diff options
| -rw-r--r-- | fs/xfs/xfs_trans.c | 27 | ||||
| -rw-r--r-- | fs/xfs/xfs_trans_ail.c | 109 | ||||
| -rw-r--r-- | fs/xfs/xfs_trans_priv.h | 10 |
3 files changed, 118 insertions, 28 deletions
diff --git a/fs/xfs/xfs_trans.c b/fs/xfs/xfs_trans.c index c83f63b..efc147f 100644 --- a/fs/xfs/xfs_trans.c +++ b/fs/xfs/xfs_trans.c @@ -1426,6 +1426,7 @@ xfs_trans_committed( 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) @@ -1434,7 +1435,7 @@ xfs_log_item_batch_insert( 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); @@ -1452,6 +1453,13 @@ xfs_log_item_batch_insert( * 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( @@ -1463,8 +1471,13 @@ 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; @@ -1493,7 +1506,9 @@ xfs_trans_committed_bulk( /* * 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) @@ -1507,7 +1522,7 @@ xfs_trans_committed_bulk( /* 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; } @@ -1515,7 +1530,11 @@ xfs_trans_committed_bulk( /* 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); } /* diff --git a/fs/xfs/xfs_trans_ail.c b/fs/xfs/xfs_trans_ail.c index 5fc2380..9a69dc0 100644 --- a/fs/xfs/xfs_trans_ail.c +++ b/fs/xfs/xfs_trans_ail.c @@ -272,9 +272,9 @@ xfs_trans_ail_cursor_clear( } /* - * 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( @@ -300,31 +300,97 @@ out: } /* - * 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); } /* @@ -645,6 +711,7 @@ xfs_trans_unlocked_item( 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) @@ -674,7 +741,7 @@ xfs_trans_ail_update_bulk( 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); diff --git a/fs/xfs/xfs_trans_priv.h b/fs/xfs/xfs_trans_priv.h index 6b164e9..c0cb408 100644 --- a/fs/xfs/xfs_trans_priv.h +++ b/fs/xfs/xfs_trans_priv.h @@ -82,6 +82,7 @@ struct xfs_ail { 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 @@ -90,7 +91,7 @@ xfs_trans_ail_update( 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, @@ -111,10 +112,13 @@ xfs_lsn_t xfs_ail_min_lsn(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); |