rcu: Dump rcuc kthread status for CPUs not reporting quiescent state
authorZqiang <qiang1.zhang@intel.com>
Mon, 25 Apr 2022 01:04:04 +0000 (09:04 +0800)
committerPaul E. McKenney <paulmck@kernel.org>
Mon, 20 Jun 2022 16:30:10 +0000 (09:30 -0700)
commit245a62982502255314b63dd2c4daaedd1cd595a6
tree6bf5103dab2e47200642fff5e6880295f44b2712
parenta111daf0c53ae91e71fd2bfe7497862d14132e3e
rcu: Dump rcuc kthread status for CPUs not reporting quiescent state

If the rcutree.use_softirq kernel boot parameter is disabled, then it is
possible that a RCU CPU stall is due to the rcuc kthreads being starved of
CPU time.  There is currently no easy way to infer this from the RCU CPU
stall warning output.  This commit therefore adds a string of the form "
rcuc=%ld jiffies(starved)" to a given CPU's output if the corresponding
rcuc kthread has been starved for more than two seconds.

[ paulmck: Eliminate extraneous space characters. ]

Signed-off-by: Zqiang <qiang1.zhang@intel.com>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
kernel/rcu/tree_stall.h