From: Thomas Gleixner <tglx@linutronix.de>
To: Marc Zyngier <maz@kernel.org>
Cc: linux-kernel@vger.kernel.org,
linux-arm-kernel@lists.infradead.org,
Lorenzo Pieralisi <lpieralisi@kernel.org>,
Sascha Bischoff <sascha.bischoff@arm.com>,
Timothy Hayes <timothy.hayes@arm.com>
Subject: Re: [PATCH v2 5/5] irqchip/gic-v3-its: Use allocation size from the prepare call
Date: Mon, 19 May 2025 14:16:58 +0200 [thread overview]
Message-ID: <87zff8hk1x.ffs@tglx> (raw)
In-Reply-To: <86wmacewjr.wl-maz@kernel.org>
On Mon, May 19 2025 at 11:15, Marc Zyngier wrote:
> On Sun, 18 May 2025 19:53:42 +0100,
> Thomas Gleixner <tglx@linutronix.de> wrote:
>>
>> On Tue, May 13 2025 at 17:31, Marc Zyngier wrote:
>>
>> > Now that .msi_prepare() gets called at the right time and not
>> > with semi-random parameters, remove the ugly hack that tried
>> > to fix up the number of allocated vectors.
>> >
>> > It is now correct by construction.
>>
>> FWIW, while looking at something related, it occured to me that with
>> this change you can enable MSI_FLAG_PCI_MSIX_ALLOC_DYN now on GIC ITS.
>
> Maybe. It is rather unclear to me what this "dynamic allocation"
> actually provides in terms of guarantees to the endpoint driver.
It allows the driver to avoid allocating a gazillion of interrupts
upfront during initialization. Instead it can allocate them on demand,
when e.g. a queue is initialized. Of course that means that such an
allocation can fail, but so can request_irq() and other things. I'm not
sure what you mean with guarantees here.
Thanks
tglx
next prev parent reply other threads:[~2025-05-19 12:37 UTC|newest]
Thread overview: 27+ messages / expand[flat|nested] mbox.gz Atom feed top
2025-05-13 16:31 [PATCH v2 0/5] genirq/msi: Fix device MSI prepare/alloc sequencing Marc Zyngier
2025-05-13 16:31 ` [PATCH v2 1/5] genirq/msi: Add .msi_teardown() callback as the reverse of .msi_prepare() Marc Zyngier
2025-05-16 10:02 ` [tip: irq/msi] " tip-bot2 for Marc Zyngier
2025-05-13 16:31 ` [PATCH v2 2/5] irqchip/gic-v3-its: Implement .msi_teardown() callback Marc Zyngier
2025-05-16 10:02 ` [tip: irq/msi] " tip-bot2 for Marc Zyngier
2025-05-13 16:31 ` [PATCH v2 3/5] genirq/msi: Move prepare() call to per-device allocation Marc Zyngier
2025-05-16 10:02 ` [tip: irq/msi] " tip-bot2 for Marc Zyngier
2025-06-03 8:22 ` [PATCH v2 3/5] " Zenghui Yu
2025-06-03 9:35 ` Lorenzo Pieralisi
2025-06-03 13:09 ` Marc Zyngier
2025-06-03 14:37 ` Lorenzo Pieralisi
2025-06-04 1:52 ` Zenghui Yu
2025-06-03 12:50 ` Marc Zyngier
2025-06-03 13:07 ` Zenghui Yu
2025-06-03 13:27 ` Marc Zyngier
2025-06-03 13:29 ` Lorenzo Pieralisi
2025-06-03 14:03 ` Marc Zyngier
2025-06-03 14:08 ` Marc Zyngier
2025-05-13 16:31 ` [PATCH v2 4/5] genirq/msi: Engage the .msi_teardown() callback on domain removal Marc Zyngier
2025-05-16 10:02 ` [tip: irq/msi] " tip-bot2 for Marc Zyngier
2025-05-13 16:31 ` [PATCH v2 5/5] irqchip/gic-v3-its: Use allocation size from the prepare call Marc Zyngier
2025-05-16 10:02 ` [tip: irq/msi] " tip-bot2 for Marc Zyngier
2025-05-18 18:53 ` [PATCH v2 5/5] " Thomas Gleixner
2025-05-19 10:15 ` Marc Zyngier
2025-05-19 12:16 ` Thomas Gleixner [this message]
2025-05-19 14:28 ` Marc Zyngier
2025-05-21 15:29 ` Thomas Gleixner
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