From: Thomas Gleixner <tglx@linutronix.de>
To: Jens Axboe <axboe@kernel.dk>
Cc: Keith Busch <keith.busch@intel.com>,
linux-block@vger.kernel.org, linux-scsi@vger.kernel.org,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH 11/14] irq: add support for allocating (and affinitizing) sets of IRQs
Date: Tue, 30 Oct 2018 18:25:47 +0100 (CET) [thread overview]
Message-ID: <alpine.DEB.2.21.1810301824570.5984@nanos.tec.linutronix.de> (raw)
In-Reply-To: <27c1017a-9560-80cb-038d-f64727a162c3@kernel.dk>
Jens,
On Tue, 30 Oct 2018, Jens Axboe wrote:
> On 10/30/18 10:02 AM, Keith Busch wrote:
> > pci_alloc_irq_vectors_affinity() starts at the provided max_vecs. If
> > that doesn't work, it will iterate down to min_vecs without returning to
> > the caller. The caller doesn't have a chance to adjust its sets between
> > iterations when you provide a range.
> >
> > The 'masks' overrun problem happens if the caller provides min_vecs
> > as a smaller value than the sum of the set (plus any reserved).
> >
> > If it's up to the caller to ensure that doesn't happen, then min and
> > max must both be the same value, and that value must also be the same as
> > the set sum + reserved vectors. The range just becomes redundant since
> > it is already bounded by the set.
> >
> > Using the nvme example, it would need something like this to prevent the
> > 'masks' overrun:
>
> OK, now I hear what you are saying. And you are right, the callers needs
> to provide minvec == maxvec for sets, and then have a loop around that
> to adjust as needed.
But then we should enforce it in the core code, right?
Thanks,
tglx
next prev parent reply other threads:[~2018-10-30 17:25 UTC|newest]
Thread overview: 63+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-10-29 16:37 [PATCHSET v2 0/14] blk-mq: Add support for multiple queue maps Jens Axboe
2018-10-29 16:37 ` [PATCH 01/14] blk-mq: kill q->mq_map Jens Axboe
2018-10-29 16:46 ` Bart Van Assche
2018-10-29 16:51 ` Jens Axboe
2018-10-29 16:37 ` [PATCH 02/14] blk-mq: abstract out queue map Jens Axboe
2018-10-29 18:33 ` Bart Van Assche
2018-10-29 16:37 ` [PATCH 03/14] blk-mq: provide dummy blk_mq_map_queue_type() helper Jens Axboe
2018-10-29 17:22 ` Bart Van Assche
2018-10-29 17:27 ` Jens Axboe
2018-10-29 16:37 ` [PATCH 04/14] blk-mq: pass in request/bio flags to queue mapping Jens Axboe
2018-10-29 17:30 ` Bart Van Assche
2018-10-29 17:33 ` Jens Axboe
2018-10-29 16:37 ` [PATCH 05/14] blk-mq: allow software queue to map to multiple hardware queues Jens Axboe
2018-10-29 17:34 ` Bart Van Assche
2018-10-29 17:35 ` Jens Axboe
2018-10-29 16:37 ` [PATCH 06/14] blk-mq: add 'type' attribute to the sysfs hctx directory Jens Axboe
2018-10-29 17:40 ` Bart Van Assche
2018-10-29 16:37 ` [PATCH 07/14] blk-mq: support multiple hctx maps Jens Axboe
2018-10-29 18:15 ` Bart Van Assche
2018-10-29 19:24 ` Jens Axboe
2018-10-29 16:37 ` [PATCH 08/14] blk-mq: separate number of hardware queues from nr_cpu_ids Jens Axboe
2018-10-29 18:31 ` Bart Van Assche
2018-10-29 16:37 ` [PATCH 09/14] blk-mq: ensure that plug lists don't straddle hardware queues Jens Axboe
2018-10-29 19:27 ` Bart Van Assche
2018-10-29 19:30 ` Jens Axboe
2018-10-29 19:49 ` Jens Axboe
2018-10-30 8:08 ` Ming Lei
2018-10-30 17:22 ` Jens Axboe
2018-10-29 16:37 ` [PATCH 10/14] blk-mq: initial support for multiple queue maps Jens Axboe
2018-10-29 19:40 ` Bart Van Assche
2018-10-29 19:53 ` Jens Axboe
2018-10-29 20:00 ` Bart Van Assche
2018-10-29 20:09 ` Jens Axboe
2018-10-29 20:25 ` Bart Van Assche
2018-10-29 20:29 ` Jens Axboe
2018-10-29 16:37 ` [PATCH 11/14] irq: add support for allocating (and affinitizing) sets of IRQs Jens Axboe
2018-10-29 17:08 ` Thomas Gleixner
2018-10-29 17:09 ` Jens Axboe
2018-10-30 9:25 ` Ming Lei
2018-10-30 14:26 ` Keith Busch
2018-10-30 14:36 ` Jens Axboe
2018-10-30 14:45 ` Keith Busch
2018-10-30 14:53 ` Jens Axboe
2018-10-30 15:08 ` Keith Busch
2018-10-30 15:18 ` Jens Axboe
2018-10-30 16:02 ` Keith Busch
2018-10-30 16:42 ` Jens Axboe
2018-10-30 17:09 ` Jens Axboe
2018-10-30 17:22 ` Keith Busch
2018-10-30 17:33 ` Jens Axboe
2018-10-30 17:35 ` Keith Busch
2018-10-30 17:25 ` Thomas Gleixner [this message]
2018-10-30 17:34 ` Jens Axboe
2018-10-30 17:43 ` Jens Axboe
2018-10-30 17:46 ` Thomas Gleixner
2018-10-30 17:47 ` Jens Axboe
2018-10-29 16:37 ` [PATCH 12/14] nvme: utilize two queue maps, one for reads and one for writes Jens Axboe
2018-10-29 16:37 ` [PATCH 13/14] block: add REQ_HIPRI and inherit it from IOCB_HIPRI Jens Axboe
2018-10-29 16:37 ` [PATCH 14/14] nvme: add separate poll queue map Jens Axboe
[not found] <20181025211626.12692-1-axboe@kernel.dk>
2018-10-25 21:16 ` [PATCH 11/14] irq: add support for allocating (and affinitizing) sets of IRQs Jens Axboe
2018-10-25 21:52 ` Keith Busch
2018-10-25 23:07 ` Jens Axboe
2018-10-29 7:43 ` Hannes Reinecke
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