From: Wei Liu <wei.liu2@citrix.com>
To: Jan Beulich <JBeulich@suse.com>
Cc: Ian Jackson <Ian.Jackson@eu.citrix.com>,
Wei Liu <wei.liu2@citrix.com>,
xen-devel <xen-devel@lists.xenproject.org>,
Stefano Stabellini <stefano.stabellini@eu.citrix.com>
Subject: Re: [PATCH v2 3/3] xl: new "loglvl" command
Date: Mon, 14 Mar 2016 15:36:58 +0000 [thread overview]
Message-ID: <20160314153658.GA22805@citrix.com> (raw)
In-Reply-To: <56E6E58702000078000DC1DB@prv-mh.provo.novell.com>
On Mon, Mar 14, 2016 at 09:23:35AM -0600, Jan Beulich wrote:
> >>> On 08.03.16 at 17:20, <wei.liu2@citrix.com> wrote:
> > On Fri, Mar 04, 2016 at 09:48:16AM -0700, Jan Beulich wrote:
> >> This is pretty simplistic for now, but I'd rather have someone better
> >> friends with the tools improve it (if desired).
> >>
> >> Signed-off-by: Jan Beulich <jbeulich@suse.com>
> >>
> >> --- a/tools/libxl/libxl.c
> >> +++ b/tools/libxl/libxl.c
> >> @@ -5958,6 +5958,26 @@ int libxl_send_debug_keys(libxl_ctx *ctx
> >> return 0;
> >> }
> >>
> >> +int libxl_log_level(libxl_ctx *ctx, bool set, bool guest,
> >> + int *lower_thresh, int *upper_thresh)
> >> +{
> >> + int ret;
> >> + GC_INIT(ctx);
> >> + if (set) {
> >> + ret = xc_set_log_level(ctx->xch, guest, *lower_thresh, *upper_thresh);
> >> + } else {
> >> + ret = xc_get_log_level(ctx->xch, guest, lower_thresh, upper_thresh);
> >> + }
> >> + if ( ret < 0 ) {
> >> + LOGE(ERROR, "%s %slog level",
> >> + set ? "setting" : "getting", guest ? "guest " : "");
> >> + GC_FREE;
> >> + return ERROR_FAIL;
> >> + }
> >> + GC_FREE;
> >> + return 0;
> >> +}
> >> +
> >
> > As Dario said, libxl tends to have getter and setter pair.
>
> "Tends to have" still leaves room for me to get away without
> adjustments. Could you please clearly state whether splitting
> this is required for acceptance?
>
Yes, please make a pair of getter and setter.
> >> --- a/tools/libxl/xl_cmdimpl.c
> >> +++ b/tools/libxl/xl_cmdimpl.c
> >> @@ -6469,6 +6469,84 @@ int main_debug_keys(int argc, char **arg
> >> return 0;
> >> }
> >>
> >> +static const struct {
> >> + int level;
> >> + char string[8];
> >> +} loglvls[] = {
> >> + { 0, "none" },
> >> + { 1, "error" },
> >> + { 2, "warning" },
> >> + { 3, "info" },
> >> + { 4, "all" },
> >> + { 4, "debug" },
> >
> > The semantics of the numbers should go into libxl_types.idl. Maybe
> > something like
> >
> > # Keep in sync with Xen log level.
> > libxl_xen_log_level = Enumeration (...);
> >
> > Then in here
> >
> > static const struct {
> > int level;
> > char string[8];
> > } loglvls[] = {
> > { LIBXL_XEN_LOG_LEVEL_NONE, "none" },
> > { ..., "error" },
> > { ..., "warning" },
> > { ..., "info" },
> > { ..., "all" },
> > { ..., "debug" },
> >
> > Please also note that after the introduction of this API, Xen log level
> > will become part of the stable API and subject to some compatibility
> > constraints. Is this what you wanted?
>
> No, and I actually I'm having trouble following your request: This
> lives in xl_cmdimpl.c, which I didn't think is subject to any stability
> requirements in the mapping of strings (from the xl command line)
> to numbers. It is _specifically_ that I do not want to fix those
> mappings.
>
The new API libxl_log_level relies on the semantics of these mappings.
To make the new API useful to all clients, the semantics of log levels
needs to go into libxl_types.idl (as mentioned a few lines above), hence
it becomes part of the stable API. Otherwise you end up with an API
accepting arbitrary magic numbers.
Wei.
> Jan
>
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next prev parent reply other threads:[~2016-03-14 15:37 UTC|newest]
Thread overview: 37+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-03-04 16:38 [PATCH v2 0/3] allow runtime log level threshold adjustments Jan Beulich
2016-03-04 16:46 ` [PATCH v2 1/3] console: allow " Jan Beulich
2016-03-04 20:55 ` Konrad Rzeszutek Wilk
2016-03-07 10:44 ` Jan Beulich
2016-03-07 14:41 ` Konrad Rzeszutek Wilk
2016-03-07 15:19 ` Jan Beulich
2016-03-04 16:47 ` [PATCH v2 2/3] libxc: wrapper for log level sysctl Jan Beulich
2016-03-05 16:00 ` Dario Faggioli
2016-03-08 16:20 ` Wei Liu
2016-03-04 16:48 ` [PATCH v2 3/3] xl: new "loglvl" command Jan Beulich
2016-03-04 18:45 ` Dario Faggioli
2016-03-07 11:46 ` Jan Beulich
2016-03-07 18:07 ` Dario Faggioli
2016-03-08 8:08 ` Jan Beulich
2016-03-08 14:05 ` George Dunlap
2016-03-08 16:09 ` Wei Liu
2016-03-08 18:05 ` Dario Faggioli
2016-03-05 15:36 ` Dario Faggioli
2016-03-07 13:20 ` Fabio Fantoni
2016-03-07 13:26 ` Jan Beulich
2016-03-08 16:20 ` Wei Liu
2016-03-14 15:23 ` Jan Beulich
2016-03-14 15:36 ` Wei Liu [this message]
2016-03-14 15:49 ` Jan Beulich
2016-03-14 16:01 ` Wei Liu
2016-03-14 17:00 ` Jan Beulich
2016-03-14 17:07 ` Ian Jackson
2016-03-15 7:37 ` Jan Beulich
2016-03-15 13:58 ` Wei Liu
2016-03-15 14:07 ` Jan Beulich
2016-03-15 14:51 ` Wei Liu
2016-03-15 15:03 ` Jan Beulich
2016-03-15 15:38 ` Ian Jackson
2016-03-16 11:22 ` Jan Beulich
2016-04-28 15:33 ` Wei Liu
2016-04-29 7:20 ` Jan Beulich
2016-05-02 11:14 ` Wei Liu
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