From 28df0988815f63e2af5e6718193c9f68681ad7ff Mon Sep 17 00:00:00 2001 From: Chuck Lever Date: Fri, 29 Apr 2022 10:06:21 -0400 Subject: [PATCH] SUNRPC: Use RMW bitops in single-threaded hot paths I noticed CPU pipeline stalls while using perf. Once an svc thread is scheduled and executing an RPC, no other processes will touch svc_rqst::rq_flags. Thus bus-locked atomics are not needed outside the svc thread scheduler. Signed-off-by: Chuck Lever --- fs/nfsd/nfs4proc.c | 7 ++++--- fs/nfsd/nfs4xdr.c | 2 +- net/sunrpc/auth_gss/svcauth_gss.c | 4 ++-- net/sunrpc/svc.c | 6 +++--- net/sunrpc/svc_xprt.c | 2 +- net/sunrpc/svcsock.c | 8 ++++---- net/sunrpc/xprtrdma/svc_rdma_transport.c | 2 +- 7 files changed, 16 insertions(+), 15 deletions(-) diff --git a/fs/nfsd/nfs4proc.c b/fs/nfsd/nfs4proc.c index 9dbce52f0f33..3895eb52d2b1 100644 --- a/fs/nfsd/nfs4proc.c +++ b/fs/nfsd/nfs4proc.c @@ -970,7 +970,7 @@ nfsd4_read(struct svc_rqst *rqstp, struct nfsd4_compound_state *cstate, * the client wants us to do more in this compound: */ if (!nfsd4_last_compound_op(rqstp)) - clear_bit(RQ_SPLICE_OK, &rqstp->rq_flags); + __clear_bit(RQ_SPLICE_OK, &rqstp->rq_flags); /* check stateid */ status = nfs4_preprocess_stateid_op(rqstp, cstate, &cstate->current_fh, @@ -2650,11 +2650,12 @@ nfsd4_proc_compound(struct svc_rqst *rqstp) cstate->minorversion = args->minorversion; fh_init(current_fh, NFS4_FHSIZE); fh_init(save_fh, NFS4_FHSIZE); + /* * Don't use the deferral mechanism for NFSv4; compounds make it * too hard to avoid non-idempotency problems. */ - clear_bit(RQ_USEDEFERRAL, &rqstp->rq_flags); + __clear_bit(RQ_USEDEFERRAL, &rqstp->rq_flags); /* * According to RFC3010, this takes precedence over all other errors. @@ -2769,7 +2770,7 @@ nfsd4_proc_compound(struct svc_rqst *rqstp) out: cstate->status = status; /* Reset deferral mechanism for RPC deferrals */ - set_bit(RQ_USEDEFERRAL, &rqstp->rq_flags); + __set_bit(RQ_USEDEFERRAL, &rqstp->rq_flags); return rpc_success; } diff --git a/fs/nfsd/nfs4xdr.c b/fs/nfsd/nfs4xdr.c index da92e7d2ab6a..61b2aae81abb 100644 --- a/fs/nfsd/nfs4xdr.c +++ b/fs/nfsd/nfs4xdr.c @@ -2411,7 +2411,7 @@ nfsd4_decode_compound(struct nfsd4_compoundargs *argp) argp->rqstp->rq_cachetype = cachethis ? RC_REPLBUFF : RC_NOCACHE; if (readcount > 1 || max_reply > PAGE_SIZE - auth_slack) - clear_bit(RQ_SPLICE_OK, &argp->rqstp->rq_flags); + __clear_bit(RQ_SPLICE_OK, &argp->rqstp->rq_flags); return true; } diff --git a/net/sunrpc/auth_gss/svcauth_gss.c b/net/sunrpc/auth_gss/svcauth_gss.c index c2ba9d4cd2c7..bcd74dddbe2d 100644 --- a/net/sunrpc/auth_gss/svcauth_gss.c +++ b/net/sunrpc/auth_gss/svcauth_gss.c @@ -900,7 +900,7 @@ unwrap_integ_data(struct svc_rqst *rqstp, struct xdr_buf *buf, u32 seq, struct g * rejecting the server-computed MIC in this somewhat rare case, * do not use splice with the GSS integrity service. */ - clear_bit(RQ_SPLICE_OK, &rqstp->rq_flags); + __clear_bit(RQ_SPLICE_OK, &rqstp->rq_flags); /* Did we already verify the signature on the original pass through? */ if (rqstp->rq_deferred) @@ -972,7 +972,7 @@ unwrap_priv_data(struct svc_rqst *rqstp, struct xdr_buf *buf, u32 seq, struct gs int pad, remaining_len, offset; u32 rseqno; - clear_bit(RQ_SPLICE_OK, &rqstp->rq_flags); + __clear_bit(RQ_SPLICE_OK, &rqstp->rq_flags); priv_len = svc_getnl(&buf->head[0]); if (rqstp->rq_deferred) { diff --git a/net/sunrpc/svc.c b/net/sunrpc/svc.c index 56bed0a57eea..7c9a0d0b1230 100644 --- a/net/sunrpc/svc.c +++ b/net/sunrpc/svc.c @@ -1244,10 +1244,10 @@ svc_process_common(struct svc_rqst *rqstp, struct kvec *argv, struct kvec *resv) goto err_short_len; /* Will be turned off by GSS integrity and privacy services */ - set_bit(RQ_SPLICE_OK, &rqstp->rq_flags); + __set_bit(RQ_SPLICE_OK, &rqstp->rq_flags); /* Will be turned off only when NFSv4 Sessions are used */ - set_bit(RQ_USEDEFERRAL, &rqstp->rq_flags); - clear_bit(RQ_DROPME, &rqstp->rq_flags); + __set_bit(RQ_USEDEFERRAL, &rqstp->rq_flags); + __clear_bit(RQ_DROPME, &rqstp->rq_flags); svc_putu32(resv, rqstp->rq_xid); diff --git a/net/sunrpc/svc_xprt.c b/net/sunrpc/svc_xprt.c index 5df90bca10ed..2c4dd7ca95b0 100644 --- a/net/sunrpc/svc_xprt.c +++ b/net/sunrpc/svc_xprt.c @@ -1238,7 +1238,7 @@ static struct cache_deferred_req *svc_defer(struct cache_req *req) trace_svc_defer(rqstp); svc_xprt_get(rqstp->rq_xprt); dr->xprt = rqstp->rq_xprt; - set_bit(RQ_DROPME, &rqstp->rq_flags); + __set_bit(RQ_DROPME, &rqstp->rq_flags); dr->handle.revisit = svc_revisit; return &dr->handle; diff --git a/net/sunrpc/svcsock.c b/net/sunrpc/svcsock.c index 05452318afec..b3c9740cfd35 100644 --- a/net/sunrpc/svcsock.c +++ b/net/sunrpc/svcsock.c @@ -298,9 +298,9 @@ static void svc_sock_setbufsize(struct svc_sock *svsk, unsigned int nreqs) static void svc_sock_secure_port(struct svc_rqst *rqstp) { if (svc_port_is_privileged(svc_addr(rqstp))) - set_bit(RQ_SECURE, &rqstp->rq_flags); + __set_bit(RQ_SECURE, &rqstp->rq_flags); else - clear_bit(RQ_SECURE, &rqstp->rq_flags); + __clear_bit(RQ_SECURE, &rqstp->rq_flags); } /* @@ -1008,9 +1008,9 @@ static int svc_tcp_recvfrom(struct svc_rqst *rqstp) rqstp->rq_xprt_ctxt = NULL; rqstp->rq_prot = IPPROTO_TCP; if (test_bit(XPT_LOCAL, &svsk->sk_xprt.xpt_flags)) - set_bit(RQ_LOCAL, &rqstp->rq_flags); + __set_bit(RQ_LOCAL, &rqstp->rq_flags); else - clear_bit(RQ_LOCAL, &rqstp->rq_flags); + __clear_bit(RQ_LOCAL, &rqstp->rq_flags); p = (__be32 *)rqstp->rq_arg.head[0].iov_base; calldir = p[1]; diff --git a/net/sunrpc/xprtrdma/svc_rdma_transport.c b/net/sunrpc/xprtrdma/svc_rdma_transport.c index 94b20fb47135..199fa012f18a 100644 --- a/net/sunrpc/xprtrdma/svc_rdma_transport.c +++ b/net/sunrpc/xprtrdma/svc_rdma_transport.c @@ -602,7 +602,7 @@ static int svc_rdma_has_wspace(struct svc_xprt *xprt) static void svc_rdma_secure_port(struct svc_rqst *rqstp) { - set_bit(RQ_SECURE, &rqstp->rq_flags); + __set_bit(RQ_SECURE, &rqstp->rq_flags); } static void svc_rdma_kill_temp_xprt(struct svc_xprt *xprt)