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Commit 4d03754f authored by Paul E. McKenney's avatar Paul E. McKenney
Browse files

Merge branches 'doc.2016.06.15a', 'fixes.2016.06.15b' and 'torture.2016.06.14a' into HEAD 

doc.2016.06.15a: Documentation updates
fixes.2016.06.15b: Documentation updates
torture.2016.06.14a: Documentation updates
parents 14ef0575 bc75e999 05dbbfe7

Documentation/sysctl/kernel.txt

+12 −0
Original line number Diff line number Diff line
@@ -58,6 +58,7 @@ show up in /proc/sys/kernel: 
- panic_on_stackoverflow

- panic_on_unrecovered_nmi

- panic_on_warn

- panic_on_rcu_stall

- perf_cpu_time_max_percent

- perf_event_paranoid

- perf_event_max_stack
@@ -618,6 +619,17 @@ a kernel rebuild when attempting to kdump at the location of a WARN(). 


==============================================================



panic_on_rcu_stall:



When set to 1, calls panic() after RCU stall detection messages. This

is useful to define the root cause of RCU stalls using a vmcore.



0: do not panic() when RCU stall takes place, default behavior.



1: panic() after printing RCU stall messages.



==============================================================



perf_cpu_time_max_percent:



Hints to the kernel how much CPU time it should be allowed to

include/linux/kernel.h

+1 −0
Original line number Diff line number Diff line
@@ -451,6 +451,7 @@ extern int panic_on_oops; 
extern int panic_on_unrecovered_nmi;

extern int panic_on_io_nmi;

extern int panic_on_warn;

extern int sysctl_panic_on_rcu_stall;

extern int sysctl_panic_on_stackoverflow;



extern bool crash_kexec_post_notifiers;

include/linux/rcupdate.h

+17 −6
Original line number Diff line number Diff line
@@ -45,6 +45,7 @@ 
#include <linux/bug.h>

#include <linux/compiler.h>

#include <linux/ktime.h>

#include <linux/irqflags.h>



#include <asm/barrier.h>
@@ -379,12 +380,13 @@ static inline void rcu_init_nohz(void) 
 * in the inner idle loop.

 *

 * This macro provides the way out:  RCU_NONIDLE(do_something_with_RCU())

 * will tell RCU that it needs to pay attending, invoke its argument

 * (in this example, a call to the do_something_with_RCU() function),

 * will tell RCU that it needs to pay attention, invoke its argument

 * (in this example, calling the do_something_with_RCU() function),

 * and then tell RCU to go back to ignoring this CPU.  It is permissible

 * to nest RCU_NONIDLE() wrappers, but the nesting level is currently

 * quite limited.  If deeper nesting is required, it will be necessary

 * to adjust DYNTICK_TASK_NESTING_VALUE accordingly.

 * to nest RCU_NONIDLE() wrappers, but not indefinitely (but the limit is

 * on the order of a million or so, even on 32-bit systems).  It is

 * not legal to block within RCU_NONIDLE(), nor is it permissible to

 * transfer control either into or out of RCU_NONIDLE()'s statement.

 */

#define RCU_NONIDLE(a) \

	do { \
@@ -649,7 +651,16 @@ static inline void rcu_preempt_sleep_check(void) 
 * please be careful when making changes to rcu_assign_pointer() and the

 * other macros that it invokes.

 */

#define rcu_assign_pointer(p, v) smp_store_release(&p, RCU_INITIALIZER(v))

#define rcu_assign_pointer(p, v)					      \

({									      \

	uintptr_t _r_a_p__v = (uintptr_t)(v);				      \

									      \

	if (__builtin_constant_p(v) && (_r_a_p__v) == (uintptr_t)NULL)	      \

		WRITE_ONCE((p), (typeof(p))(_r_a_p__v));		      \

	else								      \

		smp_store_release(&p, RCU_INITIALIZER((typeof(p))_r_a_p__v)); \

	_r_a_p__v;							      \

})



/**

 * rcu_access_pointer() - fetch RCU pointer with no dereferencing

include/linux/torture.h

+4 −0
Original line number Diff line number Diff line
@@ -50,6 +50,10 @@ 
	do { if (verbose) pr_alert("%s" TORTURE_FLAG "!!! %s\n", torture_type, s); } while (0)



/* Definitions for online/offline exerciser. */

bool torture_offline(int cpu, long *n_onl_attempts, long *n_onl_successes,

		     unsigned long *sum_offl, int *min_onl, int *max_onl);

bool torture_online(int cpu, long *n_onl_attempts, long *n_onl_successes,

		    unsigned long *sum_onl, int *min_onl, int *max_onl);

int torture_onoff_init(long ooholdoff, long oointerval);

void torture_onoff_stats(void);

bool torture_onoff_failures(void);

init/Kconfig

+1 −0
Original line number Diff line number Diff line
@@ -517,6 +517,7 @@ config SRCU 
config TASKS_RCU

	bool

	default n

	depends on !UML

	select SRCU

	help

	  This option enables a task-based RCU implementation that uses