On 9/14/23 03:32, Leonardo Bras wrote:
On Tue, Sep 12, 2023 at 09:08:34AM +0800, Guo Ren wrote:
On Mon, Sep 11, 2023 at 11:34 PM Waiman Long <longman@xxxxxxxxxx> wrote:
On 9/10/23 04:29, guoren@xxxxxxxxxx wrote:
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;
You can use __ro_after_init qualifier for enable_qspinlock_key. BTW,
this is not a static key, just a simple flag. So what is the point of
the _key suffix?
Okay, I would change it to:
bool enable_qspinlock_flag __ro_after_init = false;
IIUC, this bool / flag is used in a single file, so it makes sense for it
to be static. Being static means it does not need to be initialized to
false, as it's standard to zero-fill this areas.
Also, since it's a bool, it does not need to be called _flag.
I would go with:
static bool enable_qspinlock __ro_after_init;
I actually was thinking about the same suggestion to add static. Then I
realized that the flag was also used in another file in a later patch.
Of course, if it turns out that this flag is no longer needed outside of
this file, it should be static.
Cheers,
Longman
