diff options
| author | Frederic Weisbecker <frederic@kernel.org> | 2021-11-23 01:37:07 +0100 |
|---|---|---|
| committer | Paul E. McKenney <paulmck@kernel.org> | 2021-12-09 11:35:11 -0800 |
| commit | d2cf0854d728c42524efc169edb3505de8c1a9dc (patch) | |
| tree | 5b3b7489bccf6764c9ac1f7f802cc969ed96c259 /kernel/rcu | |
| parent | 2cf4528d6dd6f5a7f34ae07e26176a7932310eeb (diff) | |
rcu/nocb: Allow empty "rcu_nocbs" kernel parameter
Allow the rcu_nocbs kernel parameter to be specified just by itself,
without specifying any CPUs. This allows systems administrators to use
"rcu_nocbs" to specify that none of the CPUs are to be offloaded at boot
time, but than any of them may be offloaded at runtime via cpusets.
In contrast, if the "rcu_nocbs" or "nohz_full" kernel parameters are not
specified at all, then not only are none of the CPUs offloaded at boot,
none of them can be offloaded at runtime, either.
While in the area, modernize the description of the "rcuo" kthreads'
naming scheme.
Reviewed-by: Neeraj Upadhyay <quic_neeraju@quicinc.com>
Signed-off-by: Frederic Weisbecker <frederic@kernel.org>
Cc: Boqun Feng <boqun.feng@gmail.com>
Cc: Uladzislau Rezki <urezki@gmail.com>
Cc: Josh Triplett <josh@joshtriplett.org>
Cc: Joel Fernandes <joel@joelfernandes.org>
Tested-by: Juri Lelli <juri.lelli@redhat.com>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
Diffstat (limited to 'kernel/rcu')
| -rw-r--r-- | kernel/rcu/tree_nocb.h | 10 |
1 files changed, 6 insertions, 4 deletions
diff --git a/kernel/rcu/tree_nocb.h b/kernel/rcu/tree_nocb.h index f580a6b2e74e..0c1802ce4764 100644 --- a/kernel/rcu/tree_nocb.h +++ b/kernel/rcu/tree_nocb.h @@ -66,14 +66,16 @@ static bool rcu_nocb_is_setup; static int __init rcu_nocb_setup(char *str) { alloc_bootmem_cpumask_var(&rcu_nocb_mask); - if (cpulist_parse(str, rcu_nocb_mask)) { - pr_warn("rcu_nocbs= bad CPU range, all CPUs set\n"); - cpumask_setall(rcu_nocb_mask); + if (*str == '=') { + if (cpulist_parse(++str, rcu_nocb_mask)) { + pr_warn("rcu_nocbs= bad CPU range, all CPUs set\n"); + cpumask_setall(rcu_nocb_mask); + } } rcu_nocb_is_setup = true; return 1; } -__setup("rcu_nocbs=", rcu_nocb_setup); +__setup("rcu_nocbs", rcu_nocb_setup); static int __init parse_rcu_nocb_poll(char *arg) { |