xfs: embedd mru_elem into parent structure

There is no need to do a separate allocation for each mru element, just
embedd the structure into the parent one in the user.  Besides saving
a memory allocation and the infrastructure required for it this also
simplifies the API.

While we do major surgery on xfs_mru_cache.c also de-typedef it and
make struct mru_cache private to the implementation file.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
Signed-off-by: Dave Chinner <david@fromorbit.com>

1 files changed, 61 insertions, 94 deletions

diff --git a/fs/xfs/xfs_mru_cache.c b/fs/xfs/xfs_mru_cache.c
index 4aa3166..f99b493 100644
--- a/fs/xfs/xfs_mru_cache.c
+++ b/fs/xfs/xfs_mru_cache.c
@@ -100,14 +100,20 @@
  * likely result in a loop in one of the lists.  That's a sure-fire recipe for
  * an infinite loop in the code.
  */
-typedef struct xfs_mru_cache_elem
-{
-	struct list_head list_node;
-	unsigned long	key;
-	void		*value;
-} xfs_mru_cache_elem_t;
+struct xfs_mru_cache {
+	struct radix_tree_root	store;     /* Core storage data structure.  */
+	struct list_head	*lists;    /* Array of lists, one per grp.  */
+	struct list_head	reap_list; /* Elements overdue for reaping. */
+	spinlock_t		lock;      /* Lock to protect this struct.  */
+	unsigned int		grp_count; /* Number of discrete groups.    */
+	unsigned int		grp_time;  /* Time period spanned by grps.  */
+	unsigned int		lru_grp;   /* Group containing time zero.   */
+	unsigned long		time_zero; /* Time first element was added. */
+	xfs_mru_cache_free_func_t free_func; /* Function pointer for freeing. */
+	struct delayed_work	work;      /* Workqueue data for reaping.   */
+	unsigned int		queued;	   /* work has been queued */
+};
 
-static kmem_zone_t		*xfs_mru_elem_zone;
 static struct workqueue_struct	*xfs_mru_reap_wq;
 
 /*
@@ -129,12 +135,12 @@ static struct workqueue_struct	*xfs_mru_reap_wq;
  */
 STATIC unsigned long
 _xfs_mru_cache_migrate(
-	xfs_mru_cache_t	*mru,
-	unsigned long	now)
+	struct xfs_mru_cache	*mru,
+	unsigned long		now)
 {
-	unsigned int	grp;
-	unsigned int	migrated = 0;
-	struct list_head *lru_list;
+	unsigned int		grp;
+	unsigned int		migrated = 0;
+	struct list_head	*lru_list;
 
 	/* Nothing to do if the data store is empty. */
 	if (!mru->time_zero)
@@ -193,11 +199,11 @@ _xfs_mru_cache_migrate(
  */
 STATIC void
 _xfs_mru_cache_list_insert(
-	xfs_mru_cache_t		*mru,
-	xfs_mru_cache_elem_t	*elem)
+	struct xfs_mru_cache	*mru,
+	struct xfs_mru_cache_elem *elem)
 {
-	unsigned int	grp = 0;
-	unsigned long	now = jiffies;
+	unsigned int		grp = 0;
+	unsigned long		now = jiffies;
 
 	/*
 	 * If the data store is empty, initialise time zero, leave grp set to
@@ -231,10 +237,10 @@ _xfs_mru_cache_list_insert(
  */
 STATIC void
 _xfs_mru_cache_clear_reap_list(
-	xfs_mru_cache_t		*mru) __releases(mru->lock) __acquires(mru->lock)
-
+	struct xfs_mru_cache	*mru)
+		__releases(mru->lock) __acquires(mru->lock)
 {
-	xfs_mru_cache_elem_t	*elem, *next;
+	struct xfs_mru_cache_elem *elem, *next;
 	struct list_head	tmp;
 
 	INIT_LIST_HEAD(&tmp);
@@ -252,15 +258,8 @@ _xfs_mru_cache_clear_reap_list(
 	spin_unlock(&mru->lock);
 
 	list_for_each_entry_safe(elem, next, &tmp, list_node) {
-
-		/* Remove the element from the reap list. */
 		list_del_init(&elem->list_node);
-
-		/* Call the client's free function with the key and value pointer. */
-		mru->free_func(elem->key, elem->value);
-
-		/* Free the element structure. */
-		kmem_zone_free(xfs_mru_elem_zone, elem);
+		mru->free_func(elem);
 	}
 
 	spin_lock(&mru->lock);
@@ -277,7 +276,8 @@ STATIC void
 _xfs_mru_cache_reap(
 	struct work_struct	*work)
 {
-	xfs_mru_cache_t		*mru = container_of(work, xfs_mru_cache_t, work.work);
+	struct xfs_mru_cache	*mru =
+		container_of(work, struct xfs_mru_cache, work.work);
 	unsigned long		now, next;
 
 	ASSERT(mru && mru->lists);
@@ -304,28 +304,16 @@ _xfs_mru_cache_reap(
 int
 xfs_mru_cache_init(void)
 {
-	xfs_mru_elem_zone = kmem_zone_init(sizeof(xfs_mru_cache_elem_t),
-	                                 "xfs_mru_cache_elem");
-	if (!xfs_mru_elem_zone)
-		goto out;
-
 	xfs_mru_reap_wq = alloc_workqueue("xfs_mru_cache", WQ_MEM_RECLAIM, 1);
 	if (!xfs_mru_reap_wq)
-		goto out_destroy_mru_elem_zone;
-
+		return -ENOMEM;
 	return 0;
-
- out_destroy_mru_elem_zone:
-	kmem_zone_destroy(xfs_mru_elem_zone);
- out:
-	return -ENOMEM;
 }
 
 void
 xfs_mru_cache_uninit(void)
 {
 	destroy_workqueue(xfs_mru_reap_wq);
-	kmem_zone_destroy(xfs_mru_elem_zone);
 }
 
 /*
@@ -336,14 +324,14 @@ xfs_mru_cache_uninit(void)
  */
 int
 xfs_mru_cache_create(
-	xfs_mru_cache_t		**mrup,
+	struct xfs_mru_cache	**mrup,
 	unsigned int		lifetime_ms,
 	unsigned int		grp_count,
 	xfs_mru_cache_free_func_t free_func)
 {
-	xfs_mru_cache_t	*mru = NULL;
-	int		err = 0, grp;
-	unsigned int	grp_time;
+	struct xfs_mru_cache	*mru = NULL;
+	int			err = 0, grp;
+	unsigned int		grp_time;
 
 	if (mrup)
 		*mrup = NULL;
@@ -400,7 +388,7 @@ exit:
  */
 static void
 xfs_mru_cache_flush(
-	xfs_mru_cache_t		*mru)
+	struct xfs_mru_cache	*mru)
 {
 	if (!mru || !mru->lists)
 		return;
@@ -420,7 +408,7 @@ xfs_mru_cache_flush(
 
 void
 xfs_mru_cache_destroy(
-	xfs_mru_cache_t		*mru)
+	struct xfs_mru_cache	*mru)
 {
 	if (!mru || !mru->lists)
 		return;
@@ -438,45 +426,29 @@ xfs_mru_cache_destroy(
  */
 int
 xfs_mru_cache_insert(
-	xfs_mru_cache_t	*mru,
-	unsigned long	key,
-	void		*value)
+	struct xfs_mru_cache	*mru,
+	unsigned long		key,
+	struct xfs_mru_cache_elem *elem)
 {
-	xfs_mru_cache_elem_t *elem;
-	int error;
+	int			error;
 
 	ASSERT(mru && mru->lists);
 	if (!mru || !mru->lists)
 		return EINVAL;
 
-	elem = kmem_zone_zalloc(xfs_mru_elem_zone, KM_SLEEP);
-	if (!elem)
+	if (radix_tree_preload(GFP_KERNEL))
 		return ENOMEM;
 
-	if (radix_tree_preload(GFP_KERNEL)) {
-		error = ENOMEM;
-		goto out_free_item;
-	}
-
 	INIT_LIST_HEAD(&elem->list_node);
 	elem->key = key;
-	elem->value = value;
 
 	spin_lock(&mru->lock);
-
 	error = -radix_tree_insert(&mru->store, key, elem);
 	radix_tree_preload_end();
-	if (error) {
-		spin_unlock(&mru->lock);
-		goto out_free_item;
-	}
-	_xfs_mru_cache_list_insert(mru, elem);
-
+	if (!error)
+		_xfs_mru_cache_list_insert(mru, elem);
 	spin_unlock(&mru->lock);
 
-	return 0;
-out_free_item:
-	kmem_zone_free(xfs_mru_elem_zone, elem);
 	return error;
 }
 
@@ -486,13 +458,12 @@ out_free_item:
  * the client data pointer for the removed element is returned, otherwise this
  * function will return a NULL pointer.
  */
-void *
+struct xfs_mru_cache_elem *
 xfs_mru_cache_remove(
-	xfs_mru_cache_t	*mru,
-	unsigned long	key)
+	struct xfs_mru_cache	*mru,
+	unsigned long		key)
 {
-	xfs_mru_cache_elem_t *elem;
-	void		*value = NULL;
+	struct xfs_mru_cache_elem *elem;
 
 	ASSERT(mru && mru->lists);
 	if (!mru || !mru->lists)
@@ -500,17 +471,11 @@ xfs_mru_cache_remove(
 
 	spin_lock(&mru->lock);
 	elem = radix_tree_delete(&mru->store, key);
-	if (elem) {
-		value = elem->value;
+	if (elem)
 		list_del(&elem->list_node);
-	}
-
 	spin_unlock(&mru->lock);
 
-	if (elem)
-		kmem_zone_free(xfs_mru_elem_zone, elem);
-
-	return value;
+	return elem;
 }
 
 /*
@@ -519,13 +484,14 @@ xfs_mru_cache_remove(
  */
 void
 xfs_mru_cache_delete(
-	xfs_mru_cache_t	*mru,
-	unsigned long	key)
+	struct xfs_mru_cache	*mru,
+	unsigned long		key)
 {
-	void		*value = xfs_mru_cache_remove(mru, key);
+	struct xfs_mru_cache_elem *elem;
 
-	if (value)
-		mru->free_func(key, value);
+	elem = xfs_mru_cache_remove(mru, key);
+	if (elem)
+		mru->free_func(elem);
 }
 
 /*
@@ -548,12 +514,12 @@ xfs_mru_cache_delete(
  * status, we need to help it get it right by annotating the path that does
  * not release the lock.
  */
-void *
+struct xfs_mru_cache_elem *
 xfs_mru_cache_lookup(
-	xfs_mru_cache_t	*mru,
-	unsigned long	key)
+	struct xfs_mru_cache	*mru,
+	unsigned long		key)
 {
-	xfs_mru_cache_elem_t *elem;
+	struct xfs_mru_cache_elem *elem;
 
 	ASSERT(mru && mru->lists);
 	if (!mru || !mru->lists)
@@ -568,7 +534,7 @@ xfs_mru_cache_lookup(
 	} else
 		spin_unlock(&mru->lock);
 
-	return elem ? elem->value : NULL;
+	return elem;
 }
 
 /*
@@ -578,7 +544,8 @@ xfs_mru_cache_lookup(
  */
 void
 xfs_mru_cache_done(
-	xfs_mru_cache_t	*mru) __releases(mru->lock)
+	struct xfs_mru_cache	*mru)
+		__releases(mru->lock)
 {
 	spin_unlock(&mru->lock);
 }