[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]
Re: [Qemu-ppc] [Qemu-devel] [QEMU RFC PATCH v3 4/6] Migration: migrate Q
From: |
Paolo Bonzini |
Subject: |
Re: [Qemu-ppc] [Qemu-devel] [QEMU RFC PATCH v3 4/6] Migration: migrate QTAILQ |
Date: |
Tue, 7 Jun 2016 18:31:41 +0200 |
User-agent: |
Mozilla/5.0 (X11; Linux x86_64; rv:45.0) Gecko/20100101 Thunderbird/45.1.0 |
On 07/06/2016 16:43, Dr. David Alan Gilbert wrote:
> b) I think you should really try and split it into two parts:
> 1) A VMSTATE_ARRAY_CUSTOM (?) - so it's an array of elements but we've
> got a special
> way of allocating/counting/reading the elements
> 2) A version of that which is for a QTAILQ.
> It's important that whatever ends up on the migration stream doesn't
> reflect
> that it happens to be implemented as a QTAILQ; so if you decide to
> change
> it later the migration compatibility doesn't break.
(Just to clarify before Jianjun wakes up) a VMSTATE_ARRAY is just a
sequence of elements. The count, if needed as in a VARRAY, is stored
earlier and separately. Currently lists (including this QTAILQ) are
usually represented in the migration stream as a sequence of elements
preceded by "1" and terminated by a "0". Would you like to change it to
a count + sequence as well?
This would prevent using the new QTAILQ support for other existing lists
such as virtio-blk and scsi's request lists.
> c) Use new trace_ names for get_qtailq rather than misusing
> trace_vmstate_load_state*
> d) Add a trace_ for put_qtailq as well - that way when it goes horribly
> wrong we can
> turn the tracing on on both sides :-)
> e) Is there anyway to make QTAILQ_RAW_INSERT_TAIL any more readable?
> I don't think I understand why you can't use the standard QTAILQ macros.
Because they assume a particular type. The "raw" version need to work on
void*.
Thanks,
Paolo
> f) You might need to fix up Amit's scripts/vmstate-static-checker.py
Re: [Qemu-ppc] [Qemu-devel] [QEMU RFC PATCH v3 4/6] Migration: migrate QTAILQ, Jianjun Duan, 2016/06/03
Re: [Qemu-ppc] [Qemu-devel] [QEMU RFC PATCH v3 4/6] Migration: migrate QTAILQ, Paolo Bonzini, 2016/06/06