Date: Thu, 3 Jan 2002 14:23:01 -0600
From: Ken Brownfield <brownfld@irridia.com>
To: Andreas Hartmann <andihartmann@freenet.de>
Cc: Kernel-Mailingliste <linux-kernel@vger.kernel.org>
Subject: Re: [2.4.17/18pre] VM and swap - it's really unusable
Message-ID: <20020103142301.C4759@asooo.flowerfire.com>
In-Reply-To: <3C2CD326.100@athlon.maya.org>
Mime-Version: 1.0
Content-Type: text/plain; charset=us-ascii
In-Reply-To: <3C2CD326.100@athlon.maya.org>; from andihartmann@freenet.de on Fri, Dec 28, 2001 at 09:16:38PM +0100
Sender: linux-kernel-owner@vger.kernel.org

Unfortunately, I lost the response that basically said "2.4 looks stable
to me", but let me count the ways in which I agree with Andreas'
sentiment:

	A) VM has major issues
		1) about a dozen recent OOPS reports in VM code
		2) VM falls down on large-memory machines with a
		   high inode count (slocate/updatedb, i/dcache)
		3) Memory allocation failures and OOM triggers
		   even though caches remain full.
		4) Other bugs fixed in -aa and others
	B) Live- and dead-locks that I'm seeing on all 2.4 production
	   machines > 2.4.9, possibly related to A.  But how will I
	   ever find out?
	C) IO-APIC code that requires noapic on any and all SMP
	   machines that I've ever run on.

I don't have anything against anyone here -- I think everyone is doing a
fine job.  It's an issue of acceptance of the problem and focus.  These
issues are all showstoppers for me, and while I don't represent the 90%
of the Linux market that is UP desktops, IMHO future work on the kernel
will be degraded by basic functionality that continues to cause
problems.

I think seeing some of Andrea's and Andrew's et al patches actually
*happen* would be a good thing, since 2.4 kernels are decidedly not
ready for production here.  I am forced to apply 26 distinct patch sets
to my kernels, and I am NOT the right person to make these judgements.
Which is why I was interested in an LKML summary source, though I
haven't yet had a chance to catch up on that thread of comment.

Having a glitch in the radeon driver is one thing; having persistent,
fatal, and reproducable failures in universal kernel code is entirely
another.

-- 
Ken.
brownfld@irridia.com


On Fri, Dec 28, 2001 at 09:16:38PM +0100, Andreas Hartmann wrote:
| Hello all,
| 
| Again, I did a rsync-operation as described in
| "[2.4.17rc1] Swapping" MID <3C1F4014.2010705@athlon.maya.org>.
| 
| This time, the kernel had a swappartition which was about 200MB. As the 
| swap-partition was fully used, the kernel killed all processes of knode.
| Nearly 50% of RAM had been used for buffers at this moment. Why is there 
| so much memory used for buffers?
| 
| I know I repeat it, but please:
| 
| 	Fix the VM-management in kernel 2.4.x. It's unusable. Believe
| 	me! As comparison: kernel 2.2.19 didn't need nearly any swap for
| 	the same operation!
| 
| Please consider that I'm using 512 MB of RAM. This should, or better: 
| must be enough to do the rsync-operation nearly without any swapping - 
| kernel 2.2.19 does it!
| 
| The performance of kernel 2.4.18pre1 is very poor, which is no surprise, 
| because the machine swaps nearly nonstop.
| 
| 
| Regards,
| Andreas Hartmann
| 
| -
| To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
| the body of a message to majordomo@vger.kernel.org
| More majordomo info at  http://vger.kernel.org/majordomo-info.html
| Please read the FAQ at  http://www.tux.org/lkml/
-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/