On 25/03/2019 13:21, Dario Faggioli wrote: > 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
Fine with me. > > With this, FWIW, > > Reviewed-by: Dario Faggioli <dfaggi...@suse.com> > > 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 ','. The point is that for the CPU_RESUME_FAILED case we can be sure that no cpu will come up due to resume just a little bit later. So we can test for e.g. a cpupool suddenly having no more cpus available. This is in contrast to CPU_UP_CANCELLED being signalled just after the one cpu failing to come up, but before the next cpu is triggered to come up. Juergen _______________________________________________ Xen-devel mailing list Xen-devel@lists.xenproject.org https://lists.xenproject.org/mailman/listinfo/xen-devel
