From: Kevin Wolf <kwolf@redhat.com>
To: nick@bytemark.co.uk
Cc: pbonzini@redhat.com, qemu-devel@nongnu.org
Subject: Re: [Qemu-devel] [PATCH 2/3] nbd: Explicitly disconnect and fail inflight I/O requests on error, then reconnect next I/O request.
Date: Tue, 23 Oct 2012 12:40:46 +0200 [thread overview]
Message-ID: <5086742E.1030702@redhat.com> (raw)
In-Reply-To: <d5aacb323b4dcb1c9acb699e4ece02d0b0c3b2fa.1350901963.git.nick@bytemark.co.uk>
Am 22.10.2012 13:09, schrieb nick@bytemark.co.uk:
>
> The previous behaviour when an NBD connection broke was to fail just the broken I/O request
> and (sometimes) never unlock send_mutex. Now we explicitly call nbd_teardown_connection and
> fail all NBD requests in the "inflight" state - this allows werror/rerror settings to be
> applied to those requests all at once.
>
> When a new request (or a request that was pending, but not yet inflight) is issued against
> the NBD driver, if we're not connected to the NBD server, we attempt to connect (and fail
> the new request immediately if that doesn't work).
Doesn't this block the vcpu while qemu is trying to establish a new
connection? When the network is down, I think this can take quite a
while. I would actually expect that this is one of the cases where qemu
as a whole would seem to hang.
Kevin
next prev parent reply other threads:[~2012-10-23 10:41 UTC|newest]
Thread overview: 20+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-10-22 11:09 [Qemu-devel] [PATCH 0/3] NBD reconnection behaviour nick
2012-10-22 11:09 ` [Qemu-devel] [PATCH 1/3] nbd: Only try to send flush/discard commands if connected to the NBD server nick
2012-10-23 10:33 ` Kevin Wolf
2012-10-23 11:08 ` Nicholas Thomas
2012-10-23 11:26 ` Kevin Wolf
2012-10-23 15:02 ` Jamie Lokier
2012-10-24 12:16 ` Nicholas Thomas
2012-10-24 12:57 ` Kevin Wolf
2012-10-24 14:32 ` Jamie Lokier
2012-10-24 15:16 ` Paolo Bonzini
2012-10-25 6:36 ` Kevin Wolf
2012-10-25 17:09 ` Jamie Lokier
2012-10-26 7:59 ` Kevin Wolf
2012-10-24 14:03 ` Paolo Bonzini
2012-10-24 14:10 ` Paolo Bonzini
2012-10-24 14:12 ` Nicholas Thomas
2012-10-22 11:09 ` [Qemu-devel] [PATCH 2/3] nbd: Explicitly disconnect and fail inflight I/O requests on error, then reconnect next I/O request nick
2012-10-23 10:40 ` Kevin Wolf [this message]
2012-10-24 14:31 ` Paolo Bonzini
2012-10-22 11:09 ` [Qemu-devel] [PATCH 3/3] nbd: Move reconnection attempts from each new I/O request to a 5-second timer nick
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