Date: Mon, 23 Feb 2009 10:10:44 -0500 From: John Baldwin <jhb@freebsd.org> To: Scott Long <scottl@samsco.org> Cc: svn-src-head@freebsd.org, svn-src-all@freebsd.org, src-committers@freebsd.org Subject: Re: svn commit: r188832 - head/sys/nfsclient Message-ID: <200902231010.45511.jhb@freebsd.org> In-Reply-To: <499DF860.8020903@samsco.org> References: <200902192218.n1JMI1HF009245@svn.freebsd.org> <499DF860.8020903@samsco.org>
next in thread | previous in thread | raw e-mail | index | archive | help
On Thursday 19 February 2009 7:25:04 pm Scott Long wrote: > John Baldwin wrote: > > Author: jhb > > Date: Thu Feb 19 22:18:00 2009 > > New Revision: 188832 > > URL: http://svn.freebsd.org/changeset/base/188832 > > > > Log: > > When fetching attributes for a file for NFSv3 mounts, do not perform an > > opportunistic ACCESS RPC to populate both the access and attribute caches > > of the file and instead always use a GETATTR RPC. On many modern NFS > > servers, an ACCESS RPC is much more expensive to service than a GETATTR > > RPC. > > > > Not too long ago, this was a very useful and important optimization. > Can you say which servers this applies to? Could it have been made an > option instead of outright deleted? I know this applies to at least some Net-Apps. I could certainly restore the access priming under a sysctl however. Something like this: --- //depot/projects/smpng/sys/nfsclient/nfs_vnops.c 2009/02/20 15:11:39 +++ //depot/user/jhb/lock/nfsclient/nfs_vnops.c 2009/02/23 15:09:16 @@ -208,6 +208,11 @@ SYSCTL_INT(_vfs_nfs, OID_AUTO, access_cache_timeout, CTLFLAG_RW, &nfsaccess_cache_timeout, 0, "NFS ACCESS cache timeout"); +static int nfs_prime_access_cache = 0; +SYSCTL_INT(_vfs_nfs, OID_AUTO, prime_access_cache, CTLFLAG_RW, + &nfs_prime_access_cache, 0, + "Prime NFS ACCESS cache when fetching attributes"); + static int nfsv3_commit_on_close = 0; SYSCTL_INT(_vfs_nfs, OID_AUTO, nfsv3_commit_on_close, CTLFLAG_RW, &nfsv3_commit_on_close, 0, "write+commit on close, else only write"); @@ -644,6 +649,12 @@ */ if (nfs_getattrcache(vp, &vattr) == 0) goto nfsmout; + if (v3 && nfs_prime_access_cache && nfsaccess_cache_timeout > 0) { + nfsstats.accesscache_misses++; + nfs3_access_otw(vp, NFSV3ACCESS_ALL, td, ap->a_cred); + if (nfs_getattrcache(vp, &vattr) == 0) + goto nfsmout; + } nfsstats.rpccnt[NFSPROC_GETATTR]++; mreq = nfsm_reqhead(vp, NFSPROC_GETATTR, NFSX_FH(v3)); mb = mreq; -- John Baldwin
Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?200902231010.45511.jhb>