linux-kernel - Re: Potential scheduler regression

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] [day] [month] [year] [list]

Message-ID: <20170719080257.GA10514@kroah.com>
Date:   Wed, 19 Jul 2017 10:02:57 +0200
From:   Greg KH <gregkh@...uxfoundation.org>
To:     Ben Guthro <ben@...hro.net>
Cc:     Ingo Molnar <mingo@...nel.org>,
        Peter Zijlstra <peterz@...radead.org>,
        Linux Kernel Mailing List <linux-kernel@...r.kernel.org>,
        Linus Torvalds <torvalds@...ux-foundation.org>,
        Mike Galbraith <efault@....de>,
        Thomas Gleixner <tglx@...utronix.de>
Subject: Re: Potential scheduler regression

On Fri, Jul 14, 2017 at 08:54:07AM +0200, Greg KH wrote:
> On Thu, Jul 13, 2017 at 03:24:02PM -0400, Ben Guthro wrote:
> > On Tue, Jul 11, 2017 at 5:55 AM, Greg KH <gregkh@...uxfoundation.org> wrote:
> > > On Tue, Jul 11, 2017 at 10:30:14AM +0200, Ingo Molnar wrote:
> > >>
> > >> * Ben Guthro <ben@...hro.net> wrote:
> > >>
> > >> > > If people have experience with these in the "enterprise" distros, or any other
> > >> > > tree, and want to provide me with backported, and tested, patches, I'll be
> > >> > > glad to consider them for stable kernels.
> > >> > >
> > >> > > thanks,
> > >> > >
> > >> > > greg k-h
> > >> >
> > >> > I tried to do a simple cherry-pick of the suggested patches - but they
> > >> > apply against files that don't exist in the 4.9 series.
> > >>
> > >> I think there are only two strategies to maintain a backport which work in the
> > >> long run:
> > >>
> > >>  - insist on the simplest fixes and pure cherry-picks
> > >>
> > >>  - or pick up _everything_ to sync up the two versions.
> > >>
> > >> The latter would mean a lot of commits - and I'm afraid it would also involve the
> > >> scheduler header split-up, which literally involves hundreds of files plus
> > >> perpetual build-breakage risk, so it's a no-no.
> > >>
> > >> > In my release of 4.9 - I'm planning on doing the simpler revert of 1b568f0aab
> > >> > that introduced the performance degradation, rather than pulling in lots of code
> > >> > from newer kernels.
> > >>
> > >> That sounds much saner - I'd even Ack that approach for -stable as a special
> > >> exception, than to complicate things with excessive backports.
> > >
> > > Ok, I'll revert that for the next stable release after this one that is
> > > currently under review.
> > >
> > > thanks,
> > >
> > > greg k-h
> > 
> > Greg,
> > 
> > Just for clarity - is the "next one" 4.9.38 (posted today for review)
> > - or the one following?
> 
> Doh, I forgot it for this release, sorry about that, will try to get to
> it for the next one after this.

Now reverted.

thanks,

greg k-h