From 689c1b5044e701e1b695a6e6c80647b9471ba454 Mon Sep 17 00:00:00 2001 From: Pavan T C Date: Wed, 23 Feb 2011 06:23:26 +0000 Subject: Eliminate syscall tight loop when handling EAGAIN in NFS. Signed-off-by: Pavan T C Signed-off-by: Anand V. Avati BUG: 2452 (Excessive CPU usage /very low throughput while using NFS mounts) URL: http://bugs.gluster.com/cgi-bin/bugzilla3/show_bug.cgi?id=2452 --- xlators/nfs/lib/src/rpcsvc.c | 15 ++++++++++++++- 1 file changed, 14 insertions(+), 1 deletion(-) diff --git a/xlators/nfs/lib/src/rpcsvc.c b/xlators/nfs/lib/src/rpcsvc.c index 515e8738fc9..84ee7bc2234 100644 --- a/xlators/nfs/lib/src/rpcsvc.c +++ b/xlators/nfs/lib/src/rpcsvc.c @@ -2557,6 +2557,7 @@ tx_remaining: nfs_rpcsvc_socket_block_tx (conn->sockfd); } + errno = 0; written = nfs_rpcsvc_socket_write (conn->sockfd, writeaddr, writesize); if (txbuf->txbehave & RPCSVC_TXB_LAST) { @@ -2566,13 +2567,25 @@ tx_remaining: gf_log (GF_RPCSVC, GF_LOG_TRACE, "conn: 0x%lx, Tx request: %zu," " Tx sent: %zd", (long)conn, writesize, written); - /* There was an error transmitting this buffer */ + /* + * There was an error transmitting this buffer. We are polling + * for errors. So, there is no necessity to handle closure of + * the connection explicitly here. + */ if (written == -1) break; if (written >= 0) txbuf->offset += written; + if (errno == EAGAIN) { + /* + * Socket layer is indicating flow-control. We + * break-out now and wait for the next event indicating + * room for writes. + */ + break; + } /* If the current buffer has been completely transmitted, * delete it from the list and move on to the next buffer. */ -- cgit