From: kettenis <kettenis@openbsd.org>
Date: Thu, 8 Oct 2015 15:58:38 +0000 (+0000)
Subject: Lock the page queues by turning uvm_lock_pageq() and uvm_unlock_pageq() into
X-Git-Url: http://artulab.com/gitweb/?a=commitdiff_plain;h=1eaf72b8154ab782085c6d40660cd31265c95da4;p=openbsd

Lock the page queues by turning uvm_lock_pageq() and uvm_unlock_pageq() into
mtx_enter() and mtx_leave() operations.  Not 100% this won't blow up but
there is only one way to find out, and we need this to make progress on
further unlocking uvm.

prodded by deraadt@
---

diff --git a/sys/uvm/uvm.h b/sys/uvm/uvm.h
index bc42871cc7e..5a6082d35db 100644
--- a/sys/uvm/uvm.h
+++ b/sys/uvm/uvm.h
@@ -1,4 +1,4 @@
-/*	$OpenBSD: uvm.h,v 1.59 2015/05/04 10:21:15 dlg Exp $	*/
+/*	$OpenBSD: uvm.h,v 1.60 2015/10/08 15:58:38 kettenis Exp $	*/
 /*	$NetBSD: uvm.h,v 1.24 2000/11/27 08:40:02 chs Exp $	*/
 
 /*
@@ -54,6 +54,7 @@ struct uvm {
 	struct pglist page_inactive_swp;/* pages inactive (reclaim or free) */
 	struct pglist page_inactive_obj;/* pages inactive (reclaim or free) */
 	/* Lock order: pageqlock, then fpageqlock. */
+	struct mutex pageqlock;		/* lock for active/inactive page q */
 	struct mutex fpageqlock;	/* lock for free page q  + pdaemon */
 	boolean_t page_init_done;	/* TRUE if uvm_page_init() finished */
 	struct uvm_pmr_control pmr_control; /* pmemrange data */
diff --git a/sys/uvm/uvm_page.c b/sys/uvm/uvm_page.c
index 84be6eb8a38..08160054b48 100644
--- a/sys/uvm/uvm_page.c
+++ b/sys/uvm/uvm_page.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: uvm_page.c,v 1.142 2015/09/21 12:59:01 visa Exp $	*/
+/*	$OpenBSD: uvm_page.c,v 1.143 2015/10/08 15:58:38 kettenis Exp $	*/
 /*	$NetBSD: uvm_page.c,v 1.44 2000/11/27 08:40:04 chs Exp $	*/
 
 /*
@@ -179,6 +179,7 @@ uvm_page_init(vaddr_t *kvm_startp, vaddr_t *kvm_endp)
 	TAILQ_INIT(&uvm.page_active);
 	TAILQ_INIT(&uvm.page_inactive_swp);
 	TAILQ_INIT(&uvm.page_inactive_obj);
+	mtx_init(&uvm.pageqlock, IPL_NONE);
 	mtx_init(&uvm.fpageqlock, IPL_VM);
 	uvm_pmr_init();
 
diff --git a/sys/uvm/uvm_page.h b/sys/uvm/uvm_page.h
index aaf03181c81..1300b3b96b9 100644
--- a/sys/uvm/uvm_page.h
+++ b/sys/uvm/uvm_page.h
@@ -1,4 +1,4 @@
-/*	$OpenBSD: uvm_page.h,v 1.59 2015/08/21 16:04:35 visa Exp $	*/
+/*	$OpenBSD: uvm_page.h,v 1.60 2015/10/08 15:58:38 kettenis Exp $	*/
 /*	$NetBSD: uvm_page.h,v 1.19 2000/12/28 08:24:55 chs Exp $	*/
 
 /* 
@@ -285,8 +285,8 @@ int		vm_physseg_find(paddr_t, int *);
  * macros
  */
 
-#define uvm_lock_pageq()	/* lock */
-#define uvm_unlock_pageq()	/* unlock */
+#define uvm_lock_pageq()	mtx_enter(&uvm.pageqlock)
+#define uvm_unlock_pageq()	mtx_leave(&uvm.pageqlock)
 #define uvm_lock_fpageq()	mtx_enter(&uvm.fpageqlock)
 #define uvm_unlock_fpageq()	mtx_leave(&uvm.fpageqlock)
 
diff --git a/sys/uvm/uvm_pdaemon.c b/sys/uvm/uvm_pdaemon.c
index ea8961703e0..15dba9c4e6a 100644
--- a/sys/uvm/uvm_pdaemon.c
+++ b/sys/uvm/uvm_pdaemon.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: uvm_pdaemon.c,v 1.76 2015/08/21 16:04:35 visa Exp $	*/
+/*	$OpenBSD: uvm_pdaemon.c,v 1.77 2015/10/08 15:58:38 kettenis Exp $	*/
 /*	$NetBSD: uvm_pdaemon.c,v 1.23 2000/08/20 10:24:14 bjh21 Exp $	*/
 
 /* 
@@ -237,7 +237,9 @@ uvm_pageout(void *arg)
 		if (uvmexp.free - BUFPAGES_DEFICIT < uvmexp.freetarg)
 			size += uvmexp.freetarg - (uvmexp.free -
 			    BUFPAGES_DEFICIT);
+		uvm_unlock_pageq();
 		(void) bufbackoff(&constraint, size * 2);
+		uvm_lock_pageq();
 
 		/* Scan if needed to meet our targets. */
 		if (pma != NULL ||