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From: Thomas Gleixner <tglx@linutronix.de>
To: Marc Zyngier <maz@kernel.org>
Cc: LKML <linux-kernel@vger.kernel.org>,
	Alex Williamson <alex.williamson@redhat.com>, "Raj\,
	Ashok" <ashok.raj@intel.com>, Ingo Molnar <mingo@kernel.org>,
	"David S. Miller" <davem@davemloft.net>,
	Bjorn Helgaas <bhelgaas@google.com>,
	linux-pci@vger.kernel.org, Kevin Tian <kevin.tian@intel.com>,
	x86@kernel.org
Subject: Re: [patch 6/8] genirq: Provide IRQCHIP_AFFINITY_PRE_STARTUP
Date: Wed, 28 Jul 2021 12:40:18 +0200	[thread overview]
Message-ID: <87bl6m3enh.ffs@nanos.tec.linutronix.de> (raw)
In-Reply-To: <871r7q2xik.wl-maz@kernel.org>

On Thu, Jul 22 2021 at 16:12, Marc Zyngier wrote:
> On Wed, 21 Jul 2021 20:11:32 +0100,
> Thomas Gleixner <tglx@linutronix.de> wrote:
>>  #include <linux/irqdesc.h>
>> --- a/kernel/irq/chip.c
>> +++ b/kernel/irq/chip.c
>> @@ -265,8 +265,11 @@ int irq_startup(struct irq_desc *desc, b
>>  	} else {
>>  		switch (__irq_startup_managed(desc, aff, force)) {
>>  		case IRQ_STARTUP_NORMAL:
>> +			if (d->chip->flags & IRQCHIP_AFFINITY_PRE_STARTUP)
>> +				irq_setup_affinity(desc);
>
> How about moving this to activate instead? We already special-case the
> activation of MSIs for PCI (MSI_FLAG_ACTIVATE_EARLY), and this
> wouldn't look completely out of place. The startup mode could be an
> issue though...

Yes, I thought about that, but the ordering here is:

setup()
  early_activate()

early activation just needs to program a valid message. Now later we
have request_irq() invoking:

     activate()
     startup()

So, yes. We could do that in activate, but then we still have the post
startup variant in irq_startup() which makes the code hard to follow.

There is another practical issue. Assume the irq is requested with
IRQF_NOAUTOEN, then irq_startup() will be invoked when the driver calls
enable_irq(), which might be way later and then the affinity setting
might be completely different already. So I rather keep it there.

Thanks,

        tglx

  reply	other threads:[~2021-07-28 10:40 UTC|newest]

Thread overview: 30+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-07-21 19:11 [patch 0/8] PCI/MSI, x86: Cure a couple of inconsistencies Thomas Gleixner
2021-07-21 19:11 ` [patch 1/8] PCI/MSI: Enable and mask MSIX early Thomas Gleixner
2021-07-21 21:38   ` Raj, Ashok
2021-07-21 22:51     ` Thomas Gleixner
2021-07-22 21:43   ` Bjorn Helgaas
2021-07-27 20:33     ` Thomas Gleixner
2021-07-21 19:11 ` [patch 2/8] PCI/MSI: Mask all unused MSI-X entries Thomas Gleixner
2021-07-21 22:23   ` Raj, Ashok
2021-07-21 22:57     ` Thomas Gleixner
2021-07-22 13:46       ` Marc Zyngier
2021-07-28 10:04         ` Thomas Gleixner
2021-07-22 21:45   ` Bjorn Helgaas
2021-07-21 19:11 ` [patch 3/8] PCI/MSI: Enforce that MSI-X table entry is masked for update Thomas Gleixner
2021-07-21 22:32   ` Raj, Ashok
2021-07-21 22:59     ` Thomas Gleixner
2021-07-22 21:46   ` Bjorn Helgaas
2021-07-21 19:11 ` [patch 4/8] PCI/MSI: Enforce MSI[X] entry updates to be visible Thomas Gleixner
2021-07-22 21:48   ` Bjorn Helgaas
     [not found]     ` <CAHp75VdNi4rMuRz8UrW9Haf_Ge8KmNJ0w9ykheqkVhmpXHTUyg@mail.gmail.com>
2021-07-23  8:14       ` Marc Zyngier
2021-07-21 19:11 ` [patch 5/8] PCI/MSI: Simplify msi_verify_entries() Thomas Gleixner
2021-07-21 19:11 ` [patch 6/8] genirq: Provide IRQCHIP_AFFINITY_PRE_STARTUP Thomas Gleixner
2021-07-22 15:12   ` Marc Zyngier
2021-07-28 10:40     ` Thomas Gleixner [this message]
2021-07-21 19:11 ` [patch 7/8] x86/ioapic: Force affinity setup before startup Thomas Gleixner
2021-07-21 19:11 ` [patch 8/8] x86/msi: " Thomas Gleixner
2021-07-21 21:10 ` [patch 0/8] PCI/MSI, x86: Cure a couple of inconsistencies Raj, Ashok
2021-07-21 22:39   ` Thomas Gleixner
2021-07-22 15:17 ` Marc Zyngier
2021-07-22 21:43 ` Bjorn Helgaas
2021-07-27 20:38   ` Thomas Gleixner

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