Re: [PATCH 2/3] memory-hotplug: more general validation of zone during online

[Reza Arbab]

On Wed, May 11, 2016 at 08:17:41AM -0700, Yasuaki Ishimatsu wrote:
> On Tue, 10 May 2016 15:39:43 -0500
> Reza Arbab <arbab@xxxxxxxxxxxxxxxxxx> wrote:
> <snip>
> > +	if (idx < target) {
> > +		/* pages must be at end of current zone */
> > +		if (pfn + nr_pages != zone_end_pfn(zone))
> > +			return 0;
> <snip>
> > +	if (target < idx) {
> > +		/* pages must be at beginning of current zone */
> > +		if (pfn != zone->zone_start_pfn)
> > +			return 0;
>
> According your patch, memory address must be continuous for changing zone.
> So if memory address is uncontinuous as follows, memory address 0x180000000-0x1FFFFFFFF
> can be changed from ZONE_NORMAL to ZONE_MOVABLE. But memory address 0x80000000-0xFFFFFFFF
> can not be changed from ZONE_NORMAL to ZONE_MOVABLE since it does not meet
> above condition.
>
> Memory address
>  0x80000000 -  0xFFFFFFFF
> 0x180000000 - 0x1FFFFFFFF

Ah, I see. What do you think of this instead?

<snip>
+	if (idx < target) {
+		/* must be the last pages present in current zone */
+		for (i = pfn + nr_pages; i < zone_end_pfn(zone); i++)
+			if (pfn_present(i))
+				return 0;
<snip>
+	if (target < idx) {
+		/* must be the first pages present in current zone */
+		for (i = zone->zone_start_pfn; i < pfn; i++)
+			if (pfn_present(i))
+				return 0;

--
Reza Arbab