Re: [Xen-devel] [PATCH 3/6] xen: add new cpu notifier action CPU_RESUME_FAILED

[Dario Faggioli <dfaggioli@xxxxxxxx>]

On Mon, 2019-03-18 at 14:11 +0100, Juergen Gross wrote:
> --- a/xen/include/xen/cpu.h
> +++ b/xen/include/xen/cpu.h
> @@ -32,23 +32,25 @@ void register_cpu_notifier(struct notifier_block
> *nb);
>   *  (a) A CPU is going down; or (b) CPU_UP_CANCELED
>   */
>  /* CPU_UP_PREPARE: Preparing to bring CPU online. */
> -#define CPU_UP_PREPARE   (0x0001 | NOTIFY_FORWARD)
> +#define CPU_UP_PREPARE    (0x0001 | NOTIFY_FORWARD)
>
In the comment block before these definitions, there's this:

 * Possible event sequences for a given CPU:
 *  CPU_UP_PREPARE -> CPU_UP_CANCELLED           -- failed CPU up
 *  CPU_UP_PREPARE -> CPU_STARTING -> CPU_ONLINE -- successful CPU up
 *  CPU_DOWN_PREPARE -> CPU_DOWN_FAILED          -- failed CPU down
 *  CPU_DOWN_PREPARE -> CPU_DYING -> CPU_DEAD    -- successful CPU down

Shouldn't we add a line for this new hook? Something, IIUIC, like:

 CPU_UP_PREPARE -> CPU_UP_CANCELLED -> CPU_RESUME_FAILED --CPU not resuming

With this, FWIW,

Reviewed-by: Dario Faggioli <dfaggioli@xxxxxxxx>

One more (minor) thing...

>  /* CPU_REMOVE: CPU was removed. */
> -#define CPU_REMOVE       (0x0009 | NOTIFY_REVERSE)
> +#define CPU_REMOVE        (0x0009 | NOTIFY_REVERSE)
> +/* CPU_RESUME_FAILED: CPU failed to come up in resume, all other CPUs up. */
> +#define CPU_RESUME_FAILED (0x000a | NOTIFY_REVERSE)
>  
... technically, when we're dealing with CPU_RESUME_FAILED on one CPU,
we don't know if _all_ others really went up, so I think I'd remove
what follows the ','.

Regards,
Dario
-- 
<<This happens because I choose it to happen!>> (Raistlin Majere)
-----------------------------------------------------------------
Dario Faggioli, Ph.D, http://about.me/dario.faggioli
Software Engineer @ SUSE https://www.suse.com/

Attachment: signature.asc
Description: This is a digitally signed message part

_______________________________________________
Xen-devel mailing list
Xen-devel@xxxxxxxxxxxxxxxxxxxx
https://lists.xenproject.org/mailman/listinfo/xen-devel