Hi Andi,
On Tue, Dec 8, 2009 at 11:16 PM, Andi Kleen <andi@xxxxxxxxxxxxxx> wrote:
>
> Process based injection is much easier to handle for test programs,
> who can first bring a page into a specific state and then test.
> So add a new MADV_SOFT_OFFLINE to soft offline a page, similar
> to the existing hard offline injector.
I see that this made its way into 2.6.33. Could you write a short
piece on it for the madvise.2 man page?
Thanks,
Michael
> Signed-off-by: Andi Kleen <ak@xxxxxxxxxxxxxxx>
>
> ---
> include/asm-generic/mman-common.h | 1 +
> mm/madvise.c | 15 ++++++++++++---
> 2 files changed, 13 insertions(+), 3 deletions(-)
>
> Index: linux/include/asm-generic/mman-common.h
> ===================================================================
> --- linux.orig/include/asm-generic/mman-common.h
> +++ linux/include/asm-generic/mman-common.h
> @@ -35,6 +35,7 @@
> #define MADV_DONTFORK 10 /* don't inherit across fork */
> #define MADV_DOFORK 11 /* do inherit across fork */
> #define MADV_HWPOISON 100 /* poison a page for testing */
> +#define MADV_SOFT_OFFLINE 101 /* soft offline page for testing */
>
> #define MADV_MERGEABLE 12 /* KSM may merge identical pages */
> #define MADV_UNMERGEABLE 13 /* KSM may not merge identical pages */
> Index: linux/mm/madvise.c
> ===================================================================
> --- linux.orig/mm/madvise.c
> +++ linux/mm/madvise.c
> @@ -9,6 +9,7 @@
> #include <linux/pagemap.h>
> #include <linux/syscalls.h>
> #include <linux/mempolicy.h>
> +#include <linux/page-isolation.h>
> #include <linux/hugetlb.h>
> #include <linux/sched.h>
> #include <linux/ksm.h>
> @@ -222,7 +223,7 @@ static long madvise_remove(struct vm_are
> /*
> * Error injection support for memory error handling.
> */
> -static int madvise_hwpoison(unsigned long start, unsigned long end)
> +static int madvise_hwpoison(int bhv, unsigned long start, unsigned long end)
> {
> int ret = 0;
>
> @@ -233,6 +234,14 @@ static int madvise_hwpoison(unsigned lon
> int ret = get_user_pages_fast(start, 1, 0, &p);
> if (ret != 1)
> return ret;
> + if (bhv == MADV_SOFT_OFFLINE) {
> + printk(KERN_INFO "Soft offlining page %lx at %lx\n",
> + page_to_pfn(p), start);
> + ret = soft_offline_page(p, MF_COUNT_INCREASED);
> + if (ret)
> + break;
> + continue;
> + }
> printk(KERN_INFO "Injecting memory failure for page %lx at %lx\n",
> page_to_pfn(p), start);
> /* Ignore return value for now */
> @@ -333,8 +342,8 @@ SYSCALL_DEFINE3(madvise, unsigned long,
> size_t len;
>
> #ifdef CONFIG_MEMORY_FAILURE
> - if (behavior == MADV_HWPOISON)
> - return madvise_hwpoison(start, start+len_in);
> + if (behavior == MADV_HWPOISON || behavior == MADV_SOFT_OFFLINE)
> + return madvise_hwpoison(behavior, start, start+len_in);
> #endif
> if (!madvise_behavior_valid(behavior))
> return error;
>
> --
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>
--
Michael Kerrisk Linux man-pages maintainer;
http://www.kernel.org/doc/man-pages/
Author of "The Linux Programming Interface", http://blog.man7.org/
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