From: Marc Zyngier <maz@kernel.org>
To: Frank Li <frank.li@nxp.com>
Cc: "tglx@linutronix.de" <tglx@linutronix.de>,
"robh+dt@kernel.org" <robh+dt@kernel.org>,
"krzysztof.kozlowski+dt@linaro.org"
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<manivannan.sadhasivam@linaro.org>
Subject: Re: [EXT] Re: [PATCH v9 2/4] irqchip: Add IMX MU MSI controller driver
Date: Sat, 10 Sep 2022 15:35:59 +0100 [thread overview]
Message-ID: <87y1urpa9c.wl-maz@kernel.org> (raw)
In-Reply-To: <AM9PR04MB8793746D9ECC6F07FD5B841888439@AM9PR04MB8793.eurprd04.prod.outlook.com>
On Fri, 09 Sep 2022 15:59:01 +0100,
Frank Li <frank.li@nxp.com> wrote:
>
> > >
> > > [Frank Li] According to my understand, raw_spinlock skip some lockdep
> > > /debug feature to get better performance, which should be used when
> > > Frequently call, such as irq handle\polling thread.
> >
> > I'm afraid you are terribly misguided. They both have the same debug
> > features because they are both using the same core implementation, and
> > the only difference is whether this is preemptible for RT purposes or
> > not.
> >
> > > Spinlock have DEBUG feature to check wrong use lock. Allocate MSI
> > generally
> > > only is call once when driver probe.
> >
> > Again, you should really read the code and the documentation and stop
> > making things up.
>
> [Frank Li] Thanks. You give me the correct direction. Some stackoverflow's
> Doc was misleaded. I double checked spin_lock implementation. PREEMPT_RT
> Kernel map spin_lock to rt_mutex.
>
> I am curious why exist spin_lock_irqsave and raw_spin_lock_irqsave before
> PREEMTP_RT merge into kernel tree.
Because the RT merge has been going on for 10 years or so, long before
CONFIG_RT was merged. Also, a mutex has a spin lock at its core, and
it makes sense to have a single primitive for all these lock types.
M.
--
Without deviation from the norm, progress is not possible.
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next prev parent reply other threads:[~2022-09-10 14:37 UTC|newest]
Thread overview: 24+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-09-07 3:48 [PATCH v9 0/4] PCI EP driver support MSI doorbell from host Frank Li
2022-09-07 3:48 ` [PATCH v9 1/4] irqchip: allow pass down .pm field at IRQCHIP_PLATFORM_DRIVER_END Frank Li
2022-09-07 3:48 ` [PATCH v9 2/4] irqchip: Add IMX MU MSI controller driver Frank Li
2022-09-08 0:03 ` kernel test robot
2022-09-08 7:02 ` Marc Zyngier
2022-09-08 14:26 ` [EXT] " Frank Li
2022-09-08 14:35 ` Marc Zyngier
2022-09-08 7:39 ` Marc Zyngier
2022-09-08 14:23 ` [EXT] " Frank Li
2022-09-08 14:51 ` Marc Zyngier
2022-09-08 15:35 ` Frank Li
2022-09-09 12:07 ` Marc Zyngier
2022-09-09 14:59 ` Frank Li
2022-09-10 14:35 ` Marc Zyngier [this message]
2022-09-12 15:53 ` Frank Li
2022-09-13 17:44 ` Marc Zyngier
2022-09-09 14:52 ` Frank Li
2022-09-10 14:40 ` Marc Zyngier
2022-09-12 16:17 ` Frank Li
2022-09-07 3:48 ` [PATCH v9 3/4] dt-bindings: irqchip: imx mu work as msi controller Frank Li
2022-09-09 1:43 ` Rob Herring
2022-09-07 3:48 ` [PATCH v9 4/4] PCI: endpoint: Add vNTB MSI support Frank Li
2022-09-07 20:43 ` kernel test robot
2022-09-13 17:24 ` Manivannan Sadhasivam
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