Message-Id: <1667877556@web.de>
Date:	Tue, 06 Mar 2007 19:02:00 +0100
From:	devzero@....de
To:	Bill Davidsen <davidsen@....com>
Cc:	linux-kernel@...r.kernel.org
Subject: Re: [RFC] BadRAM still not ready for inclusion ? (was: Re: Free Linux Driver Development!)

bill, 
i have to admit that this sounds reasonable what you tell.

maybe this patch is just something very special, having many pro's but also con's - so this also could be one reason why it exists for so long outside mainline.

regards
roland



> -----Ursprüngliche Nachricht-----
> Von: Bill Davidsen <davidsen@....com>
> Gesendet: 06.03.07 18:11:34
> An: devzero@....de
> CC: linux-kernel@...r.kernel.org, greg@...ah.com, pavel@...e.cz
> Betreff: Re: [RFC] BadRAM still not ready for inclusion ? (was: Re: Free Linux Driver Development!)


> telling youdevzero@....de wrote:
> > Hello !
> > 
> > There's some really nice feature-patch named BadRAM at
> http://rick.vanrein.org/linux/badram/index.html for years now, being
> announced around 2000 on this list, voted for inclusion in 2.3.99.
> > 
> > BadRAM let's you tell the kernel to skip certain regions of ram, so
> you can continue using defective modules. Some older article describing
> BadRAM in more detail is at http://www.linuxjournal.com/article/4489
> 
> 	[...snip...]
> > 
> > Basically, this feature is a matter of adding/modifying 200 lines of
> code, so iŽm even more wondering, why it exists for more than 7 years
> and nothing happening here. I don`t know of any kernel patch which is
> comparable to this.
> > 
> Think about that... 200 lines of code which will have to be maintained 
> forever, once it becomes a supported feature, for the benefit of the few 
> people who can't or won't replace bad memory.
> 
> > This patch is real a ressource-saver - if being a standard Linux
> feature, it will save even more ressources: Saving user's time (because
> they are pulling their hair out to get this run with kernel XYZ) and
> also saving CPU time (no compile orgies anymore), and thus waste of energy.
> > 
> Consider one technical and one human behavour issue. While memory with 
> "bad spots" was common a decade ago, it's as likely with current memory 
> that the memory will "throw a bad bit" once in a while, on a read or 
> write anywhere in the marginal or bad chip. Depending on how the memory 
> is organized that could be 1/16th of the memory as a block of 32MB on a 
> 512MB part, or every 16th byte in the whole memory.
> 
> As for the human issue, how many more people will use this capability to 
> avoid buying memory, run with only part of the bad memory detected and 
> blocked out, get unreliable operation, and think that Linux is unreliable.
> 
> > Please comment if someone sees chances of getting this (after years
> > of
> existance) into mainline and also please jump in to make the good thing
> happen !
> > 
> I personally think that the patch is at best a balance between benefit 
> and problems. As a patch I have to use deliberately I think it's a good 
> idea. As a permanent and default part of the kernel, I'm not convinced. 
> There are some patches I would love to see in mainline, like suspend2 
> which includes resume as well as suspend, but this is not one of them, 
> hope I've explained why.
> 
> As with so many other things in life, "it's not the cost but the upkeep."
> 
> > Historical patch collection at:
> > http://rick.vanrein.org/linux/badram/download.html
> > 
> > Most recent version of BadRAM should be:
> > http://rick.vanrein.org/linux/badram/software/BadRAM-2.6.19.1.patch
> > 
> > Sorry for being a little bit "noisy" here, but I think BadRAM is a
> great feature and Linux could really benefit from that.
> > 
> > regards
> > Roland K.
> > Sysadmin
> > 
> > 
> > List:       linux-kernel
> > Subject:    Re: Free Linux Driver Development!
> > From:       devzero () web ! de
> > Date:       2007-02-04 21:37:33
> > Message-ID: 1605445807 () web ! de
> > [Download message RAW]
> > 
> > First off, compliments to this announcement, I liked it very much!
> > 
> > Some comment regarding those "volunteers, waiting to get some real work" :)
> > 
> >>> OK, but why isn't your army of volunteers fixing them?
> > 
> >> They don't know about them, or they don't have the hardware to test?
> >> Seriously, let the kernel-janitor's project know about any issues you
> >> have and they will be glad to jump on it.  Those people are just
> >> chomping a the bit to do something a bit bigger than "compiler warning
> >> cleanups" :)
> > 
> > So many times i have seen good ideas brought up, kernel patches being written, posted \
> > to lkml, being developed outside mainline for a while and then being forgotten some \
> > time later due to lack of energy of some individual to get this into mainline.
> > 
> > If there is an noticeably number of talented programmers (unfortunately, i`m not) , \
> > so why not "feeding" them the right way ? Where is those public and transparent and \
> > moderated Linux-Kernel "ToDo"- or "Keep an eye on"-list, sorted by priorities, with \
> > sort of a "vote for this feature"-button, so those guys have something they can pick \
> > up? There is so much great stuff and ideas out there where they could put their work \
> > onto or getting involved, it just needs to be found or sort of being "managed" a \
> > little bit better.
> > 
> > For myself, i`m waiting for so quite some things to get "one step further", but they \
> > are more or less tied to some single individuals, for which you just cannot send some \
> > "hey, what`s up with your project"-message every second day. The interest in many \
> > nice projects often is quite low and evolution quite slow, but not only because of \
> > the fact that they aren`t great, but more because of not getting widely known. It`s \
> > not always missing specs, it`s also some missing noise/feedback for different \
> > features or missing of some "driving force" to bring things forward. How should one \
> > developer know that somebody needs a feature if those who could probably need it \
> > don`t request it? Maybe just because of the fact that they even imagine that such \
> > feature would be possible ?
> > 
> > Where is those efforts for fixing/integrating fantastic cowloop?
> > What about badram/badmem patch ?
> > Compressed Ccaching ?
> > Somebody helping with development of dm-loop or extend loop.c to support more than \
> > 256 devices ? Replacement of proprietary, unstable and unelegant vmware-lopp for \
> > being able to mount vmware .vmdk files ? Internal Spec for this is open, dm-userspace \
> > could be some infrastructure for this, but the author seems to have other \
> > priorities.... dm-cow, zfs-fuse - anybody ?
> > Kernel based target for AoE (Ata over Ethernet) ?  (there are two independent \
> > implementations, but both got stuck at some early experimental stage) 
> > 
> > Just my 2 cents. 
> > 
> > Roland K.
> > Sysadmin
> > 
> > ps:
> > This isn`t meant to criticise any of you kernel developers since you`re doing \
> > fantastic work!
> > _______________________________________________________________________
> > Viren-Scan für Ihren PC! Jetzt für jeden. Sofort, online und kostenlos.
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> > 
> 
> 
> -- 
> Bill Davidsen <davidsen@....com>
>    "We have more to fear from the bungling of the incompetent than from
> the machinations of the wicked."  - from Slashdot
> 
> 


_______________________________________________________________________
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