linux-kernel - Re: Let's talk about the elephant in the room - the Linux kernel's inability to gracefully handle low memory pressure

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Message-ID: <20190829122909.GG28313@dhcp22.suse.cz>
Date:   Thu, 29 Aug 2019 14:29:09 +0200
From:   Michal Hocko <mhocko@...nel.org>
To:     James Courtier-Dutton <james.dutton@...il.com>
Cc:     Daniel Drake <drake@...lessm.com>,
        "Artem S. Tashkinov" <aros@....com>,
        LKML Mailing List <linux-kernel@...r.kernel.org>,
        linux@...lessm.com, hadess@...ess.net,
        Johannes Weiner <hannes@...xchg.org>
Subject: Re: Let's talk about the elephant in the room - the Linux kernel's
 inability to gracefully handle low memory pressure

On Wed 21-08-19 22:42:29, James Courtier-Dutton wrote:
> On Tue, 20 Aug 2019 at 07:47, Daniel Drake <drake@...lessm.com> wrote:
> >
> > Hi,
> >
> > And if there is a meaningful way to make the kernel behave better, that would
> > obviously be of huge value too.
> >
> > Thanks
> > Daniel
> 
> Hi,
> 
> Is there a way for an application to be told that there is a memory
> pressure situation?

PSI (CONFIG_PSI) measures global as well as per memcg pressure characteristics.

[...]

> I have also found, for the desktop, one of the biggest pressures on
> the system is disk pressure. Accessing the disk causes the UI to be
> less responsive.
> For example, if I am in vim, and trying to type letters on the
> keyboard, whether some other application is using the disk or not
> should have no impact on my letter writing. Has anyone got any ideas
> with regards to what we can do about that?

This is what we have the page cache for.
-- 
Michal Hocko
SUSE Labs