From: Christoph Hellwig <hch@infradead.org>
To: Daniel Verkamp <dverkamp@chromium.org>
Cc: virtualization@lists.linux-foundation.org,
linux-block@vger.kernel.org,
"Michael S. Tsirkin" <mst@redhat.com>,
Jason Wang <jasowang@redhat.com>, Jens Axboe <axboe@kernel.dk>,
Stefan Hajnoczi <stefanha@redhat.com>,
Changpeng Liu <changpeng.liu@intel.com>
Subject: Re: [PATCH v8] virtio_blk: add discard and write zeroes support
Date: Mon, 15 Oct 2018 02:27:40 -0700 [thread overview]
Message-ID: <20181015092740.GA3964@infradead.org> (raw)
In-Reply-To: <20181012210628.226361-1-dverkamp@chromium.org>
On Fri, Oct 12, 2018 at 02:06:28PM -0700, Daniel Verkamp wrote:
> From: Changpeng Liu <changpeng.liu@intel.com>
>
> In commit 88c85538, "virtio-blk: add discard and write zeroes features
> to specification" (https://github.com/oasis-tcs/virtio-spec), the virtio
There is some issues in this spec. For one using the multiple ranges
also for write zeroes is rather inefficient. Write zeroes really should
use the same format as read and write.
Second the unmap flag isn't properly specified at all, as nothing
says the device may not unmap without the unmap flag. Please take
a look at the SCSI or NVMe ѕpec for some guidance.
> +static inline int virtblk_setup_discard_write_zeroes(struct request *req,
> + bool unmap)
Why is this an inline function?
WARNING: multiple messages have this Message-ID (diff)
From: Christoph Hellwig <hch@infradead.org>
To: Daniel Verkamp <dverkamp@chromium.org>
Cc: Jens Axboe <axboe@kernel.dk>,
"Michael S. Tsirkin" <mst@redhat.com>,
virtualization@lists.linux-foundation.org,
linux-block@vger.kernel.org,
Stefan Hajnoczi <stefanha@redhat.com>,
Changpeng Liu <changpeng.liu@intel.com>
Subject: Re: [PATCH v8] virtio_blk: add discard and write zeroes support
Date: Mon, 15 Oct 2018 02:27:40 -0700 [thread overview]
Message-ID: <20181015092740.GA3964@infradead.org> (raw)
In-Reply-To: <20181012210628.226361-1-dverkamp@chromium.org>
On Fri, Oct 12, 2018 at 02:06:28PM -0700, Daniel Verkamp wrote:
> From: Changpeng Liu <changpeng.liu@intel.com>
>
> In commit 88c85538, "virtio-blk: add discard and write zeroes features
> to specification" (https://github.com/oasis-tcs/virtio-spec), the virtio
There is some issues in this spec. For one using the multiple ranges
also for write zeroes is rather inefficient. Write zeroes really should
use the same format as read and write.
Second the unmap flag isn't properly specified at all, as nothing
says the device may not unmap without the unmap flag. Please take
a look at the SCSI or NVMe ѕpec for some guidance.
> +static inline int virtblk_setup_discard_write_zeroes(struct request *req,
> + bool unmap)
Why is this an inline function?
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next prev parent reply other threads:[~2018-10-15 9:27 UTC|newest]
Thread overview: 50+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-06-06 4:19 [PATCH v6] virtio_blk: add DISCARD and WRIET ZEROES commands support Changpeng Liu
2018-06-07 13:10 ` Stefan Hajnoczi
2018-06-07 23:07 ` Liu, Changpeng
2018-06-08 10:20 ` Stefan Hajnoczi
2018-06-11 3:37 ` Liu, Changpeng
2018-06-12 16:05 ` Stefan Hajnoczi
2018-08-28 22:25 ` [PATCH v7] virtio_blk: add discard and write zeroes support Daniel Verkamp
2018-10-12 21:06 ` [PATCH v8] " Daniel Verkamp
2018-10-12 21:06 ` Daniel Verkamp
2018-10-15 0:54 ` Michael S. Tsirkin
2018-10-15 0:54 ` Michael S. Tsirkin
2018-10-15 9:21 ` Ming Lei
2018-10-15 9:27 ` Christoph Hellwig [this message]
2018-10-15 9:27 ` Christoph Hellwig
2018-10-15 23:16 ` Daniel Verkamp
2018-10-15 23:16 ` Daniel Verkamp
2018-10-16 1:45 ` Liu, Changpeng
2018-10-16 1:45 ` Liu, Changpeng
2018-10-16 1:40 ` Liu, Changpeng
2018-10-16 1:40 ` Liu, Changpeng
2018-10-25 23:28 ` Paolo Bonzini
2018-10-25 23:28 ` Paolo Bonzini
2018-10-26 8:26 ` Christoph Hellwig
2018-10-26 8:26 ` Christoph Hellwig
2018-10-29 3:21 ` Liu, Changpeng
2018-10-29 3:21 ` Liu, Changpeng
2018-10-29 18:03 ` Paolo Bonzini
2018-10-29 18:03 ` Paolo Bonzini
2018-10-26 8:08 ` Stefan Hajnoczi
2018-10-26 8:08 ` Stefan Hajnoczi
2018-10-26 14:47 ` Michael S. Tsirkin
2018-10-26 14:47 ` Michael S. Tsirkin
2018-10-29 5:05 ` Stefan Hajnoczi
2018-10-29 5:05 ` Stefan Hajnoczi
2018-11-01 21:25 ` Michael S. Tsirkin
2018-11-01 21:25 ` Michael S. Tsirkin
2018-11-01 22:18 ` Daniel Verkamp
2018-11-01 22:18 ` Daniel Verkamp
2018-11-01 22:40 ` [PATCH v9] " Daniel Verkamp
2018-11-01 22:40 ` Daniel Verkamp
2018-11-01 23:43 ` Dongli Zhang
2018-11-01 23:43 ` Dongli Zhang
2018-11-02 18:25 ` Daniel Verkamp
2018-11-02 18:25 ` Daniel Verkamp
2018-11-02 4:17 ` Stefan Hajnoczi
2018-11-02 4:17 ` Stefan Hajnoczi
2018-12-05 9:46 ` Liu, Changpeng
2018-12-05 9:46 ` Liu, Changpeng
2018-12-05 13:41 ` Michael S. Tsirkin
2018-12-05 13:41 ` Michael S. Tsirkin
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