Re: [PATCH 02/29] tools: add a new xen logging daemon

[Andrew Cooper <andcooper@xxxxxxxxx>]

On 02/11/2023 7:44 am, Juergen Gross wrote:
> On 01.11.23 19:36, Jason Andryuk wrote:
>> On Wed, Nov 1, 2023 at 10:27 AM Juergen Gross <jgross@xxxxxxxx> wrote:
>>>
>>> Add "xenlogd", a new logging daemon meant to support infrastructure
>>> domains (e.g. xenstore-stubdom) to write log files in dom0.
>>
>> As I understand it, your new daemon is a generic 9pfs backend, which
>> you use for logging.  I think naming it something like xen9pfsd would
>> more accurately describe its functionality.
>
> Fine with me. I'll wait a little bit to see what others think.

FWIW, I too looked at xenlogd and thought it probably wasn't ideal, but
I was going to wait until glancing at the whole series before suggesting
an alternative.

If it really is a generic 9pfs backend, then +1 to Jason's suggestion,
although preferably as xen-9pfsd for improved legibility.


But a couple of other remarks while I'm here.

It's great to see that it only uses stable libraries, and I hope that
remains true to the end of the series.  If we end up wanting unstable
APIs, can I suggest that we take the opportunity to stabilise them as a
prerequisite.

In this patch, stop_me needs to be volatile or read with
ACCESS_ONCE()/etc.  The only thing stopping GCC turning it into an
infinite loop is sleep() being an external call.  daemon_running may
need similar treatment, depending on how it gets used in later patches.

~Andrew