From: Marco Elver <elver@google.com> To: elver@google.com, Peter Zijlstra <peterz@infradead.org>, Frederic Weisbecker <frederic@kernel.org>, Ingo Molnar <mingo@kernel.org> Cc: Thomas Gleixner <tglx@linutronix.de>, Arnaldo Carvalho de Melo <acme@kernel.org>, Mark Rutland <mark.rutland@arm.com>, Alexander Shishkin <alexander.shishkin@linux.intel.com>, Jiri Olsa <jolsa@redhat.com>, Namhyung Kim <namhyung@kernel.org>, Dmitry Vyukov <dvyukov@google.com>, Michael Ellerman <mpe@ellerman.id.au>, linuxppc-dev@lists.ozlabs.org, linux-perf-users@vger.kernel.org, x86@kernel.org, linux-sh@vger.kernel.org, kasan-dev@googlegroups.com, linux-kernel@vger.kernel.org Subject: [PATCH v2 09/13] locking/percpu-rwsem: Add percpu_is_write_locked() and percpu_is_read_locked() Date: Tue, 28 Jun 2022 11:58:29 +0200 [thread overview] Message-ID: <20220628095833.2579903-10-elver@google.com> (raw) In-Reply-To: <20220628095833.2579903-1-elver@google.com> Implement simple accessors to probe percpu-rwsem's locked state: percpu_is_write_locked(), percpu_is_read_locked(). Signed-off-by: Marco Elver <elver@google.com> --- v2: * New patch. --- include/linux/percpu-rwsem.h | 6 ++++++ kernel/locking/percpu-rwsem.c | 6 ++++++ 2 files changed, 12 insertions(+) diff --git a/include/linux/percpu-rwsem.h b/include/linux/percpu-rwsem.h index 5fda40f97fe9..36b942b67b7d 100644 --- a/include/linux/percpu-rwsem.h +++ b/include/linux/percpu-rwsem.h @@ -121,9 +121,15 @@ static inline void percpu_up_read(struct percpu_rw_semaphore *sem) preempt_enable(); } +extern bool percpu_is_read_locked(struct percpu_rw_semaphore *); extern void percpu_down_write(struct percpu_rw_semaphore *); extern void percpu_up_write(struct percpu_rw_semaphore *); +static inline bool percpu_is_write_locked(struct percpu_rw_semaphore *sem) +{ + return atomic_read(&sem->block); +} + extern int __percpu_init_rwsem(struct percpu_rw_semaphore *, const char *, struct lock_class_key *); diff --git a/kernel/locking/percpu-rwsem.c b/kernel/locking/percpu-rwsem.c index 5fe4c5495ba3..213d114fb025 100644 --- a/kernel/locking/percpu-rwsem.c +++ b/kernel/locking/percpu-rwsem.c @@ -192,6 +192,12 @@ EXPORT_SYMBOL_GPL(__percpu_down_read); __sum; \ }) +bool percpu_is_read_locked(struct percpu_rw_semaphore *sem) +{ + return per_cpu_sum(*sem->read_count) != 0; +} +EXPORT_SYMBOL_GPL(percpu_is_read_locked); + /* * Return true if the modular sum of the sem->read_count per-CPU variable is * zero. If this sum is zero, then it is stable due to the fact that if any -- 2.37.0.rc0.161.g10f37bed90-goog
WARNING: multiple messages have this Message-ID (diff)
From: Marco Elver <elver@google.com> To: elver@google.com, Peter Zijlstra <peterz@infradead.org>, Frederic Weisbecker <frederic@kernel.org>, Ingo Molnar <mingo@kernel.org> Cc: Mark Rutland <mark.rutland@arm.com>, linux-sh@vger.kernel.org, Alexander Shishkin <alexander.shishkin@linux.intel.com>, x86@kernel.org, linuxppc-dev@lists.ozlabs.org, Arnaldo Carvalho de Melo <acme@kernel.org>, linux-kernel@vger.kernel.org, linux-perf-users@vger.kernel.org, kasan-dev@googlegroups.com, Namhyung Kim <namhyung@kernel.org>, Thomas Gleixner <tglx@linutronix.de>, Jiri Olsa <jolsa@redhat.com>, Dmitry Vyukov <dvyukov@google.com> Subject: [PATCH v2 09/13] locking/percpu-rwsem: Add percpu_is_write_locked() and percpu_is_read_locked() Date: Tue, 28 Jun 2022 11:58:29 +0200 [thread overview] Message-ID: <20220628095833.2579903-10-elver@google.com> (raw) In-Reply-To: <20220628095833.2579903-1-elver@google.com> Implement simple accessors to probe percpu-rwsem's locked state: percpu_is_write_locked(), percpu_is_read_locked(). Signed-off-by: Marco Elver <elver@google.com> --- v2: * New patch. --- include/linux/percpu-rwsem.h | 6 ++++++ kernel/locking/percpu-rwsem.c | 6 ++++++ 2 files changed, 12 insertions(+) diff --git a/include/linux/percpu-rwsem.h b/include/linux/percpu-rwsem.h index 5fda40f97fe9..36b942b67b7d 100644 --- a/include/linux/percpu-rwsem.h +++ b/include/linux/percpu-rwsem.h @@ -121,9 +121,15 @@ static inline void percpu_up_read(struct percpu_rw_semaphore *sem) preempt_enable(); } +extern bool percpu_is_read_locked(struct percpu_rw_semaphore *); extern void percpu_down_write(struct percpu_rw_semaphore *); extern void percpu_up_write(struct percpu_rw_semaphore *); +static inline bool percpu_is_write_locked(struct percpu_rw_semaphore *sem) +{ + return atomic_read(&sem->block); +} + extern int __percpu_init_rwsem(struct percpu_rw_semaphore *, const char *, struct lock_class_key *); diff --git a/kernel/locking/percpu-rwsem.c b/kernel/locking/percpu-rwsem.c index 5fe4c5495ba3..213d114fb025 100644 --- a/kernel/locking/percpu-rwsem.c +++ b/kernel/locking/percpu-rwsem.c @@ -192,6 +192,12 @@ EXPORT_SYMBOL_GPL(__percpu_down_read); __sum; \ }) +bool percpu_is_read_locked(struct percpu_rw_semaphore *sem) +{ + return per_cpu_sum(*sem->read_count) != 0; +} +EXPORT_SYMBOL_GPL(percpu_is_read_locked); + /* * Return true if the modular sum of the sem->read_count per-CPU variable is * zero. If this sum is zero, then it is stable due to the fact that if any -- 2.37.0.rc0.161.g10f37bed90-goog
next prev parent reply other threads:[~2022-06-28 10:00 UTC|newest] Thread overview: 64+ messages / expand[flat|nested] mbox.gz Atom feed top 2022-06-28 9:58 [PATCH v2 00/13] perf/hw_breakpoint: Optimize for thousands of tasks Marco Elver 2022-06-28 9:58 ` Marco Elver 2022-06-28 9:58 ` [PATCH v2 01/13] perf/hw_breakpoint: Add KUnit test for constraints accounting Marco Elver 2022-06-28 9:58 ` Marco Elver 2022-06-28 12:53 ` Dmitry Vyukov 2022-06-28 12:53 ` Dmitry Vyukov 2022-06-28 13:26 ` Marco Elver 2022-06-28 13:26 ` Marco Elver 2022-06-28 9:58 ` [PATCH v2 02/13] perf/hw_breakpoint: Clean up headers Marco Elver 2022-06-28 9:58 ` Marco Elver 2022-06-28 9:58 ` [PATCH v2 03/13] perf/hw_breakpoint: Optimize list of per-task breakpoints Marco Elver 2022-06-28 9:58 ` Marco Elver 2022-06-28 13:08 ` Dmitry Vyukov 2022-06-28 13:08 ` Dmitry Vyukov 2022-06-28 14:53 ` Marco Elver 2022-06-28 14:53 ` Marco Elver 2022-06-28 15:27 ` Dmitry Vyukov 2022-06-28 15:27 ` Dmitry Vyukov 2022-06-28 9:58 ` [PATCH v2 04/13] perf/hw_breakpoint: Mark data __ro_after_init Marco Elver 2022-06-28 9:58 ` Marco Elver 2022-06-28 9:58 ` [PATCH v2 05/13] perf/hw_breakpoint: Optimize constant number of breakpoint slots Marco Elver 2022-06-28 9:58 ` Marco Elver 2022-06-28 9:58 ` [PATCH v2 06/13] perf/hw_breakpoint: Make hw_breakpoint_weight() inlinable Marco Elver 2022-06-28 9:58 ` Marco Elver 2022-06-28 13:16 ` Dmitry Vyukov 2022-06-28 13:16 ` Dmitry Vyukov 2022-06-28 9:58 ` [PATCH v2 07/13] perf/hw_breakpoint: Remove useless code related to flexible breakpoints Marco Elver 2022-06-28 9:58 ` Marco Elver 2022-06-28 13:18 ` Dmitry Vyukov 2022-06-28 13:18 ` Dmitry Vyukov 2022-06-28 9:58 ` [PATCH v2 08/13] powerpc/hw_breakpoint: Avoid relying on caller synchronization Marco Elver 2022-06-28 9:58 ` Marco Elver 2022-06-28 13:21 ` Dmitry Vyukov 2022-06-28 13:21 ` Dmitry Vyukov 2022-07-01 8:54 ` Christophe Leroy 2022-07-01 8:54 ` Christophe Leroy 2022-07-01 9:41 ` Marco Elver 2022-07-01 9:41 ` Marco Elver 2022-07-01 10:15 ` Christophe Leroy 2022-07-01 10:15 ` Christophe Leroy 2022-06-28 9:58 ` Marco Elver [this message] 2022-06-28 9:58 ` [PATCH v2 09/13] locking/percpu-rwsem: Add percpu_is_write_locked() and percpu_is_read_locked() Marco Elver 2022-06-28 14:44 ` Dmitry Vyukov 2022-06-28 14:44 ` Dmitry Vyukov 2022-06-28 9:58 ` [PATCH v2 10/13] perf/hw_breakpoint: Reduce contention with large number of tasks Marco Elver 2022-06-28 9:58 ` Marco Elver 2022-06-28 14:45 ` Dmitry Vyukov 2022-06-28 14:45 ` Dmitry Vyukov 2022-06-28 9:58 ` [PATCH v2 11/13] perf/hw_breakpoint: Introduce bp_slots_histogram Marco Elver 2022-06-28 9:58 ` Marco Elver 2022-06-28 14:52 ` Dmitry Vyukov 2022-06-28 14:52 ` Dmitry Vyukov 2022-06-28 9:58 ` [PATCH v2 12/13] perf/hw_breakpoint: Optimize max_bp_pinned_slots() for CPU-independent task targets Marco Elver 2022-06-28 9:58 ` Marco Elver 2022-06-28 15:41 ` Dmitry Vyukov 2022-06-28 15:41 ` Dmitry Vyukov 2022-06-28 9:58 ` [PATCH v2 13/13] perf/hw_breakpoint: Optimize toggle_bp_slot() " Marco Elver 2022-06-28 9:58 ` Marco Elver 2022-06-28 10:54 ` Marco Elver 2022-06-28 10:54 ` Marco Elver 2022-06-28 15:45 ` Dmitry Vyukov 2022-06-28 15:45 ` Dmitry Vyukov 2022-06-28 16:00 ` Marco Elver 2022-06-28 16:00 ` Marco Elver
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