5.15-stable review patch. If anyone has any objections, please let me know.
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From: Waiman Long longman@redhat.com
[ Upstream commit 1a5620671a1b6fd9cc08761677d050f1702f910c ]
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 Stable-dep-of: f2655ac2c06a ("clocksource: Fix brown-bag boolean thinko in cs_watchdog_read()") Signed-off-by: Sasha Levin sashal@kernel.org --- Documentation/admin-guide/kernel-parameters.txt | 4 ++-- 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 d49e11962333c..2db3d5b6fc038 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 7d6d87a22ad55..38bb654d2a7e1 100644 --- a/kernel/time/clocksource.c +++ b/kernel/time/clocksource.c @@ -201,7 +201,7 @@ 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;