rcu: Remove CONFIG_RCU_CPU_STALL_INFO (75c27f11) · Commits · 戴 / test

Documentation/RCU/stallwarn.txt

+2 −10

Original line number	Diff line number	Diff line
		@@ -26,12 +26,6 @@ CONFIG_RCU_CPU_STALL_TIMEOUT
		Stall-warning messages may be enabled and disabled completely via
		/sys/module/rcupdate/parameters/rcu_cpu_stall_suppress.

		CONFIG_RCU_CPU_STALL_INFO

		This kernel configuration parameter causes the stall warning to
		print out additional per-CPU diagnostic information, including
		information on scheduling-clock ticks and RCU's idle-CPU tracking.

		RCU_STALL_DELAY_DELTA

		Although the lockdep facility is extremely useful, it does add
		@@ -101,15 +95,13 @@ interact. Please note that it is not possible to entirely eliminate this
		sort of false positive without resorting to things like stop_machine(),
		which is overkill for this sort of problem.

		If the CONFIG_RCU_CPU_STALL_INFO kernel configuration parameter is set,
		more information is printed with the stall-warning message, for example:
		Recent kernels will print a long form of the stall-warning message:

		INFO: rcu_preempt detected stall on CPU
		0: (63959 ticks this GP) idle=241/3fffffffffffffff/0 softirq=82/543
		(t=65000 jiffies)

		In kernels with CONFIG_RCU_FAST_NO_HZ, even more information is
		printed:
		In kernels with CONFIG_RCU_FAST_NO_HZ, more information is printed:

		INFO: rcu_preempt detected stall on CPU
		0: (64628 ticks this GP) idle=dd5/3fffffffffffffff/0 softirq=82/543 last_accelerate: a345/d342 nonlazy_posted: 25 .D

kernel/rcu/tree.h

+0 −4

Original line number	Diff line number	Diff line
		@@ -288,12 +288,10 @@ struct rcu_data {
		bool gpwrap; /* Possible gpnum/completed wrap. */
		struct rcu_node mynode; / This CPU's leaf of hierarchy */
		unsigned long grpmask; /* Mask to apply to leaf qsmask. */
		#ifdef CONFIG_RCU_CPU_STALL_INFO
		unsigned long ticks_this_gp; /* The number of scheduling-clock */
		/* ticks this CPU has handled */
		/* during and after the last grace */
		/* period it is aware of. */
		#endif /* #ifdef CONFIG_RCU_CPU_STALL_INFO */

		/* 2) batch handling */
		/*
		@@ -388,9 +386,7 @@ struct rcu_data {
		#endif /* #ifdef CONFIG_RCU_NOCB_CPU */

		/* 8) RCU CPU stall data. */
		#ifdef CONFIG_RCU_CPU_STALL_INFO
		unsigned int softirq_snap; /* Snapshot of softirq activity. */
		#endif /* #ifdef CONFIG_RCU_CPU_STALL_INFO */

		int cpu;
		struct rcu_state *rsp;

kernel/rcu/tree_plugin.h

+0 −45

Original line number	Diff line number	Diff line
		@@ -82,8 +82,6 @@ static void __init rcu_bootup_announce_oddness(void)
		pr_info("\tRCU lockdep checking is enabled.\n");
		if (IS_ENABLED(CONFIG_RCU_TORTURE_TEST_RUNNABLE))
		pr_info("\tRCU torture testing starts during boot.\n");
		if (IS_ENABLED(CONFIG_RCU_CPU_STALL_INFO))
		pr_info("\tAdditional per-CPU info printed with stalls.\n");
		if (RCU_NUM_LVLS >= 4)
		pr_info("\tFour(or more)-level hierarchy is enabled.\n");
		if (RCU_FANOUT_LEAF != 16)
		@@ -418,8 +416,6 @@ static void rcu_print_detail_task_stall(struct rcu_state *rsp)
		rcu_print_detail_task_stall_rnp(rnp);
		}

		#ifdef CONFIG_RCU_CPU_STALL_INFO

		static void rcu_print_task_stall_begin(struct rcu_node *rnp)
		{
		pr_err("\tTasks blocked on level-%d rcu_node (CPUs %d-%d):",
		@@ -431,18 +427,6 @@ static void rcu_print_task_stall_end(void)
		pr_cont("\n");
		}

		#else /* #ifdef CONFIG_RCU_CPU_STALL_INFO */

		static void rcu_print_task_stall_begin(struct rcu_node *rnp)
		{
		}

		static void rcu_print_task_stall_end(void)
		{
		}

		#endif /* #else #ifdef CONFIG_RCU_CPU_STALL_INFO */

		/*
		* Scan the current list of tasks blocked within RCU read-side critical
		* sections, printing out the tid of each.
		@@ -1685,8 +1669,6 @@ early_initcall(rcu_register_oom_notifier);

		#endif /* #else #if !defined(CONFIG_RCU_FAST_NO_HZ) */

		#ifdef CONFIG_RCU_CPU_STALL_INFO

		#ifdef CONFIG_RCU_FAST_NO_HZ

		static void print_cpu_stall_fast_no_hz(char *cp, int cpu)
		@@ -1775,33 +1757,6 @@ static void increment_cpu_stall_ticks(void)
		raw_cpu_inc(rsp->rda->ticks_this_gp);
		}

		#else /* #ifdef CONFIG_RCU_CPU_STALL_INFO */

		static void print_cpu_stall_info_begin(void)
		{
		pr_cont(" {");
		}

		static void print_cpu_stall_info(struct rcu_state *rsp, int cpu)
		{
		pr_cont(" %d", cpu);
		}

		static void print_cpu_stall_info_end(void)
		{
		pr_cont("} ");
		}

		static void zero_cpu_stall_ticks(struct rcu_data *rdp)
		{
		}

		static void increment_cpu_stall_ticks(void)
		{
		}

		#endif /* #else #ifdef CONFIG_RCU_CPU_STALL_INFO */

		#ifdef CONFIG_RCU_NOCB_CPU

		/*

lib/Kconfig.debug

+0 −14

Original line number	Diff line number	Diff line
		@@ -1353,20 +1353,6 @@ config RCU_CPU_STALL_TIMEOUT
		RCU grace period persists, additional CPU stall warnings are
		printed at more widely spaced intervals.

		config RCU_CPU_STALL_INFO
		bool "Print additional diagnostics on RCU CPU stall"
		depends on (TREE_RCU \|\| PREEMPT_RCU) && DEBUG_KERNEL
		default y
		help
		For each stalled CPU that is aware of the current RCU grace
		period, print out additional per-CPU diagnostic information
		regarding scheduling-clock ticks, idle state, and,
		for RCU_FAST_NO_HZ kernels, idle-entry state.

		Say N if you are unsure.

		Say Y if you want to enable such diagnostics.

		config RCU_TRACE
		bool "Enable tracing for RCU"
		depends on DEBUG_KERNEL

tools/testing/selftests/rcutorture/configs/rcu/TREE01

+0 −1

Original line number	Diff line number	Diff line
		@@ -13,7 +13,6 @@ CONFIG_MAXSMP=y
		CONFIG_RCU_NOCB_CPU=y
		CONFIG_RCU_NOCB_CPU_ZERO=y
		CONFIG_DEBUG_LOCK_ALLOC=n
		CONFIG_RCU_CPU_STALL_INFO=n
		CONFIG_RCU_BOOST=n
		CONFIG_DEBUG_OBJECTS_RCU_HEAD=n
		CONFIG_RCU_EXPERT=y

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