Re: [PATCH 2/3] mm: Avoid putting a bad page back on the LRU v2

From: Christoph Lameter
Date: Thu May 01 2008 - 21:13:12 EST


On Thu, 1 May 2008, Russ Anderson wrote:

> Index: linus/mm/migrate.c
> ===================================================================
> --- linus.orig/mm/migrate.c 2008-05-01 19:05:33.000000000 -0500
> +++ linus/mm/migrate.c 2008-05-01 19:06:15.000000000 -0500
> @@ -380,6 +380,7 @@ static void migrate_page_copy(struct pag
> SetPageChecked(newpage);
> if (PageMappedToDisk(page))
> SetPageMappedToDisk(newpage);
> + /* Do not migrate PG_memerror to the new page */

Why is the comment here?


> if (PageDirty(page)) {
> clear_page_dirty_for_io(page);
> @@ -721,6 +722,8 @@ unlock:
> */
> list_del(&page->lru);
> move_to_lru(page);
> + if (PageMemError(page))
> + totalbad_pages++;

Wouldnt this be taken care of by the lru handling?

> +#ifdef CONFIG_PAGEFLAGS_EXTENDED
> +PAGEFLAG(MemError, memerror)
> +#else
> +#define PageMemError(page) 0

Use

PAGEFLAG_FLAGS(MemError)

> #include <linux/page-flags.h>
>
> -#define PAGE_FLAGS (1 << PG_lru | 1 << PG_private | 1 << PG_locked | \
> +#define PAGE_FLAGS_BASE (1 << PG_lru | 1 << PG_private | 1 << PG_locked | \
> 1 << PG_buddy | 1 << PG_writeback | \
> 1 << PG_slab | 1 << PG_swapcache | 1 << PG_active)
> +
> +#ifdef CONFIG_PAGEFLAGS_EXTENDED
> +#define PAGE_FLAGS (PAGE_FLAGS_BASE | 1UL << PG_memerror)
> +#else
> +#define PAGE_FLAGS (PAGE_FLAGS_BASE)
> +#endif
>
> #define PAGE_FLAGS_RECLAIM (PAGE_FLAGS | 1 << PG_reclaim | 1 << PG_dirty)
> #define PAGE_FLAGS_RESERVE (PAGE_FLAGS | 1 << PG_reserved)

The groups of page flags could also be put into page-flags.h.

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