#include "xfs_trans_priv.h"
#include "xfs_error.h"
-STATIC void xfs_ail_insert(struct xfs_ail *, xfs_log_item_t *);
-STATIC void xfs_ail_delete(struct xfs_ail *, xfs_log_item_t *);
-STATIC xfs_log_item_t * xfs_ail_min(struct xfs_ail *);
-STATIC xfs_log_item_t * xfs_ail_next(struct xfs_ail *, xfs_log_item_t *);
-
#ifdef DEBUG
-STATIC void xfs_ail_check(struct xfs_ail *, xfs_log_item_t *);
-#else
+/*
+ * Check that the list is sorted as it should be.
+ */
+STATIC void
+xfs_ail_check(
+ struct xfs_ail *ailp,
+ xfs_log_item_t *lip)
+{
+ xfs_log_item_t *prev_lip;
+
+ if (list_empty(&ailp->xa_ail))
+ return;
+
+ /*
+ * Check the next and previous entries are valid.
+ */
+ ASSERT((lip->li_flags & XFS_LI_IN_AIL) != 0);
+ prev_lip = list_entry(lip->li_ail.prev, xfs_log_item_t, li_ail);
+ if (&prev_lip->li_ail != &ailp->xa_ail)
+ ASSERT(XFS_LSN_CMP(prev_lip->li_lsn, lip->li_lsn) <= 0);
+
+ prev_lip = list_entry(lip->li_ail.next, xfs_log_item_t, li_ail);
+ if (&prev_lip->li_ail != &ailp->xa_ail)
+ ASSERT(XFS_LSN_CMP(prev_lip->li_lsn, lip->li_lsn) >= 0);
+
+
+#ifdef XFS_TRANS_DEBUG
+ /*
+ * Walk the list checking lsn ordering, and that every entry has the
+ * XFS_LI_IN_AIL flag set. This is really expensive, so only do it
+ * when specifically debugging the transaction subsystem.
+ */
+ prev_lip = list_entry(&ailp->xa_ail, xfs_log_item_t, li_ail);
+ list_for_each_entry(lip, &ailp->xa_ail, li_ail) {
+ if (&prev_lip->li_ail != &ailp->xa_ail)
+ ASSERT(XFS_LSN_CMP(prev_lip->li_lsn, lip->li_lsn) <= 0);
+ ASSERT((lip->li_flags & XFS_LI_IN_AIL) != 0);
+ prev_lip = lip;
+ }
+#endif /* XFS_TRANS_DEBUG */
+}
+#else /* !DEBUG */
#define xfs_ail_check(a,l)
#endif /* DEBUG */
+/*
+ * Return a pointer to the first item in the AIL. If the AIL is empty, then
+ * return NULL.
+ */
+static xfs_log_item_t *
+xfs_ail_min(
+ struct xfs_ail *ailp)
+{
+ if (list_empty(&ailp->xa_ail))
+ return NULL;
+
+ return list_first_entry(&ailp->xa_ail, xfs_log_item_t, li_ail);
+}
+
+ /*
+ * Return a pointer to the last item in the AIL. If the AIL is empty, then
+ * return NULL.
+ */
+static xfs_log_item_t *
+xfs_ail_max(
+ struct xfs_ail *ailp)
+{
+ if (list_empty(&ailp->xa_ail))
+ return NULL;
+
+ return list_entry(ailp->xa_ail.prev, xfs_log_item_t, li_ail);
+}
/*
- * This is called by the log manager code to determine the LSN
- * of the tail of the log. This is exactly the LSN of the first
- * item in the AIL. If the AIL is empty, then this function
- * returns 0.
+ * Return a pointer to the item which follows the given item in the AIL. If
+ * the given item is the last item in the list, then return NULL.
+ */
+static xfs_log_item_t *
+xfs_ail_next(
+ struct xfs_ail *ailp,
+ xfs_log_item_t *lip)
+{
+ if (lip->li_ail.next == &ailp->xa_ail)
+ return NULL;
+
+ return list_first_entry(&lip->li_ail, xfs_log_item_t, li_ail);
+}
+
+/*
+ * This is called by the log manager code to determine the LSN of the tail of
+ * the log. This is exactly the LSN of the first item in the AIL. If the AIL
+ * is empty, then this function returns 0.
*
- * We need the AIL lock in order to get a coherent read of the
- * lsn of the last item in the AIL.
+ * We need the AIL lock in order to get a coherent read of the lsn of the last
+ * item in the AIL.
*/
xfs_lsn_t
-xfs_trans_ail_tail(
+xfs_ail_min_lsn(
struct xfs_ail *ailp)
{
- xfs_lsn_t lsn;
+ xfs_lsn_t lsn = 0;
xfs_log_item_t *lip;
spin_lock(&ailp->xa_lock);
lip = xfs_ail_min(ailp);
- if (lip == NULL) {
- lsn = (xfs_lsn_t)0;
- } else {
+ if (lip)
lsn = lip->li_lsn;
- }
spin_unlock(&ailp->xa_lock);
return lsn;
}
/*
- * xfs_trans_push_ail
- *
- * This routine is called to move the tail of the AIL forward. It does this by
- * trying to flush items in the AIL whose lsns are below the given
- * threshold_lsn.
- *
- * the push is run asynchronously in a separate thread, so we return the tail
- * of the log right now instead of the tail after the push. This means we will
- * either continue right away, or we will sleep waiting on the async thread to
- * do its work.
- *
- * We do this unlocked - we only need to know whether there is anything in the
- * AIL at the time we are called. We don't need to access the contents of
- * any of the objects, so the lock is not needed.
+ * Return the maximum lsn held in the AIL, or zero if the AIL is empty.
*/
-void
-xfs_trans_ail_push(
- struct xfs_ail *ailp,
- xfs_lsn_t threshold_lsn)
+static xfs_lsn_t
+xfs_ail_max_lsn(
+ struct xfs_ail *ailp)
{
- xfs_log_item_t *lip;
+ xfs_lsn_t lsn = 0;
+ xfs_log_item_t *lip;
- lip = xfs_ail_min(ailp);
- if (lip && !XFS_FORCED_SHUTDOWN(ailp->xa_mount)) {
- if (XFS_LSN_CMP(threshold_lsn, ailp->xa_target) > 0)
- xfsaild_wakeup(ailp, threshold_lsn);
- }
+ spin_lock(&ailp->xa_lock);
+ lip = xfs_ail_max(ailp);
+ if (lip)
+ lsn = lip->li_lsn;
+ spin_unlock(&ailp->xa_lock);
+
+ return lsn;
}
/*
- * AIL traversal cursor initialisation.
- *
- * The cursor keeps track of where our current traversal is up
- * to by tracking the next ƣtem in the list for us. However, for
- * this to be safe, removing an object from the AIL needs to invalidate
- * any cursor that points to it. hence the traversal cursor needs to
- * be linked to the struct xfs_ail so that deletion can search all the
- * active cursors for invalidation.
- *
- * We don't link the push cursor because it is embedded in the struct
- * xfs_ail and hence easily findable.
+ * The cursor keeps track of where our current traversal is up to by tracking
+ * the next item in the list for us. However, for this to be safe, removing an
+ * object from the AIL needs to invalidate any cursor that points to it. hence
+ * the traversal cursor needs to be linked to the struct xfs_ail so that
+ * deletion can search all the active cursors for invalidation.
*/
STATIC void
xfs_trans_ail_cursor_init(
struct xfs_ail_cursor *cur)
{
cur->item = NULL;
- if (cur == &ailp->xa_cursors)
- return;
-
- cur->next = ailp->xa_cursors.next;
- ailp->xa_cursors.next = cur;
+ list_add_tail(&cur->list, &ailp->xa_cursors);
}
/*
- * Set the cursor to the next item, because when we look
- * up the cursor the current item may have been freed.
- */
-STATIC void
-xfs_trans_ail_cursor_set(
- struct xfs_ail *ailp,
- struct xfs_ail_cursor *cur,
- struct xfs_log_item *lip)
-{
- if (lip)
- cur->item = xfs_ail_next(ailp, lip);
-}
-
-/*
- * Get the next item in the traversal and advance the cursor.
- * If the cursor was invalidated (inidicated by a lip of 1),
- * restart the traversal.
+ * Get the next item in the traversal and advance the cursor. If the cursor
+ * was invalidated (indicated by a lip of 1), restart the traversal.
*/
struct xfs_log_item *
xfs_trans_ail_cursor_next(
if ((__psint_t)lip & 1)
lip = xfs_ail_min(ailp);
- xfs_trans_ail_cursor_set(ailp, cur, lip);
+ if (lip)
+ cur->item = xfs_ail_next(ailp, lip);
return lip;
}
/*
- * Now that the traversal is complete, we need to remove the cursor
- * from the list of traversing cursors. Avoid removing the embedded
- * push cursor, but use the fact it is always present to make the
- * list deletion simple.
+ * When the traversal is complete, we need to remove the cursor from the list
+ * of traversing cursors.
*/
void
xfs_trans_ail_cursor_done(
struct xfs_ail *ailp,
- struct xfs_ail_cursor *done)
+ struct xfs_ail_cursor *cur)
{
- struct xfs_ail_cursor *prev = NULL;
- struct xfs_ail_cursor *cur;
-
- done->item = NULL;
- if (done == &ailp->xa_cursors)
- return;
- prev = &ailp->xa_cursors;
- for (cur = prev->next; cur; prev = cur, cur = prev->next) {
- if (cur == done) {
- prev->next = cur->next;
- break;
- }
- }
- ASSERT(cur);
+ cur->item = NULL;
+ list_del_init(&cur->list);
}
/*
- * Invalidate any cursor that is pointing to this item. This is
- * called when an item is removed from the AIL. Any cursor pointing
- * to this object is now invalid and the traversal needs to be
- * terminated so it doesn't reference a freed object. We set the
- * cursor item to a value of 1 so we can distinguish between an
- * invalidation and the end of the list when getting the next item
- * from the cursor.
+ * Invalidate any cursor that is pointing to this item. This is called when an
+ * item is removed from the AIL. Any cursor pointing to this object is now
+ * invalid and the traversal needs to be terminated so it doesn't reference a
+ * freed object. We set the low bit of the cursor item pointer so we can
+ * distinguish between an invalidation and the end of the list when getting the
+ * next item from the cursor.
*/
STATIC void
xfs_trans_ail_cursor_clear(
{
struct xfs_ail_cursor *cur;
- /* need to search all cursors */
- for (cur = &ailp->xa_cursors; cur; cur = cur->next) {
+ list_for_each_entry(cur, &ailp->xa_cursors, list) {
if (cur->item == lip)
cur->item = (struct xfs_log_item *)
((__psint_t)cur->item | 1);
}
/*
- * 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().
+ * Find the first item in the AIL with the given @lsn by searching in ascending
+ * LSN order and initialise the cursor to point to the next item for a
+ * ascending traversal. Pass a @lsn of zero to initialise the cursor to the
+ * first item in the AIL. Returns NULL if the list is empty.
*/
xfs_log_item_t *
xfs_trans_ail_cursor_first(
xfs_log_item_t *lip;
xfs_trans_ail_cursor_init(ailp, cur);
- lip = xfs_ail_min(ailp);
- if (lsn == 0)
+
+ if (lsn == 0) {
+ lip = xfs_ail_min(ailp);
goto out;
+ }
list_for_each_entry(lip, &ailp->xa_ail, li_ail) {
if (XFS_LSN_CMP(lip->li_lsn, lsn) >= 0)
goto out;
}
- lip = NULL;
+ return NULL;
+
out:
- xfs_trans_ail_cursor_set(ailp, cur, lip);
+ if (lip)
+ cur->item = xfs_ail_next(ailp, lip);
return lip;
}
+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;
+}
+
/*
- * xfsaild_push does the work of pushing on the AIL. Returning a timeout of
- * zero indicates that the caller should sleep until woken.
+ * Find the last item in the AIL with the given @lsn by searching in descending
+ * LSN order and initialise the cursor to point to that item. 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. Returns NULL if the list is empty.
*/
-long
+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. This should not be called with an empty list.
+ */
+static void
+xfs_ail_splice(
+ struct xfs_ail *ailp,
+ struct xfs_ail_cursor *cur,
+ struct list_head *list,
+ xfs_lsn_t lsn)
+{
+ struct xfs_log_item *lip;
+
+ ASSERT(!list_empty(list));
+
+ /*
+ * Use the cursor to determine the insertion point if one is
+ * provided. If not, or if the one we got is not valid,
+ * find the place in the AIL where the items belong.
+ */
+ lip = cur ? cur->item : NULL;
+ if (!lip || (__psint_t) lip & 1)
+ lip = __xfs_trans_ail_cursor_last(ailp, lsn);
+
+ /*
+ * If a cursor is provided, we know we're processing the AIL
+ * in lsn order, and future items to be spliced in will
+ * follow the last one being inserted now. Update the
+ * cursor to point to that last item, now while we have a
+ * reliable pointer to it.
+ */
+ if (cur)
+ cur->item = list_entry(list->prev, struct xfs_log_item, li_ail);
+
+ /*
+ * Finally perform the splice. Unless the AIL was empty,
+ * lip points to the item in the AIL _after_ which the new
+ * items should go. If lip is null the AIL was empty, so
+ * the new items go at the head of the AIL.
+ */
+ if (lip)
+ list_splice(list, &lip->li_ail);
+ else
+ list_splice(list, &ailp->xa_ail);
+}
+
+/*
+ * Delete the given item from the AIL. Return a pointer to the item.
+ */
+static void
+xfs_ail_delete(
+ struct xfs_ail *ailp,
+ xfs_log_item_t *lip)
+{
+ xfs_ail_check(ailp, lip);
+ list_del(&lip->li_ail);
+ xfs_trans_ail_cursor_clear(ailp, lip);
+}
+
+static long
xfsaild_push(
- struct xfs_ail *ailp,
- xfs_lsn_t *last_lsn)
+ struct xfs_ail *ailp)
{
- long tout = 0;
- xfs_lsn_t last_pushed_lsn = *last_lsn;
- xfs_lsn_t target = ailp->xa_target;
- xfs_lsn_t lsn;
- xfs_log_item_t *lip;
- int flush_log, count, stuck;
- xfs_mount_t *mp = ailp->xa_mount;
- struct xfs_ail_cursor *cur = &ailp->xa_cursors;
- int push_xfsbufd = 0;
+ xfs_mount_t *mp = ailp->xa_mount;
+ struct xfs_ail_cursor cur;
+ xfs_log_item_t *lip;
+ xfs_lsn_t lsn;
+ xfs_lsn_t target;
+ long tout = 10;
+ int flush_log = 0;
+ int stuck = 0;
+ int count = 0;
+ int push_xfsbufd = 0;
spin_lock(&ailp->xa_lock);
- xfs_trans_ail_cursor_init(ailp, cur);
- lip = xfs_trans_ail_cursor_first(ailp, cur, *last_lsn);
+ target = ailp->xa_target;
+ lip = xfs_trans_ail_cursor_first(ailp, &cur, ailp->xa_last_pushed_lsn);
if (!lip || XFS_FORCED_SHUTDOWN(mp)) {
/*
* AIL is empty or our push has reached the end.
*/
- xfs_trans_ail_cursor_done(ailp, cur);
+ xfs_trans_ail_cursor_done(ailp, &cur);
spin_unlock(&ailp->xa_lock);
- *last_lsn = 0;
- return tout;
+ goto out_done;
}
XFS_STATS_INC(xs_push_ail);
* lots of contention on the AIL lists.
*/
lsn = lip->li_lsn;
- flush_log = stuck = count = 0;
- while ((XFS_LSN_CMP(lip->li_lsn, target) < 0)) {
+ while ((XFS_LSN_CMP(lip->li_lsn, target) <= 0)) {
int lock_result;
/*
* If we can lock the item without sleeping, unlock the AIL
case XFS_ITEM_SUCCESS:
XFS_STATS_INC(xs_push_ail_success);
IOP_PUSH(lip);
- last_pushed_lsn = lsn;
+ ailp->xa_last_pushed_lsn = lsn;
break;
case XFS_ITEM_PUSHBUF:
XFS_STATS_INC(xs_push_ail_pushbuf);
- IOP_PUSHBUF(lip);
- last_pushed_lsn = lsn;
+
+ if (!IOP_PUSHBUF(lip)) {
+ stuck++;
+ flush_log = 1;
+ } else {
+ ailp->xa_last_pushed_lsn = lsn;
+ }
push_xfsbufd = 1;
break;
case XFS_ITEM_LOCKED:
XFS_STATS_INC(xs_push_ail_locked);
- last_pushed_lsn = lsn;
stuck++;
break;
if (stuck > 100)
break;
- lip = xfs_trans_ail_cursor_next(ailp, cur);
+ lip = xfs_trans_ail_cursor_next(ailp, &cur);
if (lip == NULL)
break;
lsn = lip->li_lsn;
}
- xfs_trans_ail_cursor_done(ailp, cur);
+ xfs_trans_ail_cursor_done(ailp, &cur);
spin_unlock(&ailp->xa_lock);
if (flush_log) {
wake_up_process(mp->m_ddev_targp->bt_task);
}
+ /* assume we have more work to do in a short while */
+out_done:
if (!count) {
/* We're past our target or empty, so idle */
- last_pushed_lsn = 0;
+ ailp->xa_last_pushed_lsn = 0;
+
+ tout = 50;
} else if (XFS_LSN_CMP(lsn, target) >= 0) {
/*
* We reached the target so wait a bit longer for I/O to
* start the next scan from the start of the AIL.
*/
tout = 50;
- last_pushed_lsn = 0;
+ ailp->xa_last_pushed_lsn = 0;
} else if ((stuck * 100) / count > 90) {
/*
* Either there is a lot of contention on the AIL or we
* continuing from where we were.
*/
tout = 20;
- } else {
- /* more to do, but wait a short while before continuing */
- tout = 10;
}
- *last_lsn = last_pushed_lsn;
+
return tout;
}
+static int
+xfsaild(
+ void *data)
+{
+ struct xfs_ail *ailp = data;
+ long tout = 0; /* milliseconds */
+
+ while (!kthread_should_stop()) {
+ if (tout && tout <= 20)
+ __set_current_state(TASK_KILLABLE);
+ else
+ __set_current_state(TASK_INTERRUPTIBLE);
+ schedule_timeout(tout ?
+ msecs_to_jiffies(tout) : MAX_SCHEDULE_TIMEOUT);
+
+ try_to_freeze();
+
+ tout = xfsaild_push(ailp);
+ }
+
+ return 0;
+}
+
+/*
+ * This routine is called to move the tail of the AIL forward. It does this by
+ * trying to flush items in the AIL whose lsns are below the given
+ * threshold_lsn.
+ *
+ * The push is run asynchronously in a workqueue, which means the caller needs
+ * to handle waiting on the async flush for space to become available.
+ * We don't want to interrupt any push that is in progress, hence we only queue
+ * work if we set the pushing bit approriately.
+ *
+ * We do this unlocked - we only need to know whether there is anything in the
+ * AIL at the time we are called. We don't need to access the contents of
+ * any of the objects, so the lock is not needed.
+ */
+void
+xfs_ail_push(
+ struct xfs_ail *ailp,
+ xfs_lsn_t threshold_lsn)
+{
+ xfs_log_item_t *lip;
+
+ lip = xfs_ail_min(ailp);
+ if (!lip || XFS_FORCED_SHUTDOWN(ailp->xa_mount) ||
+ XFS_LSN_CMP(threshold_lsn, ailp->xa_target) <= 0)
+ return;
+
+ /*
+ * Ensure that the new target is noticed in push code before it clears
+ * the XFS_AIL_PUSHING_BIT.
+ */
+ smp_wmb();
+ xfs_trans_ail_copy_lsn(ailp, &ailp->xa_target, &threshold_lsn);
+ smp_wmb();
+
+ wake_up_process(ailp->xa_task);
+}
+
+/*
+ * Push out all items in the AIL immediately
+ */
+void
+xfs_ail_push_all(
+ struct xfs_ail *ailp)
+{
+ xfs_lsn_t threshold_lsn = xfs_ail_max_lsn(ailp);
+
+ if (threshold_lsn)
+ xfs_ail_push(ailp, threshold_lsn);
+}
/*
* This is to be called when an item is unlocked that may have
xfs_log_move_tail(ailp->xa_mount, 1);
} /* xfs_trans_unlocked_item */
-
/*
- * Update the position of the item in the AIL with the new
- * lsn. If it is not yet in the AIL, add it. Otherwise, move
- * it to its new position by removing it and re-adding it.
+ * xfs_trans_ail_update - bulk AIL insertion operation.
+ *
+ * @xfs_trans_ail_update takes an array of log items that all need to be
+ * positioned at the same LSN in the AIL. If an item is not in the AIL, it will
+ * be added. Otherwise, it will be repositioned by removing it and re-adding
+ * it to the AIL. If we move the first item in the AIL, update the log tail to
+ * match the new minimum LSN in the AIL.
+ *
+ * This function takes the AIL lock once to execute the update operations on
+ * all the items in the array, and as such should not be called with the AIL
+ * lock held. As a result, once we have the AIL lock, we need to check each log
+ * item LSN to confirm it needs to be moved forward in the AIL.
*
- * Wakeup anyone with an lsn less than the item's lsn. If the item
- * we move in the AIL is the minimum one, update the tail lsn in the
- * log manager.
+ * To optimise the insert operation, we delete all the items from the AIL in
+ * the first pass, moving them into a temporary list, then splice the temporary
+ * list into the correct position in the AIL. This avoids needing to do an
+ * insert operation on every item.
*
- * This function must be called with the AIL lock held. The lock
- * is dropped before returning.
+ * This function must be called with the AIL lock held. The lock is dropped
+ * before returning.
*/
void
-xfs_trans_ail_update(
- struct xfs_ail *ailp,
- xfs_log_item_t *lip,
- xfs_lsn_t lsn) __releases(ailp->xa_lock)
+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)
{
- xfs_log_item_t *mlip; /* ptr to minimum lip */
+ xfs_log_item_t *mlip;
xfs_lsn_t tail_lsn;
+ int mlip_changed = 0;
+ int i;
+ LIST_HEAD(tmp);
+ ASSERT(nr_items > 0); /* Not required, but true. */
mlip = xfs_ail_min(ailp);
- if (lip->li_flags & XFS_LI_IN_AIL) {
- xfs_ail_delete(ailp, lip);
- } else {
- lip->li_flags |= XFS_LI_IN_AIL;
+ for (i = 0; i < nr_items; i++) {
+ struct xfs_log_item *lip = log_items[i];
+ if (lip->li_flags & XFS_LI_IN_AIL) {
+ /* check if we really need to move the item */
+ if (XFS_LSN_CMP(lsn, lip->li_lsn) <= 0)
+ continue;
+
+ xfs_ail_delete(ailp, lip);
+ if (mlip == lip)
+ mlip_changed = 1;
+ } else {
+ lip->li_flags |= XFS_LI_IN_AIL;
+ }
+ lip->li_lsn = lsn;
+ list_add(&lip->li_ail, &tmp);
}
- lip->li_lsn = lsn;
- xfs_ail_insert(ailp, lip);
+ if (!list_empty(&tmp))
+ xfs_ail_splice(ailp, cur, &tmp, lsn);
- if (mlip == lip) {
- mlip = xfs_ail_min(ailp);
- /*
- * It is not safe to access mlip after the AIL lock is
- * dropped, so we must get a copy of li_lsn before we do
- * so. This is especially important on 32-bit platforms
- * where accessing and updating 64-bit values like li_lsn
- * is not atomic.
- */
- tail_lsn = mlip->li_lsn;
- spin_unlock(&ailp->xa_lock);
- xfs_log_move_tail(ailp->xa_mount, tail_lsn);
- } else {
+ if (!mlip_changed) {
spin_unlock(&ailp->xa_lock);
+ return;
}
-
-} /* xfs_trans_update_ail */
+ /*
+ * It is not safe to access mlip after the AIL lock is dropped, so we
+ * must get a copy of li_lsn before we do so. This is especially
+ * important on 32-bit platforms where accessing and updating 64-bit
+ * values like li_lsn is not atomic.
+ */
+ mlip = xfs_ail_min(ailp);
+ tail_lsn = mlip->li_lsn;
+ spin_unlock(&ailp->xa_lock);
+ xfs_log_move_tail(ailp->xa_mount, tail_lsn);
+}
/*
- * Delete the given item from the AIL. It must already be in
- * the AIL.
+ * xfs_trans_ail_delete_bulk - remove multiple log items from the AIL
+ *
+ * @xfs_trans_ail_delete_bulk takes an array of log items that all need to
+ * removed from the AIL. The caller is already holding the AIL lock, and done
+ * all the checks necessary to ensure the items passed in via @log_items are
+ * ready for deletion. This includes checking that the items are in the AIL.
*
- * Wakeup anyone with an lsn less than item's lsn. If the item
- * we delete in the AIL is the minimum one, update the tail lsn in the
- * log manager.
+ * For each log item to be removed, unlink it from the AIL, clear the IN_AIL
+ * flag from the item and reset the item's lsn to 0. If we remove the first
+ * item in the AIL, update the log tail to match the new minimum LSN in the
+ * AIL.
*
- * Clear the IN_AIL flag from the item, reset its lsn to 0, and
- * bump the AIL's generation count to indicate that the tree
- * has changed.
+ * This function will not drop the AIL lock until all items are removed from
+ * the AIL to minimise the amount of lock traffic on the AIL. This does not
+ * greatly increase the AIL hold time, but does significantly reduce the amount
+ * of traffic on the lock, especially during IO completion.
*
- * This function must be called with the AIL lock held. The lock
- * is dropped before returning.
+ * This function must be called with the AIL lock held. The lock is dropped
+ * before returning.
*/
void
-xfs_trans_ail_delete(
- struct xfs_ail *ailp,
- xfs_log_item_t *lip) __releases(ailp->xa_lock)
+xfs_trans_ail_delete_bulk(
+ struct xfs_ail *ailp,
+ struct xfs_log_item **log_items,
+ int nr_items) __releases(ailp->xa_lock)
{
xfs_log_item_t *mlip;
xfs_lsn_t tail_lsn;
+ int mlip_changed = 0;
+ int i;
- if (lip->li_flags & XFS_LI_IN_AIL) {
- mlip = xfs_ail_min(ailp);
- xfs_ail_delete(ailp, lip);
-
+ mlip = xfs_ail_min(ailp);
- lip->li_flags &= ~XFS_LI_IN_AIL;
- lip->li_lsn = 0;
+ for (i = 0; i < nr_items; i++) {
+ struct xfs_log_item *lip = log_items[i];
+ if (!(lip->li_flags & XFS_LI_IN_AIL)) {
+ struct xfs_mount *mp = ailp->xa_mount;
- if (mlip == lip) {
- mlip = xfs_ail_min(ailp);
- /*
- * It is not safe to access mlip after the AIL lock
- * is dropped, so we must get a copy of li_lsn
- * before we do so. This is especially important
- * on 32-bit platforms where accessing and updating
- * 64-bit values like li_lsn is not atomic.
- */
- tail_lsn = mlip ? mlip->li_lsn : 0;
- spin_unlock(&ailp->xa_lock);
- xfs_log_move_tail(ailp->xa_mount, tail_lsn);
- } else {
spin_unlock(&ailp->xa_lock);
+ if (!XFS_FORCED_SHUTDOWN(mp)) {
+ xfs_alert_tag(mp, XFS_PTAG_AILDELETE,
+ "%s: attempting to delete a log item that is not in the AIL",
+ __func__);
+ xfs_force_shutdown(mp, SHUTDOWN_CORRUPT_INCORE);
+ }
+ return;
}
+
+ xfs_ail_delete(ailp, lip);
+ lip->li_flags &= ~XFS_LI_IN_AIL;
+ lip->li_lsn = 0;
+ if (mlip == lip)
+ mlip_changed = 1;
}
- else {
- /*
- * If the file system is not being shutdown, we are in
- * serious trouble if we get to this stage.
- */
- struct xfs_mount *mp = ailp->xa_mount;
+ if (!mlip_changed) {
spin_unlock(&ailp->xa_lock);
- if (!XFS_FORCED_SHUTDOWN(mp)) {
- xfs_cmn_err(XFS_PTAG_AILDELETE, CE_ALERT, mp,
- "%s: attempting to delete a log item that is not in the AIL",
- __func__);
- xfs_force_shutdown(mp, SHUTDOWN_CORRUPT_INCORE);
- }
+ return;
}
-}
-
+ /*
+ * It is not safe to access mlip after the AIL lock is dropped, so we
+ * must get a copy of li_lsn before we do so. This is especially
+ * important on 32-bit platforms where accessing and updating 64-bit
+ * values like li_lsn is not atomic. It is possible we've emptied the
+ * AIL here, so if that is the case, pass an LSN of 0 to the tail move.
+ */
+ mlip = xfs_ail_min(ailp);
+ tail_lsn = mlip ? mlip->li_lsn : 0;
+ spin_unlock(&ailp->xa_lock);
+ xfs_log_move_tail(ailp->xa_mount, tail_lsn);
+}
/*
* The active item list (AIL) is a doubly linked list of log
xfs_mount_t *mp)
{
struct xfs_ail *ailp;
- int error;
ailp = kmem_zalloc(sizeof(struct xfs_ail), KM_MAYFAIL);
if (!ailp)
ailp->xa_mount = mp;
INIT_LIST_HEAD(&ailp->xa_ail);
+ INIT_LIST_HEAD(&ailp->xa_cursors);
spin_lock_init(&ailp->xa_lock);
- error = xfsaild_start(ailp);
- if (error)
+
+ ailp->xa_task = kthread_run(xfsaild, ailp, "xfsaild/%s",
+ ailp->xa_mount->m_fsname);
+ if (IS_ERR(ailp->xa_task))
goto out_free_ailp;
+
mp->m_ail = ailp;
return 0;
out_free_ailp:
kmem_free(ailp);
- return error;
+ return ENOMEM;
}
void
{
struct xfs_ail *ailp = mp->m_ail;
- xfsaild_stop(ailp);
+ kthread_stop(ailp->xa_task);
kmem_free(ailp);
}
-
-/*
- * Insert the given log item into the AIL.
- * We almost always insert at the end of the list, so on inserts
- * we search from the end of the list to find where the
- * new item belongs.
- */
-STATIC void
-xfs_ail_insert(
- struct xfs_ail *ailp,
- xfs_log_item_t *lip)
-{
- xfs_log_item_t *next_lip;
-
- /*
- * If the list is empty, just insert the item.
- */
- if (list_empty(&ailp->xa_ail)) {
- list_add(&lip->li_ail, &ailp->xa_ail);
- return;
- }
-
- list_for_each_entry_reverse(next_lip, &ailp->xa_ail, li_ail) {
- if (XFS_LSN_CMP(next_lip->li_lsn, lip->li_lsn) <= 0)
- break;
- }
-
- ASSERT((&next_lip->li_ail == &ailp->xa_ail) ||
- (XFS_LSN_CMP(next_lip->li_lsn, lip->li_lsn) <= 0));
-
- list_add(&lip->li_ail, &next_lip->li_ail);
-
- xfs_ail_check(ailp, lip);
- return;
-}
-
-/*
- * Delete the given item from the AIL. Return a pointer to the item.
- */
-STATIC void
-xfs_ail_delete(
- struct xfs_ail *ailp,
- xfs_log_item_t *lip)
-{
- xfs_ail_check(ailp, lip);
- list_del(&lip->li_ail);
- xfs_trans_ail_cursor_clear(ailp, lip);
-}
-
-/*
- * Return a pointer to the first item in the AIL.
- * If the AIL is empty, then return NULL.
- */
-STATIC xfs_log_item_t *
-xfs_ail_min(
- struct xfs_ail *ailp)
-{
- if (list_empty(&ailp->xa_ail))
- return NULL;
-
- return list_first_entry(&ailp->xa_ail, xfs_log_item_t, li_ail);
-}
-
-/*
- * Return a pointer to the item which follows
- * the given item in the AIL. If the given item
- * is the last item in the list, then return NULL.
- */
-STATIC xfs_log_item_t *
-xfs_ail_next(
- struct xfs_ail *ailp,
- xfs_log_item_t *lip)
-{
- if (lip->li_ail.next == &ailp->xa_ail)
- return NULL;
-
- return list_first_entry(&lip->li_ail, xfs_log_item_t, li_ail);
-}
-
-#ifdef DEBUG
-/*
- * Check that the list is sorted as it should be.
- */
-STATIC void
-xfs_ail_check(
- struct xfs_ail *ailp,
- xfs_log_item_t *lip)
-{
- xfs_log_item_t *prev_lip;
-
- if (list_empty(&ailp->xa_ail))
- return;
-
- /*
- * Check the next and previous entries are valid.
- */
- ASSERT((lip->li_flags & XFS_LI_IN_AIL) != 0);
- prev_lip = list_entry(lip->li_ail.prev, xfs_log_item_t, li_ail);
- if (&prev_lip->li_ail != &ailp->xa_ail)
- ASSERT(XFS_LSN_CMP(prev_lip->li_lsn, lip->li_lsn) <= 0);
-
- prev_lip = list_entry(lip->li_ail.next, xfs_log_item_t, li_ail);
- if (&prev_lip->li_ail != &ailp->xa_ail)
- ASSERT(XFS_LSN_CMP(prev_lip->li_lsn, lip->li_lsn) >= 0);
-
-
-#ifdef XFS_TRANS_DEBUG
- /*
- * Walk the list checking lsn ordering, and that every entry has the
- * XFS_LI_IN_AIL flag set. This is really expensive, so only do it
- * when specifically debugging the transaction subsystem.
- */
- prev_lip = list_entry(&ailp->xa_ail, xfs_log_item_t, li_ail);
- list_for_each_entry(lip, &ailp->xa_ail, li_ail) {
- if (&prev_lip->li_ail != &ailp->xa_ail)
- ASSERT(XFS_LSN_CMP(prev_lip->li_lsn, lip->li_lsn) <= 0);
- ASSERT((lip->li_flags & XFS_LI_IN_AIL) != 0);
- prev_lip = lip;
- }
-#endif /* XFS_TRANS_DEBUG */
-}
-#endif /* DEBUG */
Code Review / linux-2.6.git / blobdiff