Re: [PATCH] [Request for inclusion] Filesystem in Userspace

From: Avi Kivity
Date: Tue Nov 30 2004 - 18:05:18 EST


Miklos Szeredi wrote:

I have observed it too (not yet fixed, but working on it). But
realize that my proposal would excempt userspace filesystem pages from
being blocked on by kswapd. That's a fundamental difference.

Since you don't believe me, I'll have to make an implementation, so
you can experiment with it. And if you'll still be able to cause a
deadlock, I'll subject myself to extreme repentance, and promise never
to touch an operating system ever again :)



with ramfs, once it accounts for memory, there would be no deadlock and no oom.



And once fuse acounts for memory there will be no deadlock and no oom.
See the symmetry?



If you plan on partitioning system memory into none-fuse and fuse memory, yes, that could work. but it's horribly inflexible - right now memory is balanced dynamically according to actual use. you may also have a hard time with mmap.

my proposal (with the per-process allocation thredsholds) only reserves a small amount of memory to the fuse(s), with the rest allocated dynamically using the normal kernel policies, with no special restrictions on fuse.

--
Do not meddle in the internals of kernels, for they are subtle and quick to panic.

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