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Date:      Sat, 18 Sep 2010 15:03:31 +0000 (UTC)
From:      Konstantin Belousov <kib@FreeBSD.org>
To:        src-committers@freebsd.org, svn-src-all@freebsd.org, svn-src-head@freebsd.org
Subject:   svn commit: r212824 - in head/sys: sys vm
Message-ID:  <201009181503.o8IF3VgV069184@svn.freebsd.org>

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Author: kib
Date: Sat Sep 18 15:03:31 2010
New Revision: 212824
URL: http://svn.freebsd.org/changeset/base/212824

Log:
  Adopt the deferring of object deallocation for the deleted map entries
  on map unlock to the lock downgrade and later read unlock operation.
  
  System map entries cannot be backed by OBJT_VNODE objects, no need to
  defer deallocation for them. Map entries from user maps do not require
  the owner map for deallocation, and can be accumulated in the
  thread-local list for freeing when a user map is unlocked.
  
  Move the collection of entries for deferred reclamation into
  vm_map_delete(). Create helper vm_map_process_deferred(), that is
  called from locations where processing is feasible. Do not process
  deferred entries in vm_map_unlock_and_wait() since map_sleep_mtx is
  held.
  
  Reviewed by:	alc, rstone (previous versions)
  Tested by:	pho
  MFC after:	2 weeks

Modified:
  head/sys/sys/proc.h
  head/sys/vm/vm_map.c
  head/sys/vm/vm_map.h

Modified: head/sys/sys/proc.h
==============================================================================
--- head/sys/sys/proc.h	Sat Sep 18 13:44:39 2010	(r212823)
+++ head/sys/sys/proc.h	Sat Sep 18 15:03:31 2010	(r212824)
@@ -262,6 +262,7 @@ struct thread {
 	struct ksiginfo td_dbgksi;	/* (c) ksi reflected to debugger. */
 	int		td_ng_outbound;	/* (k) Thread entered ng from above. */
 	struct osd	td_osd;		/* (k) Object specific data. */
+	struct vm_map_entry *td_map_def_user; /* (k) Deferred entries. */
 #define	td_endzero td_base_pri
 
 /* Copied during fork1() or thread_sched_upcall(). */

Modified: head/sys/vm/vm_map.c
==============================================================================
--- head/sys/vm/vm_map.c	Sat Sep 18 13:44:39 2010	(r212823)
+++ head/sys/vm/vm_map.c	Sat Sep 18 15:03:31 2010	(r212824)
@@ -128,6 +128,7 @@ static int vm_map_zinit(void *mem, int i
 static void vm_map_zfini(void *mem, int size);
 static void _vm_map_init(vm_map_t map, pmap_t pmap, vm_offset_t min,
     vm_offset_t max);
+static void vm_map_entry_deallocate(vm_map_entry_t entry, boolean_t system_map);
 static void vm_map_entry_dispose(vm_map_t map, vm_map_entry_t entry);
 #ifdef INVARIANTS
 static void vm_map_zdtor(void *mem, int size, void *arg);
@@ -454,30 +455,39 @@ _vm_map_lock(vm_map_t map, const char *f
 	map->timestamp++;
 }
 
-void
-_vm_map_unlock(vm_map_t map, const char *file, int line)
+static void
+vm_map_process_deferred(void)
 {
-	vm_map_entry_t free_entry, entry;
-	vm_object_t object;
+	struct thread *td;
+	vm_map_entry_t entry;
 
-	free_entry = map->deferred_freelist;
-	map->deferred_freelist = NULL;
+	td = curthread;
+
+	while ((entry = td->td_map_def_user) != NULL) {
+		td->td_map_def_user = entry->next;
+		vm_map_entry_deallocate(entry, FALSE);
+	}
+}
+
+void
+_vm_map_unlock_nodefer(vm_map_t map, const char *file, int line)
+{
 
 	if (map->system_map)
 		_mtx_unlock_flags(&map->system_mtx, 0, file, line);
 	else
 		_sx_xunlock(&map->lock, file, line);
+}
 
-	while (free_entry != NULL) {
-		entry = free_entry;
-		free_entry = free_entry->next;
-
-		if ((entry->eflags & MAP_ENTRY_IS_SUB_MAP) == 0) {
-			object = entry->object.vm_object;
-			vm_object_deallocate(object);
-		}
+void
+_vm_map_unlock(vm_map_t map, const char *file, int line)
+{
 
-		vm_map_entry_dispose(map, entry);
+	if (map->system_map)
+		_mtx_unlock_flags(&map->system_mtx, 0, file, line);
+	else {
+		_sx_xunlock(&map->lock, file, line);
+		vm_map_process_deferred();
 	}
 }
 
@@ -497,8 +507,10 @@ _vm_map_unlock_read(vm_map_t map, const 
 
 	if (map->system_map)
 		_mtx_unlock_flags(&map->system_mtx, 0, file, line);
-	else
+	else {
 		_sx_sunlock(&map->lock, file, line);
+		vm_map_process_deferred();
+	}
 }
 
 int
@@ -548,6 +560,7 @@ _vm_map_lock_upgrade(vm_map_t map, const
 		if (!_sx_try_upgrade(&map->lock, file, line)) {
 			last_timestamp = map->timestamp;
 			_sx_sunlock(&map->lock, file, line);
+			vm_map_process_deferred();
 			/*
 			 * If the map's timestamp does not change while the
 			 * map is unlocked, then the upgrade succeeds.
@@ -631,7 +644,7 @@ vm_map_unlock_and_wait(vm_map_t map, int
 {
 
 	mtx_lock(&map_sleep_mtx);
-	vm_map_unlock(map);
+	vm_map_unlock_nodefer(map);
 	return (msleep(&map->root, &map_sleep_mtx, PDROP | PVM, "vmmaps", timo));
 }
 
@@ -699,7 +712,6 @@ _vm_map_init(vm_map_t map, pmap_t pmap, 
 	map->flags = 0;
 	map->root = NULL;
 	map->timestamp = 0;
-	map->deferred_freelist = NULL;
 }
 
 void
@@ -2602,6 +2614,15 @@ vm_map_entry_unwire(vm_map_t map, vm_map
 	entry->wired_count = 0;
 }
 
+static void
+vm_map_entry_deallocate(vm_map_entry_t entry, boolean_t system_map)
+{
+
+	if ((entry->eflags & MAP_ENTRY_IS_SUB_MAP) == 0)
+		vm_object_deallocate(entry->object.vm_object);
+	uma_zfree(system_map ? kmapentzone : mapentzone, entry);
+}
+
 /*
  *	vm_map_entry_delete:	[ internal use only ]
  *
@@ -2656,6 +2677,12 @@ vm_map_entry_delete(vm_map_t map, vm_map
 		VM_OBJECT_UNLOCK(object);
 	} else
 		entry->object.vm_object = NULL;
+	if (map->system_map)
+		vm_map_entry_deallocate(entry, TRUE);
+	else {
+		entry->next = curthread->td_map_def_user;
+		curthread->td_map_def_user = entry;
+	}
 }
 
 /*
@@ -2744,8 +2771,6 @@ vm_map_delete(vm_map_t map, vm_offset_t 
 		 * will be set in the wrong object!)
 		 */
 		vm_map_entry_delete(map, entry);
-		entry->next = map->deferred_freelist;
-		map->deferred_freelist = entry;
 		entry = next;
 	}
 	return (KERN_SUCCESS);

Modified: head/sys/vm/vm_map.h
==============================================================================
--- head/sys/vm/vm_map.h	Sat Sep 18 13:44:39 2010	(r212823)
+++ head/sys/vm/vm_map.h	Sat Sep 18 15:03:31 2010	(r212824)
@@ -185,7 +185,6 @@ struct vm_map {
 	vm_flags_t flags;		/* flags for this vm_map */
 	vm_map_entry_t root;		/* Root of a binary search tree */
 	pmap_t pmap;			/* (c) Physical map */
-	vm_map_entry_t deferred_freelist;
 #define	min_offset	header.start	/* (c) */
 #define	max_offset	header.end	/* (c) */
 };
@@ -267,6 +266,7 @@ vmspace_pmap(struct vmspace *vmspace)
 
 void _vm_map_lock(vm_map_t map, const char *file, int line);
 void _vm_map_unlock(vm_map_t map, const char *file, int line);
+void _vm_map_unlock_nodefer(vm_map_t map, const char *file, int line);
 void _vm_map_lock_read(vm_map_t map, const char *file, int line);
 void _vm_map_unlock_read(vm_map_t map, const char *file, int line);
 int _vm_map_trylock(vm_map_t map, const char *file, int line);
@@ -279,6 +279,8 @@ void vm_map_wakeup(vm_map_t map);
 
 #define	vm_map_lock(map)	_vm_map_lock(map, LOCK_FILE, LOCK_LINE)
 #define	vm_map_unlock(map)	_vm_map_unlock(map, LOCK_FILE, LOCK_LINE)
+#define	vm_map_unlock_nodefer(map)	\
+			_vm_map_unlock_nodefer(map, LOCK_FILE, LOCK_LINE)
 #define	vm_map_lock_read(map)	_vm_map_lock_read(map, LOCK_FILE, LOCK_LINE)
 #define	vm_map_unlock_read(map)	_vm_map_unlock_read(map, LOCK_FILE, LOCK_LINE)
 #define	vm_map_trylock(map)	_vm_map_trylock(map, LOCK_FILE, LOCK_LINE)



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