[EXT] Re: [PATCH 0/2] qla2xxx - add nvme map_queues support

[Saurav Kashyap]

Hi Ming,
Comments inline

> -----Original Message-----
> From: Ming Lei <ming.lei at redhat.com>
> Sent: Tuesday, August 24, 2021 9:17 AM
> To: Saurav Kashyap <skashyap at marvell.com>
> Cc: Sagi Grimberg <sagi at grimberg.me>; Nilesh Javali <njavali at marvell.com>;
> martin.petersen at oracle.com; linux-nvme at lists.infradead.org; linux-
> scsi at vger.kernel.org; GR-QLogic-Storage-Upstream <GR-QLogic-Storage-
> Upstream at marvell.com>
> Subject: [EXT] Re: [PATCH 0/2] qla2xxx - add nvme map_queues support
> 
> External Email
> 
> ----------------------------------------------------------------------
> On Tue, Aug 24, 2021 at 03:38:24AM +0000, Saurav Kashyap wrote:
> > Hi Sagi,
> > Comments inline
> >
> > > -----Original Message-----
> > > From: Sagi Grimberg <sagi at grimberg.me>
> > > Sent: Monday, August 23, 2021 10:51 PM
> > > To: Nilesh Javali <njavali at marvell.com>; martin.petersen at oracle.com;
> linux-
> > > nvme at lists.infradead.org; Ming Lei <ming.lei at redhat.com>
> > > Cc: linux-scsi at vger.kernel.org; GR-QLogic-Storage-Upstream <GR-QLogic-
> > > Storage-Upstream at marvell.com>
> > > Subject: Re: [PATCH 0/2] qla2xxx - add nvme map_queues support
> > >
> > >
> > > On 8/23/21 5:56 AM, Nilesh Javali wrote:
> > > > Currently nvme fc doesn't support map queue functionality. This patch
> > > > set adds map_queue functionality to nvme_fc_mq_ops and
> > > > nvme_fc_port_template, providing an option to LLDs to map queues
> > > > similar to SCSI. For qla2xxx, minimum 10% improvement is noticed
> > > > with this change as it helps in reducing cpu thrashing.
> > >
> > > Does this make nvme-fc use managed irq?
> >
> > qla2xxx driver uses pci_alloc_irq_vectors_affinity to have affinity with each
> MSI-X vector. Currently nvme queue are not mapped based on affinity and irq
> offset. The change is to use blk_mq_pci_map_queues for mapping, this function
> consider irq affinity as well as irq offset.
> >
> 
> OK, got it. Even though without this patchset, nvme-fc actually relies
> on managed irq since qla2xxx driver uses pci_alloc_irq_vectors_affinity.
> 
> Now the patchset[1] isn't good for addressing the issue in
> blk_mq_alloc_request_hctx().

Can you please elaborate on this? Is there something needs to be done from my side?

Thanks,
~Saurav
> 
> [1] https://urldefense.proofpoint.com/v2/url?u=https-
> 3A__lore.kernel.org_linux-2Dblock_YR7demOSG6MKFVAF-40T590_T_-
> 23t&d=DwIBAg&c=nKjWec2b6R0mOyPaz7xtfQ&r=ZHZbmY_LbM3DUZK_BDO1
> OITP3ot_Vkb_5w-
> gas5TBMQ&m=CqFDnfAsZphubKXkUx5gsRF6RZ2Qe6sxWkYq4pBfFD0&s=2Nba
> EUI5eB6_R6PxW8ld1Xn2OU3_UdD6D30uvFAWhow&e=
> 
> 
> Thanks,
> Ming