orlov/nobh
Quoted 10 lines
Review
Quoted 4 lines
(quoted diff) +4
-0+oldalloc Use old allocator for new inodes. +orlov (*) Use Orlov allocator. + +nobh Do not attach buffer_heads to file pagecache.For these two it would be nice to include a description of why you'd want them or a pointer to something describing it. An admin trying to squeeze performance out of his server might see these options in such documentation and then want to know if they can help him.
See http://lwn.net/Articles/14633/ and http://lwn.net/Articles/14446/
for Orlov.
I am not aware of serious benchmark work. Simple direct tests seem either to show no significant difference or to favor Orlov. I have never seen a study on fragmentation after extended use of both allocators.
Concerning nobh, I think that is a toy by Andrew, meant for very large machines. He is in a better position to comment (in fact on both orlov and nobh).
Andries