Messages in this thread | | | Date | Thu, 05 Dec 2002 17:00:15 -0800 | From | Andrew Morton <> | Subject | Re: Maybe a VM bug in 2.4.18-18 from RH 8.0? |
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Norman Gaywood wrote: > > I think I have a trigger for a VM bug in the RH kernel-bigmem-2.4.18-18 > > 16GB > ... > tar cf /dev/tape . >
This machine will die due to buffer_heads which are attached to highmem pagecache, and due to inodes which are pinned by highmem pagecache.
> ... > while [ `expr $COUNT - 1` != 0 ] > do > date > # 2000 by 1_000_000 seems to be a 1.8G process > perl -e '$i=2000;while ($i--){ $a[$i]="x"x1_000_000; }' & > ...
This will evict the highmem pagecache. That frees the buffer_heads and unpins the inodes.
> So what do I do now?
I guess talk to Red Hat. These are well-known problems and there should be fixes for them in a "bigmem" kernel.
Otherwise, the -aa kernels have patches to address these problems. One option would be to roll your own kernel, based on a kernel.org kernel and a matching patch from http://www.kernel.org/pub/linux/kernel/people/andrea/kernels/v2.4/
> ... > Anyone have some patches for me to > try that won't take me too far from the RH 8.0 base system.
Hard. The relevant patches are:
http://www.kernel.org/pub/linux/kernel/people/andrea/kernels/v2.4/2.4.20aa1/05_vm_16_active_free_zone_bhs-1 and http://www.kernel.org/pub/linux/kernel/people/andrea/kernels/v2.4/2.4.20aa1/10_inode-highmem-2
The first one will not come vaguely close to applying to an RH 2.4.18 kernel.
The second one may well apply, and will probably fix the problem. - 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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