From ed00c2f65267f3a5a8727ac74a90d32470f91679 Mon Sep 17 00:00:00 2001 From: Trond Myklebust Date: Wed, 3 Oct 2018 13:11:51 -0400 Subject: [PATCH] knfsd: Further simplify the cache lookup Order the structure so that the key can be compared using memcmp(). Signed-off-by: Trond Myklebust Signed-off-by: J. Bruce Fields --- fs/nfsd/cache.h | 19 +++++++++++-------- fs/nfsd/nfscache.c | 45 ++++++++++++++++----------------------------- 2 files changed, 27 insertions(+), 37 deletions(-) diff --git a/fs/nfsd/cache.h b/fs/nfsd/cache.h index b7559c6f2b97..745c861237ca 100644 --- a/fs/nfsd/cache.h +++ b/fs/nfsd/cache.h @@ -19,18 +19,21 @@ * is much larger than a sockaddr_in6. */ struct svc_cacherep { - struct list_head c_lru; + struct { + /* Keep often-read xid, csum in the same cache line: */ + __be32 k_xid; + __wsum k_csum; + u32 k_proc; + u32 k_prot; + u32 k_vers; + unsigned int k_len; + struct sockaddr_in6 k_addr; + } c_key; + struct list_head c_lru; unsigned char c_state, /* unused, inprog, done */ c_type, /* status, buffer */ c_secure : 1; /* req came from port < 1024 */ - struct sockaddr_in6 c_addr; - __be32 c_xid; - u32 c_prot; - u32 c_proc; - u32 c_vers; - unsigned int c_len; - __wsum c_csum; unsigned long c_timestamp; union { struct kvec u_vec; diff --git a/fs/nfsd/nfscache.c b/fs/nfsd/nfscache.c index 527ce4c65765..230cc83921ad 100644 --- a/fs/nfsd/nfscache.c +++ b/fs/nfsd/nfscache.c @@ -131,15 +131,15 @@ nfsd_reply_cache_alloc(struct svc_rqst *rqstp, __wsum csum) rp->c_type = RC_NOCACHE; INIT_LIST_HEAD(&rp->c_lru); - rp->c_xid = rqstp->rq_xid; - rp->c_proc = rqstp->rq_proc; - memset(&rp->c_addr, 0, sizeof(rp->c_addr)); - rpc_copy_addr((struct sockaddr *)&rp->c_addr, svc_addr(rqstp)); - rpc_set_port((struct sockaddr *)&rp->c_addr, rpc_get_port(svc_addr(rqstp))); - rp->c_prot = rqstp->rq_prot; - rp->c_vers = rqstp->rq_vers; - rp->c_len = rqstp->rq_arg.len; - rp->c_csum = csum; + memset(&rp->c_key, 0, sizeof(rp->c_key)); + rp->c_key.k_xid = rqstp->rq_xid; + rp->c_key.k_proc = rqstp->rq_proc; + rpc_copy_addr((struct sockaddr *)&rp->c_key.k_addr, svc_addr(rqstp)); + rpc_set_port((struct sockaddr *)&rp->c_key.k_addr, rpc_get_port(svc_addr(rqstp))); + rp->c_key.k_prot = rqstp->rq_prot; + rp->c_key.k_vers = rqstp->rq_vers; + rp->c_key.k_len = rqstp->rq_arg.len; + rp->c_key.k_csum = csum; } return rp; } @@ -330,27 +330,14 @@ nfsd_cache_csum(struct svc_rqst *rqstp) return csum; } -static bool -nfsd_cache_match(const struct svc_cacherep *key, const struct svc_cacherep *rp) +static int +nfsd_cache_key_cmp(const struct svc_cacherep *key, const struct svc_cacherep *rp) { - /* Check RPC XID first */ - if (key->c_xid != rp->c_xid) - return false; - /* compare checksum of NFS data */ - if (key->c_csum != rp->c_csum) { + if (key->c_key.k_xid == rp->c_key.k_xid && + key->c_key.k_csum != rp->c_key.k_csum) ++payload_misses; - return false; - } - - /* Other discriminators */ - if (key->c_proc != rp->c_proc || - key->c_prot != rp->c_prot || - key->c_vers != rp->c_vers || - key->c_len != rp->c_len || - memcmp(&key->c_addr, &rp->c_addr, sizeof(key->c_addr)) != 0) - return false; - return true; + return memcmp(&key->c_key, &rp->c_key, sizeof(key->c_key)); } /* @@ -367,7 +354,7 @@ nfsd_cache_insert(struct nfsd_drc_bucket *b, struct svc_cacherep *key) list_for_each_entry(rp, rh, c_lru) { ++entries; - if (nfsd_cache_match(key, rp)) { + if (nfsd_cache_key_cmp(key, rp) == 0) { ret = rp; break; } @@ -510,7 +497,7 @@ nfsd_cache_update(struct svc_rqst *rqstp, int cachetype, __be32 *statp) if (!rp) return; - hash = nfsd_cache_hash(rp->c_xid); + hash = nfsd_cache_hash(rp->c_key.k_xid); b = &drc_hashtbl[hash]; len = resv->iov_len - ((char*)statp - (char*)resv->iov_base); -- 2.30.2