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From: "Jan Beulich" <JBeulich@suse.com>
To: Wen Congyang <wency@cn.fujitsu.com>
Cc: Ian Campbell <Ian.Campbell@citrix.com>,
	Ian Jackson <Ian.Jackson@eu.citrix.com>,
	Jiang Yunhong <yunhong.jiang@intel.com>,
	Dong Eddie <eddie.dong@intel.com>,
	xen devel <xen-devel@lists.xen.org>,
	Paul Durrant <paul.durrant@citrix.com>,
	Yang Hongyang <yanghy@cn.fujitsu.com>,
	Lai Jiangshan <laijs@cn.fujitsu.com>
Subject: Re: [RFC Patch v4 6/9] don't zero out ioreq page and handle the pended I/O after resuming
Date: Mon, 22 Sep 2014 12:22:58 +0100	[thread overview]
Message-ID: <542022B20200007800036DC2@mail.emea.novell.com> (raw)
In-Reply-To: <1411365561-29242-7-git-send-email-wency@cn.fujitsu.com>

>>> On 22.09.14 at 07:59, <wency@cn.fujitsu.com> wrote:
> I check ioreq->state after suspending the guest, and it can be
> STATE_IOREQ_NONE, STATE_IOREQ_READY or STATE_IORESP_READY.
> 1. If it is STATE_IOREQ_NONE, nothing need to be done.
> 2. If it is STATE_IOREQ_RESP_READY, we will get the response
>    in hvm_wait_for_io() before resuming.
> 3. If it is STATE_IOREQ_READY, we need to kick the event channel,
>    and qemu can handle the request.

This is contrary to what you wrote earlier in a reply to David Vrabel
asking "Under what conditions can there be pending I/O?  A domain
suspend should not complete until any I/O accesses are complete":

"IIRC, I print ioreq.state after suspending vm, and ioreq.state can be
STATE_IOREQ_NONE, STATE_IOREQ_READY or STATE_IORESP_READY. If the
state is STATE_IOREQ_READY, we should kick vcpu event channel on resume
after migration.

But I test it again today, the state is always STATE_IOREQ_NONE...

If the state is always STATE_IOREQ_NONE, no need to touch hypervisor/Qemu
to handle pending I/O req(state is STATE_IOREQ_READY)."

and will hence at least need clarification.

Jan

  reply	other threads:[~2014-09-22 11:22 UTC|newest]

Thread overview: 55+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2014-09-22  5:59 [RFC Patch v4 0/9] Some bugfix patches Wen Congyang
2014-09-22  5:59 ` [RFC Patch v4 1/9] copy the correct page to memory Wen Congyang
2014-09-22 14:38   ` Ian Campbell
2014-09-22  5:59 ` [RFC Patch v4 2/9] csum the correct page Wen Congyang
2014-09-22  5:59 ` [RFC Patch v4 3/9] pass correct file to qemu if we use blktap2 Wen Congyang
2014-12-11 16:45   ` George Dunlap
2014-12-13 17:06     ` Wei Liu
2014-12-15 10:18       ` Ian Campbell
2014-12-15 11:10         ` George Dunlap
2014-09-22  5:59 ` [RFC Patch v4 4/9] read nictype from xenstore Wen Congyang
2014-09-22  5:59 ` [RFC Patch v4 5/9] check if mfn is supported by IOCTL_PRIVCMD_MMAPBATCH before calling ioctl() Wen Congyang
2014-09-22 14:26   ` Ian Campbell
2014-09-23  1:40     ` Wen Congyang
2014-09-23 10:08       ` Ian Campbell
2014-09-24  1:36         ` Wen Congyang
2014-09-22  5:59 ` [RFC Patch v4 6/9] don't zero out ioreq page and handle the pended I/O after resuming Wen Congyang
2014-09-22 11:22   ` Jan Beulich [this message]
2014-09-22  5:59 ` [RFC Patch v4 7/9] correct xc_domain_save()'s return value Wen Congyang
2014-09-22  7:30   ` Olaf Hering
2014-09-22  7:34     ` Wen Congyang
2014-09-22  7:46       ` Olaf Hering
2014-09-22  8:06         ` Wen Congyang
2014-09-22  8:13           ` Olaf Hering
2014-09-22  8:24             ` Wen Congyang
2014-09-22  8:41             ` Wen Congyang
2014-09-22 12:42           ` Ian Campbell
2014-09-22 13:03             ` Ian Jackson
2014-09-22 13:13               ` Ian Campbell
2014-09-22 13:57                 ` [PATCH RFC 0/3] " Ian Jackson
2014-09-22 13:58                   ` Ian Campbell
2014-09-22 14:00                     ` Ian Campbell
2014-09-22 13:58                   ` [PATCH 1/3] libxl: save helper: remove redundant declaration Ian Jackson
2014-09-22 13:58                   ` [PATCH 2/3] libxl: save helper: transport errno with all callback return values Ian Jackson
2014-09-22 13:58                   ` [PATCH 3/3] libxl: save/restore callbacks: enforce a useful errno value Ian Jackson
2014-09-22 14:07                     ` Ian Campbell
2014-09-22 14:08                       ` Ian Jackson
2014-09-22 14:06                 ` [RFC Patch v4 7/9] correct xc_domain_save()'s return value Andrew Cooper
2014-09-23  2:14                   ` Wen Congyang
2014-09-23  9:00                     ` Andrew Cooper
2014-09-23  9:10                       ` Wen Congyang
2014-09-23  9:25                         ` Andrew Cooper
2014-09-23  9:29                           ` Wen Congyang
2014-09-23 10:09                             ` Ian Campbell
2014-09-23  9:52                           ` Wen Congyang
2014-09-22  5:59 ` [RFC Patch v4 8/9] store correct format into tapdisk-params/params Wen Congyang
2014-09-22 14:37   ` Ian Campbell
2014-09-23  2:07     ` Wen Congyang
2014-09-23 10:11       ` Ian Campbell
2014-09-23 10:32         ` Wen Congyang
2014-09-22  5:59 ` [RFC Patch v4 9/9] update libxl__device_disk_from_xs_be() to support blktap device Wen Congyang
2014-09-22 15:08   ` Ian Campbell
2014-09-23  3:07     ` Wen Congyang
2014-09-23 10:12       ` Ian Campbell
2014-09-22 12:44 ` [RFC Patch v4 0/9] Some bugfix patches Ian Campbell
2014-09-22 12:56   ` Wen Congyang

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