From fd55a281adf6c9b9723d369203fdd92e5ea62a09 Mon Sep 17 00:00:00 2001 From: "Paul E. McKenney" Date: Fri, 27 Apr 2018 10:06:03 -0700 Subject: srcu: Introduce srcu_read_{un,}lock_notrace() Joel Fernandes is using SRCU to protect from-idle tracepoints, which requires notrace variants of srcu_read_lock() and srcu_read_unlock() in order to avoid problems with tracepoints in lockdep. This commit therefore adds srcu_read_lock_notrace() and srcu_read_unlock_notrace(). [1] http://lkml.kernel.org/r/20180427042656.190746-1-joelaf@google.com Reported-by: Joel Fernandes Intermittently-reported-by: Steven Rostedt Signed-off-by: Paul E. McKenney --- include/linux/srcu.h | 17 +++++++++++++++++ 1 file changed, 17 insertions(+) (limited to 'include') diff --git a/include/linux/srcu.h b/include/linux/srcu.h index 91494d7e8e41..3e72a291c401 100644 --- a/include/linux/srcu.h +++ b/include/linux/srcu.h @@ -195,6 +195,16 @@ static inline int srcu_read_lock(struct srcu_struct *sp) __acquires(sp) return retval; } +/* Used by tracing, cannot be traced and cannot invoke lockdep. */ +static inline notrace int +srcu_read_lock_notrace(struct srcu_struct *sp) __acquires(sp) +{ + int retval; + + retval = __srcu_read_lock(sp); + return retval; +} + /** * srcu_read_unlock - unregister a old reader from an SRCU-protected structure. * @sp: srcu_struct in which to unregister the old reader. @@ -209,6 +219,13 @@ static inline void srcu_read_unlock(struct srcu_struct *sp, int idx) __srcu_read_unlock(sp, idx); } +/* Used by tracing, cannot be traced and cannot call lockdep. */ +static inline notrace void +srcu_read_unlock_notrace(struct srcu_struct *sp, int idx) __releases(sp) +{ + __srcu_read_unlock(sp, idx); +} + /** * smp_mb__after_srcu_read_unlock - ensure full ordering after srcu_read_unlock * -- cgit v1.2.3 From 90127d605f403d814f4986436871210bf8ceb335 Mon Sep 17 00:00:00 2001 From: "Paul E. McKenney" Date: Wed, 9 May 2018 10:29:18 -0700 Subject: torture: Make online/offline messages appear only for verbose=2 Some bugs reproduce quickly only at high CPU-hotplug rates, so the rcutorture TREE03 scenario now has only 200 milliseconds spacing between CPU-hotplug operations. At this rate, the torture-test pair of console messages per operation becomes a bit voluminous. This commit therefore converts the torture-test set of "verbose" kernel-boot arguments from bool to int, and prints the extra console messages only when verbose=2. The default is still verbose=1. Signed-off-by: Paul E. McKenney --- include/linux/torture.h | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'include') diff --git a/include/linux/torture.h b/include/linux/torture.h index 66272862070b..a55e80817dae 100644 --- a/include/linux/torture.h +++ b/include/linux/torture.h @@ -79,7 +79,7 @@ void stutter_wait(const char *title); int torture_stutter_init(int s); /* Initialization and cleanup. */ -bool torture_init_begin(char *ttype, bool v); +bool torture_init_begin(char *ttype, int v); void torture_init_end(void); bool torture_cleanup_begin(void); void torture_cleanup_end(void); -- cgit v1.2.3 From 477351f7829d2268769c5d545511081555066529 Mon Sep 17 00:00:00 2001 From: "Paul E. McKenney" Date: Tue, 1 May 2018 12:54:11 -0700 Subject: rcu: Convert rcu_grace_period tracepoint to gp_seq This commit makes the rcu_grace_period tracepoint use gp_seq instead of ->gpnum or ->completed. It also introduces a "cpuofl-bgp" string to less obscurely indicate when a CPU has gone offline while a grace period is waiting on it. Signed-off-by: Paul E. McKenney --- include/trace/events/rcu.h | 13 +++++++------ 1 file changed, 7 insertions(+), 6 deletions(-) (limited to 'include') diff --git a/include/trace/events/rcu.h b/include/trace/events/rcu.h index 5936aac357ab..cd229e82ec8b 100644 --- a/include/trace/events/rcu.h +++ b/include/trace/events/rcu.h @@ -52,6 +52,7 @@ TRACE_EVENT(rcu_utilization, * "cpuqs": CPU passes through a quiescent state. * "cpuonl": CPU comes online. * "cpuofl": CPU goes offline. + * "cpuofl-bgp": CPU goes offline while blocking a grace period. * "reqwait": GP kthread sleeps waiting for grace-period request. * "reqwaitsig": GP kthread awakened by signal from reqwait state. * "fqswait": GP kthread waiting until time to force quiescent states. @@ -63,24 +64,24 @@ TRACE_EVENT(rcu_utilization, */ TRACE_EVENT(rcu_grace_period, - TP_PROTO(const char *rcuname, unsigned long gpnum, const char *gpevent), + TP_PROTO(const char *rcuname, unsigned long gp_seq, const char *gpevent), - TP_ARGS(rcuname, gpnum, gpevent), + TP_ARGS(rcuname, gp_seq, gpevent), TP_STRUCT__entry( __field(const char *, rcuname) - __field(unsigned long, gpnum) + __field(unsigned long, gp_seq) __field(const char *, gpevent) ), TP_fast_assign( __entry->rcuname = rcuname; - __entry->gpnum = gpnum; + __entry->gp_seq = gp_seq; __entry->gpevent = gpevent; ), TP_printk("%s %lu %s", - __entry->rcuname, __entry->gpnum, __entry->gpevent) + __entry->rcuname, __entry->gp_seq, __entry->gpevent) ); /* @@ -753,7 +754,7 @@ TRACE_EVENT(rcu_barrier, #else /* #ifdef CONFIG_RCU_TRACE */ -#define trace_rcu_grace_period(rcuname, gpnum, gpevent) do { } while (0) +#define trace_rcu_grace_period(rcuname, gp_seq, gpevent) do { } while (0) #define trace_rcu_future_grace_period(rcuname, gpnum, completed, c, \ level, grplo, grphi, event) \ do { } while (0) -- cgit v1.2.3 From abd13fdd9516e5baae2257721b921684ecb090d3 Mon Sep 17 00:00:00 2001 From: "Paul E. McKenney" Date: Tue, 1 May 2018 13:08:46 -0700 Subject: rcu: Convert rcu_future_grace_period tracepoint to gp_seq This commit makes the rcu_future_grace_period tracepoint use gp_seq instead of ->gpnum and ->completed. Signed-off-by: Paul E. McKenney --- include/trace/events/rcu.h | 22 +++++++++------------- 1 file changed, 9 insertions(+), 13 deletions(-) (limited to 'include') diff --git a/include/trace/events/rcu.h b/include/trace/events/rcu.h index cd229e82ec8b..286047d22314 100644 --- a/include/trace/events/rcu.h +++ b/include/trace/events/rcu.h @@ -103,16 +103,14 @@ TRACE_EVENT(rcu_grace_period, */ TRACE_EVENT(rcu_future_grace_period, - TP_PROTO(const char *rcuname, unsigned long gpnum, unsigned long completed, - unsigned long c, u8 level, int grplo, int grphi, - const char *gpevent), + TP_PROTO(const char *rcuname, unsigned long gp_seq, unsigned long c, + u8 level, int grplo, int grphi, const char *gpevent), - TP_ARGS(rcuname, gpnum, completed, c, level, grplo, grphi, gpevent), + TP_ARGS(rcuname, gp_seq, c, level, grplo, grphi, gpevent), TP_STRUCT__entry( __field(const char *, rcuname) - __field(unsigned long, gpnum) - __field(unsigned long, completed) + __field(unsigned long, gp_seq) __field(unsigned long, c) __field(u8, level) __field(int, grplo) @@ -122,8 +120,7 @@ TRACE_EVENT(rcu_future_grace_period, TP_fast_assign( __entry->rcuname = rcuname; - __entry->gpnum = gpnum; - __entry->completed = completed; + __entry->gp_seq = gp_seq; __entry->c = c; __entry->level = level; __entry->grplo = grplo; @@ -131,10 +128,9 @@ TRACE_EVENT(rcu_future_grace_period, __entry->gpevent = gpevent; ), - TP_printk("%s %lu %lu %lu %u %d %d %s", - __entry->rcuname, __entry->gpnum, __entry->completed, - __entry->c, __entry->level, __entry->grplo, __entry->grphi, - __entry->gpevent) + TP_printk("%s %lu %lu %u %d %d %s", + __entry->rcuname, __entry->gp_seq, __entry->c, __entry->level, + __entry->grplo, __entry->grphi, __entry->gpevent) ); /* @@ -755,7 +751,7 @@ TRACE_EVENT(rcu_barrier, #else /* #ifdef CONFIG_RCU_TRACE */ #define trace_rcu_grace_period(rcuname, gp_seq, gpevent) do { } while (0) -#define trace_rcu_future_grace_period(rcuname, gpnum, completed, c, \ +#define trace_rcu_future_grace_period(rcuname, gp_seq, c, \ level, grplo, grphi, event) \ do { } while (0) #define trace_rcu_grace_period_init(rcuname, gpnum, level, grplo, grphi, \ -- cgit v1.2.3 From 63d86a7e85f84b8ac3b2f394570965aedbb03787 Mon Sep 17 00:00:00 2001 From: "Paul E. McKenney" Date: Tue, 1 May 2018 13:08:46 -0700 Subject: rcu: Convert rcu_grace_period_init tracepoint to gp_seq This commit makes the rcu_grace_period_init tracepoint use gp_seq instead of ->gpnum. Signed-off-by: Paul E. McKenney --- include/trace/events/rcu.h | 12 ++++++------ 1 file changed, 6 insertions(+), 6 deletions(-) (limited to 'include') diff --git a/include/trace/events/rcu.h b/include/trace/events/rcu.h index 286047d22314..892016ad0647 100644 --- a/include/trace/events/rcu.h +++ b/include/trace/events/rcu.h @@ -142,14 +142,14 @@ TRACE_EVENT(rcu_future_grace_period, */ TRACE_EVENT(rcu_grace_period_init, - TP_PROTO(const char *rcuname, unsigned long gpnum, u8 level, + TP_PROTO(const char *rcuname, unsigned long gp_seq, u8 level, int grplo, int grphi, unsigned long qsmask), - TP_ARGS(rcuname, gpnum, level, grplo, grphi, qsmask), + TP_ARGS(rcuname, gp_seq, level, grplo, grphi, qsmask), TP_STRUCT__entry( __field(const char *, rcuname) - __field(unsigned long, gpnum) + __field(unsigned long, gp_seq) __field(u8, level) __field(int, grplo) __field(int, grphi) @@ -158,7 +158,7 @@ TRACE_EVENT(rcu_grace_period_init, TP_fast_assign( __entry->rcuname = rcuname; - __entry->gpnum = gpnum; + __entry->gp_seq = gp_seq; __entry->level = level; __entry->grplo = grplo; __entry->grphi = grphi; @@ -166,7 +166,7 @@ TRACE_EVENT(rcu_grace_period_init, ), TP_printk("%s %lu %u %d %d %lx", - __entry->rcuname, __entry->gpnum, __entry->level, + __entry->rcuname, __entry->gp_seq, __entry->level, __entry->grplo, __entry->grphi, __entry->qsmask) ); @@ -754,7 +754,7 @@ TRACE_EVENT(rcu_barrier, #define trace_rcu_future_grace_period(rcuname, gp_seq, c, \ level, grplo, grphi, event) \ do { } while (0) -#define trace_rcu_grace_period_init(rcuname, gpnum, level, grplo, grphi, \ +#define trace_rcu_grace_period_init(rcuname, gp_seq, level, grplo, grphi, \ qsmask) do { } while (0) #define trace_rcu_exp_grace_period(rcuname, gqseq, gpevent) \ do { } while (0) -- cgit v1.2.3 From 598ce09480efb6b48799df60c66bac70bea5ef54 Mon Sep 17 00:00:00 2001 From: "Paul E. McKenney" Date: Tue, 1 May 2018 13:35:20 -0700 Subject: rcu: Convert rcu_preempt_task tracepoint to ->gp_seq This commit makes the rcu_preempt_task tracepoint use ->gp_seq instead of ->gpnum. Signed-off-by: Paul E. McKenney --- include/trace/events/rcu.h | 12 ++++++------ 1 file changed, 6 insertions(+), 6 deletions(-) (limited to 'include') diff --git a/include/trace/events/rcu.h b/include/trace/events/rcu.h index 892016ad0647..38dbd97d65a3 100644 --- a/include/trace/events/rcu.h +++ b/include/trace/events/rcu.h @@ -298,24 +298,24 @@ TRACE_EVENT(rcu_nocb_wake, */ TRACE_EVENT(rcu_preempt_task, - TP_PROTO(const char *rcuname, int pid, unsigned long gpnum), + TP_PROTO(const char *rcuname, int pid, unsigned long gp_seq), - TP_ARGS(rcuname, pid, gpnum), + TP_ARGS(rcuname, pid, gp_seq), TP_STRUCT__entry( __field(const char *, rcuname) - __field(unsigned long, gpnum) + __field(unsigned long, gp_seq) __field(int, pid) ), TP_fast_assign( __entry->rcuname = rcuname; - __entry->gpnum = gpnum; + __entry->gp_seq = gp_seq; __entry->pid = pid; ), TP_printk("%s %lu %d", - __entry->rcuname, __entry->gpnum, __entry->pid) + __entry->rcuname, __entry->gp_seq, __entry->pid) ); /* @@ -761,7 +761,7 @@ TRACE_EVENT(rcu_barrier, #define trace_rcu_exp_funnel_lock(rcuname, level, grplo, grphi, gpevent) \ do { } while (0) #define trace_rcu_nocb_wake(rcuname, cpu, reason) do { } while (0) -#define trace_rcu_preempt_task(rcuname, pid, gpnum) do { } while (0) +#define trace_rcu_preempt_task(rcuname, pid, gp_seq) do { } while (0) #define trace_rcu_unlock_preempted_task(rcuname, gpnum, pid) do { } while (0) #define trace_rcu_quiescent_state_report(rcuname, gpnum, mask, qsmask, level, \ grplo, grphi, gp_tasks) do { } \ -- cgit v1.2.3 From 865aa1e08d8aefdfd1f5d30ecfce1b8ef8cd520a Mon Sep 17 00:00:00 2001 From: "Paul E. McKenney" Date: Tue, 1 May 2018 13:35:20 -0700 Subject: rcu: Convert rcu_unlock_preempted_task tracepoint to ->gp_seq This commit makes the rcu_unlock_preempted_task tracepoint use ->gp_seq instead of ->gpnum. Signed-off-by: Paul E. McKenney --- include/trace/events/rcu.h | 12 ++++++------ 1 file changed, 6 insertions(+), 6 deletions(-) (limited to 'include') diff --git a/include/trace/events/rcu.h b/include/trace/events/rcu.h index 38dbd97d65a3..95b7491196aa 100644 --- a/include/trace/events/rcu.h +++ b/include/trace/events/rcu.h @@ -325,23 +325,23 @@ TRACE_EVENT(rcu_preempt_task, */ TRACE_EVENT(rcu_unlock_preempted_task, - TP_PROTO(const char *rcuname, unsigned long gpnum, int pid), + TP_PROTO(const char *rcuname, unsigned long gp_seq, int pid), - TP_ARGS(rcuname, gpnum, pid), + TP_ARGS(rcuname, gp_seq, pid), TP_STRUCT__entry( __field(const char *, rcuname) - __field(unsigned long, gpnum) + __field(unsigned long, gp_seq) __field(int, pid) ), TP_fast_assign( __entry->rcuname = rcuname; - __entry->gpnum = gpnum; + __entry->gp_seq = gp_seq; __entry->pid = pid; ), - TP_printk("%s %lu %d", __entry->rcuname, __entry->gpnum, __entry->pid) + TP_printk("%s %lu %d", __entry->rcuname, __entry->gp_seq, __entry->pid) ); /* @@ -762,7 +762,7 @@ TRACE_EVENT(rcu_barrier, do { } while (0) #define trace_rcu_nocb_wake(rcuname, cpu, reason) do { } while (0) #define trace_rcu_preempt_task(rcuname, pid, gp_seq) do { } while (0) -#define trace_rcu_unlock_preempted_task(rcuname, gpnum, pid) do { } while (0) +#define trace_rcu_unlock_preempted_task(rcuname, gp_seq, pid) do { } while (0) #define trace_rcu_quiescent_state_report(rcuname, gpnum, mask, qsmask, level, \ grplo, grphi, gp_tasks) do { } \ while (0) -- cgit v1.2.3 From db023296f0115d2fe01fdabad54678f2b806da23 Mon Sep 17 00:00:00 2001 From: "Paul E. McKenney" Date: Tue, 1 May 2018 13:35:20 -0700 Subject: rcu: Convert rcu_quiescent_state_report tracepoint to ->gp_seq This commit makes the rcu_quiescent_state_report tracepoint use ->gp_seq instead of ->gpnum. Signed-off-by: Paul E. McKenney --- include/trace/events/rcu.h | 12 ++++++------ 1 file changed, 6 insertions(+), 6 deletions(-) (limited to 'include') diff --git a/include/trace/events/rcu.h b/include/trace/events/rcu.h index 95b7491196aa..ac4d9d4a1ebf 100644 --- a/include/trace/events/rcu.h +++ b/include/trace/events/rcu.h @@ -354,15 +354,15 @@ TRACE_EVENT(rcu_unlock_preempted_task, */ TRACE_EVENT(rcu_quiescent_state_report, - TP_PROTO(const char *rcuname, unsigned long gpnum, + TP_PROTO(const char *rcuname, unsigned long gp_seq, unsigned long mask, unsigned long qsmask, u8 level, int grplo, int grphi, int gp_tasks), - TP_ARGS(rcuname, gpnum, mask, qsmask, level, grplo, grphi, gp_tasks), + TP_ARGS(rcuname, gp_seq, mask, qsmask, level, grplo, grphi, gp_tasks), TP_STRUCT__entry( __field(const char *, rcuname) - __field(unsigned long, gpnum) + __field(unsigned long, gp_seq) __field(unsigned long, mask) __field(unsigned long, qsmask) __field(u8, level) @@ -373,7 +373,7 @@ TRACE_EVENT(rcu_quiescent_state_report, TP_fast_assign( __entry->rcuname = rcuname; - __entry->gpnum = gpnum; + __entry->gp_seq = gp_seq; __entry->mask = mask; __entry->qsmask = qsmask; __entry->level = level; @@ -383,7 +383,7 @@ TRACE_EVENT(rcu_quiescent_state_report, ), TP_printk("%s %lu %lx>%lx %u %d %d %u", - __entry->rcuname, __entry->gpnum, + __entry->rcuname, __entry->gp_seq, __entry->mask, __entry->qsmask, __entry->level, __entry->grplo, __entry->grphi, __entry->gp_tasks) ); @@ -763,7 +763,7 @@ TRACE_EVENT(rcu_barrier, #define trace_rcu_nocb_wake(rcuname, cpu, reason) do { } while (0) #define trace_rcu_preempt_task(rcuname, pid, gp_seq) do { } while (0) #define trace_rcu_unlock_preempted_task(rcuname, gp_seq, pid) do { } while (0) -#define trace_rcu_quiescent_state_report(rcuname, gpnum, mask, qsmask, level, \ +#define trace_rcu_quiescent_state_report(rcuname, gp_seq, mask, qsmask, level, \ grplo, grphi, gp_tasks) do { } \ while (0) #define trace_rcu_fqs(rcuname, gpnum, cpu, qsevent) do { } while (0) -- cgit v1.2.3 From fee5997c17562e95fb1fecc142efb2da0934baa4 Mon Sep 17 00:00:00 2001 From: "Paul E. McKenney" Date: Tue, 1 May 2018 13:35:20 -0700 Subject: rcu: Convert rcu_fqs tracepoint to ->gp_seq This commit makes the rcu_fqs tracepoint use ->gp_seq instead of ->gpnum. Signed-off-by: Paul E. McKenney --- include/trace/events/rcu.h | 12 ++++++------ 1 file changed, 6 insertions(+), 6 deletions(-) (limited to 'include') diff --git a/include/trace/events/rcu.h b/include/trace/events/rcu.h index ac4d9d4a1ebf..7d3650cc9d30 100644 --- a/include/trace/events/rcu.h +++ b/include/trace/events/rcu.h @@ -398,26 +398,26 @@ TRACE_EVENT(rcu_quiescent_state_report, */ TRACE_EVENT(rcu_fqs, - TP_PROTO(const char *rcuname, unsigned long gpnum, int cpu, const char *qsevent), + TP_PROTO(const char *rcuname, unsigned long gp_seq, int cpu, const char *qsevent), - TP_ARGS(rcuname, gpnum, cpu, qsevent), + TP_ARGS(rcuname, gp_seq, cpu, qsevent), TP_STRUCT__entry( __field(const char *, rcuname) - __field(unsigned long, gpnum) + __field(unsigned long, gp_seq) __field(int, cpu) __field(const char *, qsevent) ), TP_fast_assign( __entry->rcuname = rcuname; - __entry->gpnum = gpnum; + __entry->gp_seq = gp_seq; __entry->cpu = cpu; __entry->qsevent = qsevent; ), TP_printk("%s %lu %d %s", - __entry->rcuname, __entry->gpnum, + __entry->rcuname, __entry->gp_seq, __entry->cpu, __entry->qsevent) ); @@ -766,7 +766,7 @@ TRACE_EVENT(rcu_barrier, #define trace_rcu_quiescent_state_report(rcuname, gp_seq, mask, qsmask, level, \ grplo, grphi, gp_tasks) do { } \ while (0) -#define trace_rcu_fqs(rcuname, gpnum, cpu, qsevent) do { } while (0) +#define trace_rcu_fqs(rcuname, gp_seq, cpu, qsevent) do { } while (0) #define trace_rcu_dyntick(polarity, oldnesting, newnesting, dyntick) do { } while (0) #define trace_rcu_callback(rcuname, rhp, qlen_lazy, qlen) do { } while (0) #define trace_rcu_kfree_callback(rcuname, rhp, offset, qlen_lazy, qlen) \ -- cgit v1.2.3 From a2165e416878b325747f871df4b236b49bf61486 Mon Sep 17 00:00:00 2001 From: "Paul E. McKenney" Date: Sat, 12 May 2018 07:42:20 -0700 Subject: rcu: Don't funnel-lock above leaf node if GP in progress The old grace-period start code would acquire only the leaf's rcu_node structure's ->lock if that structure believed that a grace period was in progress. The new code advances to the leaf's parent in this case, needlessly acquiring then leaf's parent's ->lock. This commit therefore checks the grace-period state after marking the leaf with the need for the specified grace period, and if the leaf believes that a grace period is in progress, takes an early exit. Reported-by: Joel Fernandes Signed-off-by: Paul E. McKenney [ paulmck: Add "Startedleaf" tracing as suggested by Joel Fernandes. ] --- include/trace/events/rcu.h | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) (limited to 'include') diff --git a/include/trace/events/rcu.h b/include/trace/events/rcu.h index 7d3650cc9d30..5ab1df0a2801 100644 --- a/include/trace/events/rcu.h +++ b/include/trace/events/rcu.h @@ -91,8 +91,8 @@ TRACE_EVENT(rcu_grace_period, * * "Startleaf": Request a grace period based on leaf-node data. * "Prestarted": Someone beat us to the request - * "Startedleaf": Leaf-node start proved sufficient. - * "Startedleafroot": Leaf-node start proved sufficient after checking root. + * "Startedleaf": Leaf node marked for future GP. + * "Startedleafroot": All nodes from leaf to root marked for future GP. * "Startedroot": Requested a nocb grace period based on root-node data. * "NoGPkthread": The RCU grace-period kthread has not yet started. * "StartWait": Start waiting for the requested grace period. -- cgit v1.2.3 From b73de91d6a4c97ed586b2a5a6ce7c6fe395d9a3b Mon Sep 17 00:00:00 2001 From: Joel Fernandes Date: Sun, 20 May 2018 21:42:18 -0700 Subject: rcu: Rename the grace-period-request variables and parameters The name 'c' is used for variables and parameters holding the requested grace-period sequence number. However it is no longer very meaningful given the conversions from ->gpnum and (especially) ->completed to ->gp_seq. This commit therefore renames 'c' to 'gp_seq_req'. Previous patch discussion is at: https://patchwork.kernel.org/patch/10396579/ Signed-off-by: Joel Fernandes Signed-off-by: Paul E. McKenney --- include/trace/events/rcu.h | 15 ++++++++------- 1 file changed, 8 insertions(+), 7 deletions(-) (limited to 'include') diff --git a/include/trace/events/rcu.h b/include/trace/events/rcu.h index 5ab1df0a2801..759e7e83733d 100644 --- a/include/trace/events/rcu.h +++ b/include/trace/events/rcu.h @@ -103,15 +103,16 @@ TRACE_EVENT(rcu_grace_period, */ TRACE_EVENT(rcu_future_grace_period, - TP_PROTO(const char *rcuname, unsigned long gp_seq, unsigned long c, - u8 level, int grplo, int grphi, const char *gpevent), + TP_PROTO(const char *rcuname, unsigned long gp_seq, + unsigned long gp_seq_req, u8 level, int grplo, int grphi, + const char *gpevent), - TP_ARGS(rcuname, gp_seq, c, level, grplo, grphi, gpevent), + TP_ARGS(rcuname, gp_seq, gp_seq_req, level, grplo, grphi, gpevent), TP_STRUCT__entry( __field(const char *, rcuname) __field(unsigned long, gp_seq) - __field(unsigned long, c) + __field(unsigned long, gp_seq_req) __field(u8, level) __field(int, grplo) __field(int, grphi) @@ -121,7 +122,7 @@ TRACE_EVENT(rcu_future_grace_period, TP_fast_assign( __entry->rcuname = rcuname; __entry->gp_seq = gp_seq; - __entry->c = c; + __entry->gp_seq_req = gp_seq_req; __entry->level = level; __entry->grplo = grplo; __entry->grphi = grphi; @@ -129,7 +130,7 @@ TRACE_EVENT(rcu_future_grace_period, ), TP_printk("%s %lu %lu %u %d %d %s", - __entry->rcuname, __entry->gp_seq, __entry->c, __entry->level, + __entry->rcuname, __entry->gp_seq, __entry->gp_seq_req, __entry->level, __entry->grplo, __entry->grphi, __entry->gpevent) ); @@ -751,7 +752,7 @@ TRACE_EVENT(rcu_barrier, #else /* #ifdef CONFIG_RCU_TRACE */ #define trace_rcu_grace_period(rcuname, gp_seq, gpevent) do { } while (0) -#define trace_rcu_future_grace_period(rcuname, gp_seq, c, \ +#define trace_rcu_future_grace_period(rcuname, gp_seq, gp_seq_req, \ level, grplo, grphi, event) \ do { } while (0) #define trace_rcu_grace_period_init(rcuname, gp_seq, level, grplo, grphi, \ -- cgit v1.2.3 From e05121ba5b81e2f85349f038642410578457f6db Mon Sep 17 00:00:00 2001 From: "Paul E. McKenney" Date: Mon, 7 May 2018 12:07:48 -0700 Subject: rcu: Remove CPU-hotplug failsafe from force-quiescent-state code path Now that quiescent states for newly offlined CPUs are reported either when that CPU goes offline or at the end of grace-period initialization, the CPU-hotplug failsafe in the force-quiescent-state code path is no longer needed. This commit therefore removes this failsafe. Signed-off-by: Paul E. McKenney --- include/trace/events/rcu.h | 10 +++++----- 1 file changed, 5 insertions(+), 5 deletions(-) (limited to 'include') diff --git a/include/trace/events/rcu.h b/include/trace/events/rcu.h index 759e7e83733d..a8d07feff6a0 100644 --- a/include/trace/events/rcu.h +++ b/include/trace/events/rcu.h @@ -391,11 +391,11 @@ TRACE_EVENT(rcu_quiescent_state_report, /* * Tracepoint for quiescent states detected by force_quiescent_state(). - * These trace events include the type of RCU, the grace-period number that - * was blocked by the CPU, the CPU itself, and the type of quiescent state, - * which can be "dti" for dyntick-idle mode, "ofl" for CPU offline, "kick" - * when kicking a CPU that has been in dyntick-idle mode for too long, or - * "rqc" if the CPU got a quiescent state via its rcu_qs_ctr. + * These trace events include the type of RCU, the grace-period number + * that was blocked by the CPU, the CPU itself, and the type of quiescent + * state, which can be "dti" for dyntick-idle mode, "kick" when kicking + * a CPU that has been in dyntick-idle mode for too long, or "rqc" if the + * CPU got a quiescent state via its rcu_qs_ctr. */ TRACE_EVENT(rcu_fqs, -- cgit v1.2.3 From 3949fa9bac090ad217534c30bc3b6572289abf21 Mon Sep 17 00:00:00 2001 From: "Paul E. McKenney" Date: Tue, 8 May 2018 15:29:10 -0700 Subject: rcu: Make rcu_read_unlock_special() static Because rcu_read_unlock_special() is no longer used outside of kernel/rcu/tree_plugin.h, this commit makes it static. Signed-off-by: Paul E. McKenney --- include/linux/rcupdate.h | 1 - 1 file changed, 1 deletion(-) (limited to 'include') diff --git a/include/linux/rcupdate.h b/include/linux/rcupdate.h index 65163aa0bb04..67ec077c7ee5 100644 --- a/include/linux/rcupdate.h +++ b/include/linux/rcupdate.h @@ -64,7 +64,6 @@ void rcu_barrier_tasks(void); void __rcu_read_lock(void); void __rcu_read_unlock(void); -void rcu_read_unlock_special(struct task_struct *t); void synchronize_rcu(void); /* -- cgit v1.2.3 From 07f27570dcd148a5f4de7dc3513c1d1cd069b362 Mon Sep 17 00:00:00 2001 From: Byungchul Park Date: Fri, 11 May 2018 17:30:34 +0900 Subject: rcu: Improve rcu_note_voluntary_context_switch() reporting We expect a quiescent state of TASKS_RCU when cond_resched_tasks_rcu_qs() is called, no matter whether it actually be scheduled or not. However, it currently doesn't report the quiescent state when the task enters into __schedule() as it's called with preempt = true. So make it report the quiescent state unconditionally when cond_resched_tasks_rcu_qs() is called. And in TINY_RCU, even though the quiescent state of rcu_bh also should be reported when the tick interrupt comes from user, it doesn't. So make it reported. Lastly in TREE_RCU, rcu_note_voluntary_context_switch() should be reported when the tick interrupt comes from not only user but also idle, as an extended quiescent state. Signed-off-by: Byungchul Park Signed-off-by: Paul E. McKenney [ paulmck: Simplify rcutiny portion given no RCU-tasks for !PREEMPT. ] --- include/linux/rcupdate.h | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) (limited to 'include') diff --git a/include/linux/rcupdate.h b/include/linux/rcupdate.h index 67ec077c7ee5..5cab15e7ec83 100644 --- a/include/linux/rcupdate.h +++ b/include/linux/rcupdate.h @@ -194,8 +194,8 @@ static inline void exit_tasks_rcu_finish(void) { } */ #define cond_resched_tasks_rcu_qs() \ do { \ - if (!cond_resched()) \ - rcu_note_voluntary_context_switch_lite(current); \ + rcu_note_voluntary_context_switch_lite(current); \ + cond_resched(); \ } while (0) /* -- cgit v1.2.3 From 1445e9175bead409bb9930f3c745246a09f22cf6 Mon Sep 17 00:00:00 2001 From: Mauro Carvalho Chehab Date: Mon, 7 May 2018 06:35:46 -0300 Subject: rcu: rcupdate.h: Get rid of Sphinx warnings at rcu_pointer_handoff() The code example at rcupdate.h currently produce lots of warnings: ./include/linux/rcupdate.h:572: WARNING: Unexpected indentation. ./include/linux/rcupdate.h:576: WARNING: Unexpected indentation. ./include/linux/rcupdate.h:580: WARNING: Block quote ends without a blank line; unexpected unindent. ./include/linux/rcupdate.h:582: WARNING: Block quote ends without a blank line; unexpected unindent. ./include/linux/rcupdate.h:582: WARNING: Inline literal start-string without end-string. This commit therefore changes it to a code-block. Signed-off-by: Mauro Carvalho Chehab Signed-off-by: Paul E. McKenney --- include/linux/rcupdate.h | 5 ++--- 1 file changed, 2 insertions(+), 3 deletions(-) (limited to 'include') diff --git a/include/linux/rcupdate.h b/include/linux/rcupdate.h index 5cab15e7ec83..dacc90358b33 100644 --- a/include/linux/rcupdate.h +++ b/include/linux/rcupdate.h @@ -566,8 +566,8 @@ static inline void rcu_preempt_sleep_check(void) { } * This is simply an identity function, but it documents where a pointer * is handed off from RCU to some other synchronization mechanism, for * example, reference counting or locking. In C11, it would map to - * kill_dependency(). It could be used as follows: - * `` + * kill_dependency(). It could be used as follows:: + * * rcu_read_lock(); * p = rcu_dereference(gp); * long_lived = is_long_lived(p); @@ -578,7 +578,6 @@ static inline void rcu_preempt_sleep_check(void) { } * p = rcu_pointer_handoff(p); * } * rcu_read_unlock(); - *`` */ #define rcu_pointer_handoff(p) (p) -- cgit v1.2.3 From 6f56f714db067056c80f5d71510118f82872e34c Mon Sep 17 00:00:00 2001 From: "Paul E. McKenney" Date: Mon, 14 May 2018 13:52:27 -0700 Subject: rcu: Improve RCU-tasks naming and comments The naming and comments associated with some RCU-tasks code make the faulty assumption that context switches due to cond_resched() are voluntary. As several people pointed out, this is not the case. This commit therefore updates function names and comments to better reflect current reality. Reported-by: Byungchul Park Reported-by: Joel Fernandes Reported-by: Steven Rostedt Signed-off-by: Paul E. McKenney --- include/linux/rcupdate.h | 12 ++++++------ include/linux/rcutiny.h | 2 +- 2 files changed, 7 insertions(+), 7 deletions(-) (limited to 'include') diff --git a/include/linux/rcupdate.h b/include/linux/rcupdate.h index dacc90358b33..75e5b393cf44 100644 --- a/include/linux/rcupdate.h +++ b/include/linux/rcupdate.h @@ -158,11 +158,11 @@ static inline void rcu_init_nohz(void) { } } while (0) /* - * Note a voluntary context switch for RCU-tasks benefit. This is a - * macro rather than an inline function to avoid #include hell. + * Note a quasi-voluntary context switch for RCU-tasks's benefit. + * This is a macro rather than an inline function to avoid #include hell. */ #ifdef CONFIG_TASKS_RCU -#define rcu_note_voluntary_context_switch_lite(t) \ +#define rcu_tasks_qs(t) \ do { \ if (READ_ONCE((t)->rcu_tasks_holdout)) \ WRITE_ONCE((t)->rcu_tasks_holdout, false); \ @@ -170,14 +170,14 @@ static inline void rcu_init_nohz(void) { } #define rcu_note_voluntary_context_switch(t) \ do { \ rcu_all_qs(); \ - rcu_note_voluntary_context_switch_lite(t); \ + rcu_tasks_qs(t); \ } while (0) void call_rcu_tasks(struct rcu_head *head, rcu_callback_t func); void synchronize_rcu_tasks(void); void exit_tasks_rcu_start(void); void exit_tasks_rcu_finish(void); #else /* #ifdef CONFIG_TASKS_RCU */ -#define rcu_note_voluntary_context_switch_lite(t) do { } while (0) +#define rcu_tasks_qs(t) do { } while (0) #define rcu_note_voluntary_context_switch(t) rcu_all_qs() #define call_rcu_tasks call_rcu_sched #define synchronize_rcu_tasks synchronize_sched @@ -194,7 +194,7 @@ static inline void exit_tasks_rcu_finish(void) { } */ #define cond_resched_tasks_rcu_qs() \ do { \ - rcu_note_voluntary_context_switch_lite(current); \ + rcu_tasks_qs(current); \ cond_resched(); \ } while (0) diff --git a/include/linux/rcutiny.h b/include/linux/rcutiny.h index 7b3c82e8a625..8d9a0ea8f0b5 100644 --- a/include/linux/rcutiny.h +++ b/include/linux/rcutiny.h @@ -93,7 +93,7 @@ static inline void kfree_call_rcu(struct rcu_head *head, #define rcu_note_context_switch(preempt) \ do { \ rcu_sched_qs(); \ - rcu_note_voluntary_context_switch_lite(current); \ + rcu_tasks_qs(current); \ } while (0) static inline int rcu_needs_cpu(u64 basemono, u64 *nextevt) -- cgit v1.2.3 From b7b6f94cf6e6d961f78064315b6f5de5d9c6414b Mon Sep 17 00:00:00 2001 From: NeilBrown Date: Mon, 18 Jun 2018 14:22:40 +1000 Subject: rculist: Improve documentation for list_for_each_entry_from_rcu() Unfortunately the patch for adding list_for_each_entry_from_rcu() wasn't the final patch after all review. It is functionally correct but the documentation was incomplete. This patch adds this missing documentation which includes an update to the documentation for list_for_each_entry_continue_rcu() to match the documentation for the new list_for_each_entry_from_rcu(), and adds list_for_each_entry_from_rcu() and the already existing hlist_for_each_entry_from_rcu() to section 7 of whatisRCU.txt. Reviewed-by: Paul E. McKenney Signed-off-by: NeilBrown Signed-off-by: Paul E. McKenney --- include/linux/rculist.h | 19 ++++++++++++++++++- 1 file changed, 18 insertions(+), 1 deletion(-) (limited to 'include') diff --git a/include/linux/rculist.h b/include/linux/rculist.h index 36df6ccbc874..4786c2235b98 100644 --- a/include/linux/rculist.h +++ b/include/linux/rculist.h @@ -396,7 +396,16 @@ static inline void list_splice_tail_init_rcu(struct list_head *list, * @member: the name of the list_head within the struct. * * Continue to iterate over list of given type, continuing after - * the current position. + * the current position which must have been in the list when the RCU read + * lock was taken. + * This would typically require either that you obtained the node from a + * previous walk of the list in the same RCU read-side critical section, or + * that you held some sort of non-RCU reference (such as a reference count) + * to keep the node alive *and* in the list. + * + * This iterator is similar to list_for_each_entry_from_rcu() except + * this starts after the given position and that one starts at the given + * position. */ #define list_for_each_entry_continue_rcu(pos, head, member) \ for (pos = list_entry_rcu(pos->member.next, typeof(*pos), member); \ @@ -411,6 +420,14 @@ static inline void list_splice_tail_init_rcu(struct list_head *list, * * Iterate over the tail of a list starting from a given position, * which must have been in the list when the RCU read lock was taken. + * This would typically require either that you obtained the node from a + * previous walk of the list in the same RCU read-side critical section, or + * that you held some sort of non-RCU reference (such as a reference count) + * to keep the node alive *and* in the list. + * + * This iterator is similar to list_for_each_entry_continue_rcu() except + * this starts from the given position and that one starts from the position + * after the given position. */ #define list_for_each_entry_from_rcu(pos, head, member) \ for (; &(pos)->member != (head); \ -- cgit v1.2.3 From 3025520ec424df8b0fd5cdc319ad6b83406d9954 Mon Sep 17 00:00:00 2001 From: "Paul E. McKenney" Date: Tue, 22 May 2018 11:38:47 -0700 Subject: rcutorture: Use per-CPU random state for rcu_torture_timer() Currently, the rcu_torture_timer() function uses a single global torture_random_state structure protected by a single global lock. This conflicts to some extent with performance and scalability, but even more with the goal of consolidating read-side testing with rcu_torture_reader(). This commit therefore creates a per-CPU torture_random_state structure for use by rcu_torture_timer() and eliminates the lock. Signed-off-by: Paul E. McKenney [ paulmck: Make rcu_torture_timer_rand static, per 0day Test Robot report. ] --- include/linux/torture.h | 2 ++ 1 file changed, 2 insertions(+) (limited to 'include') diff --git a/include/linux/torture.h b/include/linux/torture.h index a55e80817dae..61dfd93b6ee4 100644 --- a/include/linux/torture.h +++ b/include/linux/torture.h @@ -64,6 +64,8 @@ struct torture_random_state { long trs_count; }; #define DEFINE_TORTURE_RANDOM(name) struct torture_random_state name = { 0, 0 } +#define DEFINE_TORTURE_RANDOM_PERCPU(name) \ + DEFINE_PER_CPU(struct torture_random_state, name) unsigned long torture_random(struct torture_random_state *trsp); /* Task shuffler, which causes CPUs to occasionally go idle. */ -- cgit v1.2.3