From 7b2b1fee30df7e2165525cd03f7d1d01a3a56794 Mon Sep 17 00:00:00 2001 From: Greg Banks Date: Wed, 4 Oct 2006 02:15:50 -0700 Subject: [PATCH] [PATCH] knfsd: knfsd: cache ipmap per TCP socket Speed up high call-rate workloads by caching the struct ip_map for the peer on the connected struct svc_sock instead of looking it up in the ip_map cache hashtable on every call. This helps workloads using AUTH_SYS authentication over TCP. Testing was on a 4 CPU 4 NIC Altix using 4 IRIX clients, each with 16 synthetic client threads simulating an rsync (i.e. recursive directory listing) workload reading from an i386 RH9 install image (161480 regular files in 10841 directories) on the server. That tree is small enough to fill in the server's RAM so no disk traffic was involved. This setup gives a sustained call rate in excess of 60000 calls/sec before being CPU-bound on the server. Profiling showed strcmp(), called from ip_map_match(), was taking 4.8% of each CPU, and ip_map_lookup() was taking 2.9%. This patch drops both contribution into the profile noise. Note that the above result overstates this value of this patch for most workloads. The synthetic clients are all using separate IP addresses, so there are 64 entries in the ip_map cache hash. Because the kernel measured contained the bug fixed in commit commit 1f1e030bf75774b6a283518e1534d598e14147d4 and was running on 64bit little-endian machine, probably all of those 64 entries were on a single chain, thus increasing the cost of ip_map_lookup(). With a modern kernel you would need more clients to see the same amount of performance improvement. This patch has helped to scale knfsd to handle a deployment with 2000 NFS clients. Signed-off-by: Greg Banks Signed-off-by: Neil Brown Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- include/linux/sunrpc/cache.h | 11 ++++++++ include/linux/sunrpc/svcauth.h | 1 + include/linux/sunrpc/svcsock.h | 3 +++ net/sunrpc/svcauth_unix.c | 47 +++++++++++++++++++++++++++++++--- net/sunrpc/svcsock.c | 2 ++ 5 files changed, 61 insertions(+), 3 deletions(-) diff --git a/include/linux/sunrpc/cache.h b/include/linux/sunrpc/cache.h index b5612c958c..3699dff7db 100644 --- a/include/linux/sunrpc/cache.h +++ b/include/linux/sunrpc/cache.h @@ -163,6 +163,17 @@ static inline void cache_put(struct cache_head *h, struct cache_detail *cd) kref_put(&h->ref, cd->cache_put); } +static inline int cache_valid(struct cache_head *h) +{ + /* If an item has been unhashed pending removal when + * the refcount drops to 0, the expiry_time will be + * set to 0. We don't want to consider such items + * valid in this context even though CACHE_VALID is + * set. + */ + return (h->expiry_time != 0 && test_bit(CACHE_VALID, &h->flags)); +} + extern int cache_check(struct cache_detail *detail, struct cache_head *h, struct cache_req *rqstp); extern void cache_flush(void); diff --git a/include/linux/sunrpc/svcauth.h b/include/linux/sunrpc/svcauth.h index a6601650de..de92619b08 100644 --- a/include/linux/sunrpc/svcauth.h +++ b/include/linux/sunrpc/svcauth.h @@ -126,6 +126,7 @@ extern struct auth_domain *auth_domain_find(char *name); extern struct auth_domain *auth_unix_lookup(struct in_addr addr); extern int auth_unix_forget_old(struct auth_domain *dom); extern void svcauth_unix_purge(void); +extern void svcauth_unix_info_release(void *); static inline unsigned long hash_str(char *name, int bits) { diff --git a/include/linux/sunrpc/svcsock.h b/include/linux/sunrpc/svcsock.h index 4c296152cb..98b21ad370 100644 --- a/include/linux/sunrpc/svcsock.h +++ b/include/linux/sunrpc/svcsock.h @@ -54,6 +54,9 @@ struct svc_sock { int sk_reclen; /* length of record */ int sk_tcplen; /* current read length */ time_t sk_lastrecv; /* time of last received request */ + + /* cache of various info for TCP sockets */ + void *sk_info_authunix; }; /* diff --git a/net/sunrpc/svcauth_unix.c b/net/sunrpc/svcauth_unix.c index 40d41a2831..e1bd933629 100644 --- a/net/sunrpc/svcauth_unix.c +++ b/net/sunrpc/svcauth_unix.c @@ -9,6 +9,7 @@ #include #include #include +#include #define RPCDBG_FACILITY RPCDBG_AUTH @@ -375,6 +376,44 @@ void svcauth_unix_purge(void) cache_purge(&ip_map_cache); } +static inline struct ip_map * +ip_map_cached_get(struct svc_rqst *rqstp) +{ + struct ip_map *ipm = rqstp->rq_sock->sk_info_authunix; + if (ipm != NULL) { + if (!cache_valid(&ipm->h)) { + /* + * The entry has been invalidated since it was + * remembered, e.g. by a second mount from the + * same IP address. + */ + rqstp->rq_sock->sk_info_authunix = NULL; + cache_put(&ipm->h, &ip_map_cache); + return NULL; + } + cache_get(&ipm->h); + } + return ipm; +} + +static inline void +ip_map_cached_put(struct svc_rqst *rqstp, struct ip_map *ipm) +{ + struct svc_sock *svsk = rqstp->rq_sock; + + if (svsk->sk_sock->type == SOCK_STREAM && svsk->sk_info_authunix == NULL) + svsk->sk_info_authunix = ipm; /* newly cached, keep the reference */ + else + cache_put(&ipm->h, &ip_map_cache); +} + +void +svcauth_unix_info_release(void *info) +{ + struct ip_map *ipm = info; + cache_put(&ipm->h, &ip_map_cache); +} + static int svcauth_unix_set_client(struct svc_rqst *rqstp) { @@ -384,8 +423,10 @@ svcauth_unix_set_client(struct svc_rqst *rqstp) if (rqstp->rq_proc == 0) return SVC_OK; - ipm = ip_map_lookup(rqstp->rq_server->sv_program->pg_class, - rqstp->rq_addr.sin_addr); + ipm = ip_map_cached_get(rqstp); + if (ipm == NULL) + ipm = ip_map_lookup(rqstp->rq_server->sv_program->pg_class, + rqstp->rq_addr.sin_addr); if (ipm == NULL) return SVC_DENIED; @@ -400,7 +441,7 @@ svcauth_unix_set_client(struct svc_rqst *rqstp) case 0: rqstp->rq_client = &ipm->m_client->h; kref_get(&rqstp->rq_client->ref); - cache_put(&ipm->h, &ip_map_cache); + ip_map_cached_put(rqstp, ipm); break; } return SVC_OK; diff --git a/net/sunrpc/svcsock.c b/net/sunrpc/svcsock.c index 1d512337cc..b39e7e2b64 100644 --- a/net/sunrpc/svcsock.c +++ b/net/sunrpc/svcsock.c @@ -1610,6 +1610,8 @@ svc_delete_socket(struct svc_sock *svsk) sockfd_put(svsk->sk_sock); else sock_release(svsk->sk_sock); + if (svsk->sk_info_authunix != NULL) + svcauth_unix_info_release(svsk->sk_info_authunix); kfree(svsk); } else { spin_unlock_bh(&serv->sv_lock); -- 2.39.5