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Re: [Qemu-devel] [PATCH v3] monitor: let cur_mon be per-thread
From: |
Eric Blake |
Subject: |
Re: [Qemu-devel] [PATCH v3] monitor: let cur_mon be per-thread |
Date: |
Thu, 12 Apr 2018 10:22:00 -0500 |
User-agent: |
Mozilla/5.0 (X11; Linux x86_64; rv:52.0) Gecko/20100101 Thunderbird/52.7.0 |
On 04/12/2018 01:11 AM, Peter Xu wrote:
> In the future the monitor iothread may be accessing the cur_mon as
> well (via monitor_qmp_dispatch_one()). Before we introduce a real
> Out-Of-Band command, let's convert the cur_mon variable to be a
> per-thread variable to make sure there won't be a race between threads.
>
> Note that thread variables are not initialized to a valid value when new
> thread is created. However for our case we don't need to set it up,
> since the cur_mon variable is only used in such a pattern:
>
> old_mon = cur_mon;
> cur_mon = xxx;
> (do something, read cur_mon if necessary in the stack)
> cur_mon = old_mon;
>
> It plays a role as stack variable, so no need to be initialized at all.
> We only need to make sure the variable won't be changed unexpectedly by
> other threads.
>
> Signed-off-by: Peter Xu <address@hidden>
> ---
Reviewed-by: Eric Blake <address@hidden>
--
Eric Blake, Principal Software Engineer
Red Hat, Inc. +1-919-301-3266
Virtualization: qemu.org | libvirt.org
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- [Qemu-devel] [PATCH v3] monitor: let cur_mon be per-thread, Peter Xu, 2018/04/12
- Re: [Qemu-devel] [PATCH v3] monitor: let cur_mon be per-thread,
Eric Blake <=
- Re: [Qemu-devel] [PATCH v3] monitor: let cur_mon be per-thread, Marc-André Lureau, 2018/04/13
- Re: [Qemu-devel] [PATCH v3] monitor: let cur_mon be per-thread, Stefan Hajnoczi, 2018/04/16
- Re: [Qemu-devel] [PATCH v3] monitor: let cur_mon be per-thread, Peter Xu, 2018/04/16
- Re: [Qemu-devel] [PATCH v3] monitor: let cur_mon be per-thread, Stefan Hajnoczi, 2018/04/17
- Re: [Qemu-devel] [PATCH v3] monitor: let cur_mon be per-thread, Markus Armbruster, 2018/04/17
- Re: [Qemu-devel] [PATCH v3] monitor: let cur_mon be per-thread, Stefan Hajnoczi, 2018/04/18
- Re: [Qemu-devel] [PATCH v3] monitor: let cur_mon be per-thread, Peter Xu, 2018/04/18
- Re: [Qemu-devel] [PATCH v3] monitor: let cur_mon be per-thread, Markus Armbruster, 2018/04/18
- Re: [Qemu-devel] [PATCH v3] monitor: let cur_mon be per-thread, Peter Xu, 2018/04/18