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McKenney" To: linux-kernel@vger.kernel.org Cc: mingo@elte.hu, laijs@cn.fujitsu.com, dipankar@in.ibm.com, akpm@linux-foundation.org, mathieu.desnoyers@polymtl.ca, josh@joshtriplett.org, niv@us.ibm.com, tglx@linutronix.de, peterz@infradead.org, rostedt@goodmis.org, Valdis.Kletnieks@vt.edu, dhowells@redhat.com, edumazet@google.com, darren@dvhart.com, fweisbec@gmail.com, sbw@mit.edu, patches@linaro.org, "Paul E. McKenney" , "Paul E. McKenney" Subject: [PATCH tip/core/rcu 7/7] rcu: Instrument synchronize_rcu_expedited() for debugfs tracing Date: Tue, 30 Oct 2012 09:54:36 -0700 Message-Id: <1351616076-25617-7-git-send-email-paulmck@linux.vnet.ibm.com> X-Mailer: git-send-email 1.7.8 In-Reply-To: <1351616076-25617-1-git-send-email-paulmck@linux.vnet.ibm.com> References: <20121030165415.GA25438@linux.vnet.ibm.com> <1351616076-25617-1-git-send-email-paulmck@linux.vnet.ibm.com> X-Content-Scanned: Fidelis XPS MAILER x-cbid: 12103016-9360-0000-0000-00000C369320 X-Gm-Message-State: ALoCoQl3uIDwL8PkwrHwyYBGzMKFLVdw5MP75ArA0jZMzIaJ/s1coyeQWbAQHllxm30NFHQR0c1f From: "Paul E. McKenney" This commit adds the counters to rcu_state and updates them in synchronize_rcu_expedited() to provide the data needed for debugfs tracing. Signed-off-by: Paul E. McKenney Signed-off-by: Paul E. McKenney --- kernel/rcutree.c | 18 +++++++++++++++--- kernel/rcutree.h | 9 +++++++++ 2 files changed, 24 insertions(+), 3 deletions(-) diff --git a/kernel/rcutree.c b/kernel/rcutree.c index 3c72e5e..b966d56 100644 --- a/kernel/rcutree.c +++ b/kernel/rcutree.c @@ -2321,6 +2321,7 @@ void synchronize_sched_expedited(void) (ulong)atomic_long_read(&rsp->expedited_done) + ULONG_MAX / 8)) { synchronize_sched(); + atomic_long_inc(&rsp->expedited_wrap); return; } @@ -2341,11 +2342,14 @@ void synchronize_sched_expedited(void) synchronize_sched_expedited_cpu_stop, NULL) == -EAGAIN) { put_online_cpus(); + atomic_long_inc(&rsp->expedited_tryfail); /* Check to see if someone else did our work for us. */ s = atomic_long_read(&rsp->expedited_done); if (ULONG_CMP_GE((ulong)s, (ulong)firstsnap)) { - smp_mb(); /* ensure test happens before caller kfree */ + /* ensure test happens before caller kfree */ + smp_mb__before_atomic_inc(); /* ^^^ */ + atomic_long_inc(&rsp->expedited_workdone1); return; } @@ -2354,13 +2358,16 @@ void synchronize_sched_expedited(void) udelay(trycount * num_online_cpus()); } else { synchronize_sched(); + atomic_long_inc(&rsp->expedited_normal); return; } /* Recheck to see if someone else did our work for us. */ s = atomic_long_read(&rsp->expedited_done); if (ULONG_CMP_GE((ulong)s, (ulong)firstsnap)) { - smp_mb(); /* ensure test happens before caller kfree */ + /* ensure test happens before caller kfree */ + smp_mb__before_atomic_inc(); /* ^^^ */ + atomic_long_inc(&rsp->expedited_workdone2); return; } @@ -2375,6 +2382,7 @@ void synchronize_sched_expedited(void) snap = atomic_long_read(&rsp->expedited_start); smp_mb(); /* ensure read is before try_stop_cpus(). */ } + atomic_long_inc(&rsp->expedited_stoppedcpus); /* * Everyone up to our most recent fetch is covered by our grace @@ -2383,12 +2391,16 @@ void synchronize_sched_expedited(void) * than we did already did their update. */ do { + atomic_long_inc(&rsp->expedited_done_tries); s = atomic_long_read(&rsp->expedited_done); if (ULONG_CMP_GE((ulong)s, (ulong)snap)) { - smp_mb(); /* ensure test happens before caller kfree */ + /* ensure test happens before caller kfree */ + smp_mb__before_atomic_inc(); /* ^^^ */ + atomic_long_inc(&rsp->expedited_done_lost); break; } } while (atomic_long_cmpxchg(&rsp->expedited_done, s, snap) != s); + atomic_long_inc(&rsp->expedited_done_exit); put_online_cpus(); } diff --git a/kernel/rcutree.h b/kernel/rcutree.h index 88f3d9d..d274af3 100644 --- a/kernel/rcutree.h +++ b/kernel/rcutree.h @@ -406,6 +406,15 @@ struct rcu_state { atomic_long_t expedited_start; /* Starting ticket. */ atomic_long_t expedited_done; /* Done ticket. */ + atomic_long_t expedited_wrap; /* # near-wrap incidents. */ + atomic_long_t expedited_tryfail; /* # acquisition failures. */ + atomic_long_t expedited_workdone1; /* # done by others #1. */ + atomic_long_t expedited_workdone2; /* # done by others #2. */ + atomic_long_t expedited_normal; /* # fallbacks to normal. */ + atomic_long_t expedited_stoppedcpus; /* # successful stop_cpus. */ + atomic_long_t expedited_done_tries; /* # tries to update _done. */ + atomic_long_t expedited_done_lost; /* # times beaten to _done. */ + atomic_long_t expedited_done_exit; /* # times exited _done loop. */ unsigned long jiffies_force_qs; /* Time at which to invoke */ /* force_quiescent_state(). */