On Wed, 2019-06-19 at 15:03 -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. I have resent the patches to include LKML. https://lkml.org/lkml/2019/6/21/923 > > 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 > PCI/MSI: Free MSI-X resources by group > Documentation: PCI/MSI: Document dynamic MSI-X infrastructure > > 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(-) >
