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

[Avi Kivity <avi@argo.co.il>]

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.