kernel.git/kernel/rcu/rcuperf.c, branch linux-4.19.y

rcuperf: Fix cleanup path for invalid perf_type strings

2019-05-31T13:46:30Z

[ Upstream commit ad092c027713a68a34168942a5ef422e42e039f4 ] If the specified rcuperf.perf_type is not in the rcu_perf_init() function's perf_ops[] array, rcuperf prints some console messages and then invokes rcu_perf_cleanup() to set state so that a future torture test can run. However, rcu_perf_cleanup() also attempts to end the test that didn't actually start, and in doing so relies on the value of cur_ops, a value that is not particularly relevant in this case. This can result in confusing output or even follow-on failures due to attempts to use facilities that have not been properly initialized. This commit therefore sets the value of cur_ops to NULL in this case and inserts a check near the beginning of rcu_perf_cleanup(), thus avoiding relying on an irrelevant cur_ops value. Signed-off-by: Paul E. McKenney Signed-off-by: Sasha Levin

Merge branches 'fixes1.2018.07.12b' and 'torture1.2018.07.12b' into HEAD

2018-07-12T22:42:41Z

fixes1.2018.07.12b: Post-gp_seq miscellaneous fixes torture1.2018.07.12b: Post-gp_seq torture-test updates

rcuperf: Remove unused torturing_tasks() function

2018-07-12T22:42:02Z

The torturing_tasks() function in rcuperf.c is not used, so this commit removes it. Signed-off-by: Paul E. McKenney

rcu: Remove "inline" from rcu_perf_print_module_parms()

2018-07-12T22:39:19Z

This function is in rcuperf.c, which is not an include file, so there is no problem dropping the "inline", especially given that this function is invoked only twice per rcuperf run. This commit therefore delegates the inlining decision to the compiler by dropping the "inline". 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: Correctly handle grace-period sequence wrap

2018-07-12T22:38:55Z

The new ->gq_seq grace-period sequence numbers must be shifted down, which give artifacts when these numbers wrap. This commit therefore enables rcutorture and rcuperf to handle grace-period sequence numbers even if they do wrap. It does this by allowing a special subtraction function to be specified, and this function subtracts before shifting. Signed-off-by: Paul E. McKenney

rcu: Make rcutorture's batches-completed API use ->gp_seq

2018-07-12T21:27:47Z

The rcutorture test invokes rcu_batches_started(), rcu_batches_completed(), rcu_batches_started_bh(), rcu_batches_completed_bh(), rcu_batches_started_sched(), and rcu_batches_completed_sched() to do grace-period consistency checks, and rcuperf uses the _completed variants for statistics. These functions use ->gpnum and ->completed. This commit therefore replaces them with rcu_get_gp_seq(), rcu_bh_get_gp_seq(), and rcu_sched_get_gp_seq(), adjusting rcutorture and rcuperf to make use of them. Signed-off-by: Paul E. McKenney

torture: Keep old-school dmesg format

2018-06-25T18:30:10Z

This commit adds "#define pr_fmt(fmt) fmt" to the torture-test files in order to keep the current dmesg format. Once Joe's commits have hit mainline, these definitions will be changed in order to automatically generate the dmesg line prefix that the scripts expect. This will have the beneficial side-effect of allowing printk() formats to be used more widely and of shortening some pr_*() lines. Signed-off-by: Paul E. McKenney Cc: Joe Perches

torture: Make online/offline messages appear only for verbose=2

2018-06-25T18:30:10Z

Some bugs reproduce quickly only at high CPU-hotplug rates, so the rcutorture TREE03 scenario now has only 200 milliseconds spacing between CPU-hotplug operations. At this rate, the torture-test pair of console messages per operation becomes a bit voluminous. This commit therefore converts the torture-test set of "verbose" kernel-boot arguments from bool to int, and prints the extra console messages only when verbose=2. The default is still verbose=1. Signed-off-by: Paul E. McKenney

rcu: Rename cond_resched_rcu_qs() to cond_resched_tasks_rcu_qs()

2018-05-15T17:27:29Z

Commit e31d28b6ab8f ("trace: Eliminate cond_resched_rcu_qs() in favor of cond_resched()") substituted cond_resched() for the earlier call to cond_resched_rcu_qs(). However, the new-age cond_resched() does not do anything to help RCU-tasks grace periods because (1) RCU-tasks is only enabled when CONFIG_PREEMPT=y and (2) cond_resched() is a complete no-op when preemption is enabled. This situation results in hangs when running the trace benchmarks. A number of potential fixes were discussed on LKML (https://lkml.kernel.org/r/20180224151240.0d63a059@vmware.local.home), including making cond_resched() not be a no-op; making cond_resched() not be a no-op, but only when running tracing benchmarks; reverting the aforementioned commit (which works because cond_resched_rcu_qs() does provide an RCU-tasks quiescent state; and adding a call to the scheduler/RCU rcu_note_voluntary_context_switch() function. All were deemed unsatisfactory, either due to added cond_resched() overhead or due to magic functions inviting cargo culting. This commit renames cond_resched_rcu_qs() to cond_resched_tasks_rcu_qs(), which provides a clear hint as to what this function is doing and why and where it should be used, and then replaces the call to cond_resched() with cond_resched_tasks_rcu_qs() in the trace benchmark's benchmark_event_kthread() function. Reported-by: Steven Rostedt Signed-off-by: Paul E. McKenney Tested-by: Nicholas Piggin