Re: [PATCH] [9/16] HWPOISON: Handle hardware poisoned pages in try_to_unmap

Wu Fengguang
2009-06-04T04:36:01Z

On Thu, Jun 04, 2009 at 02:46:42AM +0800, Andi Kleen wrote:
>
> When a page has the poison bit set replace the PTE with a poison entry.
> This causes the right error handling to be done later when a process runs
> into it.
>
> Also add a new flag to not do that (needed for the memory-failure handler
> later)
>
> Signed-off-by: Andi Kleen <ak@linux.intel.com>
>
> ---
> include/linux/rmap.h | 1 +
> mm/rmap.c | 9 ++++++++-
> 2 files changed, 9 insertions(+), 1 deletion(-)
>
> Index: linux/mm/rmap.c
> ===================================================================
> --- linux.orig/mm/rmap.c 2009-06-03 19:36:23.000000000 +0200
> +++ linux/mm/rmap.c 2009-06-03 20:39:49.000000000 +0200
> @@ -943,7 +943,14 @@
> /* Update high watermark before we lower rss */
> update_hiwater_rss(mm);
>
> - if (PageAnon(page)) {
> + if (PageHWPoison(page) && !(flags & TTU_IGNORE_HWPOISON)) {
> + if (PageAnon(page))
> + dec_mm_counter(mm, anon_rss);
> + else if (!is_migration_entry(pte_to_swp_entry(*pte)))
> + dec_mm_counter(mm, file_rss);
> + set_pte_at(mm, address, pte,
> + swp_entry_to_pte(make_hwpoison_entry(page)));
> + } else if (PageAnon(page)) {
> swp_entry_t entry = { .val = page_private(page) };
>
> if (PageSwapCache(page)) {
> Index: linux/include/linux/rmap.h
> ===================================================================
> --- linux.orig/include/linux/rmap.h 2009-06-03 19:36:23.000000000 +0200
> +++ linux/include/linux/rmap.h 2009-06-03 19:36:23.000000000 +0200
> @@ -93,6 +93,7 @@
>
> TTU_IGNORE_MLOCK = (1 << 8), /* ignore mlock */
> TTU_IGNORE_ACCESS = (1 << 9), /* don't age */
> + TTU_IGNORE_HWPOISON = (1 << 10),/* corrupted page is recoverable */

Or more precisely comment it as "corrupted data is recoverable"?