linux-kernel - Re: [PATCH v2 0/5] Statsfs: a new ram-based file sytem for Linux kernel statistics

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Date:   Tue, 5 May 2020 10:07:29 -0700 (PDT)
From:   David Rientjes <rientjes@...gle.com>
To:     Paolo Bonzini <pbonzini@...hat.com>
cc:     Jim Mattson <jmattson@...gle.com>,
        Emanuele Giuseppe Esposito <eesposit@...hat.com>,
        Jonathan Adams <jwadams@...gle.com>,
        kvm list <kvm@...r.kernel.org>,
        Christian Borntraeger <borntraeger@...ibm.com>,
        David Hildenbrand <david@...hat.com>,
        Cornelia Huck <cohuck@...hat.com>,
        Vitaly Kuznetsov <vkuznets@...hat.com>,
        Alexander Viro <viro@...iv.linux.org.uk>,
        Emanuele Giuseppe Esposito <e.emanuelegiuseppe@...il.com>,
        LKML <linux-kernel@...r.kernel.org>, linux-mips@...r.kernel.org,
        kvm-ppc@...r.kernel.org, linuxppc-dev@...ts.ozlabs.org,
        linux-s390@...r.kernel.org,
        Linux FS Devel <linux-fsdevel@...r.kernel.org>
Subject: Re: [PATCH v2 0/5] Statsfs: a new ram-based file sytem for Linux
 kernel statistics

On Tue, 5 May 2020, Paolo Bonzini wrote:

> >>> Since this is becoming a generic API (good!!), maybe we can discuss
> >>> possible ways to optimize gathering of stats in mass?
> >> Sure, the idea of a binary format was considered from the beginning in
> >> [1], and it can be done either together with the current filesystem, or
> >> as a replacement via different mount options.
> > 
> > ASCII stats are not scalable. A binary format is definitely the way to go.
> 
> I am totally in favor of having a binary format, but it should be
> introduced as a separate series on top of this one---and preferably by
> someone who has already put some thought into the problem (which
> Emanuele and I have not, beyond ensuring that the statsfs concept and
> API is flexible enough).
> 

The concern is that once this series is merged then /sys/kernel/stats 
could be considered an ABI and there would be a reasonable expectation 
that it will remain stable, in so far as the stats that userspace is 
interested in are stable and not obsoleted.

So is this a suggestion that the binary format becomes complementary to 
statsfs and provide a means for getting all stats from a single subsystem, 
or that this series gets converted to such a format before it is merged?

> ASCII stats are necessary for quick userspace consumption and for
> backwards compatibility with KVM debugfs (which is not an ABI, but it's
> damn useful and should not be dropped without providing something as
> handy), so this is what this series starts from.
>