static inline void
xfs_log_item_batch_insert(
struct xfs_ail *ailp,
+ struct xfs_ail_cursor *cur,
struct xfs_log_item **log_items,
int nr_items,
xfs_lsn_t commit_lsn)
spin_lock(&ailp->xa_lock);
/* xfs_trans_ail_update_bulk drops ailp->xa_lock */
- xfs_trans_ail_update_bulk(ailp, log_items, nr_items, commit_lsn);
+ xfs_trans_ail_update_bulk(ailp, cur, log_items, nr_items, commit_lsn);
for (i = 0; i < nr_items; i++)
IOP_UNPIN(log_items[i], 0);
* as an iclog write error even though we haven't started any IO yet. Hence in
* this case all we need to do is IOP_COMMITTED processing, followed by an
* IOP_UNPIN(aborted) call.
+ *
+ * The AIL cursor is used to optimise the insert process. If commit_lsn is not
+ * at the end of the AIL, the insert cursor avoids the need to walk
+ * the AIL to find the insertion point on every xfs_log_item_batch_insert()
+ * call. This saves a lot of needless list walking and is a net win, even
+ * though it slightly increases that amount of AIL lock traffic to set it up
+ * and tear it down.
*/
void
xfs_trans_committed_bulk(
#define LOG_ITEM_BATCH_SIZE 32
struct xfs_log_item *log_items[LOG_ITEM_BATCH_SIZE];
struct xfs_log_vec *lv;
+ struct xfs_ail_cursor cur;
int i = 0;
+ spin_lock(&ailp->xa_lock);
+ xfs_trans_ail_cursor_last(ailp, &cur, commit_lsn);
+ spin_unlock(&ailp->xa_lock);
+
/* unpin all the log items */
for (lv = log_vector; lv; lv = lv->lv_next ) {
struct xfs_log_item *lip = lv->lv_item;
/*
* Not a bulk update option due to unusual item_lsn.
* Push into AIL immediately, rechecking the lsn once
- * we have the ail lock. Then unpin the item.
+ * we have the ail lock. Then unpin the item. This does
+ * not affect the AIL cursor the bulk insert path is
+ * using.
*/
spin_lock(&ailp->xa_lock);
if (XFS_LSN_CMP(item_lsn, lip->li_lsn) > 0)
/* Item is a candidate for bulk AIL insert. */
log_items[i++] = lv->lv_item;
if (i >= LOG_ITEM_BATCH_SIZE) {
- xfs_log_item_batch_insert(ailp, log_items,
+ xfs_log_item_batch_insert(ailp, &cur, log_items,
LOG_ITEM_BATCH_SIZE, commit_lsn);
i = 0;
}
/* make sure we insert the remainder! */
if (i)
- xfs_log_item_batch_insert(ailp, log_items, i, commit_lsn);
+ xfs_log_item_batch_insert(ailp, &cur, log_items, i, commit_lsn);
+
+ spin_lock(&ailp->xa_lock);
+ xfs_trans_ail_cursor_done(ailp, &cur);
+ spin_unlock(&ailp->xa_lock);
}
/*
}
/*
- * Return the item in the AIL with the current lsn.
- * Return the current tree generation number for use
- * in calls to xfs_trans_next_ail().
+ * Initialise the cursor to the first item in the AIL with the given @lsn.
+ * This searches the list from lowest LSN to highest. Pass a @lsn of zero
+ * to initialise the cursor to the first item in the AIL.
*/
xfs_log_item_t *
xfs_trans_ail_cursor_first(
}
/*
- * splice the log item list into the AIL at the given LSN.
+ * Initialise the cursor to the last item in the AIL with the given @lsn.
+ * This searches the list from highest LSN to lowest. If there is no item with
+ * the value of @lsn, then it sets the cursor to the last item with an LSN lower
+ * than @lsn.
+ */
+static struct xfs_log_item *
+__xfs_trans_ail_cursor_last(
+ struct xfs_ail *ailp,
+ xfs_lsn_t lsn)
+{
+ xfs_log_item_t *lip;
+
+ list_for_each_entry_reverse(lip, &ailp->xa_ail, li_ail) {
+ if (XFS_LSN_CMP(lip->li_lsn, lsn) <= 0)
+ return lip;
+ }
+ return NULL;
+}
+
+/*
+ * Initialise the cursor to the last item in the AIL with the given @lsn.
+ * This searches the list from highest LSN to lowest.
+ */
+struct xfs_log_item *
+xfs_trans_ail_cursor_last(
+ struct xfs_ail *ailp,
+ struct xfs_ail_cursor *cur,
+ xfs_lsn_t lsn)
+{
+ xfs_trans_ail_cursor_init(ailp, cur);
+ cur->item = __xfs_trans_ail_cursor_last(ailp, lsn);
+ return cur->item;
+}
+
+/*
+ * splice the log item list into the AIL at the given LSN. We splice to the
+ * tail of the given LSN to maintain insert order for push traversals. The
+ * cursor is optional, allowing repeated updates to the same LSN to avoid
+ * repeated traversals.
*/
static void
xfs_ail_splice(
- struct xfs_ail *ailp,
- struct list_head *list,
- xfs_lsn_t lsn)
+ struct xfs_ail *ailp,
+ struct xfs_ail_cursor *cur,
+ struct list_head *list,
+ xfs_lsn_t lsn)
{
- xfs_log_item_t *next_lip;
+ struct xfs_log_item *lip = cur ? cur->item : NULL;
+ struct xfs_log_item *next_lip;
- /* If the list is empty, just insert the item. */
- if (list_empty(&ailp->xa_ail)) {
- list_splice(list, &ailp->xa_ail);
- return;
+ /*
+ * Get a new cursor if we don't have a placeholder or the existing one
+ * has been invalidated.
+ */
+ if (!lip || (__psint_t)lip & 1) {
+ lip = __xfs_trans_ail_cursor_last(ailp, lsn);
+
+ if (!lip) {
+ /* The list is empty, so just splice and return. */
+ if (cur)
+ cur->item = NULL;
+ list_splice(list, &ailp->xa_ail);
+ return;
+ }
}
- list_for_each_entry_reverse(next_lip, &ailp->xa_ail, li_ail) {
- if (XFS_LSN_CMP(next_lip->li_lsn, lsn) <= 0)
- break;
+ /*
+ * Our cursor points to the item we want to insert _after_, so we have
+ * to update the cursor to point to the end of the list we are splicing
+ * in so that it points to the correct location for the next splice.
+ * i.e. before the splice
+ *
+ * lsn -> lsn -> lsn + x -> lsn + x ...
+ * ^
+ * | cursor points here
+ *
+ * After the splice we have:
+ *
+ * lsn -> lsn -> lsn -> lsn -> .... -> lsn -> lsn + x -> lsn + x ...
+ * ^ ^
+ * | cursor points here | needs to move here
+ *
+ * So we set the cursor to the last item in the list to be spliced
+ * before we execute the splice, resulting in the cursor pointing to
+ * the correct item after the splice occurs.
+ */
+ if (cur) {
+ next_lip = list_entry(list->prev, struct xfs_log_item, li_ail);
+ cur->item = next_lip;
}
-
- ASSERT(&next_lip->li_ail == &ailp->xa_ail ||
- XFS_LSN_CMP(next_lip->li_lsn, lsn) <= 0);
-
- list_splice_init(list, &next_lip->li_ail);
+ list_splice(list, &lip->li_ail);
}
/*
void
xfs_trans_ail_update_bulk(
struct xfs_ail *ailp,
+ struct xfs_ail_cursor *cur,
struct xfs_log_item **log_items,
int nr_items,
xfs_lsn_t lsn) __releases(ailp->xa_lock)
list_add(&lip->li_ail, &tmp);
}
- xfs_ail_splice(ailp, &tmp, lsn);
+ xfs_ail_splice(ailp, cur, &tmp, lsn);
if (!mlip_changed) {
spin_unlock(&ailp->xa_lock);
extern struct workqueue_struct *xfs_ail_wq; /* AIL workqueue */
void xfs_trans_ail_update_bulk(struct xfs_ail *ailp,
+ struct xfs_ail_cursor *cur,
struct xfs_log_item **log_items, int nr_items,
xfs_lsn_t lsn) __releases(ailp->xa_lock);
static inline void
struct xfs_log_item *lip,
xfs_lsn_t lsn) __releases(ailp->xa_lock)
{
- xfs_trans_ail_update_bulk(ailp, &lip, 1, lsn);
+ xfs_trans_ail_update_bulk(ailp, NULL, &lip, 1, lsn);
}
void xfs_trans_ail_delete_bulk(struct xfs_ail *ailp,
void xfs_trans_unlocked_item(struct xfs_ail *,
xfs_log_item_t *);
-struct xfs_log_item *xfs_trans_ail_cursor_first(struct xfs_ail *ailp,
+struct xfs_log_item * xfs_trans_ail_cursor_first(struct xfs_ail *ailp,
struct xfs_ail_cursor *cur,
xfs_lsn_t lsn);
-struct xfs_log_item *xfs_trans_ail_cursor_next(struct xfs_ail *ailp,
+struct xfs_log_item * xfs_trans_ail_cursor_last(struct xfs_ail *ailp,
+ struct xfs_ail_cursor *cur,
+ xfs_lsn_t lsn);
+struct xfs_log_item * xfs_trans_ail_cursor_next(struct xfs_ail *ailp,
struct xfs_ail_cursor *cur);
void xfs_trans_ail_cursor_done(struct xfs_ail *ailp,
struct xfs_ail_cursor *cur);
git.openpandora.org / pandora-kernel.git / commitdiff