diff options
Diffstat (limited to 'fs/xfs/xfs_trans_ail.c')
| -rw-r--r-- | fs/xfs/xfs_trans_ail.c | 999 |
1 files changed, 521 insertions, 478 deletions
diff --git a/fs/xfs/xfs_trans_ail.c b/fs/xfs/xfs_trans_ail.c index dc9069568ff..cb0f3a84cc6 100644 --- a/fs/xfs/xfs_trans_ail.c +++ b/fs/xfs/xfs_trans_ail.c @@ -18,98 +18,127 @@ */ #include "xfs.h" #include "xfs_fs.h" -#include "xfs_types.h" -#include "xfs_log.h" -#include "xfs_inum.h" -#include "xfs_trans.h" +#include "xfs_log_format.h" +#include "xfs_trans_resv.h" #include "xfs_sb.h" #include "xfs_ag.h" #include "xfs_mount.h" +#include "xfs_trans.h" #include "xfs_trans_priv.h" +#include "xfs_trace.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 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 *); +#include "xfs_log.h" #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); + + +} +#else /* !DEBUG */ #define xfs_ail_check(a,l) #endif /* DEBUG */ +/* + * 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( @@ -117,31 +146,12 @@ 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( @@ -152,45 +162,30 @@ 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( @@ -199,8 +194,7 @@ 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); @@ -208,9 +202,10 @@ 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(). + * 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( @@ -221,123 +216,224 @@ 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; +} + +/* + * 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. + */ +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); +} + /* - * xfsaild_push does the work of pushing on the AIL. Returning a timeout of - * zero indicates that the caller should sleep until woken. + * Delete the given item from the AIL. Return a pointer to the item. */ -long +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; + int stuck = 0; + int flushing = 0; + int count = 0; + + /* + * If we encountered pinned items or did not finish writing out all + * buffers the last time we ran, force the log first and wait for it + * before pushing again. + */ + if (ailp->xa_log_flush && ailp->xa_last_pushed_lsn == 0 && + (!list_empty_careful(&ailp->xa_buf_list) || + xfs_ail_min_lsn(ailp))) { + ailp->xa_log_flush = 0; + + XFS_STATS_INC(xs_push_ail_flush); + xfs_log_force(mp, XFS_LOG_SYNC); + } spin_lock(&ailp->xa_lock); - xfs_trans_ail_cursor_init(ailp, cur); - lip = xfs_trans_ail_cursor_first(ailp, cur, *last_lsn); - if (!lip || XFS_FORCED_SHUTDOWN(mp)) { + + /* barrier matches the xa_target update in xfs_ail_push() */ + smp_rmb(); + target = ailp->xa_target; + ailp->xa_target_prev = target; + + lip = xfs_trans_ail_cursor_first(ailp, &cur, ailp->xa_last_pushed_lsn); + if (!lip) { /* - * AIL is empty or our push has reached the end. + * If the AIL is empty or our push has reached the end we are + * done now. */ - xfs_trans_ail_cursor_done(ailp, cur); + xfs_trans_ail_cursor_done(&cur); spin_unlock(&ailp->xa_lock); - *last_lsn = 0; - return tout; + goto out_done; } XFS_STATS_INC(xs_push_ail); - /* - * While the item we are looking at is below the given threshold - * 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 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. - */ 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 - * 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. + * Note that iop_push may unlock and reacquire the AIL lock. We + * rely on the AIL cursor implementation to be able to deal with + * the dropped lock. */ - lock_result = IOP_TRYLOCK(lip); - spin_unlock(&ailp->xa_lock); + lock_result = lip->li_ops->iop_push(lip, &ailp->xa_buf_list); switch (lock_result) { case XFS_ITEM_SUCCESS: XFS_STATS_INC(xs_push_ail_success); - IOP_PUSH(lip); - last_pushed_lsn = lsn; + trace_xfs_ail_push(lip); + + 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; - push_xfsbufd = 1; + case XFS_ITEM_FLUSHING: + /* + * The item or its backing buffer is already beeing + * flushed. The typical reason for that is that an + * inode buffer is locked because we already pushed the + * updates to it as part of inode clustering. + * + * We do not want to to stop flushing just because lots + * of items are already beeing flushed, but we need to + * re-try the flushing relatively soon if most of the + * AIL is beeing flushed. + */ + XFS_STATS_INC(xs_push_ail_flushing); + trace_xfs_ail_flushing(lip); + + flushing++; + ailp->xa_last_pushed_lsn = lsn; break; case XFS_ITEM_PINNED: XFS_STATS_INC(xs_push_ail_pinned); + trace_xfs_ail_pinned(lip); + stuck++; - flush_log = 1; + ailp->xa_log_flush++; break; - case XFS_ITEM_LOCKED: XFS_STATS_INC(xs_push_ail_locked); - last_pushed_lsn = lsn; + trace_xfs_ail_locked(lip); + stuck++; break; - default: ASSERT(0); break; } - spin_lock(&ailp->xa_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 @@ -351,248 +447,318 @@ xfsaild_push( 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(&cur); spin_unlock(&ailp->xa_lock); - if (flush_log) { - /* - * If something we need to push out was pinned, then - * push out the log so it will become unpinned and - * move forward in the AIL. - */ - XFS_STATS_INC(xs_push_ail_flush); - xfs_log_force(mp, 0); - } + if (xfs_buf_delwri_submit_nowait(&ailp->xa_buf_list)) + ailp->xa_log_flush++; - if (push_xfsbufd) { - /* we've got delayed write buffers to flush */ - wake_up_process(mp->m_ddev_targp->bt_task); - } - - if (!count) { - /* We're past our target or empty, so idle */ - last_pushed_lsn = 0; - } else if (XFS_LSN_CMP(lsn, target) >= 0) { + if (!count || XFS_LSN_CMP(lsn, target) >= 0) { +out_done: /* - * 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. + * We reached the target or the AIL is empty, 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. */ tout = 50; - last_pushed_lsn = 0; - } else if ((stuck * 100) / count > 90) { + ailp->xa_last_pushed_lsn = 0; + } else if (((stuck + flushing) * 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. + * 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. + * restarting from the start of the AIL. This prevents us from + * spinning on the same items, and if they are pinned will all + * the restart to issue a log force to unpin the stuck items. */ tout = 20; + ailp->xa_last_pushed_lsn = 0; } else { - /* more to do, but wait a short while before continuing */ + /* + * Assume we have more work to do in a short while. + */ tout = 10; } - *last_lsn = last_pushed_lsn; + return tout; } +static int +xfsaild( + void *data) +{ + struct xfs_ail *ailp = data; + long tout = 0; /* milliseconds */ + + current->flags |= PF_MEMALLOC; + + while (!kthread_should_stop()) { + if (tout && tout <= 20) + __set_current_state(TASK_KILLABLE); + else + __set_current_state(TASK_INTERRUPTIBLE); + + spin_lock(&ailp->xa_lock); + + /* + * Idle if the AIL is empty and we are not racing with a target + * update. We check the AIL after we set the task to a sleep + * state to guarantee that we either catch an xa_target update + * or that a wake_up resets the state to TASK_RUNNING. + * Otherwise, we run the risk of sleeping indefinitely. + * + * The barrier matches the xa_target update in xfs_ail_push(). + */ + smp_rmb(); + if (!xfs_ail_min(ailp) && + ailp->xa_target == ailp->xa_target_prev) { + spin_unlock(&ailp->xa_lock); + schedule(); + tout = 0; + continue; + } + spin_unlock(&ailp->xa_lock); + + if (tout) + schedule_timeout(msecs_to_jiffies(tout)); + + __set_current_state(TASK_RUNNING); + + try_to_freeze(); + + tout = xfsaild_push(ailp); + } + + return 0; +} /* - * This is to be called when an item is unlocked that may have - * been in the AIL. It will wake up the first member of the AIL - * wait list if this item's unlocking might allow it to progress. - * If the item is in the AIL, then we need to get the AIL lock - * while doing our checking so we don't race with someone going - * to sleep waiting for this event in 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 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_trans_unlocked_item( +xfs_ail_push( struct xfs_ail *ailp, - xfs_log_item_t *lip) + xfs_lsn_t threshold_lsn) { - xfs_log_item_t *min_lip; + xfs_log_item_t *lip; - /* - * If we're forcibly shutting down, we may have - * unlocked log items arbitrarily. The last thing - * we want to do is to move the tail of the log - * over some potentially valid data. - */ - if (!(lip->li_flags & XFS_LI_IN_AIL) || - XFS_FORCED_SHUTDOWN(ailp->xa_mount)) { + lip = xfs_ail_min(ailp); + if (!lip || XFS_FORCED_SHUTDOWN(ailp->xa_mount) || + XFS_LSN_CMP(threshold_lsn, ailp->xa_target) <= 0) return; - } /* - * This is the one case where we can call into xfs_ail_min() - * without holding the AIL lock because we only care about the - * case where we are at the tail of the AIL. If the object isn't - * at the tail, it doesn't matter what result we get back. This - * is slightly racy because since we were just unlocked, we could - * go to sleep between the call to xfs_ail_min and the call to - * xfs_log_move_tail, have someone else lock us, commit to us disk, - * move us out of the tail of the AIL, and then we wake up. However, - * 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. + * Ensure that the new target is noticed in push code before it clears + * the XFS_AIL_PUSHING_BIT. */ - min_lip = xfs_ail_min(ailp); + smp_wmb(); + xfs_trans_ail_copy_lsn(ailp, &ailp->xa_target, &threshold_lsn); + smp_wmb(); + + wake_up_process(ailp->xa_task); +} - if (min_lip == lip) - xfs_log_move_tail(ailp->xa_mount, 1); -} /* xfs_trans_unlocked_item */ +/* + * 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); +} /* - * 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. + * Push out all items in the AIL immediately and wait until the AIL is empty. + */ +void +xfs_ail_push_all_sync( + struct xfs_ail *ailp) +{ + struct xfs_log_item *lip; + DEFINE_WAIT(wait); + + spin_lock(&ailp->xa_lock); + while ((lip = xfs_ail_max(ailp)) != NULL) { + prepare_to_wait(&ailp->xa_empty, &wait, TASK_UNINTERRUPTIBLE); + ailp->xa_target = lip->li_lsn; + wake_up_process(ailp->xa_task); + spin_unlock(&ailp->xa_lock); + schedule(); + spin_lock(&ailp->xa_lock); + } + spin_unlock(&ailp->xa_lock); + + finish_wait(&ailp->xa_empty, &wait); +} + +/* + * xfs_trans_ail_update - bulk AIL insertion operation. * - * 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. + * @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 must be called with the AIL lock held. The lock - * is dropped before returning. + * 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. + * + * 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_ail_cursor *cur, + 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_lsn_t tail_lsn; + xfs_log_item_t *mlip; + 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) { - 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; + + trace_xfs_ail_move(lip, lip->li_lsn, lsn); + xfs_ail_delete(ailp, lip); + if (mlip == lip) + mlip_changed = 1; + } else { + lip->li_flags |= XFS_LI_IN_AIL; + trace_xfs_ail_insert(lip, 0, lsn); + } + 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 == 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; + if (mlip_changed) { + if (!XFS_FORCED_SHUTDOWN(ailp->xa_mount)) + xlog_assign_tail_lsn_locked(ailp->xa_mount); spin_unlock(&ailp->xa_lock); - xfs_log_move_tail(ailp->xa_mount, tail_lsn); + + xfs_log_space_wake(ailp->xa_mount); } else { spin_unlock(&ailp->xa_lock); } - - -} /* xfs_trans_update_ail */ +} /* - * 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, + int shutdown_type) __releases(ailp->xa_lock) { - xfs_log_item_t *dlip; xfs_log_item_t *mlip; - xfs_lsn_t tail_lsn; - - 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); + int mlip_changed = 0; + int i; + 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_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_type); + } + return; } + + trace_xfs_ail_delete(lip, mlip->li_lsn, lip->li_lsn); + 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) { + if (!XFS_FORCED_SHUTDOWN(ailp->xa_mount)) + xlog_assign_tail_lsn_locked(ailp->xa_mount); + if (list_empty(&ailp->xa_ail)) + wake_up_all(&ailp->xa_empty); + spin_unlock(&ailp->xa_lock); + + xfs_log_space_wake(ailp->xa_mount); + } 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); - } } } - - -/* - * The active item list (AIL) is a doubly linked list of log - * items sorted by ascending lsn. The base of the list is - * a forw/back pointer pair embedded in the xfs mount structure. - * The base is initialized with both pointers pointing to the - * base. This case always needs to be distinguished, because - * the base has no lsn to look at. 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. - */ - -/* - * Initialize the doubly linked list to point only to itself. - */ int xfs_trans_ail_init( xfs_mount_t *mp) { struct xfs_ail *ailp; - int error; ailp = kmem_zalloc(sizeof(struct xfs_ail), KM_MAYFAIL); if (!ailp) @@ -600,16 +766,22 @@ xfs_trans_ail_init( 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) + INIT_LIST_HEAD(&ailp->xa_buf_list); + init_waitqueue_head(&ailp->xa_empty); + + 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 @@ -618,135 +790,6 @@ xfs_trans_ail_destroy( { 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) -/* ARGSUSED */ -{ - 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. - */ -/*ARGSUSED*/ -STATIC xfs_log_item_t * -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; -} - -/* - * 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) -/* ARGSUSED */ -{ - 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) -/* ARGSUSED */ -{ - 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 */ |