Re: [PATCH 04/10] hugetlb: hugepage migration core

[Christoph Lameter]

On Fri, 3 Sep 2010, Naoya Horiguchi wrote:

> diff --git v2.6.36-rc2/mm/vmscan.c v2.6.36-rc2/mm/vmscan.c
> index c391c32..69ce2a3 100644
> --- v2.6.36-rc2/mm/vmscan.c
> +++ v2.6.36-rc2/mm/vmscan.c
> @@ -40,6 +40,7 @@
>  #include <linux/memcontrol.h>
>  #include <linux/delayacct.h>
>  #include <linux/sysctl.h>
> +#include <linux/hugetlb.h>
>
>  #include <asm/tlbflush.h>
>  #include <asm/div64.h>
> @@ -508,6 +509,10 @@ void putback_lru_page(struct page *page)
>
>  	VM_BUG_ON(PageLRU(page));
>
> +	if (PageHuge(page)) {
> +		put_page(page);
> +		return;
> +	}
>  redo:
>  	ClearPageUnevictable(page);
>
> @@ -1112,7 +1117,9 @@ int isolate_lru_page(struct page *page)
>  {
>  	int ret = -EBUSY;
>
> -	if (PageLRU(page)) {
> +	if (PageHuge(page) && get_page_unless_zero(compound_head(page)))
> +		ret = 0;
> +	else if (PageLRU(page)) {
>  		struct zone *zone = page_zone(page);
>
>  		spin_lock_irq(&zone->lru_lock);
>

Huge pages are not on the LRU right? So why use the lru functions for
them and then not use the lru? Its a bit stranger. The caller must aware
of the different handling of huge pages since there is no toying around
with the lru. So just have the caller do a put or get page instead.

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/