Re: [PATCH 3/9] mm: postpone page table allocation until do_set_pte()

From: Dave Hansen
Date: Tue Dec 01 2015 - 15:53:31 EST


On 11/18/2015 03:25 PM, Kirill A. Shutemov wrote:
> --- a/mm/filemap.c
> +++ b/mm/filemap.c
> @@ -2068,11 +2068,6 @@ void filemap_map_pages(struct fault_env *fe,
...
> if (file->f_ra.mmap_miss > 0)
> file->f_ra.mmap_miss--;
> - do_set_pte(fe, page);
> +
> + fe->address += (iter.index - last_pgoff) << PAGE_SHIFT;
> + if (fe->pte)
> + fe->pte += iter.index - last_pgoff;
> + last_pgoff = iter.index;
> + if (do_set_pte(fe, NULL, page)) {
> + /* failed to setup page table: giving up */
> + if (!fe->pte)
> + break;
> + goto unlock;
> + }
> unlock_page(page);
> goto next;

Hey Kirill,

Is there a case here where do_set_pte() returns an error and _still_
manages to populate fe->pte?

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