This commit adds a message that is printed if the relevant grace-period
kthread has not been able to run for the two seconds preceding the
stall warning. (The two seconds is double the maximum interval between
successive bouts of quiescent-state forcing.)
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Git-repo: git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
Git-commit: fb81a44b88e6173ed0f6e9d6a1afa5305fb63f6e
[pdaly@codeaurora.org resolve trivial conflicts]
Change-Id: I6861d0e4be1e9c83ce4fd17ec94ef047db38861a
Signed-off-by: Patrick Daly <pdaly@codeaurora.org>
One way that an RCU CPU stall warning can happen is if the grace-period
kthread is not allowed to execute. One proxy for this kthread's
forward progress is the number of force-quiescent-state (fqs) scans.
This commit therefore adds the number of fqs scans to the RCU CPU stall
warning printouts when CONFIG_RCU_CPU_STALL_INFO=y.
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Git-repo: git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
Git-commit: fc908ed33e7c1428f799abb12399f906da03b397
[pdaly@codeaurora.org Resolve convlicts from declining
26cdfedf6a902345f8604ea8e0b7dd2566b37a46]
Change-Id: I6d4a5088dff2a499593862bb0a2e2fb604ffc393
Signed-off-by: Patrick Daly <pdaly@codeaurora.org>
The current RCU CPU stall warning code will print "Stall ended before
state dump start" any time that the stall-warning code is triggered on
a CPU that has already reported a quiescent state for the current grace
period and if all quiescent states have been reported for the current
grace period. However, a true stall can result in these symptoms, for
example, by preventing RCU's grace-period kthreads from ever running
This commit therefore checks for this condition, reporting the end of
the stall only if one of the grace-period counters has actually advanced.
Otherwise, it reports the last time that the grace-period kthread made
meaningful progress. (In normal situations, the grace-period kthread
should make meaningful progress at least every jiffies_till_next_fqs
jiffies.)
Reported-by: Miroslav Benes <mbenes@suse.cz>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Tested-by: Miroslav Benes <mbenes@suse.cz>
Git-repo: git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
Git-commit: 6ccd2ecd422644277b7d8b37222e3af3f43ea9ae
[pdaly@codeaurora.org resolve conflict on gpnum from declining
26cdfedf6a902345f8604ea8e0b7dd2566b37a46]
Change-Id: I03d23a023650cf69986fb6f1032b4122a17daba6
Signed-off-by: Patrick Daly <pdaly@codeaurora.org>
Paul E. McKenney