From 2eb15b506b7d7b69a41d0fcdf2d7a806d723e4c7 Mon Sep 17 00:00:00 2001
From: alc <alc@FreeBSD.org>
Date: Wed, 7 Feb 2007 06:37:30 +0000
Subject: Change the pagedaemon, vm_wait(), and vm_waitpfault() to sleep on the
 vm page queue free mutex instead of the vm page queue mutex.

---
 sys/vm/vm_page.c    | 16 +++++++++-------
 sys/vm/vm_pageout.c | 20 ++++++++++++--------
 2 files changed, 21 insertions(+), 15 deletions(-)

(limited to 'sys')

diff --git a/sys/vm/vm_page.c b/sys/vm/vm_page.c
index 4234635..4e96e2f 100644
--- a/sys/vm/vm_page.c
+++ b/sys/vm/vm_page.c
@@ -984,17 +984,17 @@ void
 vm_wait(void)
 {
 
-	vm_page_lock_queues();
+	mtx_lock(&vm_page_queue_free_mtx);
 	if (curproc == pageproc) {
 		vm_pageout_pages_needed = 1;
-		msleep(&vm_pageout_pages_needed, &vm_page_queue_mtx,
+		msleep(&vm_pageout_pages_needed, &vm_page_queue_free_mtx,
 		    PDROP | PSWP, "VMWait", 0);
 	} else {
 		if (!vm_pages_needed) {
 			vm_pages_needed = 1;
 			wakeup(&vm_pages_needed);
 		}
-		msleep(&cnt.v_free_count, &vm_page_queue_mtx, PDROP | PVM,
+		msleep(&cnt.v_free_count, &vm_page_queue_free_mtx, PDROP | PVM,
 		    "vmwait", 0);
 	}
 }
@@ -1013,12 +1013,12 @@ void
 vm_waitpfault(void)
 {
 
-	vm_page_lock_queues();
+	mtx_lock(&vm_page_queue_free_mtx);
 	if (!vm_pages_needed) {
 		vm_pages_needed = 1;
 		wakeup(&vm_pages_needed);
 	}
-	msleep(&cnt.v_free_count, &vm_page_queue_mtx, PDROP | PUSER,
+	msleep(&cnt.v_free_count, &vm_page_queue_free_mtx, PDROP | PUSER,
 	    "pfault", 0);
 }
 
@@ -1066,7 +1066,7 @@ static inline void
 vm_page_free_wakeup(void)
 {
 
-	mtx_assert(&vm_page_queue_mtx, MA_OWNED);
+	mtx_assert(&vm_page_queue_free_mtx, MA_OWNED);
 	/*
 	 * if pageout daemon needs pages, then tell it that there are
 	 * some free.
@@ -1165,8 +1165,8 @@ vm_page_free_toq(vm_page_t m)
 	} else {
 		TAILQ_INSERT_HEAD(&pq->pl, m, pageq);
 	}
-	mtx_unlock(&vm_page_queue_free_mtx);
 	vm_page_free_wakeup();
+	mtx_unlock(&vm_page_queue_free_mtx);
 }
 
 /*
@@ -1404,7 +1404,9 @@ vm_page_cache(vm_page_t m)
 	}
 	vm_pageq_remove_nowakeup(m);
 	vm_pageq_enqueue(PQ_CACHE + m->pc, m);
+	mtx_lock(&vm_page_queue_free_mtx);
 	vm_page_free_wakeup();
+	mtx_unlock(&vm_page_queue_free_mtx);
 }
 
 /*
diff --git a/sys/vm/vm_pageout.c b/sys/vm/vm_pageout.c
index 9ef9cfa..c0611ba 100644
--- a/sys/vm/vm_pageout.c
+++ b/sys/vm/vm_pageout.c
@@ -1479,13 +1479,13 @@ vm_pageout()
 	 * The pageout daemon is never done, so loop forever.
 	 */
 	while (TRUE) {
-		vm_page_lock_queues();
 		/*
 		 * If we have enough free memory, wakeup waiters.  Do
 		 * not clear vm_pages_needed until we reach our target,
 		 * otherwise we may be woken up over and over again and
 		 * waste a lot of cpu.
 		 */
+		mtx_lock(&vm_page_queue_free_mtx);
 		if (vm_pages_needed && !vm_page_count_min()) {
 			if (!vm_paging_needed())
 				vm_pages_needed = 0;
@@ -1499,8 +1499,9 @@ vm_pageout()
 			 */
 			++pass;
 			if (pass > 1)
-				msleep(&vm_pages_needed, &vm_page_queue_mtx, PVM,
-				       "psleep", hz/2);
+				msleep(&vm_pages_needed,
+				    &vm_page_queue_free_mtx, PVM, "psleep",
+				    hz / 2);
 		} else {
 			/*
 			 * Good enough, sleep & handle stats.  Prime the pass
@@ -1510,10 +1511,13 @@ vm_pageout()
 				pass = 1;
 			else
 				pass = 0;
-			error = msleep(&vm_pages_needed, &vm_page_queue_mtx, PVM,
-				    "psleep", vm_pageout_stats_interval * hz);
+			error = msleep(&vm_pages_needed,
+			    &vm_page_queue_free_mtx, PVM, "psleep",
+			    vm_pageout_stats_interval * hz);
 			if (error && !vm_pages_needed) {
+				mtx_unlock(&vm_page_queue_free_mtx);
 				pass = 0;
+				vm_page_lock_queues();
 				vm_pageout_page_stats();
 				vm_page_unlock_queues();
 				continue;
@@ -1521,16 +1525,16 @@ vm_pageout()
 		}
 		if (vm_pages_needed)
 			cnt.v_pdwakeups++;
-		vm_page_unlock_queues();
+		mtx_unlock(&vm_page_queue_free_mtx);
 		vm_pageout_scan(pass);
 	}
 }
 
 /*
- * Unless the page queue lock is held by the caller, this function
+ * Unless the free page queue lock is held by the caller, this function
  * should be regarded as advisory.  Specifically, the caller should
  * not msleep() on &cnt.v_free_count following this function unless
- * the page queue lock is held until the msleep() is performed.
+ * the free page queue lock is held until the msleep() is performed.
  */
 void
 pagedaemon_wakeup()
-- 
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