpoint_is_used()) > > + return -EBUSY; > > + > > + return 0; > > } > > > > static void test_exit(struct kunit *test) > > @@ -308,6 +315,9 @@ static void test_exit(struct kunit *test) > > kthread_stop(__other_task); > > __other_task = NULL; > > } > > + > > + /* Verify that internal state agrees that no breakpoints are in use. */ > > + KUNIT_EXPECT_FALSE(test, hw_breakpoint_is_used()); > > } > > > > static struct kunit_suite hw_breakpoint_test_suite = { > > -- > > 2.37.0.rc0.161.g10f37bed90-goog > >
diff --git a/include/linux/hw_breakpoint.h b/include/linux/hw_breakpoint.h index 78dd7035d1e5..a3fb846705eb 100644 --- a/include/linux/hw_breakpoint.h +++ b/include/linux/hw_breakpoint.h @@ -74,6 +74,7 @@ register_wide_hw_breakpoint(struct perf_event_attr *attr, extern int register_perf_hw_breakpoint(struct perf_event *bp); extern void unregister_hw_breakpoint(struct perf_event *bp); extern void unregister_wide_hw_breakpoint(struct perf_event * __percpu *cpu_events); +extern bool hw_breakpoint_is_used(void); extern int dbg_reserve_bp_slot(struct perf_event *bp); extern int dbg_release_bp_slot(struct perf_event *bp); @@ -121,6 +122,8 @@ register_perf_hw_breakpoint(struct perf_event *bp) { return -ENOSYS; } static inline void unregister_hw_breakpoint(struct perf_event *bp) { } static inline void unregister_wide_hw_breakpoint(struct perf_event * __percpu *cpu_events) { } +static inline bool hw_breakpoint_is_used(void) { return false; } + static inline int reserve_bp_slot(struct perf_event *bp) {return -ENOSYS; } static inline void release_bp_slot(struct perf_event *bp) { } diff --git a/kernel/events/hw_breakpoint.c b/kernel/events/hw_breakpoint.c index f32320ac02fd..fd5cd1f9e7fc 100644 --- a/kernel/events/hw_breakpoint.c +++ b/kernel/events/hw_breakpoint.c @@ -604,6 +604,35 @@ void unregister_wide_hw_breakpoint(struct perf_event * __percpu *cpu_events) } EXPORT_SYMBOL_GPL(unregister_wide_hw_breakpoint); +/** + * hw_breakpoint_is_used - check if breakpoints are currently used + * + * Returns: true if breakpoints are used, false otherwise. + */ +bool hw_breakpoint_is_used(void) +{ + int cpu; + + if (!constraints_initialized) + return false; + + for_each_possible_cpu(cpu) { + for (int type = 0; type < TYPE_MAX; ++type) { + struct bp_cpuinfo *info = get_bp_info(cpu, type); + + if (info->cpu_pinned) + return true; + + for (int slot = 0; slot < nr_slots[type]; ++slot) { + if (info->tsk_pinned[slot]) + return true; + } + } + } + + return false; +} + static struct notifier_block hw_breakpoint_exceptions_nb = { .notifier_call = hw_breakpoint_exceptions_notify, /* we need to be notified first */ diff --git a/kernel/events/hw_breakpoint_test.c b/kernel/events/hw_breakpoint_test.c index 433c5c45e2a5..5ced822df788 100644 --- a/kernel/events/hw_breakpoint_test.c +++ b/kernel/events/hw_breakpoint_test.c @@ -294,7 +294,14 @@ static struct kunit_case hw_breakpoint_test_cases[] = { static int test_init(struct kunit *test) { /* Most test cases want 2 distinct CPUs. */ - return num_online_cpus() < 2 ? -EINVAL : 0; + if (num_online_cpus() < 2) + return -EINVAL; + + /* Want the system to not use breakpoints elsewhere. */ + if (hw_breakpoint_is_used()) + return -EBUSY; + + return 0; } static void test_exit(struct kunit *test) @@ -308,6 +315,9 @@ static void test_exit(struct kunit *test) kthread_stop(__other_task); __other_task = NULL; } + + /* Verify that internal state agrees that no breakpoints are in use. */ + KUNIT_EXPECT_FALSE(test, hw_breakpoint_is_used()); } static struct kunit_suite hw_breakpoint_test_suite = {
Provide hw_breakpoint_is_used() to check if breakpoints are in use on the system. Use it in the KUnit test to verify the global state before and after a test case. Signed-off-by: Marco Elver <elver@google.com> --- v3: * New patch. --- include/linux/hw_breakpoint.h | 3 +++ kernel/events/hw_breakpoint.c | 29 +++++++++++++++++++++++++++++ kernel/events/hw_breakpoint_test.c | 12 +++++++++++- 3 files changed, 43 insertions(+), 1 deletion(-)