[systemd-devel] [PATCH] readahead: read /usr files last for rotational media, skip /var

[Tom Gundersen]

On Fri, Sep 30, 2011 at 5:23 PM, Paolo Bonzini <bonzini at gnu.org> wrote:
> It's actually pretty hard unless you give up the ability to replay/collect
> at the same time, which I think would be really bad.  The problem is that
> replay will read files for "after basic.target" long before that target has
> completed, and this will fool collect.

Just to clarify what I meant:

When I said "before basic.target" I didn't mean the files accessed
before basic.target is  satisfied. However, I meant files accessed by
processes belonging to services that have an (possibly indirect)
Before relationship with basic.target (so this is not entirely trivial
as we need to get the pid from the fanotify event, the service from
the cgroup hirearchy and then trace the relationship to basic.target,
but it is definitely doable).

Obviously, fanotify events originating in
systemd-readahead-repaly.service would have to be excluded (actually
we probably want to exclude such events altogether, to avoid stale
entries in /.readahead).

Cheers,

Tom