diff options
author | Paul E. McKenney <paulmck@kernel.org> | 2020-08-07 04:21:48 +0200 |
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committer | Paul E. McKenney <paulmck@kernel.org> | 2020-08-25 03:40:26 +0200 |
commit | 933ada2c3310aa88807e65c8d498b74a2159a9a2 (patch) | |
tree | 3a1a7aaf22c5fee7531a343df5cc037aa5c2ed3c /kernel | |
parent | rcu: Attempt QS when CPU discovers GP for strict GPs (diff) | |
download | linux-933ada2c3310aa88807e65c8d498b74a2159a9a2.tar.xz linux-933ada2c3310aa88807e65c8d498b74a2159a9a2.zip |
rcu: IPI all CPUs at GP start for strict GPs
Currently, each CPU discovers the beginning of a given grace period
on its own time, which is again good for efficiency but bad for fast
grace periods. This commit therefore uses on_each_cpu() to IPI each
CPU after grace-period initialization in order to inform each CPU of
the new grace period in a timely manner, but only in kernels build with
CONFIG_RCU_STRICT_GRACE_PERIOD=y.
Reported-by Jann Horn <jannh@google.com>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
Diffstat (limited to 'kernel')
-rw-r--r-- | kernel/rcu/tree.c | 13 |
1 files changed, 13 insertions, 0 deletions
diff --git a/kernel/rcu/tree.c b/kernel/rcu/tree.c index 36a860c4648b..88f4fa639964 100644 --- a/kernel/rcu/tree.c +++ b/kernel/rcu/tree.c @@ -1696,6 +1696,15 @@ static void rcu_gp_torture_wait(void) } /* + * Handler for on_each_cpu() to invoke the target CPU's RCU core + * processing. + */ +static void rcu_strict_gp_boundary(void *unused) +{ + invoke_rcu_core(); +} + +/* * Initialize a new grace period. Return false if no grace period required. */ static bool rcu_gp_init(void) @@ -1823,6 +1832,10 @@ static bool rcu_gp_init(void) WRITE_ONCE(rcu_state.gp_activity, jiffies); } + // If strict, make all CPUs aware of new grace period. + if (IS_ENABLED(CONFIG_RCU_STRICT_GRACE_PERIOD)) + on_each_cpu(rcu_strict_gp_boundary, NULL, 0); + return true; } |