On Wed, May 15, 2013 at 02:42:42PM +0100, James Vanns wrote: > > fs/nfsd/nfssvc.c:nfsd_get_default_maxblksize() is probably a good > > starting point. Its caller, nfsd_create_serv(), calls > > svc_create_pooled() with the result that's calculated. > > Hmm. If I've read this section of code correctly, it seems to me > that on most modern NFS servers (using TCP as the transport) the default > and preferred blocksize negotiated with clients will almost always be > 1MB - the maximum RPC payload. The nfsd_get_default_maxblksize() function > seems obsolete for modern 64-bit servers with at least 4G of RAM as it'll > always prefer this upper bound instead of any value calculated according to > available RAM. Well, "obsolete" is an odd way to put it--the code is still expected to work on smaller machines. Arguments welcome about the defaults, though I wonder whether it would be better to be doing this sort of calculation in user space. > For what it's worth (not sure if I specified this) I'm running kernel 2.6.32. > > Anyway, this file/function appears to set the default *max* blocksize. I haven't > read all the related code yet, but does the preferred block size derive > from this maximum too? See: > > For fsinfo see fs/nfsd/nfs3proc.c:nfsd3_proc_fsinfo, which uses > > svc_max_payload(). I'm not sure what the history is behind that logic, though. --b. -- 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
