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Re: [Qemu-devel] [PATCH] Add interface to traverse the qmp command list
From: |
Michael Roth |
Subject: |
Re: [Qemu-devel] [PATCH] Add interface to traverse the qmp command list by QmpCommand |
Date: |
Fri, 27 Sep 2013 11:07:26 -0500 |
User-agent: |
alot/0.3.4 |
Quoting Eric Blake (2013-09-25 21:57:39)
> On 09/25/2013 07:56 PM, Mark Wu wrote:
> > In the original code, qmp_get_command_list is used to construct
> > a list of all commands' name. To get the information of all qga
> > commands, it traverses the name list and search the command info
> > with its name. So it can cause O(n^2) in the number of commands.
> >
> > This patch adds an interface to traverse the qmp command list by
> > QmpCommand to replace qmp_get_command_list. It can decrease the
> > complexity from O(n) to O(n^2)
>
> from O(n^2) to O(n)
>
> >
> > Signed-off-by: Mark Wu <address@hidden>
> > ---
> > include/qapi/qmp/dispatch.h | 3 +-
> > qapi/qmp-registry.c | 28 ++-----------------
> > qga/commands.c | 39 ++++++++++----------------
> > qga/main.c | 68
> > +++++++++++++++++----------------------------
> > 4 files changed, 45 insertions(+), 93 deletions(-)
> >
>
> >
> > -bool qmp_command_is_enabled(const char *name)
>
> I think one of Michael's suggestions was that you may still want
> qmp_command_is_enabled, but with a new signature:
>
> bool qmp_command_is_enabled(const QmpCommand *cmd)
> {
> return cmd->enabled;
> }
That would still be my preference, as I can see the underlying
fields changing somewhat in a future where QMP starts using the same
infrastructure, and new users come along like qemu-ga guest->host
commands we did as part of GSoC.
Wouldn't hold things up in the meantime, but if we're re-spinning
anyway let's maintain the precedence of using getter/setter funcs
for QmpCommand.
>
> > -struct GuestAgentInfo *qmp_guest_info(Error **err)
> > +static void qmp_command_info(QmpCommand *cmd, void *opaque)
> > {
> > - GuestAgentInfo *info = g_malloc0(sizeof(GuestAgentInfo));
> > + GuestAgentInfo *info = (GuestAgentInfo *)opaque;
>
>
> > - cmd_info->enabled = qmp_command_is_enabled(cmd_info->name);
> >
> > - cmd_info_list = g_malloc0(sizeof(GuestAgentCommandInfoList));
> > - cmd_info_list->value = cmd_info;
> > - cmd_info_list->next = info->supported_commands;
> > - info->supported_commands = cmd_info_list;
> > + cmd_info = g_malloc0(sizeof(GuestAgentCommandInfo));
> > + cmd_info->name = g_strdup(cmd->name);
> > + cmd_info->enabled = cmd->enabled;
>
> I guess it all depends on whether we want QmpCommand to be an opaque
> type outside of a single file. But I don't have a strong argument for
> making it opaque, and your approach works if we don't mind exposing the
> details of QmpCommand across multiple files. So I can live with your
> patch as-is.
>
>
> > +static void ga_enable_non_blacklisted(QmpCommand *cmd, void *opaque)
> > {
>
> > + GList *blacklist = (GList *)opaque;
>
> Again, the cast is not necessary.
>
> Overall, I like the patch. Just a few tweaks suggested, but I can live
> with you adding:
>
> Reviewed-by: Eric Blake <address@hidden>
>
> --
> Eric Blake eblake redhat com +1-919-301-3266
> Libvirt virtualization library http://libvirt.org