Re: [PATCH 5/7] Introduce a means of compacting memory within a zone

[Yasunori Goto <y-goto@jp.fujitsu.com>]

Hi Mel-san.
This is very interesting feature.

Now, I'm testing your patches.

> +static int isolate_migratepages(struct zone *zone,
> +					struct compact_control *cc)
> +{
> +	unsigned long high_pfn, low_pfn, end_pfn, start_pfn;

(snip)

> +	/* Time to isolate some pages for migration */
> +	spin_lock_irq(&zone->lru_lock);
> +	for (; low_pfn < end_pfn; low_pfn++) {
> +		if (!pfn_valid_within(low_pfn))
> +			continue;
> +
> +		/* Get the page and skip if free */
> +		page = pfn_to_page(low_pfn);

I met panic at here on my tiger4.

I compiled with CONFIG_SPARSEMEM. So, CONFIG_HOLES_IN_ZONE is not set.
pfn_valid_within() returns 1 every time on this configuration.
(This config is for only virtual memmap)
But, my tiger4 box has memory holes in normal zone.

When it is changed to normal pfn_valid(), no panic occurs.

Hmmm.

Bye.
-- 
Yasunori Goto 


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