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| author | Alison Chaiken <achaiken@aurora.tech> | 2022-01-11 15:32:52 -0800 |
|---|---|---|
| committer | Paul E. McKenney <paulmck@kernel.org> | 2022-02-01 17:19:25 -0800 |
| commit | c8b16a65267e35ecc5621dbc81cbe7e5b0992fce (patch) | |
| tree | 99ff340a284841b875aa4ca4b2d146ce97ebf181 /kernel/rcu/tree_nocb.h | |
| parent | 54577e23fa0791599db1a3d86fc8e7a205d3da75 (diff) | |
| download | lwn-c8b16a65267e35ecc5621dbc81cbe7e5b0992fce.tar.gz lwn-c8b16a65267e35ecc5621dbc81cbe7e5b0992fce.zip | |
rcu: Elevate priority of offloaded callback threads
When CONFIG_PREEMPT_RT=y, the rcutree.kthread_prio command-line
parameter signals initialization code to boost the priority of rcuc
callbacks to the designated value. With the additional
CONFIG_RCU_NOCB_CPU=y configuration and an additional rcu_nocbs
command-line parameter, the callbacks on the listed cores are
offloaded to new rcuop kthreads that are not pinned to the cores whose
post-grace-period work is performed. While the rcuop kthreads perform
the same function as the rcuc kthreads they offload, the kthread_prio
parameter only boosts the priority of the rcuc kthreads. Fix this
inconsistency by elevating rcuop kthreads to the same priority as the rcuc
kthreads.
Signed-off-by: Alison Chaiken <achaiken@aurora.tech>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
Diffstat (limited to 'kernel/rcu/tree_nocb.h')
| -rw-r--r-- | kernel/rcu/tree_nocb.h | 3 |
1 files changed, 3 insertions, 0 deletions
diff --git a/kernel/rcu/tree_nocb.h b/kernel/rcu/tree_nocb.h index ea889cbfc3b9..547c41437c76 100644 --- a/kernel/rcu/tree_nocb.h +++ b/kernel/rcu/tree_nocb.h @@ -1270,6 +1270,9 @@ static void rcu_spawn_cpu_nocb_kthread(int cpu) "rcuo%c/%d", rcu_state.abbr, cpu); if (WARN_ONCE(IS_ERR(t), "%s: Could not start rcuo CB kthread, OOM is now expected behavior\n", __func__)) return; + + if (kthread_prio) + sched_setscheduler_nocheck(t, SCHED_FIFO, &sp); WRITE_ONCE(rdp->nocb_cb_kthread, t); WRITE_ONCE(rdp->nocb_gp_kthread, rdp_gp->nocb_gp_kthread); } |