From: Kevin Wolf <kwolf@redhat.com>
To: Christoph Hellwig <hch@lst.de>
Cc: qemu-devel@nongnu.org
Subject: Re: [Qemu-devel] [PATCH] block: prevent multiwrite_merge from creating too large iovecs
Date: Wed, 20 Jan 2010 17:29:25 +0100 [thread overview]
Message-ID: <4B572F65.7070201@redhat.com> (raw)
In-Reply-To: <20100120162434.GA7212@lst.de>
Am 20.01.2010 17:24, schrieb Christoph Hellwig:
> On Wed, Jan 20, 2010 at 12:37:51PM +0100, Kevin Wolf wrote:
>> Am 19.01.2010 22:15, schrieb Christoph Hellwig:
>>> If we go over the maximum number of iovecs support by syscall we get
>>> back EINVAL from the kernel which translate to I/O errors for the guest.
>>>
>>> Signed-off-by: Christoph Hellwig <hch@lst.de>
>>
>> Is this really enough? We don't check for IOV_MAX in any other place, so
>> can't we get a too big request directly from virtio-blk?
>
> Currently the virtqueue is limited to 1024 iovecs, but I plan to put in
> some better infrastructure to deal with the queue limit. For now this
> patch fixes an issue that we see with real life setups.
Ok, if you're planning to replace it by something real, I'm not opposed
to using this as a quick fix for the meantime. However, it needs an
#ifdef for the mingw build breakage at least.
Kevin
next prev parent reply other threads:[~2010-01-20 16:30 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-01-19 21:15 [Qemu-devel] [PATCH] block: prevent multiwrite_merge from creating too large iovecs Christoph Hellwig
2010-01-20 11:37 ` Kevin Wolf
2010-01-20 16:24 ` Christoph Hellwig
2010-01-20 16:29 ` Kevin Wolf [this message]
2010-01-26 9:21 ` Christoph Hellwig
2010-01-26 13:08 ` Anthony Liguori
2010-01-26 13:42 ` Christoph Hellwig
2010-01-20 14:56 ` Anthony Liguori
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