From: Guo Ren <guoren@xxxxxxxxxxxxxxxxx>
Allow cmdline to force the kernel to use queued_spinlock when
CONFIG_RISCV_COMBO_SPINLOCKS=y.
Signed-off-by: Guo Ren <guoren@xxxxxxxxxxxxxxxxx>
Signed-off-by: Guo Ren <guoren@xxxxxxxxxx>
---
Documentation/admin-guide/kernel-parameters.txt | 2 ++
arch/riscv/kernel/setup.c | 16 +++++++++++++++-
2 files changed, 17 insertions(+), 1 deletion(-)
diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt
index 7dfb540c4f6c..61cacb8dfd0e 100644
--- a/Documentation/admin-guide/kernel-parameters.txt
+++ b/Documentation/admin-guide/kernel-parameters.txt
@@ -4693,6 +4693,8 @@
[KNL] Number of legacy pty's. Overwrites compiled-in
default number.
+ qspinlock [RISCV] Force to use qspinlock or auto-detect spinlock.
+
qspinlock.numa_spinlock_threshold_ns= [NUMA, PV_OPS]
Set the time threshold in nanoseconds for the
number of intra-node lock hand-offs before the
diff --git a/arch/riscv/kernel/setup.c b/arch/riscv/kernel/setup.c
index a447cf360a18..0f084f037651 100644
--- a/arch/riscv/kernel/setup.c
+++ b/arch/riscv/kernel/setup.c
@@ -270,6 +270,15 @@ static void __init parse_dtb(void)
}
#ifdef CONFIG_RISCV_COMBO_SPINLOCKS
+bool enable_qspinlock_key = false;
+static int __init queued_spinlock_setup(char *p)
+{
+ enable_qspinlock_key = true;
+
+ return 0;
+}
+early_param("qspinlock", queued_spinlock_setup);
+
DEFINE_STATIC_KEY_TRUE(combo_qspinlock_key);
EXPORT_SYMBOL(combo_qspinlock_key);
#endif
@@ -277,7 +286,12 @@ EXPORT_SYMBOL(combo_qspinlock_key);
static void __init riscv_spinlock_init(void)
{
#ifdef CONFIG_RISCV_COMBO_SPINLOCKS
- static_branch_disable(&combo_qspinlock_key);
+ if (!enable_qspinlock_key) {
+ static_branch_disable(&combo_qspinlock_key);
+ pr_info("Ticket spinlock: enabled\n");
+ } else {
+ pr_info("Queued spinlock: enabled\n");
+ }
#endif
}
--
2.36.1
