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| author | Paul E. McKenney <paulmck@kernel.org> | 2024-10-09 11:02:53 -0700 |
|---|---|---|
| committer | Frederic Weisbecker <frederic@kernel.org> | 2024-11-12 23:05:11 +0100 |
| commit | 80e935c8c154d8fbdd85a20d89b4962662ceddd7 (patch) | |
| tree | 30da78c85569c95e92d37a790bee81e4f5cf8830 | |
| parent | ff9ba8db87222be8d344f7c1cc3c28b1e22f6429 (diff) | |
| download | lwn-80e935c8c154d8fbdd85a20d89b4962662ceddd7.tar.gz lwn-80e935c8c154d8fbdd85a20d89b4962662ceddd7.zip | |
rcutorture: Avoid printing cpu=-1 for no-fault RCU boost failure
If a CPU runs throughout the stalled grace period without passing
through a quiescent state, RCU priority boosting cannot help.
The rcu_torture_boost_failed() function therefore prints a message
flagging the first such CPU. However, if the stall was instead due to
(for example) RCU's grace-period kthread being starved of CPU, there will
be no such CPU, causing rcu_check_boost_fail() to instead pass back -1
through its cpup CPU-pointer parameter.
Therefore, the current message complains about a mythical CPU -1.
This commit therefore checks for this situation, and notes that all CPUs
have passed through a quiescent state.
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
Reviewed-by: Neeraj Upadhyay <Neeraj.Upadhyay@amd.com>
Signed-off-by: Frederic Weisbecker <frederic@kernel.org>
| -rw-r--r-- | kernel/rcu/rcutorture.c | 9 |
1 files changed, 7 insertions, 2 deletions
diff --git a/kernel/rcu/rcutorture.c b/kernel/rcu/rcutorture.c index bb75dbf5c800..e92fa97fc76f 100644 --- a/kernel/rcu/rcutorture.c +++ b/kernel/rcu/rcutorture.c @@ -1059,8 +1059,13 @@ static bool rcu_torture_boost_failed(unsigned long gp_state, unsigned long *star // At most one persisted message per boost test. j = jiffies; lp = READ_ONCE(last_persist); - if (time_after(j, lp + mininterval) && cmpxchg(&last_persist, lp, j) == lp) - pr_info("Boost inversion persisted: No QS from CPU %d\n", cpu); + if (time_after(j, lp + mininterval) && + cmpxchg(&last_persist, lp, j) == lp) { + if (cpu < 0) + pr_info("Boost inversion persisted: QS from all CPUs\n"); + else + pr_info("Boost inversion persisted: No QS from CPU %d\n", cpu); + } return false; // passed on a technicality } VERBOSE_TOROUT_STRING("rcu_torture_boost boosting failed"); |