Return-Path: Received: from mail-it0-f68.google.com ([209.85.214.68]:54789 "EHLO mail-it0-f68.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751462AbeCEUNP (ORCPT ); Mon, 5 Mar 2018 15:13:15 -0500 Subject: [PATCH 4/9] SUNRPC: Make num_reqs a non-atomic integer From: Chuck Lever To: anna.schumaker@netapp.com Cc: linux-rdma@vger.kernel.org, linux-nfs@vger.kernel.org Date: Mon, 05 Mar 2018 15:13:13 -0500 Message-ID: <20180305201313.10904.4611.stgit@manet.1015granger.net> In-Reply-To: <20180305200825.10904.40829.stgit@manet.1015granger.net> References: <20180305200825.10904.40829.stgit@manet.1015granger.net> MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Sender: linux-nfs-owner@vger.kernel.org List-ID: If recording xprt->stat.max_slots is moved into xprt_alloc_slot, then xprt->num_reqs is never manipulated outside xprt->reserve_lock. There's no longer a need for xprt->num_reqs to be atomic. Signed-off-by: Chuck Lever --- include/linux/sunrpc/xprt.h | 2 +- net/sunrpc/xprt.c | 17 +++++++++-------- 2 files changed, 10 insertions(+), 9 deletions(-) diff --git a/include/linux/sunrpc/xprt.h b/include/linux/sunrpc/xprt.h index ad322ce..5fea0fb 100644 --- a/include/linux/sunrpc/xprt.h +++ b/include/linux/sunrpc/xprt.h @@ -197,7 +197,7 @@ struct rpc_xprt { struct list_head free; /* free slots */ unsigned int max_reqs; /* max number of slots */ unsigned int min_reqs; /* min number of slots */ - atomic_t num_reqs; /* total slots */ + unsigned int num_reqs; /* total slots */ unsigned long state; /* transport state */ unsigned char resvport : 1; /* use a reserved port */ atomic_t swapper; /* we're swapping over this diff --git a/net/sunrpc/xprt.c b/net/sunrpc/xprt.c index 73f05a1..70f0050 100644 --- a/net/sunrpc/xprt.c +++ b/net/sunrpc/xprt.c @@ -1009,7 +1009,7 @@ void xprt_transmit(struct rpc_task *task) struct rpc_rqst *req = task->tk_rqstp; struct rpc_xprt *xprt = req->rq_xprt; unsigned int connect_cookie; - int status, numreqs; + int status; dprintk("RPC: %5u xprt_transmit(%u)\n", task->tk_pid, req->rq_slen); @@ -1047,9 +1047,6 @@ void xprt_transmit(struct rpc_task *task) xprt->ops->set_retrans_timeout(task); - numreqs = atomic_read(&xprt->num_reqs); - if (numreqs > xprt->stat.max_slots) - xprt->stat.max_slots = numreqs; xprt->stat.sends++; xprt->stat.req_u += xprt->stat.sends - xprt->stat.recvs; xprt->stat.bklog_u += xprt->backlog.qlen; @@ -1111,14 +1108,15 @@ static struct rpc_rqst *xprt_dynamic_alloc_slot(struct rpc_xprt *xprt) { struct rpc_rqst *req = ERR_PTR(-EAGAIN); - if (!atomic_add_unless(&xprt->num_reqs, 1, xprt->max_reqs)) + if (xprt->num_reqs >= xprt->max_reqs) goto out; + ++xprt->num_reqs; spin_unlock(&xprt->reserve_lock); req = kzalloc(sizeof(struct rpc_rqst), GFP_NOFS); spin_lock(&xprt->reserve_lock); if (req != NULL) goto out; - atomic_dec(&xprt->num_reqs); + --xprt->num_reqs; req = ERR_PTR(-ENOMEM); out: return req; @@ -1126,7 +1124,8 @@ static struct rpc_rqst *xprt_dynamic_alloc_slot(struct rpc_xprt *xprt) static bool xprt_dynamic_free_slot(struct rpc_xprt *xprt, struct rpc_rqst *req) { - if (atomic_add_unless(&xprt->num_reqs, -1, xprt->min_reqs)) { + if (xprt->num_reqs > xprt->min_reqs) { + --xprt->num_reqs; kfree(req); return true; } @@ -1162,6 +1161,8 @@ void xprt_alloc_slot(struct rpc_xprt *xprt, struct rpc_task *task) spin_unlock(&xprt->reserve_lock); return; out_init_req: + xprt->stat.max_slots = max_t(unsigned int, xprt->stat.max_slots, + xprt->num_reqs); task->tk_status = 0; task->tk_rqstp = req; xprt_request_init(task, xprt); @@ -1229,7 +1230,7 @@ struct rpc_xprt *xprt_alloc(struct net *net, size_t size, else xprt->max_reqs = num_prealloc; xprt->min_reqs = num_prealloc; - atomic_set(&xprt->num_reqs, num_prealloc); + xprt->num_reqs = num_prealloc; return xprt;