On Fri, Jul 3, 2020 at 1:30 PM Michal Hocko [off-list ref] wrote:

On Fri 03-07-20 10:34:09, Catangiu, Adrian Costin wrote:

quoted

This patch adds logic to the kernel power code to zero out contents of
all MADV_WIPEONSUSPEND VMAs present in the system during its transition
to any suspend state equal or greater/deeper than Suspend-to-memory,
known as S3.

How does the application learn that its memory got wiped? S2disk is an
async operation and it can happen at any time during the task execution.
So how does the application work to prevent from corrupted state - e.g.
when suspended between two memory loads?

You can do it seqlock-style, kind of - you reserve the first byte of
the page or so as a "is this page initialized" marker, and after every
read from the page, you do a compiler barrier and check whether that
byte has been cleared.