From: Paolo Bonzini <pbonzini@redhat.com>
To: Ming Lei <ming.lei@canonical.com>
Cc: Kevin Wolf <kwolf@redhat.com>,
qemu-stable@nongnu.org, Stefan Hajnoczi <stefanha@redhat.com>,
qemu-devel <qemu-devel@nongnu.org>
Subject: Re: [Qemu-devel] [PATCH] block: fix big write
Date: Wed, 10 Dec 2014 13:55:17 +0100 [thread overview]
Message-ID: <548842B5.9090009@redhat.com> (raw)
In-Reply-To: <CACVXFVMytNhDRvOzxN2b2Zu_HT9SvtSHaaXJEiJBioEzYDF1-g@mail.gmail.com>
On 10/12/2014 13:23, Ming Lei wrote:
>> >
>> > Again, we're talking of 2GB and this is something that should never
>> > happen in practice.
> Again, the 2GB limit can be avoided if I/O is splitted, isn't it?
Sure. The guest kernel is doing the split.
> It is _not_ never happen at all, and easy to be triggered when using
> mkfs.
mkfs is not something to optimize for, it's just something that should
work. (Also, some hardware may time out if you do write same with too
high a block count).
Both Linux and Windows will always use UNMAP on QEMU, except for the
small time period where Linux used WRITE SAME and this bug was
discovered. And all versions of Linux that used WRITE SAME honored the
max_ws_blocks field.
Paolo
next prev parent reply other threads:[~2014-12-10 13:48 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-12-05 16:15 [Qemu-devel] [PATCH] block: fix big write Ming Lei
2014-12-05 16:33 ` Paolo Bonzini
2014-12-08 7:19 ` Ming Lei
2014-12-09 17:45 ` Paolo Bonzini
2014-12-10 1:41 ` Ming Lei
2014-12-10 9:56 ` Paolo Bonzini
2014-12-10 12:23 ` Ming Lei
2014-12-10 12:55 ` Paolo Bonzini [this message]
2014-12-10 14:35 ` Ming Lei
2014-12-10 15:02 ` Paolo Bonzini
2014-12-10 15:47 ` Ming Lei
2014-12-10 16:44 ` Paolo Bonzini
2014-12-05 17:03 ` Max Reitz
2014-12-05 17:04 ` Paolo Bonzini
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