Skip site navigation (1)Skip section navigation (2) 
Date:      Wed, 7 Dec 2016 08:12:03 +0000 (UTC)
From:      Sepherosa Ziehau <sephe@FreeBSD.org>
To:        src-committers@freebsd.org, svn-src-all@freebsd.org, svn-src-head@freebsd.org
Subject:   svn commit: r309670 - head/sys/dev/hyperv/vmbus
Message-ID:  <201612070812.uB78C3go047956@repo.freebsd.org>
next in thread | raw e-mail | index | archive | help 
Author: sephe
Date: Wed Dec  7 08:12:02 2016
New Revision: 309670
URL: https://svnweb.freebsd.org/changeset/base/309670

Log:
  hyperv/vmbus: Use pause if possible.
  
  This makes booting on Hyper-V w/ small # of vCPUs work properly.
  
  Reported by:	Hongxiong Xian <v-hoxian microsoft com>, Hongjiang Zhang <honzhan microsoft com>
  MFC after:	1 week
  Sponsored by:	Microsoft

Modified:
  head/sys/dev/hyperv/vmbus/vmbus_chan.c

Modified: head/sys/dev/hyperv/vmbus/vmbus_chan.c
==============================================================================
--- head/sys/dev/hyperv/vmbus/vmbus_chan.c	Wed Dec  7 07:27:47 2016	(r309669)
+++ head/sys/dev/hyperv/vmbus/vmbus_chan.c	Wed Dec  7 08:12:02 2016	(r309670)
@@ -67,7 +67,7 @@ static void			vmbus_chan_set_chmap(struc
 static void			vmbus_chan_clear_chmap(struct vmbus_channel *);
 static void			vmbus_chan_detach(struct vmbus_channel *);
 static bool			vmbus_chan_wait_revoke(
-				    const struct vmbus_channel *);
+				    const struct vmbus_channel *, bool);
 
 static void			vmbus_chan_ins_prilist(struct vmbus_softc *,
 				    struct vmbus_channel *);
@@ -478,14 +478,14 @@ vmbus_chan_open_br(struct vmbus_channel 
 				msg = vmbus_msghc_poll_result(sc, mh);
 				if (msg != NULL)
 					break;
-				DELAY(1000);
+				pause("rchopen", 1);
 			}
 #undef REVOKE_LINGER
 			if (msg == NULL)
 				vmbus_msghc_exec_cancel(sc, mh);
 			break;
 		}
-		DELAY(1000);
+		pause("chopen", 1);
 	}
 	if (msg != NULL) {
 		status = ((const struct vmbus_chanmsg_chopen_resp *)
@@ -658,7 +658,7 @@ vmbus_chan_gpadl_connect(struct vmbus_ch
 }
 
 static bool
-vmbus_chan_wait_revoke(const struct vmbus_channel *chan)
+vmbus_chan_wait_revoke(const struct vmbus_channel *chan, bool can_sleep)
 {
 #define WAIT_COUNT	200	/* 200ms */
 
@@ -667,8 +667,10 @@ vmbus_chan_wait_revoke(const struct vmbu
 	for (i = 0; i < WAIT_COUNT; ++i) {
 		if (vmbus_chan_is_revoked(chan))
 			return (true);
-		/* Not sure about the context; use busy-wait. */
-		DELAY(1000);
+		if (can_sleep)
+			pause("wchrev", 1);
+		else
+			DELAY(1000);
 	}
 	return (false);
 
@@ -705,7 +707,7 @@ vmbus_chan_gpadl_disconnect(struct vmbus
 	if (error) {
 		vmbus_msghc_put(sc, mh);
 
-		if (vmbus_chan_wait_revoke(chan)) {
+		if (vmbus_chan_wait_revoke(chan, true)) {
 			/*
 			 * Error is benign; this channel is revoked,
 			 * so this GPADL will not be touched anymore.

Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?201612070812.uB78C3go047956>