not seriously, because that would need a lot more knowledge about the internal workings of the NFS-Client than I have. The Solaris client seems to be working along that lines, but the code to modify the readahead window looks complicated. The Solaris client also seems to be a lot less agressive when doing readahead. Maximum seems to be 4x8k. As far as I see, the Linux client doesn't really care about the readahead handling at all. It just fills "server->backing_dev_info.ra_pages" and leaves the handling to the MM system.


 Basically one has to know that the problem exists (that is easily detected) and that the readahead factor is involved.

 My patch has of course some pitfalls. at least:

a) as implemented, the nfs_ra_factor will be used for all NFS mounts. It should/could be per filesystem, but that needs a new mount option and I did not want to touch that code due to lack of understanding (and no time to aquire said understanding). But frankly, so far we have not observed any serious performance drawbacks with ra_factor=1.
b) changing the factor needs a remount, as the NFS client only cares about it at that time.

 Not a problem in my situation of course.

Cheers
Martin

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