diff options
Diffstat (limited to 'fs/xfs/xfs_trans_ail.c')
| -rw-r--r-- | fs/xfs/xfs_trans_ail.c | 232 |
1 files changed, 122 insertions, 110 deletions
diff --git a/fs/xfs/xfs_trans_ail.c b/fs/xfs/xfs_trans_ail.c index dc9069568ff7..c5bbbc45db91 100644 --- a/fs/xfs/xfs_trans_ail.c +++ b/fs/xfs/xfs_trans_ail.c @@ -28,8 +28,8 @@ #include "xfs_trans_priv.h" #include "xfs_error.h" -STATIC void xfs_ail_insert(struct xfs_ail *, xfs_log_item_t *); -STATIC xfs_log_item_t * xfs_ail_delete(struct xfs_ail *, xfs_log_item_t *); +STATIC void xfs_ail_splice(struct xfs_ail *, struct list_head *, xfs_lsn_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 *); @@ -449,129 +449,152 @@ xfs_trans_unlocked_item( 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. * - * 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. + * 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. * - * This function must be called with the AIL lock held. The lock - * is dropped before returning. + * 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. */ 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_log_item **log_items, + int nr_items, + xfs_lsn_t lsn) __releases(ailp->xa_lock) { - xfs_log_item_t *dlip = NULL; - 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); mlip = xfs_ail_min(ailp); - if (lip->li_flags & XFS_LI_IN_AIL) { - dlip = xfs_ail_delete(ailp, lip); - ASSERT(dlip == lip); - xfs_trans_ail_cursor_clear(ailp, dlip); - } 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); + xfs_ail_splice(ailp, &tmp, lsn); - if (mlip == dlip) { - 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 * - * 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. + * @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. * - * 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. + * 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. * - * This function must be called with the AIL lock held. The lock - * is dropped before returning. + * 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. */ 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 *dlip; 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); - dlip = xfs_ail_delete(ailp, lip); - ASSERT(dlip == lip); - xfs_trans_ail_cursor_clear(ailp, dlip); - + 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 == dlip) { - 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_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; } + + 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 @@ -623,16 +646,13 @@ xfs_trans_ail_destroy( } /* - * 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. + * splice the log item list into the AIL at the given LSN. */ STATIC void -xfs_ail_insert( +xfs_ail_splice( struct xfs_ail *ailp, - xfs_log_item_t *lip) -/* ARGSUSED */ + struct list_head *list, + xfs_lsn_t lsn) { xfs_log_item_t *next_lip; @@ -640,39 +660,33 @@ xfs_ail_insert( * If the list is empty, just insert the item. */ if (list_empty(&ailp->xa_ail)) { - list_add(&lip->li_ail, &ailp->xa_ail); + 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, lip->li_lsn) <= 0) + if (XFS_LSN_CMP(next_lip->li_lsn, 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_LSN_CMP(next_lip->li_lsn, lsn) <= 0)); - xfs_ail_check(ailp, lip); + list_splice_init(list, &next_lip->li_ail); return; } /* * Delete the given item from the AIL. Return a pointer to the item. */ -/*ARGSUSED*/ -STATIC xfs_log_item_t * +STATIC void xfs_ail_delete( struct xfs_ail *ailp, xfs_log_item_t *lip) -/* ARGSUSED */ { xfs_ail_check(ailp, lip); - list_del(&lip->li_ail); - - return lip; + xfs_trans_ail_cursor_clear(ailp, lip); } /* @@ -682,7 +696,6 @@ xfs_ail_delete( STATIC xfs_log_item_t * xfs_ail_min( struct xfs_ail *ailp) -/* ARGSUSED */ { if (list_empty(&ailp->xa_ail)) return NULL; @@ -699,7 +712,6 @@ STATIC xfs_log_item_t * xfs_ail_next( struct xfs_ail *ailp, xfs_log_item_t *lip) -/* ARGSUSED */ { if (lip->li_ail.next == &ailp->xa_ail) return NULL; |