Re: [PATCH] ubi: fastmap: Check each mapping only once

From: Greg KH <greg@kroah.com>
To: Richard Weinberger <richard@nod.at>
Cc: Martin Kepplinger <martin.kepplinger@ginzinger.com>,
	stable@vger.kernel.org, dedekind1@gmail.com,
	linux-mtd@lists.infradead.org, linux-kernel@vger.kernel.org,
	Sudip Mukherjee <sudipm.mukherjee@gmail.com>,
	Juergen <juergen.lachmann@harman.com>
Subject: Re: [PATCH] ubi: fastmap: Check each mapping only once
Date: Thu, 6 Dec 2018 12:09:01 +0100	[thread overview]
Message-ID: <20181206110901.GN19891@kroah.com> (raw)
In-Reply-To: <1676802.TThbbZSlzy@blindfold>

On Sun, Dec 02, 2018 at 09:51:34AM +0100, Richard Weinberger wrote:
> Greg,
> 
> Am Donnerstag, 29. November 2018, 09:09:23 CET schrieb Greg KH:
> > On Mon, Nov 26, 2018 at 11:38:42AM +0100, Martin Kepplinger wrote:
> > > From: Richard Weinberger <richard@nod.at>
> > > 
> > > [ Upstream commit 34653fd8c46e771585fce5975e4243f8fd401914 ]
> > > 
> > > This commit got merged along with commit 781932375ffc
> > > ("ubi: fastmap: Correctly handle interrupted erasures in EBA") upstream but
> > > only the latter has been applied to stable v4.14.54 as commit a23cf10d9abb.
> > > This resulted in a performance regression. Startup on i.MX platforms is
> > > delayed for up to a few seconds depending on the platform.
> > > This fixes ubi fastmap to be of the same performance as it has been before
> > > said fastmap changes.
> > > 
> > > Fixes: a23cf10d9abb ("ubi: fastmap: Correctly handle interrupted erasures in EBA")
> > > Signed-off-by: Richard Weinberger <richard@nod.at>
> > > Signed-off-by: Martin Kepplinger <martin.kepplinger@ginzinger.com>
> > > ---
> > > 
> > > Richard, although this fixes a major slowdown regression in -stable, do you
> > > consider this "stable" too?
> > > 
> > > This applies and is tested only for the 4.14 stable tree. It seems to be
> > > equally relevant for 4.9 and 4.4 though.
> > 
> > Now queued up for 4.14.y, thanks.
> 
> can you *please* slow a little down?
> 
> There are times (e.g. when I travel, visit customers on-site, being sick, etc...)
> where I don't have the resources to monitor the mailinglists
> in detail. Adding patches to stable on shout asks for trouble.
> 
> As Sudip points out, this patch needs a further fix patch:
> 25677478474a ("ubi: Initialize Fastmap checkmapping correctly")

This is now in 4.14.86 so all should be fine now.

As for "speed", most of the time people are complaining that I move too
slow in getting fixes backported and to their patches.  Rarely am I told
I am moving too fast, that's a nice change :)

As for doing releases on a "regular" schedule, I've tried it, and it
didn't work any better/worse than what I'm doing now as everyone who
consumes these kernels have their own cadence / acceptance process and I
can never get in sync with _everyone_ let alone almost _anyone_.

And due to travel and other things (like security issues coming up),
trying to nail down a specific day-of-the-week doesn't work out at all
either.

thanks,

greg k-h