From: Bjorn Helgaas <helgaas@kernel.org>
To: Megha Dey <megha.dey@linux.intel.com>
Cc: linux-pci@vger.kernel.org, linux-kernel@vger.kernel.org,
tglx@linutronix.de, marc.zyngier@arm.com, ashok.raj@intel.com,
jacob.jun.pan@linux.intel.com, megha.dey@intel.com
Subject: Re: [RFC V1 RESEND 0/6] Introduce dynamic allocation/freeing of MSI-X vectors
Date: Thu, 1 Aug 2019 19:24:42 -0500 [thread overview]
Message-ID: <20190802002442.GI151852@google.com> (raw)
In-Reply-To: <1561162778-12669-1-git-send-email-megha.dey@linux.intel.com>
Hi Megha,
On Fri, Jun 21, 2019 at 05:19:32PM -0700, Megha Dey wrote:
> Currently, MSI-X vector enabling and allocation for a PCIe device is
> static i.e. a device driver gets only one chance to enable a specific
> number of MSI-X vectors, usually during device probe. Also, in many
> cases, drivers usually reserve more than required number of vectors
> anticipating their use, which unnecessarily blocks resources that
> could have been made available to other devices. Lastly, there is no
> way for drivers to reserve more vectors, if the MSI-x has already been
> enabled for that device.
>
> Hence, a dynamic MSI-X kernel infrastructure can benefit drivers by
> deferring MSI-X allocation to post probe phase, where actual demand
> information is available.
>
> This patchset enables the dynamic allocation/de-allocation of MSI-X
> vectors by introducing 2 new APIs:
> pci_alloc_irq_vectors_dyn() and pci_free_irq_vectors_grp():
>
> We have had requests from some of the NIC/RDMA users who have lots of
> interrupt resources and would like to allocate them on demand,
> instead of using an all or none approach.
>
> The APIs are fairly well tested (multiple allocations/deallocations),
> but we have no early adopters yet. Hence, sending this series as an
> RFC for review and comments.
>
> The patches are based out of Linux 5.2-rc5.
>
> Megha Dey (6):
> PCI/MSI: New structures/macros for dynamic MSI-X allocation
> PCI/MSI: Dynamic allocation of MSI-X vectors by group
> x86: Introduce the dynamic teardown function
> PCI/MSI: Introduce new structure to manage MSI-x entries
s/MSI-x/MSI-X/
If "entries" here means the same as "vectors" above, please use the
same word.
> PCI/MSI: Free MSI-X resources by group
Is "resources" the same as "vectors"?
> Documentation: PCI/MSI: Document dynamic MSI-X infrastructure
When you post a v2 after addressing Thomas' comments, please make
these subject lines imperative sentences beginning with a descriptive
verb. You can run "git log --oneline drivers/pci" to see the style.
If you're adding a specific interface or structure, mention it by name
in the subject if it's practical. The "x86" line needs a little more
context; I assume it should include "IRQ", "MSI-X", or something.
> Documentation/PCI/MSI-HOWTO.txt | 38 +++++
> arch/x86/include/asm/x86_init.h | 1 +
> arch/x86/kernel/x86_init.c | 6 +
> drivers/pci/msi.c | 363 +++++++++++++++++++++++++++++++++++++---
> drivers/pci/probe.c | 9 +
> include/linux/device.h | 3 +
> include/linux/msi.h | 13 ++
> include/linux/pci.h | 61 +++++++
> kernel/irq/msi.c | 34 +++-
> 9 files changed, 497 insertions(+), 31 deletions(-)
>
> --
> 2.7.4
>
next prev parent reply other threads:[~2019-08-02 0:24 UTC|newest]
Thread overview: 24+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-06-22 0:19 [RFC V1 RESEND 0/6] Introduce dynamic allocation/freeing of MSI-X vectors Megha Dey
2019-06-22 0:19 ` [RFC V1 RESEND 1/6] PCI/MSI: New structures/macros for dynamic MSI-X allocation Megha Dey
2019-06-22 0:19 ` [RFC V1 RESEND 2/6] PCI/MSI: Dynamic allocation of MSI-X vectors by group Megha Dey
2019-06-29 7:59 ` Thomas Gleixner
2019-08-06 19:05 ` Megha Dey
2019-08-07 13:56 ` Thomas Gleixner
2019-08-07 14:18 ` Marc Zyngier
2019-08-11 7:20 ` Thomas Gleixner
2019-08-12 17:54 ` Megha Dey
2019-08-12 17:48 ` Megha Dey
2019-08-12 17:47 ` Megha Dey
2021-01-07 22:30 ` Jacob Keller
2019-06-22 0:19 ` [RFC V1 RESEND 3/6] x86: Introduce the dynamic teardown function Megha Dey
2019-06-29 8:01 ` Thomas Gleixner
2019-08-06 19:06 ` Megha Dey
2019-06-22 0:19 ` [RFC V1 RESEND 4/6] PCI/MSI: Introduce new structure to manage MSI-x entries Megha Dey
2019-06-22 0:19 ` [RFC V1 RESEND 5/6] PCI/MSI: Free MSI-X resources by group Megha Dey
2019-06-29 8:08 ` Thomas Gleixner
2019-08-06 19:09 ` Megha Dey
2019-08-11 7:18 ` Thomas Gleixner
2019-08-12 18:13 ` Megha Dey
2019-06-22 0:19 ` [RFC V1 RESEND 6/6] Documentation: PCI/MSI: Document dynamic MSI-X infrastructure Megha Dey
2019-08-02 0:24 ` Bjorn Helgaas [this message]
2019-08-06 19:12 ` [RFC V1 RESEND 0/6] Introduce dynamic allocation/freeing of MSI-X vectors Megha Dey
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