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Re: [Qemu-block] [Qemu-devel] [PATCH 06/16] block: add BDS field to coun
From: |
Paolo Bonzini |
Subject: |
Re: [Qemu-block] [Qemu-devel] [PATCH 06/16] block: add BDS field to count in-flight requests |
Date: |
Wed, 9 Mar 2016 08:43:09 +0100 |
User-agent: |
Mozilla/5.0 (X11; Linux x86_64; rv:38.0) Gecko/20100101 Thunderbird/38.6.0 |
On 09/03/2016 04:35, Fam Zheng wrote:
>> > enum BdrvTrackedRequestType {
>> > BDRV_TRACKED_READ,
>> > BDRV_TRACKED_WRITE,
>> > - BDRV_TRACKED_FLUSH,
>> > - BDRV_TRACKED_IOCTL,
>> > BDRV_TRACKED_DISCARD,
> Okay, so flush and ioctl are not needed, but why is discard different?
Discard can modify the contents of the device, so I think it's safer to
serialize it against RMW and copy-on-read operations.
Paolo