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.
