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| author | Paul E. McKenney <paulmck@linux.vnet.ibm.com> | 2016-10-11 15:09:59 +0200 |
|---|---|---|
| committer | Paul E. McKenney <paulmck@linux.vnet.ibm.com> | 2016-11-14 19:46:31 +0100 |
| commit | 0742ac3e2f9f4b8a3a394a270d8685078837662b (patch) | |
| tree | 6dfbe100d17a13adb28bc6f068dfda0afab91a09 /kernel/rcu/tree.h | |
| parent | torture: Trace long read-side delays (diff) | |
| download | linux-0742ac3e2f9f4b8a3a394a270d8685078837662b.tar.xz linux-0742ac3e2f9f4b8a3a394a270d8685078837662b.zip | |
rcu: Make expedited grace periods recheck dyntick idle state
Expedited grace periods check dyntick-idle state, and avoid sending
IPIs to idle CPUs, including those running guest OSes, and, on NOHZ_FULL
kernels, nohz_full CPUs. However, the kernel has been observed checking
a CPU while it was non-idle, but sending the IPI after it has gone
idle. This commit therefore rechecks idle state immediately before
sending the IPI, refraining from IPIing CPUs that have since gone idle.
Reported-by: Rik van Riel <riel@redhat.com>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Diffstat (limited to 'kernel/rcu/tree.h')
| -rw-r--r-- | kernel/rcu/tree.h | 1 |
1 files changed, 1 insertions, 0 deletions
diff --git a/kernel/rcu/tree.h b/kernel/rcu/tree.h index e99a5234d9ed..fe98dd24adf8 100644 --- a/kernel/rcu/tree.h +++ b/kernel/rcu/tree.h @@ -404,6 +404,7 @@ struct rcu_data { atomic_long_t exp_workdone1; /* # done by others #1. */ atomic_long_t exp_workdone2; /* # done by others #2. */ atomic_long_t exp_workdone3; /* # done by others #3. */ + int exp_dynticks_snap; /* Double-check need for IPI. */ /* 7) Callback offloading. */ #ifdef CONFIG_RCU_NOCB_CPU |