From d7455de2f603518cf6470bbca9aa19fe5a41c4ca Mon Sep 17 00:00:00 2001
From: Ingo Weinhold <ingo_weinhold@gmx.de>
Date: Mon, 11 Jan 2010 16:36:31 +0000
Subject: [PATCH] allocate_page_run(): Use temporary lists to store the pages
 we're allocating. This makes appending the pages to the active queue more
 efficient and we don't need the vm_page::is_cleared bit anymore.

git-svn-id: file:///srv/svn/repos/haiku/haiku/trunk@35011 a95241bf-73f2-0310-859d-f6bbb57e9c96
---
 headers/private/kernel/vm/vm_types.h |  5 +----
 src/system/kernel/vm/vm_page.cpp     | 26 ++++++++++++--------------
 2 files changed, 13 insertions(+), 18 deletions(-)

diff --git a/headers/private/kernel/vm/vm_types.h b/headers/private/kernel/vm/vm_types.h
index 0e453c9d83..4922e1636e 100644
--- a/headers/private/kernel/vm/vm_types.h
+++ b/headers/private/kernel/vm/vm_types.h
@@ -96,11 +96,8 @@ struct vm_page {
 
 	uint8					type : 2;
 	uint8					state : 3;
-
-	uint8					is_cleared : 1;
-		// is currently only used in vm_page_allocate_page_run()
 	uint8					busy_writing : 1;
-	uint8					unused : 1;
+	uint8					unused : 2;
 		// used in VMAnonymousCache::Merge()
 
 	int8					usage_count;
diff --git a/src/system/kernel/vm/vm_page.cpp b/src/system/kernel/vm/vm_page.cpp
index 6758c681af..adeddc471f 100644
--- a/src/system/kernel/vm/vm_page.cpp
+++ b/src/system/kernel/vm/vm_page.cpp
@@ -2189,39 +2189,37 @@ allocate_page_run(page_num_t start, page_num_t length, int pageState,
 	T(AllocatePageRun(length));
 
 	// pull the pages out of the appropriate queues
+	VMPageQueue::PageList freePages;
+	VMPageQueue::PageList clearPages;
 	for (page_num_t i = 0; i < length; i++) {
 		vm_page& page = sPages[start + i];
 		DEBUG_PAGE_ACCESS_START(&page);
 		if (page.state == PAGE_STATE_CLEAR) {
-			page.is_cleared = true;
 			sClearPageQueue.Remove(&page);
+			clearPages.Add(&page);
 		} else {
-			page.is_cleared = false;
 			sFreePageQueue.Remove(&page);
+			freePages.Add(&page);
 		}
 
 		page.state = PAGE_STATE_BUSY;
+		page.usage_count = 1;
 	}
 
 	freeClearQueueLocker.Unlock();
 
-	// add the pages to the active queue
-	for (page_num_t i = 0; i < length; i++) {
-		vm_page& page = sPages[start + i];
-		sActivePageQueue.AppendUnlocked(&page);
-			// TODO: We could do this more efficiently, if we used a temporary
-			// on-stack queue and added all pages at once.
-		page.usage_count = 1;
-	}
-
 	// clear pages, if requested
 	if (pageState == PAGE_STATE_CLEAR) {
-		for (page_num_t i = 0; i < length; i++) {
-			if (!sPages[start + i].is_cleared)
-	 			clear_page(&sPages[start + i]);
+		for (VMPageQueue::PageList::Iterator it = freePages.GetIterator();
+				vm_page* page = it.Next();) {
+ 			clear_page(page);
 		}
 	}
 
+	// add pages to active queue
+	freePages.MoveFrom(&clearPages);
+	sActivePageQueue.AppendUnlocked(freePages, length);
+
 	// Note: We don't unreserve the pages since we pulled them out of the
 	// free/clear queues without adjusting sUnreservedFreePages.