BMC/Intel-BMC/linux.git/kernel/rcu/rcu.h, branch dev-4.6

tiny_rcu: Directly force QS when call_rcu_[bh|sched]() on idle_task

2015-01-06T19:01:12+00:00

For RCU in UP, context-switch = QS = GP, thus we can force a context-switch when any call_rcu_[bh|sched]() is happened on idle_task. After doing so, rcu_idle/irq_enter/exit() are useless, so we can simply make these functions empty. More important, this change does not change the functionality logically. Note: raise_softirq(RCU_SOFTIRQ)/rcu_sched_qs() in rcu_idle_enter() and outmost rcu_irq_exit() will have to wake up the ksoftirqd (due to in_interrupt() == 0). Before this patch After this patch: call_rcu_sched() in idle; call_rcu_sched() in idle set resched do other stuffs; do other stuffs outmost rcu_irq_exit() outmost rcu_irq_exit() (empty function) (or rcu_idle_enter()) (or rcu_idle_enter(), also empty function) start to resched. (see above) rcu_sched_qs() rcu_sched_qs() QS,and GP and advance cb QS,and GP and advance cb wake up the ksoftirqd wake up the ksoftirqd set resched resched to ksoftirqd (or other) resched to ksoftirqd (or other) These two code patches are almost the same. Size changed after patched: size kernel/rcu/tiny-old.o kernel/rcu/tiny-patched.o text data bss dec hex filename 3449 206 8 3663 e4f kernel/rcu/tiny-old.o 2406 144 8 2558 9fe kernel/rcu/tiny-patched.o Signed-off-by: Lai Jiangshan Signed-off-by: Paul E. McKenney

rcutorture: Add early boot self tests

2014-11-04T03:26:37+00:00

Add early boot self tests for RCU under CONFIG_PROVE_RCU. Currently the only test is adding a dummy callback which increments a counter which we then later verify after calling rcu_barrier*(). Signed-off-by: Pranith Kumar Signed-off-by: Paul E. McKenney

rcu: Fix __rcu_reclaim() to use true/false for bool

2014-07-09T16:15:32+00:00

The __rcu_reclaim() function returned 0/1, which is not proper for a function of type bool. This commit therefore converts to false/true. Signed-off-by: Paul E. McKenney Reviewed-by: Lai Jiangshan

rcu: Ensure kernel/rcu/rcu.h can be sourced/used stand-alone

2014-02-26T14:35:18+00:00

The kbuild test bot uncovered an implicit dependence on the trace header being present before rcu.h in ia64 allmodconfig that looks like this: In file included from kernel/ksysfs.c:22:0: kernel/rcu/rcu.h: In function '__rcu_reclaim': kernel/rcu/rcu.h:107:3: error: implicit declaration of function 'trace_rcu_invoke_kfree_callback' [-Werror=implicit-function-declaration] kernel/rcu/rcu.h:112:3: error: implicit declaration of function 'trace_rcu_invoke_callback' [-Werror=implicit-function-declaration] cc1: some warnings being treated as errors Looking at other rcu.h users, we can find that they all were sourcing the trace header in advance of rcu.h itself, as seen in the context of this diff. There were also some inconsistencies as to whether it was or wasn't sourced based on the parent tracing Kconfig. Rather than "fix" it at each use site, and have inconsistent use based on whether "#ifdef CONFIG_RCU_TRACE" was used or not, lets just source the trace header just once, in the actual consumer of it, which is rcu.h itself. We include it unconditionally, as build testing shows us that is a hard requirement for some files. Reported-by: kbuild test robot Signed-off-by: Paul Gortmaker Signed-off-by: Paul E. McKenney

rcu: Fix sparse warning for rcu_expedited from kernel/ksysfs.c

2014-02-26T14:35:16+00:00

This commit fixes the follwoing warning: kernel/ksysfs.c:143:5: warning: symbol 'rcu_expedited' was not declared. Should it be static? Signed-off-by: Paul Gortmaker [ paulmck: Moved the declaration to include/linux/rcupdate.h to avoid including the RCU-internal rcu.h file outside of RCU. ] Signed-off-by: Paul E. McKenney Reviewed-by: Josh Triplett

rcu: Stop tracking FSF's postal address

2014-02-17T23:01:37+00:00

All of the RCU source files have the usual GPL header, which contains a long-obsolete postal address for FSF. To avoid the need to track the FSF office's movements, this commit substitutes the URL where GPL may be found. Reported-by: Greg KH Reported-by: Steven Rostedt Signed-off-by: Paul E. McKenney Reviewed-by: Josh Triplett

rcu: Remove "extern" from function declarations in kernel/rcu/rcu.h

2013-12-12T20:34:17+00:00

Function prototypes don't need to have the "extern" keyword since this is the default behavior. Its explicit use is redundant. This commit therefore removes them. Signed-off-by: Teodora Baluta Signed-off-by: Paul E. McKenney

rcu: Provide better diagnostics for blocking in RCU callback functions

2013-12-09T23:12:39+00:00

Currently blocking in an RCU callback function will result in "scheduling while atomic", which could be triggered for any number of reasons. To aid debugging, this patch introduces a rcu_callback_map that is used to tie the inappropriate voluntary context switch back to the fact that the function is being invoked from within a callback. Signed-off-by: Paul E. McKenney

rcu: Move RCU-related source code to kernel/rcu directory

2013-10-15T19:53:31+00:00

Signed-off-by: Paul E. McKenney Reviewed-by: Ingo Molnar