diff options
Diffstat (limited to 'fs/xfs/xfs_trans_ail.c')
| -rw-r--r-- | fs/xfs/xfs_trans_ail.c | 340 |
1 files changed, 220 insertions, 120 deletions
diff --git a/fs/xfs/xfs_trans_ail.c b/fs/xfs/xfs_trans_ail.c index 5b2ff59..4d6330e 100644 --- a/fs/xfs/xfs_trans_ail.c +++ b/fs/xfs/xfs_trans_ail.c @@ -34,9 +34,9 @@ STATIC xfs_log_item_t * xfs_ail_min(xfs_ail_entry_t *); STATIC xfs_log_item_t * xfs_ail_next(xfs_ail_entry_t *, xfs_log_item_t *); #ifdef DEBUG -STATIC void xfs_ail_check(xfs_ail_entry_t *); +STATIC void xfs_ail_check(xfs_ail_entry_t *, xfs_log_item_t *); #else -#define xfs_ail_check(a) +#define xfs_ail_check(a,l) #endif /* DEBUG */ @@ -55,16 +55,15 @@ xfs_trans_tail_ail( { xfs_lsn_t lsn; xfs_log_item_t *lip; - SPLDECL(s); - AIL_LOCK(mp,s); - lip = xfs_ail_min(&(mp->m_ail)); + spin_lock(&mp->m_ail_lock); + lip = xfs_ail_min(&(mp->m_ail.xa_ail)); if (lip == NULL) { lsn = (xfs_lsn_t)0; } else { lsn = lip->li_lsn; } - AIL_UNLOCK(mp, s); + spin_unlock(&mp->m_ail_lock); return lsn; } @@ -72,120 +71,185 @@ xfs_trans_tail_ail( /* * 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; - SPLDECL(s); -#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; - AIL_LOCK(mp,s); - lip = xfs_trans_first_ail(mp, &gen); - if (lip == NULL || XFS_FORCED_SHUTDOWN(mp)) { + 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_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. */ - AIL_UNLOCK(mp, s); - return (xfs_lsn_t)0; + spin_unlock(&mp->m_ail_lock); + 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: - AIL_UNLOCK(mp, s); + case XFS_ITEM_SUCCESS: XFS_STATS_INC(xs_push_ail_success); IOP_PUSH(lip); - AIL_LOCK(mp,s); + last_pushed_lsn = lsn; break; - case XFS_ITEM_PUSHBUF: - AIL_UNLOCK(mp, s); + 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); - AIL_LOCK(mp,s); + 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. - */ - AIL_UNLOCK(mp, s); - 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) { /* @@ -193,22 +257,35 @@ xfs_trans_push_ail( * push out the log so it will become unpinned and * move forward in the AIL. */ - AIL_UNLOCK(mp, s); XFS_STATS_INC(xs_push_ail_flush); xfs_log_force(mp, (xfs_lsn_t)0, XFS_LOG_FORCE); - AIL_LOCK(mp, s); } - 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; } - - AIL_UNLOCK(mp, s); - return lsn; -} /* xfs_trans_push_ail */ +out: + *last_lsn = last_pushed_lsn; + return tout; +} /* xfsaild_push */ /* @@ -249,7 +326,7 @@ xfs_trans_unlocked_item( * 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); @@ -269,21 +346,19 @@ xfs_trans_unlocked_item( * has changed. * * This function must be called with the AIL lock held. The lock - * is dropped before returning, so the caller must pass in the - * cookie returned by AIL_LOCK. + * is dropped before returning. */ void xfs_trans_update_ail( xfs_mount_t *mp, xfs_log_item_t *lip, - xfs_lsn_t lsn, - unsigned long s) __releases(mp->m_ail_lock) + xfs_lsn_t lsn) __releases(mp->m_ail_lock) { xfs_ail_entry_t *ailp; 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) { @@ -296,14 +371,14 @@ xfs_trans_update_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)); - AIL_UNLOCK(mp, s); + mlip = xfs_ail_min(&(mp->m_ail.xa_ail)); + spin_unlock(&mp->m_ail_lock); xfs_log_move_tail(mp, mlip->li_lsn); } else { - AIL_UNLOCK(mp, s); + spin_unlock(&mp->m_ail_lock); } @@ -322,21 +397,19 @@ xfs_trans_update_ail( * has changed. * * This function must be called with the AIL lock held. The lock - * is dropped before returning, so the caller must pass in the - * cookie returned by AIL_LOCK. + * is dropped before returning. */ void xfs_trans_delete_ail( xfs_mount_t *mp, - xfs_log_item_t *lip, - unsigned long s) __releases(mp->m_ail_lock) + xfs_log_item_t *lip) __releases(mp->m_ail_lock) { xfs_ail_entry_t *ailp; xfs_log_item_t *dlip; 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); @@ -344,14 +417,14 @@ xfs_trans_delete_ail( 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)); - AIL_UNLOCK(mp, s); + 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 { - AIL_UNLOCK(mp, s); + spin_unlock(&mp->m_ail_lock); } } else { @@ -360,12 +433,12 @@ xfs_trans_delete_ail( * serious trouble if we get to this stage. */ if (XFS_FORCED_SHUTDOWN(mp)) - AIL_UNLOCK(mp, s); + spin_unlock(&mp->m_ail_lock); else { xfs_cmn_err(XFS_PTAG_AILDELETE, CE_ALERT, mp, "%s: attempting to delete a log item that is not in the AIL", __FUNCTION__); - AIL_UNLOCK(mp, s); + spin_unlock(&mp->m_ail_lock); xfs_force_shutdown(mp, SHUTDOWN_CORRUPT_INCORE); } } @@ -385,10 +458,10 @@ xfs_trans_first_ail( { 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; } /* @@ -408,11 +481,11 @@ xfs_trans_next_ail( 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)++; @@ -437,12 +510,20 @@ xfs_trans_next_ail( /* * 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); } /* @@ -482,7 +563,7 @@ xfs_ail_insert( next_lip->li_ail.ail_forw = lip; lip->li_ail.ail_forw->li_ail.ail_back = lip; - xfs_ail_check(base); + xfs_ail_check(base, lip); return; } @@ -496,12 +577,12 @@ xfs_ail_delete( xfs_log_item_t *lip) /* ARGSUSED */ { + xfs_ail_check(base, lip); lip->li_ail.ail_forw->li_ail.ail_back = lip->li_ail.ail_back; lip->li_ail.ail_back->li_ail.ail_forw = lip->li_ail.ail_forw; lip->li_ail.ail_forw = NULL; lip->li_ail.ail_back = NULL; - xfs_ail_check(base); return lip; } @@ -545,13 +626,13 @@ xfs_ail_next( */ STATIC void xfs_ail_check( - xfs_ail_entry_t *base) + xfs_ail_entry_t *base, + xfs_log_item_t *lip) { - xfs_log_item_t *lip; xfs_log_item_t *prev_lip; - lip = base->ail_forw; - if (lip == (xfs_log_item_t*)base) { + prev_lip = base->ail_forw; + if (prev_lip == (xfs_log_item_t*)base) { /* * Make sure the pointers are correct when the list * is empty. @@ -561,9 +642,27 @@ xfs_ail_check( } /* + * Check the next and previous entries are valid. + */ + ASSERT((lip->li_flags & XFS_LI_IN_AIL) != 0); + prev_lip = lip->li_ail.ail_back; + if (prev_lip != (xfs_log_item_t*)base) { + ASSERT(prev_lip->li_ail.ail_forw == lip); + ASSERT(XFS_LSN_CMP(prev_lip->li_lsn, lip->li_lsn) <= 0); + } + prev_lip = lip->li_ail.ail_forw; + if (prev_lip != (xfs_log_item_t*)base) { + ASSERT(prev_lip->li_ail.ail_back == lip); + ASSERT(XFS_LSN_CMP(prev_lip->li_lsn, lip->li_lsn) >= 0); + } + + +#ifdef XFS_TRANS_DEBUG + /* * Walk the list checking forward and backward pointers, * lsn ordering, and that every entry has the XFS_LI_IN_AIL - * flag set. + * flag set. This is really expensive, so only do it when + * specifically debugging the transaction subsystem. */ prev_lip = (xfs_log_item_t*)base; while (lip != (xfs_log_item_t*)base) { @@ -578,5 +677,6 @@ xfs_ail_check( } ASSERT(lip == (xfs_log_item_t*)base); ASSERT(base->ail_back == prev_lip); +#endif /* XFS_TRANS_DEBUG */ } #endif /* DEBUG */ |
