linux/kernel/rcu/srcutree.c, branch v4.19

srcu: Add grace-period number to rcutorture statistics printout

2018-07-12T22:39:25Z

This commit adds the SRCU grace-period number to the rcutorture statistics printout, which allows it to be compared to the rcutorture "Writer stall state" message. Signed-off-by: Paul E. McKenney

rcu: Use pr_fmt to prefix "rcu: " to logging output

2018-07-12T22:39:13Z

This commit also adjusts some whitespace while in the area. Signed-off-by: Joe Perches Signed-off-by: Paul E. McKenney [ paulmck: Revert string-breaking %s as requested by Andy Shevchenko. ]

rcutorture: Convert rcutorture_get_gp_data() to ->gp_seq

2018-07-12T21:27:57Z

SRCU has long used ->srcu_gp_seq, and now RCU uses ->gp_seq. This commit therefore moves the rcutorture_get_gp_data() function from a ->gpnum / ->completed pair to ->gp_seq. Signed-off-by: Paul E. McKenney

srcu: Add address of first callback to rcutorture output

2018-06-25T18:26:24Z

This commit adds the address of the first callback to the per-CPU rcutorture output in order to allow lost wakeups to be more efficiently tracked down. Signed-off-by: Paul E. McKenney

srcu: Document that srcu_funnel_gp_start() implies srcu_funnel_exp_start()

2018-06-25T18:26:24Z

This commit updates the header comment of srcu_funnel_gp_start() to document the fact that srcu_funnel_gp_start() does the work of srcu_funnel_exp_start(), in some cases by invoking it directly. Signed-off-by: Paul E. McKenney

srcu: Fix typos in __call_srcu() header comment

2018-06-25T18:26:24Z

This commit simply changes some copy-pasta call_rcu() instances to the correct call_srcu(). Signed-off-by: Paul E. McKenney

srcu: Add cleanup_srcu_struct_quiesced()

2018-05-15T17:27:56Z

The current cleanup_srcu_struct() flushes work, which prevents it from being invoked from some workqueue contexts, as well as from atomic (non-blocking) contexts. This patch therefore introduced a cleanup_srcu_struct_quiesced(), which can be invoked only after all activity on the specified srcu_struct has completed. This restriction allows cleanup_srcu_struct_quiesced() to be invoked from workqueue contexts as well as from atomic contexts. Suggested-by: Christoph Hellwig Signed-off-by: Paul E. McKenney Tested-by: Nitzan Carmi Tested-by: Nicholas Piggin

Merge branches 'fixes.2018.02.23a', 'srcu.2018.02.20a' and 'torture.2018.02.20a' into HEAD

2018-02-23T23:15:41Z

fixes.2018.02.23a: Miscellaneous fixes srcu.2018.02.20a: SRCU updates torture.2018.02.20a: Torture-test updates

rcu: Create RCU-specific workqueues with rescuers

2018-02-23T23:14:40Z

RCU's expedited grace periods can participate in out-of-memory deadlocks due to all available system_wq kthreads being blocked and there not being memory available to create more. This commit prevents such deadlocks by allocating an RCU-specific workqueue_struct at early boot time, and providing it with a rescuer to ensure forward progress. This uses the shiny new init_rescuer() function provided by Tejun (but indirectly). This commit also causes SRCU to use this new RCU-specific workqueue_struct. Note that SRCU's use of workqueues never blocks them waiting for readers, so this should be safe from a forward-progress viewpoint. Note that this moves SRCU from system_power_efficient_wq to a normal workqueue. In the unlikely event that this results in measurable degradation, a separate power-efficient workqueue will be creates for SRCU. Reported-by: Prateek Sood Reported-by: Tejun Heo Signed-off-by: Paul E. McKenney Acked-by: Tejun Heo

rcu: Remove SRCU throttling

2018-02-21T00:21:13Z

The code in srcu_gp_end() inserts a delay every 0x3ff grace periods in order to prevent SRCU grace-period work from consuming an entire CPU when there is a long sequence of expedited SRCU grace-period requests. However, all of SRCU's grace-period work is carried out in workqueues, which are in turn within kthreads, which are automatically throttled as needed by the scheduler. In particular, if there is plenty of idle time, there is no point in throttling. This commit therefore removes the expedited SRCU grace-period throttling. Signed-off-by: Paul E. McKenney