Hi, Regards, Rishi Agrawal -----Original Message----- From: Steve Dickson [mailto:SteveD@xxxxxxxxxx] Sent: Monday, August 04, 2014 8:01 PM To: Rishi Agrawal; linux-nfs@xxxxxxxxxxxxxxx Cc: Rajesh Ghanekar; Ram Pandiri; Sreeharsha Sarabu; Abhijit Dey; Tushar Shinde; bfields@xxxxxxxxxx Subject: Re: Patch For Making Readdir_plus configurable Hello, On 25/07/14 12:19, Rishi Agrawal wrote: > Hi, > One of our customer's application only needs file names not file > attributes. With directories having 10K+ inodes (assuming buffer cache > has directory blocks cached having file names, but inode cache is > limited and hence need eviction of older cached inodes), older inodes > are evicted periodically. So if they keep on doing > readdir(2) from NSF client on multiple directories, some directory's > files are periodically removed from inode cache and hence new > readdir(2) on same directory requires disk access to bring back inodes > again to inode cache. > > As READDIRPLUS request fetches attributes also, doing getattr on each > file on server, it causes unnecessary disk accesses. If READDIRPLUS on > NFS client is returned with -ENOTSUPP, NFS client uses READDIR request > which just gets the names of the files in a directory, not attributes, > hence avoiding disk accesses on server. > > Can this be per-export tunable so that different application can use > it in different ways, some supporting readdirplus and others not > supporting readdirplus? > > I have worked on a patch against 3.15.6 for this. Also I am adding a > patch against latest nfs-utils to have an export option for this. Can > someone let me know if these patches are adequate or if any other > changes are required. Patches attached, although with minimal testing. > I would like to know if something like this can be added and if the > patch can be reworked if I am missing something for NFSv4. I just notice that the nfs-utils patch does not update the exports(5) man page. In that update please note this is a v3 only thing.... Not clear what we are going to do in the v4 case. Finally, please inline your patch posting in the your email as its is explained there https://www.kernel.org/doc/Documentation/SubmittingPatches It just makes it easier for everyone to do the review... tia, steved. [[[Rishi]]] I will take care of the changes and resubmit the patch. -- Rishi -- To unsubscribe from this list: send the line "unsubscribe linux-nfs" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
