[PATCH V11 07/17] riscv: qspinlock: Introduce qspinlock param for command line

[Guo Ren]

On Mon, Sep 11, 2023 at 11:34 PM Waiman Long <longman at redhat.com> wrote:
>
> On 9/10/23 04:29, guoren at kernel.org wrote:
> > From: Guo Ren <guoren at linux.alibaba.com>
> >
> > Allow cmdline to force the kernel to use queued_spinlock when
> > CONFIG_RISCV_COMBO_SPINLOCKS=y.
> >
> > Signed-off-by: Guo Ren <guoren at linux.alibaba.com>
> > Signed-off-by: Guo Ren <guoren at kernel.org>
> > ---
> >   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;

>
> Cheers,
> Longman
>


-- 
Best Regards
 Guo Ren