On Thu, Oct 17, 2019 at 04:21:21PM +0200, Oscar Salvador wrote:
> Currently, there is an inconsistency when calling soft-offline from
> different paths on a page that is already poisoned.
>
> 1) madvise:
>
> madvise_inject_error skips any poisoned page and continues
> the loop.
> If that was the only page to madvise, it returns 0.
>
> 2) /sys/devices/system/memory/:
>
> Whe calling soft_offline_page_store()->soft_offline_page(),
> we return -EBUSY in case the page is already poisoned.
> This is inconsistent with a) the above example and b)
> memory_failure, where we return 0 if the page was poisoned.
>
> Fix this by dropping the PageHWPoison() check in madvise_inject_error,
> and let soft_offline_page return 0 if it finds the page already poisoned.
>
> Please, note that this represents an user-api change, since now the return
> error when calling soft_offline_page_store()->soft_offline_page() will be different.
>
> Signed-off-by: Oscar Salvador <osalvador@xxxxxxx>
Looks good to me.
Acked-by: Naoya Horiguchi <n-horiguchi@xxxxxxxxxxxxx>
> ---
> mm/madvise.c | 3 ---
> mm/memory-failure.c | 4 ++--
> 2 files changed, 2 insertions(+), 5 deletions(-)
>
> diff --git a/mm/madvise.c b/mm/madvise.c
> index 8a0b1f901d72..9ca48345ce45 100644
> --- a/mm/madvise.c
> +++ b/mm/madvise.c
> @@ -887,9 +887,6 @@ static int madvise_inject_error(int behavior,
> */
> put_page(page);
>
> - if (PageHWPoison(page))
> - continue;
> -
> if (behavior == MADV_SOFT_OFFLINE) {
> pr_info("Soft offlining pfn %#lx at process virtual address %#lx\n",
> pfn, start);
> diff --git a/mm/memory-failure.c b/mm/memory-failure.c
> index 3d491c0d3f91..c038896bedf0 100644
> --- a/mm/memory-failure.c
> +++ b/mm/memory-failure.c
> @@ -1767,7 +1767,7 @@ static int __soft_offline_page(struct page *page)
> unlock_page(page);
> put_page(page);
> pr_info("soft offline: %#lx page already poisoned\n", pfn);
> - return -EBUSY;
> + return 0;
> }
>
> if (!PageHuge(page))
> @@ -1866,7 +1866,7 @@ int soft_offline_page(struct page *page)
>
> if (PageHWPoison(page)) {
> pr_info("soft offline: %#lx page already poisoned\n", pfn);
> - return -EBUSY;
> + return 0;
> }
>
> get_online_mems();
> --
> 2.12.3
>
>
