On Tue, Apr 28, 2020 at 06:51:26PM -0700, Matthew Wilcox wrote: > On Wed, Apr 29, 2020 at 03:26:24AM +0300, Kirill A. Shutemov wrote: > > On Tue, Apr 28, 2020 at 12:44:42PM -0700, Matthew Wilcox wrote: > > > From: "Matthew Wilcox (Oracle)" <willy@xxxxxxxxxxxxx> > > > > > > Pages which are in use as page tables have some space unused in struct > > > page. It would be handy to have a pointer to the struct mm_struct that > > > they belong to so that we can handle uncorrectable errors in page tables > > > more gracefully. There are a few other things we could use it for too, > > > such as checking that the page table entry actually belongs to the task > > > we think it ought to. This patch series does none of that, but does > > > lay the groundwork for it. > > > > > > Matthew Wilcox (Oracle) (7): > > > > How does it work for kernel side of virtual address space? > > init_mm A note to keep in mind is that most of the kernel page tables are seen as PG_reserved rather than PageTable(). > > And your employer may be interested in semantics around > > CONFIG_ARCH_WANT_HUGE_PMD_SHARE :P > > I was thinking about that. Right now, it's only useful for debugging > purposes (as you point out in a later email). I think it's OK if shared > PMDs aren't supported as well as regular PTEs, just because there are > so few of them that uncorrectable errors are less likely to strike in > those pages. > -- Sincerely yours, Mike.
