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Date:      Sun, 4 Oct 2009 18:53:10 +0000 (UTC)
From:      Alan Cox <alc@FreeBSD.org>
To:        src-committers@freebsd.org, svn-src-all@freebsd.org, svn-src-head@freebsd.org
Subject:   svn commit: r197750 - head/sys/vm
Message-ID:  <200910041853.n94IrAf7082338@svn.freebsd.org>
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Author: alc
Date: Sun Oct  4 18:53:10 2009
New Revision: 197750
URL: http://svn.freebsd.org/changeset/base/197750

Log:
  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

Modified:
  head/sys/vm/vm_page.c
  head/sys/vm/vm_page.h

Modified: head/sys/vm/vm_page.c
==============================================================================
--- head/sys/vm/vm_page.c	Sun Oct  4 17:22:51 2009	(r197749)
+++ head/sys/vm/vm_page.c	Sun Oct  4 18:53:10 2009	(r197750)
@@ -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;

Modified: head/sys/vm/vm_page.h
==============================================================================
--- head/sys/vm/vm_page.h	Sun Oct  4 17:22:51 2009	(r197749)
+++ head/sys/vm/vm_page.h	Sun Oct  4 18:53:10 2009	(r197750)
@@ -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)

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