This commit adds a stall_only module parameter that shuts off all rcutorture kthreads other than the RCU CPU stall-warning test kthreads. The purpose of this is to test production applictions' reactions to CPU stalls, and with minimal additional overhead. Or you can omit the stall-warning tests as well and get a heavy no-op, your choice!
Signed-off-by: Paul E. McKenney <[email protected]> --- .../admin-guide/kernel-parameters.txt | 9 +++++++++ kernel/rcu/rcutorture.c | 18 ++++++++++++++++++ 2 files changed, 27 insertions(+) diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt index b942149720c9bf..40d2831add4a21 100644 --- a/Documentation/admin-guide/kernel-parameters.txt +++ b/Documentation/admin-guide/kernel-parameters.txt @@ -6211,6 +6211,15 @@ Kernel parameters and stall_gp_kthread are specified, the kthread is starved first, then the CPU. + rcutorture.stall_only= [KNL] + Shut off all rcutorture kthreads other than the + RCU CPU stall-warning test kthreads. The purpose + of this is to test production applictions' + reactions to CPU stalls, and with minimal + additional overhead. Or you can omit the + stall-warning tests as well and get a heavy + no-op, your choice! + rcutorture.stat_interval= [KNL] Time (s) between statistics printk()s. diff --git a/kernel/rcu/rcutorture.c b/kernel/rcu/rcutorture.c index a6a8b9ba342d02..a0d27756141846 100644 --- a/kernel/rcu/rcutorture.c +++ b/kernel/rcu/rcutorture.c @@ -140,6 +140,7 @@ torture_param(int, stall_cpu_irqsoff, 0, "Disable interrupts while stalling."); torture_param(int, stall_cpu_block, 0, "Sleep while stalling."); torture_param(int, stall_cpu_repeat, 0, "Number of additional stalls after the first one."); torture_param(int, stall_gp_kthread, 0, "Grace-period kthread stall duration (s)."); +torture_param(bool, stall_only, 0, "Suppress all non-CPU-stall kthreads."); torture_param(int, stat_interval, 60, "Number of seconds between stats printk()s"); torture_param(int, stutter, 5, "Number of seconds to run/halt test"); torture_param(int, test_boost, 1, "Test RCU prio boost: 0=no, 1=maybe, 2=yes."); @@ -4649,6 +4650,23 @@ rcu_torture_init(void) cur_ops = NULL; goto unwind; } + if (stall_only) { + pr_alert("rcu-torture: stall_only specified, suppressing all else.\n"); + fqs_stutter = 0; + fwd_progress = 0; + n_barrier_cbs = 0; + nfakewriters = 0; + nocbs_nthreads = 0; + nreaders = 0; + n_up_down = 0; + nwriters = 0; + onoff_interval = 0; + preempt_duration = 0; + read_exit_burst = 0; + shuffle_interval = 0; + stutter = 0; + test_boost = 0; + } if (cur_ops->fqs == NULL && fqs_duration != 0) { pr_alert("rcu-torture: ->fqs NULL and non-zero fqs_duration, fqs disabled.\n"); fqs_duration = 0; -- 2.40.1
