On Tue, Feb 16, 2016 at 07:31:58AM -0800, Dave Hansen wrote: > On 02/16/2016 02:00 AM, Kirill A. Shutemov wrote: > > On Fri, Feb 12, 2016 at 10:33:37AM -0800, Dave Hansen wrote: > >> On 02/11/2016 06:21 AM, Kirill A. Shutemov wrote: > >>> 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. > > Ahh... Do we just never split in any fault contexts, or do we just > retry the fault? In fault contexts we would just continue fault handling as if we had pmd_none(). -- Kirill A. Shutemov -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxx. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>