Hi!

> * Following a suggestion from Jeff Garzik to save the disk from heavy
>   trashing during my mem=8M test, I've tried to use a ramdisk for
>   swapping - Yes, I know, this is pretty stupid in normal use and might
>   even be illegal (i.e. not expected to work by design). Anyway, I've
>   tried it and was working when used as a swapdevice (size=64M, bs=4k).
>   Added with priority 0 and the normal swap partition kept for fallback
>   with prio=-1. No problems. It did even gracefully swapoff the ramdisk
>   while it was already filled and the box was swapping to disk.
>   To make thinks even more stupid, I've tried a second thing: create
>   an ext2-fs (bs=4k) on the ramdisk, mount it, and use a swapfile on
>   top of it. This deadlocks (with kswapd being current forever) at the
>   very moment the swapfile ist filled and swapping has to go to the
>   fallback raw swap partition.
>   As already said, I wouldn't be surprised, if swapping to rd were
>   broken. But swapping to a rd-partition appears solid while a rd-based
>   swapfile deadlocks. Could the difference be explained somehow or might
>   it indicate some deadlock path due to VM-fs interaction not
>   covered otherwise - so far?

This really should be documented, somewhere.

For example swapping over nbd to localhost can not work.

Swapping over nbd to any other host can not work, too; but it might be
fixable.

Swapping to /dev/loop* probably can not work.

Swapping to file on nfs does not work.

Perhaps this should be added to Documentation/swap.txt?

(Rik, you know about this issues... Do you feel like creating
Documentation/swap.txt?)

                                                                Pavel
-- 
I'm [EMAIL PROTECTED] "In my country we have almost anarchy and I don't care."
Panos Katsaloulis describing me w.r.t. patents at [EMAIL PROTECTED]
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