On Mon, 2018-10-01 at 10:41 -0400, Trond Myklebust wrote: > The following set of patches aim to remove some of the global > spinlocks > that are currently being taken during the processing of every > incoming > RPC call. Most of these spinlocks are protecting read-mostly > structures, > and so can be replaced with taking an RCU read lock. > > The patchset also replaces the current reader/writer spinlock in the > server cache implementation with an RCU read lock + a regular > spinlock. > This gives a slight scalability improvement by allowing lookups to be > concurrent with updates rather than excluding them. > > Finally, there is a set of changes to the NFSv2/v3/v4.0 duplicate > reply > cache to further optimise it for the common case where we're only > inserting new entries. By using a red-black tree rather than a simple > linked list, we reduce the typical number of entries we need to check > (a.k.a. "chain length" in /proc/fs/nfsd/reply_cache_stats) from > roughly 80 to 9 per incoming RPC request. This significantly reduces > the > total amount of time spent in nfsd_cache_lookup() according to > 'perf'. > > Trond Myklebust (15): > SUNRPC: Remove the server 'authtab_lock' and just use RCU > SUNRPC: Add lockless lookup of the server's auth domain > SUNRPC: Allow cache lookups to use RCU protection rather than the > r/w > spinlock > SUNRPC: Make server side AUTH_UNIX use lockless lookups > knfsd: Allow lockless lookups of the exports > SUNRPC: Lockless server RPCSEC_GSS context lookup > knfsd: Lockless lookup of NFSv4 identities. > NFS: Lockless DNS lookups > SUNRPC: Remove non-RCU protected lookup > SUNRPC: Replace the cache_detail->hash_lock with a regular spinlock > SUNRPC: Simplify TCP receive code > knfsd: Remove dead code from nfsd_cache_lookup > knfsd: Simplify NFS duplicate replay cache > knfsd: Further simplify the cache lookup > knfsd: Improve lookup performance in the duplicate reply cache > using > an rbtree > > Documentation/filesystems/nfs/rpc-cache.txt | 6 +- > fs/nfs/dns_resolve.c | 15 +- > fs/nfsd/cache.h | 19 ++- > fs/nfsd/export.c | 14 +- > fs/nfsd/export.h | 2 + > fs/nfsd/nfs4idmap.c | 11 +- > fs/nfsd/nfscache.c | 142 +++++++++--------- > include/linux/sunrpc/cache.h | 18 ++- > include/linux/sunrpc/svcauth.h | 1 + > net/sunrpc/auth_gss/svcauth_gss.c | 41 +++++- > net/sunrpc/cache.c | 153 ++++++++++++---- > ---- > net/sunrpc/svcauth.c | 74 +++++++--- > net/sunrpc/svcauth_unix.c | 24 ++- > net/sunrpc/svcsock.c | 53 ++----- > 14 files changed, 327 insertions(+), 246 deletions(-) > I forgot to add. The full patchset is also hosted on git://git.linux- nfs.org/projects/trondmy/linux-nfs.git in the 'knfsd-devel' branch: git pull git://git.linux-nfs.org/projects/trondmy/linux-nfs.git knfsd- devel -- Trond Myklebust Linux NFS client maintainer, Hammerspace trond.myklebust@xxxxxxxxxxxxxxx
