Re: is hibernation usable?

[Chris Murphy <lists@colorremedies.com>]

On Thu, Feb 20, 2020 at 12:45 PM Luigi Semenzato <semenzato@google.com> wrote:
>
> On Thu, Feb 20, 2020 at 11:09 AM Chris Murphy <lists@colorremedies.com> wrote:
> >
> > On Thu, Feb 20, 2020 at 10:16 AM Luigi Semenzato <semenzato@google.com> wrote:
> > >
> > > I think this is the right group for the memory issues.
> > >
> > > I suspect that the problem with failed allocations (ENOMEM) boils down
> > > to the unreliability of the page allocator.  In my experience, under
> > > pressure (i.e. pages must be swapped out to be reclaimed) allocations
> > > can fail even when in theory they should succeed.  (I wish I were
> > > wrong and that someone would convincingly correct me.)
> >
> > What is vm.swappiness set to on your system? A fellow Fedora
> > contributor who has consistently reproduced what you describe, has
> > discovered he has vm.swappiness=0, and even if it's set to 1, the
> > problem no longer happens. And this is not a documented consequence of
> > using a value of 0.
>
> I am using the default value of 60.
>
> A zero value should cause all file pages to be discarded before any
> anonymous pages are swapped.  I wonder if the fellow Fedora
> contributor's workload has a lot of file pages, so that discarding
> them is enough for the image allocator to succeed. In that case "sync;
> echo 1 > /proc/sys/vm/drop_caches" would be a better way of achieving
> the same result.  (By the way, in my experiments I do that just before
> hibernating.)

He reports hibernation failure even if he drops caches beforehand.

https://lists.fedoraproject.org/archives/list/desktop@lists.fedoraproject.org/message/XYWYF33RFVISVZTPYSJRRXP7TFXPV4GD/

-- 
Chris Murphy