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authorPaul E. McKenney <paulmck@linux.ibm.com>2019-03-06 14:47:56 -0800
committerPaul E. McKenney <paulmck@linux.ibm.com>2019-03-26 14:37:49 -0700
commit497e42600b69aca1b799c840d2cfc7ad60bb8017 (patch)
tree701b61118019723ddd2d7867acd2ae42f5599551 /kernel/rcu
parentda8739f23fadf05809c6c37c327367b229467045 (diff)
downloadlinux-497e42600b69aca1b799c840d2cfc7ad60bb8017.tar.bz2
rcu: Report error for bad rcu_nocbs= parameter values
This commit prints a console message when cpulist_parse() reports a bad list of CPUs, and sets all CPUs' bits in that case. The reason for setting all CPUs' bits is that this is the safe(r) choice for real-time workloads, which would normally be the ones using the rcu_nocbs= kernel boot parameter. Either way, later RCU console log messages list the actual set of CPUs whose RCU callbacks will be offloaded. Signed-off-by: Paul E. McKenney <paulmck@linux.ibm.com>
Diffstat (limited to 'kernel/rcu')
-rw-r--r--kernel/rcu/tree_plugin.h12
1 files changed, 10 insertions, 2 deletions
diff --git a/kernel/rcu/tree_plugin.h b/kernel/rcu/tree_plugin.h
index ed4a6dabf31d..f0aeb7416dcc 100644
--- a/kernel/rcu/tree_plugin.h
+++ b/kernel/rcu/tree_plugin.h
@@ -1772,14 +1772,22 @@ static void zero_cpu_stall_ticks(struct rcu_data *rdp)
*/
-/* Parse the boot-time rcu_nocb_mask CPU list from the kernel parameters. */
+/*
+ * Parse the boot-time rcu_nocb_mask CPU list from the kernel parameters.
+ * The string after the "rcu_nocbs=" is either "all" for all CPUs, or a
+ * comma-separated list of CPUs and/or CPU ranges. If an invalid list is
+ * given, a warning is emitted and all CPUs are offloaded.
+ */
static int __init rcu_nocb_setup(char *str)
{
alloc_bootmem_cpumask_var(&rcu_nocb_mask);
if (!strcasecmp(str, "all"))
cpumask_setall(rcu_nocb_mask);
else
- cpulist_parse(str, 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);
+ }
return 1;
}
__setup("rcu_nocbs=", rcu_nocb_setup);