From 613707929b304737e6eb841588772f1994f6702b Mon Sep 17 00:00:00 2001 From: "Uladzislau Rezki (Sony)" Date: Mon, 20 Jan 2020 15:42:26 +0100 Subject: rcu: Add a trace event for kfree_rcu() use of kfree_bulk() The event is given three parameters, first one is the name of RCU flavour, second one is the number of elements in array for free and last one is an address of the array holding pointers to be freed by the kfree_bulk() function. To enable the trace event your kernel has to be build with CONFIG_RCU_TRACE=y, after that it is possible to track the events using ftrace subsystem. Signed-off-by: Uladzislau Rezki (Sony) Signed-off-by: Paul E. McKenney --- include/trace/events/rcu.h | 28 ++++++++++++++++++++++++++++ 1 file changed, 28 insertions(+) (limited to 'include/trace') diff --git a/include/trace/events/rcu.h b/include/trace/events/rcu.h index 5e49b06e8104..49a49e68b916 100644 --- a/include/trace/events/rcu.h +++ b/include/trace/events/rcu.h @@ -623,6 +623,34 @@ TRACE_EVENT_RCU(rcu_invoke_kfree_callback, __entry->rcuname, __entry->rhp, __entry->offset) ); +/* + * Tracepoint for the invocation of a single RCU callback of the special + * kfree_bulk() form. The first argument is the RCU flavor, the second + * argument is a number of elements in array to free, the third is an + * address of the array holding nr_records entries. + */ +TRACE_EVENT_RCU(rcu_invoke_kfree_bulk_callback, + + TP_PROTO(const char *rcuname, unsigned long nr_records, void **p), + + TP_ARGS(rcuname, nr_records, p), + + TP_STRUCT__entry( + __field(const char *, rcuname) + __field(unsigned long, nr_records) + __field(void **, p) + ), + + TP_fast_assign( + __entry->rcuname = rcuname; + __entry->nr_records = nr_records; + __entry->p = p; + ), + + TP_printk("%s bulk=0x%p nr_records=%lu", + __entry->rcuname, __entry->p, __entry->nr_records) +); + /* * Tracepoint for exiting rcu_do_batch after RCU callbacks have been * invoked. The first argument is the name of the RCU flavor, -- cgit v1.2.3 From 127e29815b4b2206c0a97ac1d83f92ffc0e25c34 Mon Sep 17 00:00:00 2001 From: "Paul E. McKenney" Date: Tue, 11 Feb 2020 06:17:33 -0800 Subject: rcu: Make rcu_barrier() account for offline no-CBs CPUs Currently, rcu_barrier() ignores offline CPUs, However, it is possible for an offline no-CBs CPU to have callbacks queued, and rcu_barrier() must wait for those callbacks. This commit therefore makes rcu_barrier() directly invoke the rcu_barrier_func() with interrupts disabled for such CPUs. This requires passing the CPU number into this function so that it can entrain the rcu_barrier() callback onto the correct CPU's callback list, given that the code must instead execute on the current CPU. While in the area, this commit fixes a bug where the first CPU's callback might have been invoked before rcu_segcblist_entrain() returned, which would also result in an early wakeup. Fixes: 5d6742b37727 ("rcu/nocb: Use rcu_segcblist for no-CBs CPUs") Signed-off-by: Paul E. McKenney [ paulmck: Apply optimization feedback from Boqun Feng. ] Cc: # 5.5.x --- include/trace/events/rcu.h | 1 + 1 file changed, 1 insertion(+) (limited to 'include/trace') diff --git a/include/trace/events/rcu.h b/include/trace/events/rcu.h index 5e49b06e8104..d56d54c17497 100644 --- a/include/trace/events/rcu.h +++ b/include/trace/events/rcu.h @@ -712,6 +712,7 @@ TRACE_EVENT_RCU(rcu_torture_read, * "Begin": rcu_barrier() started. * "EarlyExit": rcu_barrier() piggybacked, thus early exit. * "Inc1": rcu_barrier() piggyback check counter incremented. + * "OfflineNoCBQ": rcu_barrier() found offline no-CBs CPU with callbacks. * "OnlineQ": rcu_barrier() found online CPU with callbacks. * "OnlineNQ": rcu_barrier() found online CPU, no callbacks. * "IRQ": An rcu_barrier_callback() callback posted on remote CPU. -- cgit v1.2.3