On Fri, 2 Jul 2010, Naoya Horiguchi wrote:
> --- v2.6.35-rc3-hwpoison/mm/migrate.c
> +++ v2.6.35-rc3-hwpoison/mm/migrate.c
> @@ -32,6 +32,7 @@
> #include <linux/security.h>
> #include <linux/memcontrol.h>
> #include <linux/syscalls.h>
> +#include <linux/hugetlb.h>
> #include <linux/gfp.h>
>
> #include "internal.h"
> @@ -74,6 +75,8 @@ void putback_lru_pages(struct list_head *l)
> struct page *page2;
>
> list_for_each_entry_safe(page, page2, l, lru) {
> + if (PageHuge(page))
> + break;
> list_del(&page->lru);
Argh. Hugepages in putpack_lru_pages()? Huge pages are not on the lru.
Come up with something cleaner here.
> @@ -267,7 +284,14 @@ static int migrate_page_move_mapping(struct address_space *mapping,
> * Note that anonymous pages are accounted for
> * via NR_FILE_PAGES and NR_ANON_PAGES if they
> * are mapped to swap space.
> + *
> + * Not account hugepage here for now because hugepage has
> + * separate accounting rule.
> */
> + if (PageHuge(newpage)) {
> + spin_unlock_irq(&mapping->tree_lock);
> + return 0;
> + }
> __dec_zone_page_state(page, NR_FILE_PAGES);
> __inc_zone_page_state(newpage, NR_FILE_PAGES);
> if (PageSwapBacked(page)) {
This looks wrong here. Too many special casing added to basic migration
functionality.
> @@ -284,7 +308,17 @@ static int migrate_page_move_mapping(struct address_space *mapping,
> */
> static void migrate_page_copy(struct page *newpage, struct page *page)
> {
> - copy_highpage(newpage, page);
> + int i;
> + struct hstate *h;
> + if (!PageHuge(newpage))
> + copy_highpage(newpage, page);
> + else {
> + h = page_hstate(newpage);
> + for (i = 0; i < pages_per_huge_page(h); i++) {
> + cond_resched();
> + copy_highpage(newpage + i, page + i);
> + }
> + }
>
> if (PageError(page))
> SetPageError(newpage);
Could you generalize this for migrating an order N page?
> @@ -718,6 +752,11 @@ unlock:
> put_page(page);
>
> if (rc != -EAGAIN) {
> + if (PageHuge(newpage)) {
> + put_page(newpage);
> + goto out;
> + }
> +
I dont like this kind of inconsistency with the refcounting. Page
migration is complicated enough already.
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