From: Venkatesh Srinivas <me@endeavour.zapto.org>
Date: Wed, 25 Aug 2010 03:31:07 +0000 (-0700)
Subject: vm: Idlezero changes
X-Git-Tag: v2.9.0~408
X-Git-Url: https://gitweb.dragonflybsd.org/dragonfly.git/commitdiff_plain/8787825a65f14bcf19955bf9fd4fe5bcfc25865e

vm: Idlezero changes

* Restore yield to idlezero loop; we lwkt_yield() every 64-bytes rather than
  every page now.
* Unmark as MPSAFE; we are not MPSAFE, we hold the MP lock. When the page
  queues are safe to access with the vm token alone, we can revert to a prior
  edition of this code, which was mpsafe.
---

diff --git a/sys/vm/vm_zeroidle.c b/sys/vm/vm_zeroidle.c
index ae5ff93d97..2d286e6e48 100644
--- a/sys/vm/vm_zeroidle.c
+++ b/sys/vm/vm_zeroidle.c
@@ -1,6 +1,4 @@
 /*
- * (MPSAFE)
- *
  * Copyright (c) 1994 John Dyson
  * Copyright (c) 2001 Matt Dillon
  * Copyright (c) 2010 The DragonFly Project
@@ -62,7 +60,7 @@
 #define ZIDLE_HI(v)	((v) * 4 / 5)
 
 /* Number of bytes to zero between reschedule checks */
-#define IDLEZERO_RUN	(32)
+#define IDLEZERO_RUN	(64)
 
 /* Maximum number of pages per second to zero */
 #define NPAGES_RUN	(20000)
@@ -204,8 +202,7 @@ vm_pagezero(void __unused *arg)
 			break;
 		case STATE_ZERO_PAGE:
 			/*
-			 * Zero-out the page, stop immediately if a
-			 * resched has been requested.
+			 * Zero-out the page
 			 */
 			while (i < PAGE_SIZE) {
 				if (idlezero_nocache == 1)
@@ -213,9 +210,9 @@ vm_pagezero(void __unused *arg)
 				else
 					bzero(&pg[i], IDLEZERO_RUN);
 				i += IDLEZERO_RUN;
+				lwkt_yield();
 			}
-			if (i == PAGE_SIZE)
-				state = STATE_RELEASE_PAGE;
+			state = STATE_RELEASE_PAGE;
 			break;
 		case STATE_RELEASE_PAGE:
 			lwbuf_free(buf);