From e67e0775e6f7f349bb1dca6b821a265499b9def8 Mon Sep 17 00:00:00 2001
From: Alan Cox <alc@FreeBSD.org>
Date: Sun, 4 Oct 2009 18:53:10 +0000
Subject: [PATCH] Align and pad the page queue and free page queue locks so
 that the linker can't possibly place them together within the same cache
 line.

MFC after:	3 weeks
---
 sys/vm/vm_page.c |  4 ++--
 sys/vm/vm_page.h | 14 ++++++++++++--
 2 files changed, 14 insertions(+), 4 deletions(-)

diff --git a/sys/vm/vm_page.c b/sys/vm/vm_page.c
index ac363b701666..c6bcfa07eb1f 100644
--- a/sys/vm/vm_page.c
+++ b/sys/vm/vm_page.c
@@ -135,8 +135,8 @@ __FBSDID("$FreeBSD$");
  */
 
 struct vpgqueues vm_page_queues[PQ_COUNT];
-struct mtx vm_page_queue_mtx;
-struct mtx vm_page_queue_free_mtx;
+struct vpglocks vm_page_queue_lock;
+struct vpglocks vm_page_queue_free_lock;
 
 vm_page_t vm_page_array = 0;
 int vm_page_array_size = 0;
diff --git a/sys/vm/vm_page.h b/sys/vm/vm_page.h
index b1b1070ae48d..662af98be83a 100644
--- a/sys/vm/vm_page.h
+++ b/sys/vm/vm_page.h
@@ -170,7 +170,15 @@ struct vpgqueues {
 };
 
 extern struct vpgqueues vm_page_queues[PQ_COUNT];
-extern struct mtx vm_page_queue_free_mtx;
+
+struct vpglocks {
+	struct mtx	data;
+	char		pad[CACHE_LINE_SIZE - sizeof(struct mtx)];
+} __aligned(CACHE_LINE_SIZE);
+
+extern struct vpglocks vm_page_queue_free_lock;
+
+#define	vm_page_queue_free_mtx	vm_page_queue_free_lock.data
 
 /*
  * These are the flags defined for vm_page.
@@ -258,7 +266,9 @@ PHYS_TO_VM_PAGE(vm_paddr_t pa)
 #endif
 }
 
-extern struct mtx vm_page_queue_mtx;
+extern struct vpglocks vm_page_queue_lock;
+
+#define	vm_page_queue_mtx	vm_page_queue_lock.data
 #define vm_page_lock_queues()   mtx_lock(&vm_page_queue_mtx)
 #define vm_page_unlock_queues() mtx_unlock(&vm_page_queue_mtx)