diff options
| author | Waiman Long <longman@redhat.com> | 2021-11-18 20:14:37 +0100 |
|---|---|---|
| committer | Paul E. McKenney <paulmck@kernel.org> | 2021-12-01 02:22:29 +0100 |
| commit | 1a5620671a1b6fd9cc08761677d050f1702f910c (patch) | |
| tree | 4e57d639dbbb2b30439391cbe312d2fa43e7a139 | |
| parent | clocksource: Avoid accidental unstable marking of clocksources (diff) | |
| download | linux-1a5620671a1b6fd9cc08761677d050f1702f910c.tar.xz linux-1a5620671a1b6fd9cc08761677d050f1702f910c.zip | |
clocksource: Reduce the default clocksource_watchdog() retries to 2
With the previous patch, there is an extra watchdog read in each retry.
Now the total number of clocksource reads is increased to 4 per iteration.
In order to avoid increasing the clock skew check overhead, the default
maximum number of retries is reduced from 3 to 2 to maintain the same 12
clocksource reads in the worst case.
Suggested-by: Paul E. McKenney <paulmck@kernel.org>
Signed-off-by: Waiman Long <longman@redhat.com>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
| -rw-r--r-- | Documentation/admin-guide/kernel-parameters.txt | 4 | ||||
| -rw-r--r-- | kernel/time/clocksource.c | 2 |
2 files changed, 3 insertions, 3 deletions
diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt index 9725c546a0d4..3ea934b034f7 100644 --- a/Documentation/admin-guide/kernel-parameters.txt +++ b/Documentation/admin-guide/kernel-parameters.txt @@ -603,8 +603,8 @@ clocksource.max_cswd_read_retries= [KNL] Number of clocksource_watchdog() retries due to external delays before the clock will be marked - unstable. Defaults to three retries, that is, - four attempts to read the clock under test. + unstable. Defaults to two retries, that is, + three attempts to read the clock under test. clocksource.verify_n_cpus= [KNL] Limit the number of CPUs checked for clocksources diff --git a/kernel/time/clocksource.c b/kernel/time/clocksource.c index bcad1a1e5dcf..b7e52a642948 100644 --- a/kernel/time/clocksource.c +++ b/kernel/time/clocksource.c @@ -199,7 +199,7 @@ void clocksource_mark_unstable(struct clocksource *cs) spin_unlock_irqrestore(&watchdog_lock, flags); } -ulong max_cswd_read_retries = 3; +ulong max_cswd_read_retries = 2; module_param(max_cswd_read_retries, ulong, 0644); EXPORT_SYMBOL_GPL(max_cswd_read_retries); static int verify_n_cpus = 8; |