From 58d1dcf5a8ebb0ce8a521286a99efdd636012bf0 Mon Sep 17 00:00:00 2001 From: Chuck Lever Date: Tue, 26 May 2015 11:53:13 -0400 Subject: xprtrdma: Split rb_lock /proc/lock_stat showed contention between rpcrdma_buffer_get/put and the MR allocation functions during I/O intensive workloads. Now that MRs are no longer allocated in rpcrdma_buffer_get(), there's no reason the rb_mws list has to be managed using the same lock as the send/receive buffers. Split that lock. The new lock does not need to disable interrupts because buffer get/put is never called in an interrupt context. struct rpcrdma_buffer is re-arranged to ensure rb_mwlock and rb_mws are always in a different cacheline than rb_lock and the buffer pointers. Signed-off-by: Chuck Lever Reviewed-by: Steve Wise Reviewed-by: Sagi Grimberg Tested-By: Devesh Sharma Reviewed-by: Doug Ledford Signed-off-by: Anna Schumaker --- net/sunrpc/xprtrdma/verbs.c | 10 ++++------ 1 file changed, 4 insertions(+), 6 deletions(-) (limited to 'net/sunrpc/xprtrdma/verbs.c') diff --git a/net/sunrpc/xprtrdma/verbs.c b/net/sunrpc/xprtrdma/verbs.c index cc1a52609974..234083560d0e 100644 --- a/net/sunrpc/xprtrdma/verbs.c +++ b/net/sunrpc/xprtrdma/verbs.c @@ -1173,15 +1173,14 @@ rpcrdma_get_mw(struct rpcrdma_xprt *r_xprt) { struct rpcrdma_buffer *buf = &r_xprt->rx_buf; struct rpcrdma_mw *mw = NULL; - unsigned long flags; - spin_lock_irqsave(&buf->rb_lock, flags); + spin_lock(&buf->rb_mwlock); if (!list_empty(&buf->rb_mws)) { mw = list_first_entry(&buf->rb_mws, struct rpcrdma_mw, mw_list); list_del_init(&mw->mw_list); } - spin_unlock_irqrestore(&buf->rb_lock, flags); + spin_unlock(&buf->rb_mwlock); if (!mw) pr_err("RPC: %s: no MWs available\n", __func__); @@ -1192,11 +1191,10 @@ void rpcrdma_put_mw(struct rpcrdma_xprt *r_xprt, struct rpcrdma_mw *mw) { struct rpcrdma_buffer *buf = &r_xprt->rx_buf; - unsigned long flags; - spin_lock_irqsave(&buf->rb_lock, flags); + spin_lock(&buf->rb_mwlock); list_add_tail(&mw->mw_list, &buf->rb_mws); - spin_unlock_irqrestore(&buf->rb_lock, flags); + spin_unlock(&buf->rb_mwlock); } static void -- cgit