Re: [PATCH v2 14/20] mm: Provide speculative fault infrastructure
From: Peter Zijlstra
Date: Wed Aug 30 2017 - 01:58:33 EST
On Wed, Aug 30, 2017 at 10:33:50AM +0530, Anshuman Khandual wrote:
> diff --git a/mm/filemap.c b/mm/filemap.c
> index a497024..08f3042 100644
> --- a/mm/filemap.c
> +++ b/mm/filemap.c
> @@ -1181,6 +1181,18 @@ int __lock_page_killable(struct page *__page)
> int __lock_page_or_retry(struct page *page, struct mm_struct *mm,
> unsigned int flags)
> {
> + if (flags & FAULT_FLAG_SPECULATIVE) {
> + if (flags & FAULT_FLAG_KILLABLE) {
> + int ret;
> +
> + ret = __lock_page_killable(page);
> + if (ret)
> + return 0;
> + } else
> + __lock_page(page);
> + return 1;
> + }
> +
> if (flags & FAULT_FLAG_ALLOW_RETRY) {
> /*
> * CAUTION! In this case, mmap_sem is not released
Yeah, that looks right.
> @@ -4012,17 +4010,7 @@ int handle_speculative_fault(struct mm_struct *mm, unsigned long address,
> goto unlock;
> }
>
> + if (unlikely(vma_is_anonymous(vma) && !vma->anon_vma)) {
> trace_spf_vma_notsup(_RET_IP_, vma, address);
> goto unlock;
> }
As riel pointed out on IRC slightly later, private file maps also need
->anon_vma and those actually have ->vm_ops IIRC so the condition needs
to be slightly more complicated.