Re: [Devel] Re: [PATCH 2.6.19-rc3] VFS: per-sb dentry lru list

[Kirill Korotaev <dev@sw.ru>]

David,

>>The proposed fix prevents this issue by using per-sb dentry LRU list. It
>>provides very quickly search for the unused dentries for given super block thus
>>forcing shrinking always making good progress.
> 
> 
> We've been down this path before:
> 
> http://marc.theaimsgroup.com/?l=linux-kernel&m=114861109717260&w=2
> 
> A lot of comments on per-sb unused dentry lists were made in
> the threads associated with the above. other solutions were
> found to the problem that the above patch addressed, but I don't
> think any of them have made it to mainline yet. You might want
> to have a bit of a read of these threads first...
The major difference between our patch and the one discussed in the link
it that we keep both global and per-sb dentry LRU lists.
Thus, when needed normal LRU is used and prune logic is unchanged,
while umount/remount use per-sb list and do its job faster.

Thanks,
Kirill