rcu: Restrict default jiffies_till_first_fqs for strict RCU GPs

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If there are idle CPUs, RCU's grace-period kthread will wait several
jiffies before even thinking about polling them.  This promotes
efficiency, which is normally a good thing, but when the kernel
has been built with CONFIG_RCU_STRICT_GRACE_PERIOD=y, we care more
about short grace periods.  This commit therefore restricts the
default jiffies_till_first_fqs value to zero in kernels built with
CONFIG_RCU_STRICT_GRACE_PERIOD=y, which causes RCU's grace-period kthread
to poll for idle CPUs immediately after starting a grace period.

Reported-by Jann Horn <jannh@google.com>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>

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Paul E. McKenney 2020-08-05 17:25:23 -07:00

parent dc1269186b

commit aecd34b976

1 changed files with 1 additions and 1 deletions

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kernel/rcu/tree.c

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