Re: [2.4.17/18pre] VM and swap - it's really unusable

From: Ken Brownfield (brownfld@irridia.com)
Date: Thu Jan 03 2002 - 15:23:01 EST


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/



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