xfs_log_item_t *lip;
spin_lock(&mp->m_ail_lock);
- lip = xfs_ail_min(&(mp->m_ail));
+ lip = xfs_ail_min(&(mp->m_ail.xa_ail));
if (lip == NULL) {
lsn = (xfs_lsn_t)0;
} else {
/*
* 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.
+ * 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 routine returns the lsn of the tail of the log.
+ * 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 it's 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.
*/
-xfs_lsn_t
+void
xfs_trans_push_ail(
xfs_mount_t *mp,
xfs_lsn_t threshold_lsn)
{
- xfs_lsn_t lsn;
xfs_log_item_t *lip;
- int gen;
- int restarts;
- int lock_result;
- int flush_log;
-#define XFS_TRANS_PUSH_AIL_RESTARTS 1000
+ lip = xfs_ail_min(&mp->m_ail.xa_ail);
+ if (lip && !XFS_FORCED_SHUTDOWN(mp)) {
+ if (XFS_LSN_CMP(threshold_lsn, mp->m_ail.xa_target) > 0)
+ xfsaild_wakeup(mp, threshold_lsn);
+ }
+}
+
+/*
+ * 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().
+ */
+STATIC xfs_log_item_t *
+xfs_trans_first_push_ail(
+ xfs_mount_t *mp,
+ int *gen,
+ xfs_lsn_t lsn)
+{
+ xfs_log_item_t *lip;
+
+ lip = xfs_ail_min(&(mp->m_ail.xa_ail));
+ *gen = (int)mp->m_ail.xa_gen;
+ if (lsn == 0)
+ return lip;
+
+ while (lip && (XFS_LSN_CMP(lip->li_lsn, lsn) < 0))
+ lip = lip->li_ail.ail_forw;
+
+ return lip;
+}
+
+/*
+ * Function that does the work of pushing on the AIL
+ */
+long
+xfsaild_push(
+ xfs_mount_t *mp,
+ xfs_lsn_t *last_lsn)
+{
+ long tout = 1000; /* milliseconds */
+ xfs_lsn_t last_pushed_lsn = *last_lsn;
+ xfs_lsn_t target = mp->m_ail.xa_target;
+ xfs_lsn_t lsn;
+ xfs_log_item_t *lip;
+ int gen;
+ int restarts;
+ int flush_log, count, stuck;
+
+#define XFS_TRANS_PUSH_AIL_RESTARTS 10
spin_lock(&mp->m_ail_lock);
- lip = xfs_trans_first_ail(mp, &gen);
- if (lip == NULL || XFS_FORCED_SHUTDOWN(mp)) {
+ lip = xfs_trans_first_push_ail(mp, &gen, *last_lsn);
+ if (!lip || XFS_FORCED_SHUTDOWN(mp)) {
/*
- * Just return if the AIL is empty.
+ * AIL is empty or our push has reached the end.
*/
spin_unlock(&mp->m_ail_lock);
- return (xfs_lsn_t)0;
+ last_pushed_lsn = 0;
+ goto out;
}
XFS_STATS_INC(xs_push_ail);
/*
* While the item we are looking at is below the given threshold
- * try to flush it out. Make sure to limit the number of times
- * we allow xfs_trans_next_ail() to restart scanning from the
- * beginning of the list. We'd like not to stop until we've at least
+ * try to flush it out. We'd like not to stop until we've at least
* tried to push on everything in the AIL with an LSN less than
- * the given threshold. However, we may give up before that if
- * we realize that we've been holding the AIL lock for 'too long',
- * blocking interrupts. Currently, too long is < 500us roughly.
+ * the given threshold.
+ *
+ * However, we will stop after a certain number of pushes and wait
+ * for a reduced timeout to fire before pushing further. This
+ * prevents use from spinning when we can't do anything or there is
+ * lots of contention on the AIL lists.
*/
- flush_log = 0;
- restarts = 0;
- while (((restarts < XFS_TRANS_PUSH_AIL_RESTARTS) &&
- (XFS_LSN_CMP(lip->li_lsn, threshold_lsn) < 0))) {
+ tout = 10;
+ lsn = lip->li_lsn;
+ flush_log = stuck = count = restarts = 0;
+ while ((XFS_LSN_CMP(lip->li_lsn, target) < 0)) {
+ int lock_result;
/*
- * If we can lock the item without sleeping, unlock
- * the AIL lock and flush the item. Then re-grab the
- * AIL lock so we can look for the next item on the
- * AIL. Since we unlock the AIL while we flush the
- * item, the next routine may start over again at the
- * the beginning of the list if anything has changed.
- * That is what the generation count is for.
+ * If we can lock the item without sleeping, unlock the AIL
+ * lock and flush the item. Then re-grab the AIL lock so we
+ * can look for the next item on the AIL. List changes are
+ * handled by the AIL lookup functions internally
*
- * If we can't lock the item, either its holder will flush
- * it or it is already being flushed or it is being relogged.
- * In any of these case it is being taken care of and we
- * can just skip to the next item in the list.
+ * If we can't lock the item, either its holder will flush it
+ * or it is already being flushed or it is being relogged. In
+ * any of these case it is being taken care of and we can just
+ * skip to the next item in the list.
*/
lock_result = IOP_TRYLOCK(lip);
+ spin_unlock(&mp->m_ail_lock);
switch (lock_result) {
- case XFS_ITEM_SUCCESS:
- spin_unlock(&mp->m_ail_lock);
+ case XFS_ITEM_SUCCESS:
XFS_STATS_INC(xs_push_ail_success);
IOP_PUSH(lip);
- spin_lock(&mp->m_ail_lock);
+ last_pushed_lsn = lsn;
break;
- case XFS_ITEM_PUSHBUF:
- spin_unlock(&mp->m_ail_lock);
+ case XFS_ITEM_PUSHBUF:
XFS_STATS_INC(xs_push_ail_pushbuf);
-#ifdef XFSRACEDEBUG
- delay_for_intr();
- delay(300);
-#endif
- ASSERT(lip->li_ops->iop_pushbuf);
- ASSERT(lip);
IOP_PUSHBUF(lip);
- spin_lock(&mp->m_ail_lock);
+ last_pushed_lsn = lsn;
break;
- case XFS_ITEM_PINNED:
+ case XFS_ITEM_PINNED:
XFS_STATS_INC(xs_push_ail_pinned);
+ stuck++;
flush_log = 1;
break;
- case XFS_ITEM_LOCKED:
+ case XFS_ITEM_LOCKED:
XFS_STATS_INC(xs_push_ail_locked);
+ last_pushed_lsn = lsn;
+ stuck++;
break;
- case XFS_ITEM_FLUSHING:
+ case XFS_ITEM_FLUSHING:
XFS_STATS_INC(xs_push_ail_flushing);
+ last_pushed_lsn = lsn;
+ stuck++;
break;
- default:
+ default:
ASSERT(0);
break;
}
- lip = xfs_trans_next_ail(mp, lip, &gen, &restarts);
- if (lip == NULL) {
+ spin_lock(&mp->m_ail_lock);
+ /* should we bother continuing? */
+ if (XFS_FORCED_SHUTDOWN(mp))
+ break;
+ ASSERT(mp->m_log);
+
+ count++;
+
+ /*
+ * Are there too many items we can't do anything with?
+ * If we we are skipping too many items because we can't flush
+ * them or they are already being flushed, we back off and
+ * given them time to complete whatever operation is being
+ * done. i.e. remove pressure from the AIL while we can't make
+ * progress so traversals don't slow down further inserts and
+ * removals to/from the AIL.
+ *
+ * The value of 100 is an arbitrary magic number based on
+ * observation.
+ */
+ if (stuck > 100)
break;
- }
- if (XFS_FORCED_SHUTDOWN(mp)) {
- /*
- * Just return if we shut down during the last try.
- */
- spin_unlock(&mp->m_ail_lock);
- return (xfs_lsn_t)0;
- }
+ lip = xfs_trans_next_ail(mp, lip, &gen, &restarts);
+ if (lip == NULL)
+ break;
+ if (restarts > XFS_TRANS_PUSH_AIL_RESTARTS)
+ break;
+ lsn = lip->li_lsn;
}
+ spin_unlock(&mp->m_ail_lock);
if (flush_log) {
/*
* push out the log so it will become unpinned and
* move forward in the AIL.
*/
- spin_unlock(&mp->m_ail_lock);
XFS_STATS_INC(xs_push_ail_flush);
xfs_log_force(mp, (xfs_lsn_t)0, XFS_LOG_FORCE);
- spin_lock(&mp->m_ail_lock);
}
- lip = xfs_ail_min(&(mp->m_ail));
- if (lip == NULL) {
- lsn = (xfs_lsn_t)0;
- } else {
- lsn = lip->li_lsn;
+ /*
+ * We reached the target so wait a bit longer for I/O to complete and
+ * remove pushed items from the AIL before we start the next scan from
+ * the start of the AIL.
+ */
+ if ((XFS_LSN_CMP(lsn, target) >= 0)) {
+ tout += 20;
+ last_pushed_lsn = 0;
+ } else if ((restarts > XFS_TRANS_PUSH_AIL_RESTARTS) ||
+ (count && ((stuck * 100) / count > 90))) {
+ /*
+ * Either there is a lot of contention on the AIL or we
+ * are stuck due to operations in progress. "Stuck" in this
+ * case is defined as >90% of the items we tried to push
+ * were stuck.
+ *
+ * Backoff a bit more to allow some I/O to complete before
+ * continuing from where we were.
+ */
+ tout += 10;
}
-
- spin_unlock(&mp->m_ail_lock);
- return lsn;
-} /* xfs_trans_push_ail */
+out:
+ *last_lsn = last_pushed_lsn;
+ return tout;
+} /* xfsaild_push */
/*
* the call to xfs_log_move_tail() doesn't do anything if there's
* not enough free space to wake people up so we're safe calling it.
*/
- min_lip = xfs_ail_min(&mp->m_ail);
+ min_lip = xfs_ail_min(&mp->m_ail.xa_ail);
if (min_lip == lip)
xfs_log_move_tail(mp, 1);
xfs_log_item_t *dlip=NULL;
xfs_log_item_t *mlip; /* ptr to minimum lip */
- ailp = &(mp->m_ail);
+ ailp = &(mp->m_ail.xa_ail);
mlip = xfs_ail_min(ailp);
if (lip->li_flags & XFS_LI_IN_AIL) {
lip->li_lsn = lsn;
xfs_ail_insert(ailp, lip);
- mp->m_ail_gen++;
+ mp->m_ail.xa_gen++;
if (mlip == dlip) {
- mlip = xfs_ail_min(&(mp->m_ail));
+ mlip = xfs_ail_min(&(mp->m_ail.xa_ail));
spin_unlock(&mp->m_ail_lock);
xfs_log_move_tail(mp, mlip->li_lsn);
} else {
xfs_log_item_t *mlip;
if (lip->li_flags & XFS_LI_IN_AIL) {
- ailp = &(mp->m_ail);
+ ailp = &(mp->m_ail.xa_ail);
mlip = xfs_ail_min(ailp);
dlip = xfs_ail_delete(ailp, lip);
ASSERT(dlip == lip);
lip->li_flags &= ~XFS_LI_IN_AIL;
lip->li_lsn = 0;
- mp->m_ail_gen++;
+ mp->m_ail.xa_gen++;
if (mlip == dlip) {
- mlip = xfs_ail_min(&(mp->m_ail));
+ mlip = xfs_ail_min(&(mp->m_ail.xa_ail));
spin_unlock(&mp->m_ail_lock);
xfs_log_move_tail(mp, (mlip ? mlip->li_lsn : 0));
} else {
{
xfs_log_item_t *lip;
- lip = xfs_ail_min(&(mp->m_ail));
- *gen = (int)mp->m_ail_gen;
+ lip = xfs_ail_min(&(mp->m_ail.xa_ail));
+ *gen = (int)mp->m_ail.xa_gen;
- return (lip);
+ return lip;
}
/*
xfs_log_item_t *nlip;
ASSERT(mp && lip && gen);
- if (mp->m_ail_gen == *gen) {
- nlip = xfs_ail_next(&(mp->m_ail), lip);
+ if (mp->m_ail.xa_gen == *gen) {
+ nlip = xfs_ail_next(&(mp->m_ail.xa_ail), lip);
} else {
- nlip = xfs_ail_min(&(mp->m_ail));
- *gen = (int)mp->m_ail_gen;
+ nlip = xfs_ail_min(&(mp->m_ail).xa_ail);
+ *gen = (int)mp->m_ail.xa_gen;
if (restarts != NULL) {
XFS_STATS_INC(xs_push_ail_restarts);
(*restarts)++;
/*
* Initialize the doubly linked list to point only to itself.
*/
-void
+int
xfs_trans_ail_init(
xfs_mount_t *mp)
{
- mp->m_ail.ail_forw = (xfs_log_item_t*)&(mp->m_ail);
- mp->m_ail.ail_back = (xfs_log_item_t*)&(mp->m_ail);
+ mp->m_ail.xa_ail.ail_forw = (xfs_log_item_t*)&mp->m_ail.xa_ail;
+ mp->m_ail.xa_ail.ail_back = (xfs_log_item_t*)&mp->m_ail.xa_ail;
+ return xfsaild_start(mp);
+}
+
+void
+xfs_trans_ail_destroy(
+ xfs_mount_t *mp)
+{
+ xfsaild_stop(mp);
}
/*
projects / linux-2.6 / commitdiff