On 2022/10/22 4:01, Tony Luck wrote:
> Cannot call memory_failure() directly from the fault handler because
> mmap_lock (and others) are held.
Could you please explain which lock makes it unfeasible to call memory_failure() directly and
why? I'm somewhat confused. But I agree using memory_failure_queue() should be a good idea.
>
> It is important, but not urgent, to mark the source page as h/w poisoned
> and unmap it from other tasks.
>
> Use memory_failure_queue() to request a call to memory_failure() for the
> page with the error.
>
> Also provide a stub version for CONFIG_MEMORY_FAILURE=n
>
> Signed-off-by: Tony Luck <tony.luck@xxxxxxxxx>
> ---
> include/linux/mm.h | 5 ++++-
> mm/memory.c | 4 +++-
> 2 files changed, 7 insertions(+), 2 deletions(-)
>
> diff --git a/include/linux/mm.h b/include/linux/mm.h
> index 8bbcccbc5565..03ced659eb58 100644
> --- a/include/linux/mm.h
> +++ b/include/linux/mm.h
> @@ -3268,7 +3268,6 @@ enum mf_flags {
> int mf_dax_kill_procs(struct address_space *mapping, pgoff_t index,
> unsigned long count, int mf_flags);
> extern int memory_failure(unsigned long pfn, int flags);
> -extern void memory_failure_queue(unsigned long pfn, int flags);
> extern void memory_failure_queue_kick(int cpu);
> extern int unpoison_memory(unsigned long pfn);
> extern int sysctl_memory_failure_early_kill;
> @@ -3277,8 +3276,12 @@ extern void shake_page(struct page *p);
> extern atomic_long_t num_poisoned_pages __read_mostly;
> extern int soft_offline_page(unsigned long pfn, int flags);
> #ifdef CONFIG_MEMORY_FAILURE
> +extern void memory_failure_queue(unsigned long pfn, int flags);
> extern int __get_huge_page_for_hwpoison(unsigned long pfn, int flags);
> #else
> +static inline void memory_failure_queue(unsigned long pfn, int flags)
> +{
> +}
> static inline int __get_huge_page_for_hwpoison(unsigned long pfn, int flags)
> {
> return 0;
> diff --git a/mm/memory.c b/mm/memory.c
> index b6056eef2f72..eae242351726 100644
> --- a/mm/memory.c
> +++ b/mm/memory.c
> @@ -2866,8 +2866,10 @@ static inline int __wp_page_copy_user(struct page *dst, struct page *src,
> unsigned long addr = vmf->address;
>
> if (likely(src)) {
> - if (copy_mc_user_highpage(dst, src, addr, vma))
> + if (copy_mc_user_highpage(dst, src, addr, vma)) {
> + memory_failure_queue(page_to_pfn(src), 0);
It seems MF_ACTION_REQUIRED is not needed for memory_failure_queue() here. Thanks for your patch.
Reviewed-by: Miaohe Lin <linmiaohe@xxxxxxxxxx>
Thanks,
Miaohe Lin
