On Tue, Mar 22, 2022 at 5:13 PM Minchan Kim <minchan@xxxxxxxxxx> wrote: > > On Mon, Mar 21, 2022 at 07:50:37AM -0700, Brian Geffon wrote: > > Today it's only possible to write back as a page, idle, or huge. > > A user might want to writeback pages which are huge and idle first > > as these idle pages do not require decompression and make a good > > first pass for writeback. > > > > Idle writeback specifically has the advantage that a refault is > > unlikely given that the page has been swapped for some amount of > > time without being refaulted. > > > > Huge writeback has the advantage that you're guaranteed to get > > the maximum benefit from a single page writeback, that is, you're > > reclaiming one full page of memory. Pages which are compressed in > > zram being written back result in some benefit which is always > > less than a page size because of the fact that it was compressed. > > > > This change allows for users to write back huge pages which are > > also idle. > > Hey Brian, > > I really want to add your explanation about the storage endurance > because it's real issue. > > So, could't you add up below in the description? Sure thing. > > From your previous reply > " > we're trying to be very sensitive to our devices storage endurance, > for this reason we will have a fairly conservative writeback limit. > Given that, we want to make sure we're maximizing what lands on disk > while still minimizing the refault time. We could take the approach > where we always writeback huge pages but then we may result in very > quick refaults which would be a huge waste of time. So idle writeback > is a must for us and being able to writeback the pages which have > maximum value (huge) would be very useful > " > > > > > Signed-off-by: Brian Geffon <bgeffon@xxxxxxxxxx> > > Other than that, feel free to add my > Acked-by: Minchan Kim <minchan@xxxxxxxxxx> Thanks Minchan. > > Thanks.
