On Fri, Feb 12, 2016 at 10:33:37AM -0800, Dave Hansen wrote:

On 02/11/2016 06:21 AM, Kirill A. Shutemov wrote:

quoted

For file pages we don't deposit page table on mapping: no need to
withdraw it.

I thought the deposit thing was to guarantee we could always do a PMD
split.  It still seems like if you wanted to split a huge-tmpfs page,
you'd need to first split the PMD which might need the deposited one.

Why not?

For file thp, split_huge_pmd() is implemented by clearing out the pmd: we
can setup and fill pte table later. Therefore no need to deposit page
table -- we would not use it. DAX does the same.

-- 
 Kirill A. Shutemov

--
To unsubscribe, send a message with 'unsubscribe linux-mm' in
the body to majordomo@kvack.org.  For more info on Linux MM,
see: http://www.linux-mm.org/ .
Don't email: <a href=mailto:"dont@kvack.org"> email@kvack.org </a>