From: Wei Liu <wei.liu2@citrix.com>
To: Jan Beulich <JBeulich@suse.com>
Cc: Wei Liu <wei.liu2@citrix.com>,
Ian Jackson <Ian.Jackson@eu.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: Thu, 28 Apr 2016 16:33:11 +0100 [thread overview]
Message-ID: <20160428153311.GB18194@citrix.com> (raw)
In-Reply-To: <56E9500302000078000DD11F@prv-mh.provo.novell.com>
On Wed, Mar 16, 2016 at 05:22:27AM -0600, Jan Beulich wrote:
> >>> On 15.03.16 at 16:38, <Ian.Jackson@eu.citrix.com> wrote:
> > Jan Beulich writes ("Re: [PATCH v2 3/3] xl: new "loglvl" command"):
> >> Yes and no. If all of the sudden the hypervisor didn't have an "error"
> >> log level anymore, what would you do? Mapping "error" to "warning"
> >> wouldn't be right. Nor would mapping it to anything else. Correct
> >> behavior in that case would simply be failure, and it wouldn't seem
> >> too relevant to me at what layer that failure would get signaled.
> >
> > I think you are looking at this the wrong way.
>
> Quite possible, and all of what you write makes sense. Yet that
> wasn't my intention here. I specifically put the string <-> number
> mapping in xl, so it could be that (and only that, outside the
> hypervisor itself) which gets changed if the hypervisor log levels
> ever change. The tool could use version information or some
> other detection mechanism to provide backwards compatibility
> (and be independent of the precise hypervisor version it got
> built in parallel with, if that's desired). And hence I specifically
> made the interfaces dumb - raw numbers, with no meaning
> assigned to their values.
>
> And then, with what you describe I assume the current hypervisor
> side implementation wouldn't be suitable anymore anyway, as the
> translation between the interface exposed log levels and the
> internally used ones would need to happen in the sysctl handler.
>
> To me, all of this looks increasingly like over-engineering for a
> very simple debugging aid (which is all the new command was
> meant for). If you and Wei can settle on some alternative
> implementation, I'm fine to accept that, but I don't think I'm
> going to spend much more time on fiddling with any of the 3
> patches. It's going to be sad though if even the serial console
> based log level adjustment won't make it into 4.7, despite it
> having got posted months ago (with this v2 just extending on
> it).
>
If this is just a debugging aid and not intending to be consumed by high
level toolstack, maybe we can make a dedicated helper program? We
already have a bunch of those. Should the need really arises we can
then consider making it proper stable API / ABI.
Wei.
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next prev parent reply other threads:[~2016-04-28 15:33 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
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 [this message]
2016-04-29 7:20 ` Jan Beulich
2016-05-02 11:14 ` Wei Liu
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