From: Stefan Hajnoczi <stefanha@redhat.com>
To: "Philippe Mathieu-Daudé" <philmd@redhat.com>
Cc: Kevin Wolf <kwolf@redhat.com>, Fam Zheng <fam@euphon.net>,
qemu-block@nongnu.org, qemu-devel@nongnu.org,
Maxim Levitsky <mlevitsk@redhat.com>,
Max Reitz <mreitz@redhat.com>
Subject: Re: [PATCH v2 12/12] block/nvme: Use per-queue AIO context
Date: Wed, 1 Jul 2020 17:03:28 +0100 [thread overview]
Message-ID: <20200701160328.GS126613@stefanha-x1.localdomain> (raw)
In-Reply-To: <20200630191318.30021-13-philmd@redhat.com>
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On Tue, Jun 30, 2020 at 09:13:18PM +0200, Philippe Mathieu-Daudé wrote:
> To be able to use multiple queues on the same hardware,
> we need to have each queue able to receive IRQ notifications
> in the correct AIO context.
> The AIO context and the notification handler have to be proper
> to each queue, not to the block driver. Move aio_context and
> irq_notifier from BDRVNVMeState to NVMeQueuePair.
If I understand correctly, after this patch:
1. Each queue pair has an EventNotifier irq_notifier but only the admin
queuepair's irq_notifier is hooked up to VFIO. This means all
interrupts come via the admin queuepair.
(This also means all queuepairs still need to be polled for
completions when the interrupt fires because we don't know which
queuepair had a completion event.)
2. AioContexts must be identical across all queuepairs and
BlockDriverStates. Although they all have their own AioContext
pointer there is no true support for different AioContexts yet.
(For example, nvme_cmd_sync() is called with a bs argument but
AIO_WAIT_WHILE(q->aio_context, ...) uses the queuepair aio_context so
the assumption is that they match.)
Please confirm and add something equivalent into the commit description
so the assumptions/limitations are clear.
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next prev parent reply other threads:[~2020-07-01 16:06 UTC|newest]
Thread overview: 20+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-06-30 19:13 [PATCH v2 00/12] block/nvme: Various cleanups required to use multiple queues Philippe Mathieu-Daudé
2020-06-30 19:13 ` [PATCH v2 01/12] block/nvme: Replace magic value by SCALE_MS definition Philippe Mathieu-Daudé
2020-07-01 15:48 ` Stefan Hajnoczi
2020-06-30 19:13 ` [PATCH v2 02/12] block/nvme: Avoid further processing if trace event not enabled Philippe Mathieu-Daudé
2020-07-01 15:48 ` Stefan Hajnoczi
2020-06-30 19:13 ` [PATCH v2 03/12] block/nvme: Let nvme_create_queue_pair() fail gracefully Philippe Mathieu-Daudé
2020-06-30 19:13 ` [PATCH v2 04/12] block/nvme: Define QUEUE_INDEX macros to ease code review Philippe Mathieu-Daudé
2020-06-30 19:13 ` [PATCH v2 05/12] block/nvme: Rename local variable Philippe Mathieu-Daudé
2020-07-01 15:49 ` Stefan Hajnoczi
2020-06-30 19:13 ` [PATCH v2 06/12] block/nvme: Use union of NvmeIdCtrl / NvmeIdNs structures Philippe Mathieu-Daudé
2020-07-01 15:51 ` Stefan Hajnoczi
2020-06-30 19:13 ` [PATCH v2 07/12] block/nvme: Replace qemu_try_blockalign0 by qemu_try_blockalign/memset Philippe Mathieu-Daudé
2020-06-30 19:13 ` [PATCH v2 08/12] block/nvme: Replace qemu_try_blockalign(bs) by qemu_try_memalign(pg_sz) Philippe Mathieu-Daudé
2020-07-01 15:51 ` Stefan Hajnoczi
2020-06-30 19:13 ` [PATCH v2 09/12] block/nvme: Simplify nvme_init_queue() arguments Philippe Mathieu-Daudé
2020-06-30 19:13 ` [PATCH v2 10/12] block/nvme: Replace BDRV_POLL_WHILE by AIO_WAIT_WHILE Philippe Mathieu-Daudé
2020-06-30 19:13 ` [PATCH v2 11/12] block/nvme: Simplify nvme_create_queue_pair() arguments Philippe Mathieu-Daudé
2020-06-30 19:13 ` [PATCH v2 12/12] block/nvme: Use per-queue AIO context Philippe Mathieu-Daudé
2020-07-01 16:03 ` Stefan Hajnoczi [this message]
2020-07-04 21:27 ` Philippe Mathieu-Daudé
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