add patch series

4 files changed, 735 insertions, 0 deletions

diff --git a/debian/patches/series b/debian/patches/series
index 50dcd13..40ca28c 100644
--- a/debian/patches/series
+++ b/debian/patches/series
@@ -12,3 +12,6 @@ sysenter0001-yyy-sysenter-prototype.patch
 
 fix-locking0004-vm-fix-locking-issues.patch
 fix-locking0005-ipc-fix-locking-issues.patch
+vm-cache-policy0001-VM-cache-policy-change.patch
+vm-cache-policy0002-vm-keep-track-of-clean-pages.patch
+vm-cache-policy0003-vm-evict-clean-pages-first.patch
diff --git a/debian/patches/vm-cache-policy0001-VM-cache-policy-change.patch b/debian/patches/vm-cache-policy0001-VM-cache-policy-change.patch
new file mode 100644
index 0000000..2fef1e2
--- /dev/null
+++ b/debian/patches/vm-cache-policy0001-VM-cache-policy-change.patch
@@ -0,0 +1,346 @@
+From dcbdadadcd006e6b9b8ced1dffa4d47a91557d08 Mon Sep 17 00:00:00 2001
+From: Richard Braun <rbraun@sceen.net>
+Date: Wed, 9 Oct 2013 11:51:54 +0200
+Subject: [PATCH gnumach 1/3] VM cache policy change
+
+This patch lets the kernel unconditionnally cache non empty unreferenced
+objects instead of using a fixed arbitrary limit. As the pageout daemon
+evicts pages, it collects cached objects that have become empty. The
+effective result is a graceful adjustment of the number of objects
+related to memory management (virtual memory objects, their associated
+ports, and potentially objects maintained in the external memory
+managers). Physical memory can now be almost entirely filled up with
+cached pages. In addition, these cached pages are not automatically
+deactivated as objects can quickly be referenced again.
+
+There are problems with this patch however. The first is that, on
+machines with a large amount of physical memory (above 1 GiB but it also
+depends on usage patterns), scalability issues are exposed. For example,
+file systems which don't throttle their writeback requests can create
+thread storms, strongly reducing system responsiveness. Other issues
+such as linear scans of memory objects also add visible CPU overhead.
+
+The second is that, as most memory is used, it increases the chances of
+swapping deadlocks. Applications that map large objects and quickly
+cause lots of page faults can still easily bring the system to its
+knees.
+---
+ vm/vm_object.c   | 166 ++++++++++++++++++-------------------------------------
+ vm/vm_object.h   |   7 ++-
+ vm/vm_pageout.c  |   7 ++-
+ vm/vm_resident.c |   4 +-
+ 4 files changed, 68 insertions(+), 116 deletions(-)
+
+diff --git a/vm/vm_object.c b/vm/vm_object.c
+index a026348..44c13f4 100644
+--- a/vm/vm_object.c
++++ b/vm/vm_object.c
+@@ -59,6 +59,11 @@
+ #include <ddb/db_output.h>
+ #endif	/* MACH_KDB */
+ 
++void memory_object_release(
++	ipc_port_t	pager,
++	pager_request_t	pager_request,
++	ipc_port_t	pager_name); /* forward */
++
+ /*
+  *	Virtual memory objects maintain the actual data
+  *	associated with allocated virtual memory.  A given
+@@ -159,8 +164,9 @@ vm_object_t		kernel_object = &kernel_object_store;
+  *
+  *	The kernel may choose to terminate objects from this
+  *	queue in order to reclaim storage.  The current policy
+- *	is to permit a fixed maximum number of unreferenced
+- *	objects (vm_object_cached_max).
++ *	is to let memory pressure dynamically adjust the number
++ *	of unreferenced objects. The pageout daemon attempts to
++ *	collect objects after removing pages from them.
+  *
+  *	A simple lock (accessed by routines
+  *	vm_object_cache_{lock,lock_try,unlock}) governs the
+@@ -176,7 +182,6 @@ vm_object_t		kernel_object = &kernel_object_store;
+  */
+ queue_head_t	vm_object_cached_list;
+ int		vm_object_cached_count;
+-int		vm_object_cached_max = 4000;	/* may be patched*/
+ 
+ decl_simple_lock_data(,vm_object_cached_lock_data)
+ 
+@@ -343,6 +348,33 @@ void vm_object_init(void)
+ 			IKOT_PAGING_NAME);
+ }
+ 
++void vm_object_collect(
++	register vm_object_t	object)
++{
++	vm_object_unlock(object);
++
++	/*
++	 *	The cache lock must be acquired in the proper order.
++	 */
++
++	vm_object_cache_lock();
++	vm_object_lock(object);
++
++	/*
++	 *	If the object was referenced while the lock was
++	 *	dropped, cancel the termination.
++	 */
++
++	if (!vm_object_collectable(object)) {
++		vm_object_unlock(object);
++		vm_object_cache_unlock();
++		return;
++	}
++
++	queue_remove(&vm_object_cached_list, object, vm_object_t, cached_list);
++	vm_object_terminate(object);
++}
++
+ /*
+  *	vm_object_reference:
+  *
+@@ -403,103 +435,35 @@ void vm_object_deallocate(
+ 
+ 		/*
+ 		 *	See whether this object can persist.  If so, enter
+-		 *	it in the cache, then deactivate all of its
+-		 *	pages.
++		 *	it in the cache.
+ 		 */
+-		if (object->can_persist) {
+-			boolean_t	overflow;
+-
+-			/*
+-			 *	Enter the object onto the queue
+-			 *	of "cached" objects.  Remember whether
+-			 *	we've caused the queue to overflow,
+-			 *	as a hint.
+-			 */
+-
++		if (object->can_persist && (object->resident_page_count > 0)) {
+ 			queue_enter(&vm_object_cached_list, object,
+ 				vm_object_t, cached_list);
+-			overflow = (++vm_object_cached_count > vm_object_cached_max);
++			vm_object_cached_count++;
+ 			vm_object_cached_pages_update(object->resident_page_count);
+ 			vm_object_cache_unlock();
+ 
+-			vm_object_deactivate_pages(object);
+ 			vm_object_unlock(object);
++			return;
++		}
+ 
+-			/*
+-			 *	If we didn't overflow, or if the queue has
+-			 *	been reduced back to below the specified
+-			 *	minimum, then quit.
+-			 */
+-			if (!overflow)
+-				return;
+-
+-			while (TRUE) {
+-				vm_object_cache_lock();
+-				if (vm_object_cached_count <=
+-				    vm_object_cached_max) {
+-					vm_object_cache_unlock();
+-					return;
+-				}
+-
+-				/*
+-				 *	If we must trim down the queue, take
+-				 *	the first object, and proceed to
+-				 *	terminate it instead of the original
+-				 *	object.	 Have to wait for pager init.
+-				 *  if it's in progress.
+-				 */
+-				object= (vm_object_t)
+-				    queue_first(&vm_object_cached_list);
+-				vm_object_lock(object);
+-
+-				if (!(object->pager_created &&
+-				    !object->pager_initialized)) {
+-
+-					/*
+-					 *  Ok to terminate, hang on to lock.
+-					 */
+-					break;
+-				}
+-
+-				vm_object_assert_wait(object,
+-					VM_OBJECT_EVENT_INITIALIZED, FALSE);
+-				vm_object_unlock(object);
+-				vm_object_cache_unlock();
+-				thread_block((void (*)()) 0);
+-
+-				/*
+-				 *  Continue loop to check if cache still
+-				 *  needs to be trimmed.
+-				 */
+-			}
++		if (object->pager_created &&
++		    !object->pager_initialized) {
+ 
+ 			/*
+-			 *	Actually remove object from cache.
++			 *	Have to wait for initialization.
++			 *	Put reference back and retry
++			 *	when it's initialized.
+ 			 */
+ 
+-			queue_remove(&vm_object_cached_list, object,
+-					vm_object_t, cached_list);
+-			vm_object_cached_count--;
+-
+-			assert(object->ref_count == 0);
+-		}
+-		else {
+-			if (object->pager_created &&
+-			    !object->pager_initialized) {
+-
+-				/*
+-				 *	Have to wait for initialization.
+-				 *	Put reference back and retry
+-				 *	when it's initialized.
+-				 */
+-				object->ref_count++;
+-				vm_object_assert_wait(object,
+-					VM_OBJECT_EVENT_INITIALIZED, FALSE);
+-				vm_object_unlock(object);
+-				vm_object_cache_unlock();
+-				thread_block((void (*)()) 0);
+-				continue;
+-			  }
++			object->ref_count++;
++			vm_object_assert_wait(object,
++				VM_OBJECT_EVENT_INITIALIZED, FALSE);
++			vm_object_unlock(object);
++			vm_object_cache_unlock();
++			thread_block((void (*)()) 0);
++			continue;
+ 		}
+ 
+ 		/*
+@@ -862,28 +826,6 @@ kern_return_t memory_object_destroy(
+ }
+ 
+ /*
+- *	vm_object_deactivate_pages
+- *
+- *	Deactivate all pages in the specified object.  (Keep its pages
+- *	in memory even though it is no longer referenced.)
+- *
+- *	The object must be locked.
+- */
+-void vm_object_deactivate_pages(
+-	vm_object_t	object)
+-{
+-	vm_page_t	p;
+-
+-	queue_iterate(&object->memq, p, vm_page_t, listq) {
+-		vm_page_lock_queues();
+-		if (!p->busy)
+-			vm_page_deactivate(p);
+-		vm_page_unlock_queues();
+-	}
+-}
+-
+-
+-/*
+  *	Routine:	vm_object_pmap_protect
+  *
+  *	Purpose:
+@@ -2701,7 +2643,7 @@ void vm_object_page_remove(
+ 	 *	It balances vm_object_lookup vs iteration.
+ 	 */
+ 
+-	if (atop(end - start) < (unsigned)object->resident_page_count/16) {
++	if (atop(end - start) < object->resident_page_count/16) {
+ 		vm_object_page_remove_lookup++;
+ 
+ 		for (; start < end; start += PAGE_SIZE) {
+@@ -2926,7 +2868,7 @@ void vm_object_print(
+ 	iprintf("Object 0x%X: size=0x%X, %d references\n",
+ 		(vm_offset_t) object, (vm_offset_t) object->size,
+ 		object->ref_count);
+-	iprintf("%d resident pages,", object->resident_page_count);
++	iprintf("%lu resident pages,", object->resident_page_count);
+ 	 printf(" %d absent pages,", object->absent_count);
+ 	 printf(" %d paging ops\n", object->paging_in_progress);
+ 	indent += 1;
+diff --git a/vm/vm_object.h b/vm/vm_object.h
+index 3bfc67a..fa208aa 100644
+--- a/vm/vm_object.h
++++ b/vm/vm_object.h
+@@ -72,7 +72,7 @@ struct vm_object {
+ 						 */
+ 
+ 	int			ref_count;	/* Number of references */
+-	int			resident_page_count;
++	unsigned long		resident_page_count;
+ 						/* number of resident pages */
+ 
+ 	struct vm_object	*copy;		/* Object that should receive
+@@ -169,6 +169,7 @@ vm_object_t	kernel_object;		/* the single kernel object */
+ 
+ extern void		vm_object_bootstrap(void);
+ extern void		vm_object_init(void);
++extern void		vm_object_collect(vm_object_t);
+ extern void		vm_object_terminate(vm_object_t);
+ extern vm_object_t	vm_object_allocate(vm_size_t);
+ extern void		vm_object_reference(vm_object_t);
+@@ -290,6 +291,10 @@ vm_object_t vm_object_copy_delayed(
+  *	Routines implemented as macros
+  */
+ 
++#define vm_object_collectable(object)					\
++	(((object)->ref_count == 0)					\
++	&& ((object)->resident_page_count == 0))
++
+ #define	vm_object_paging_begin(object) 					\
+ 	((object)->paging_in_progress++)
+ 
+diff --git a/vm/vm_pageout.c b/vm/vm_pageout.c
+index 51a6a0d..5e1ad1d 100644
+--- a/vm/vm_pageout.c
++++ b/vm/vm_pageout.c
+@@ -748,7 +748,12 @@ void vm_pageout_scan(void)
+ 		    reclaim_page:
+ 			vm_page_free(m);
+ 			vm_page_unlock_queues();
+-			vm_object_unlock(object);
++
++			if (vm_object_collectable(object))
++				vm_object_collect(object);
++			else
++				vm_object_unlock(object);
++
+ 			continue;
+ 		}
+ 
+diff --git a/vm/vm_resident.c b/vm/vm_resident.c
+index c70fa73..b65b756 100644
+--- a/vm/vm_resident.c
++++ b/vm/vm_resident.c
+@@ -523,7 +523,7 @@ void vm_page_insert(
+ 	 */
+ 
+ 	object->resident_page_count++;
+-	assert(object->resident_page_count >= 0);
++	assert(object->resident_page_count != 0);
+ 
+ 	if (object->can_persist && (object->ref_count == 0))
+ 		vm_object_cached_pages_update(1);
+@@ -630,7 +630,7 @@ void vm_page_replace(
+ 	 */
+ 
+ 	object->resident_page_count++;
+-	assert(object->resident_page_count >= 0);
++	assert(object->resident_page_count != 0);
+ 
+ 	if (object->can_persist && (object->ref_count == 0))
+ 		vm_object_cached_pages_update(1);
+-- 
+2.1.4
+
diff --git a/debian/patches/vm-cache-policy0002-vm-keep-track-of-clean-pages.patch b/debian/patches/vm-cache-policy0002-vm-keep-track-of-clean-pages.patch
new file mode 100644
index 0000000..0fe3447
--- /dev/null
+++ b/debian/patches/vm-cache-policy0002-vm-keep-track-of-clean-pages.patch
@@ -0,0 +1,329 @@
+From 8916ad116ede76a2061c2e89e9a944edde54103d Mon Sep 17 00:00:00 2001
+From: Justus Winter <4winter@informatik.uni-hamburg.de>
+Date: Sat, 21 Feb 2015 00:05:31 +0100
+Subject: [PATCH gnumach 2/3] vm: keep track of clean pages
+
+* vm/vm_page.h (struct vm_page): New field `cleanq'.
+(vm_page_queue_clean): New declaration.
+(vm_page_clean_count): Likewise.
+(vm_page_queue_clean_lock): Likewise.
+(vm_page_mark_dirty): New function to set and clear the dirty flag.
+* vm/vm_resident.c (vm_page_queue_clean): New variable.
+(vm_page_queue_clean_lock): Likewise.
+(vm_page_clean_count): Likewise.
+(vm_page_bootstrap): Initialize field `cleanq', the queue and the lock.
+(vm_page_free): Get freed pages off the clean queue.
+* linux/dev/glue/block.c: Use `vm_page_mark_dirty'.
+* vm/memory_object.c: Likewise.
+* vm/vm_debug.c: Likewise.
+* vm/vm_fault.c: Likewise.
+* vm/vm_map.c: Likewise.
+* vm/vm_object.c: Likewise.
+* vm/vm_pageout.c: Likewise.
+* xen/block.c: Likewise.
+---
+ linux/dev/glue/block.c |  2 +-
+ vm/memory_object.c     |  4 ++--
+ vm/vm_debug.c          |  2 +-
+ vm/vm_fault.c          |  6 +++---
+ vm/vm_map.c            |  2 +-
+ vm/vm_object.c         |  4 ++--
+ vm/vm_page.h           | 33 +++++++++++++++++++++++++++++++--
+ vm/vm_pageout.c        |  8 ++++----
+ vm/vm_resident.c       | 10 ++++++++++
+ xen/block.c            |  2 +-
+ 10 files changed, 56 insertions(+), 17 deletions(-)
+
+diff --git a/linux/dev/glue/block.c b/linux/dev/glue/block.c
+index da4ef38..3bd2c5b 100644
+--- a/linux/dev/glue/block.c
++++ b/linux/dev/glue/block.c
+@@ -1537,7 +1537,7 @@ device_read (void *d, ipc_port_t reply_port,
+ 	  if (dirty)
+ 	    {
+ 	      PAGE_WAKEUP_DONE (m);
+-	      m->dirty = TRUE;
++	      vm_page_mark_dirty (m, TRUE);
+ 	      vm_page_insert (m, object, o);
+ 	    }
+ 	  else
+diff --git a/vm/memory_object.c b/vm/memory_object.c
+index 097ed23..7a0dbb8 100644
+--- a/vm/memory_object.c
++++ b/vm/memory_object.c
+@@ -209,7 +209,7 @@ retry_lookup:
+ 		 */
+ 
+ 		data_m->busy = FALSE;
+-		data_m->dirty = FALSE;
++		vm_page_mark_dirty (data_m, FALSE);
+ 		pmap_clear_modify(data_m->phys_addr);
+ 
+ 		data_m->page_lock = lock_value;
+@@ -555,7 +555,7 @@ memory_object_lock_result_t memory_object_lock_page(
+ 		 */
+ 
+ 		if (!m->dirty)
+-			m->dirty = pmap_is_modified(m->phys_addr);
++			vm_page_mark_dirty (m, pmap_is_modified(m->phys_addr));
+ 
+ 		if (m->dirty || (m->precious &&
+ 				 should_return == MEMORY_OBJECT_RETURN_ALL)) {
+diff --git a/vm/vm_debug.c b/vm/vm_debug.c
+index 227090e..822ca86 100644
+--- a/vm/vm_debug.c
++++ b/vm/vm_debug.c
+@@ -352,7 +352,7 @@ mach_vm_object_pages(
+ 		if (((state & (VPI_STATE_NODATA|VPI_STATE_DIRTY)) == 0) &&
+ 		    pmap_is_modified(p->phys_addr)) {
+ 			state |= VPI_STATE_DIRTY;
+-			p->dirty = TRUE;
++			vm_page_mark_dirty (p, TRUE);
+ 		}
+ 
+ 		vm_page_lock_queues();
+diff --git a/vm/vm_fault.c b/vm/vm_fault.c
+index 46779f6..b3f92b3 100644
+--- a/vm/vm_fault.c
++++ b/vm/vm_fault.c
+@@ -976,7 +976,7 @@ vm_fault_return_t vm_fault_page(
+ 
+ 			vm_page_lock_queues();
+ 			pmap_page_protect(m->phys_addr, VM_PROT_NONE);
+-			copy_m->dirty = TRUE;
++			vm_page_mark_dirty (copy_m, TRUE);
+ 			vm_page_unlock_queues();
+ 
+ 			/*
+@@ -1075,7 +1075,7 @@ vm_fault_return_t vm_fault_page(
+ 	 */
+ 
+ 	if (vm_fault_dirty_handling && (*protection & VM_PROT_WRITE))
+-		m->dirty = TRUE;
++		vm_page_mark_dirty (m, TRUE);
+ 
+ 	return(VM_FAULT_SUCCESS);
+ 
+@@ -1955,7 +1955,7 @@ kern_return_t	vm_fault_copy(
+ 			vm_page_zero_fill(dst_page);
+ 		else
+ 			vm_page_copy(src_page, dst_page);
+-		dst_page->dirty = TRUE;
++		vm_page_mark_dirty (dst_page, TRUE);
+ 
+ 		/*
+ 		 *	Unlock everything, and return
+diff --git a/vm/vm_map.c b/vm/vm_map.c
+index 3a231de..6bbf614 100644
+--- a/vm/vm_map.c
++++ b/vm/vm_map.c
+@@ -2947,7 +2947,7 @@ insert_pages:
+ 		assert(!m->wanted);
+ 
+ 		m->busy = FALSE;
+-		m->dirty = TRUE;
++		vm_page_mark_dirty (m, TRUE);
+ 		vm_page_replace(m, object, old_last_offset + offset);
+ 		if (must_wire) {
+ 			vm_page_wire(m);
+diff --git a/vm/vm_object.c b/vm/vm_object.c
+index 44c13f4..332bd3d 100644
+--- a/vm/vm_object.c
++++ b/vm/vm_object.c
+@@ -581,7 +581,7 @@ void vm_object_terminate(
+ 		}
+ 
+ 		if (!p->dirty)
+-			p->dirty = pmap_is_modified(p->phys_addr);
++			vm_page_mark_dirty (p, pmap_is_modified(p->phys_addr));
+ 
+ 		if (p->dirty || p->precious) {
+ 			p->busy = TRUE;
+@@ -1083,7 +1083,7 @@ kern_return_t vm_object_copy_slowly(
+ 					 */
+ 
+ 					new_page->busy = FALSE;
+-					new_page->dirty = TRUE;
++					vm_page_mark_dirty (new_page, TRUE);
+ 					vm_object_lock(result_page->object);
+ 					PAGE_WAKEUP_DONE(result_page);
+ 
+diff --git a/vm/vm_page.h b/vm/vm_page.h
+index e6a8c49..41c5711 100644
+--- a/vm/vm_page.h
++++ b/vm/vm_page.h
+@@ -70,8 +70,10 @@
+  *	and sundry status bits.
+  *
+  *	Fields in this structure are locked either by the lock on the
+- *	object that the page belongs to (O) or by the lock on the page
+- *	queues (P).  [Some fields require that both locks be held to
++ *	object that the page belongs to (O), by the lock on the page
++ *	queues (P), or by vm_page_queue_clean_lock (C).
++ *
++ *	[Some fields require that both locks, O and P, be held to
+  *	change that field; holding either lock is sufficient to read.]
+  */
+ 
+@@ -79,6 +81,7 @@ struct vm_page {
+ 	queue_chain_t	pageq;		/* queue info for FIFO
+ 					 * queue or free list (P) */
+ 	queue_chain_t	listq;		/* all pages in same object (O) */
++	queue_chain_t	cleanq;		/* all clean pages (C) */
+ 	struct vm_page	*next;		/* VP bucket link (O) */
+ 
+ 	vm_object_t	object;		/* which object am I in (O,P) */
+@@ -147,8 +150,12 @@ extern
+ queue_head_t	vm_page_queue_active;	/* active memory queue */
+ extern
+ queue_head_t	vm_page_queue_inactive;	/* inactive memory queue */
++extern
++queue_head_t	vm_page_queue_clean;	/* clean memory queue */
+ 
+ extern
++int	vm_page_clean_count;	/* How many pages are clean? */
++extern
+ int	vm_page_free_count;	/* How many pages are free? */
+ extern
+ int	vm_page_fictitious_count;/* How many fictitious pages are free? */
+@@ -184,6 +191,8 @@ decl_simple_lock_data(extern,vm_page_queue_lock)/* lock on active and inactive
+ 						   page queues */
+ decl_simple_lock_data(extern,vm_page_queue_free_lock)
+ 						/* lock on free page queue */
++decl_simple_lock_data(extern,vm_page_queue_clean_lock)
++						/* lock on clean page queue */
+ 
+ extern unsigned int	vm_page_free_wanted;
+ 				/* how many threads are waiting for memory */
+@@ -312,4 +321,24 @@ extern unsigned int	vm_page_info(
+ 	}							\
+ 	MACRO_END
+ 
++static inline void
++vm_page_mark_dirty (vm_page_t m, boolean_t dirty)
++{
++	if (m->dirty == dirty && (dirty || m->cleanq.next))
++		return;	/* No action necessary.  */
++
++	simple_lock (&vm_page_queue_clean_lock);
++	if (dirty && m->cleanq.next) {
++		queue_remove (&vm_page_queue_clean, m, vm_page_t, cleanq);
++		vm_page_clean_count -= 1;
++		m->cleanq.next = NULL;
++	}
++	if (! dirty) {
++		queue_enter (&vm_page_queue_clean, m, vm_page_t, cleanq);
++		vm_page_clean_count += 1;
++	}
++	simple_unlock (&vm_page_queue_clean_lock);
++	m->dirty = dirty;
++}
++
+ #endif	/* _VM_VM_PAGE_H_ */
+diff --git a/vm/vm_pageout.c b/vm/vm_pageout.c
+index 5e1ad1d..6ea2951 100644
+--- a/vm/vm_pageout.c
++++ b/vm/vm_pageout.c
+@@ -293,7 +293,7 @@ vm_pageout_setup(
+ 		vm_page_insert(m, new_object, new_offset);
+ 		vm_page_unlock_queues();
+ 
+-		m->dirty = TRUE;
++		vm_page_mark_dirty (m, TRUE);
+ 		m->precious = FALSE;
+ 		m->page_lock = VM_PROT_NONE;
+ 		m->unlock_request = VM_PROT_NONE;
+@@ -306,7 +306,7 @@ vm_pageout_setup(
+ 		vm_page_copy(m, new_m);
+ 
+ 		vm_object_lock(old_object);
+-		m->dirty = FALSE;
++		vm_page_mark_dirty (m, FALSE);
+ 		pmap_clear_modify(m->phys_addr);
+ 
+ 		/*
+@@ -336,7 +336,7 @@ vm_pageout_setup(
+ 		 *	Use the new page below.
+ 		 */
+ 		m = new_m;
+-		m->dirty = TRUE;
++		vm_page_mark_dirty (m, TRUE);
+ 		assert(!m->precious);
+ 		PAGE_WAKEUP_DONE(m);
+ 	}
+@@ -780,7 +780,7 @@ void vm_pageout_scan(void)
+ 		m->busy = TRUE;
+ 		pmap_page_protect(m->phys_addr, VM_PROT_NONE);
+ 		if (!m->dirty)
+-			m->dirty = pmap_is_modified(m->phys_addr);
++			vm_page_mark_dirty (m, pmap_is_modified(m->phys_addr));
+ 
+ 		if (m->external) {
+ 			/* Figure out if we still care about this
+diff --git a/vm/vm_resident.c b/vm/vm_resident.c
+index b65b756..46980fc 100644
+--- a/vm/vm_resident.c
++++ b/vm/vm_resident.c
+@@ -148,9 +148,12 @@ vm_offset_t vm_page_fictitious_addr = (vm_offset_t) -1;
+ queue_head_t	vm_page_queue_active;
+ queue_head_t	vm_page_queue_inactive;
+ decl_simple_lock_data(,vm_page_queue_lock)
++queue_head_t	vm_page_queue_clean;
++decl_simple_lock_data(,vm_page_queue_clean_lock)
+ int	vm_page_active_count;
+ int	vm_page_inactive_count;
+ int	vm_page_wire_count;
++int	vm_page_clean_count;
+ 
+ /*
+  *	Several page replacement parameters are also
+@@ -200,6 +203,7 @@ void vm_page_bootstrap(
+ 	 */
+ 
+ 	m = &vm_page_template;
++	m->cleanq.next = NULL;
+ 	m->object = VM_OBJECT_NULL;	/* reset later */
+ 	m->offset = 0;			/* reset later */
+ 	m->wire_count = 0;
+@@ -231,12 +235,14 @@ void vm_page_bootstrap(
+ 	 */
+ 
+ 	simple_lock_init(&vm_page_queue_free_lock);
++	simple_lock_init(&vm_page_queue_clean_lock);
+ 	simple_lock_init(&vm_page_queue_lock);
+ 
+ 	vm_page_queue_free = VM_PAGE_NULL;
+ 	vm_page_queue_fictitious = VM_PAGE_NULL;
+ 	queue_init(&vm_page_queue_active);
+ 	queue_init(&vm_page_queue_inactive);
++	queue_init(&vm_page_queue_clean);
+ 
+ 	vm_page_free_wanted = 0;
+ 
+@@ -1304,6 +1310,10 @@ void vm_page_free(
+ 	if (mem->absent)
+ 		vm_object_absent_release(mem->object);
+ 
++
++	/* Get it off the clean list.  */
++	vm_page_mark_dirty (mem, TRUE);
++
+ 	/*
+ 	 *	XXX The calls to vm_page_init here are
+ 	 *	really overkill.
+diff --git a/xen/block.c b/xen/block.c
+index d98b31e..175955a 100644
+--- a/xen/block.c
++++ b/xen/block.c
+@@ -539,7 +539,7 @@ device_read (void *d, ipc_port_t reply_port,
+ 	  assert (m->busy);
+ 	  vm_page_lock_queues ();
+ 	  PAGE_WAKEUP_DONE (m);
+-	  m->dirty = TRUE;
++	  vm_page_mark_dirty (m, TRUE);
+ 	  vm_page_insert (m, object, o);
+ 	  vm_page_unlock_queues ();
+ 	  o += PAGE_SIZE;
+-- 
+2.1.4
+
diff --git a/debian/patches/vm-cache-policy0003-vm-evict-clean-pages-first.patch b/debian/patches/vm-cache-policy0003-vm-evict-clean-pages-first.patch
new file mode 100644
index 0000000..2ba5794
--- /dev/null
+++ b/debian/patches/vm-cache-policy0003-vm-evict-clean-pages-first.patch
@@ -0,0 +1,57 @@
+From 3f0c838e24d6765688c28ff1d852cc03809878b1 Mon Sep 17 00:00:00 2001
+From: Justus Winter <4winter@informatik.uni-hamburg.de>
+Date: Sat, 21 Feb 2015 15:20:46 +0100
+Subject: [PATCH gnumach 3/3] vm: evict clean pages first
+
+* vm/vm_pageout.c (vm_pageout_scan): Evict clean pages from the list
+of clean pages first, without requiring an expensive scan through the
+inactive list.
+---
+ vm/vm_pageout.c | 24 +++++++++++++++++++++++-
+ 1 file changed, 23 insertions(+), 1 deletion(-)
+
+diff --git a/vm/vm_pageout.c b/vm/vm_pageout.c
+index 6ea2951..a22dfeb 100644
+--- a/vm/vm_pageout.c
++++ b/vm/vm_pageout.c
+@@ -681,6 +681,28 @@ void vm_pageout_scan(void)
+ 			/*NOTREACHED*/
+ 		}
+ 
++		/* Try to evict a clean page first.  */
++		simple_lock (&vm_page_queue_clean_lock);
++		int tries;
++		for (tries = vm_page_clean_count; tries; tries--)
++		  {
++		    assert (! queue_empty (&vm_page_queue_clean));
++		    queue_remove_first (&vm_page_queue_clean,
++					m, vm_page_t, cleanq);
++		    if (! m->active && m->inactive
++			&& (want_pages || m->external))
++		      {
++			m->cleanq.next = NULL;
++			vm_page_clean_count -= 1;
++			simple_unlock (&vm_page_queue_clean_lock);
++			goto got_one;
++		      }
++		    else
++		      queue_enter (&vm_page_queue_clean,
++				   m, vm_page_t, cleanq);
++		  }
++		simple_unlock (&vm_page_queue_clean_lock);
++
+ 		vm_pageout_inactive++;
+ 
+ 		/* Find a page we are interested in paging out.  If we
+@@ -697,7 +719,7 @@ void vm_pageout_scan(void)
+ 		    if (!m)
+ 		      goto pause;
+ 		  }
+-		
++	got_one:
+ 		object = m->object;
+ 
+ 		/*
+-- 
+2.1.4
+