From de08dbc1977419efa47eb71f10d96a98eb5bb111 Mon Sep 17 00:00:00 2001 From: David Chinner Date: Tue, 5 Feb 2008 12:13:38 +1100 Subject: [PATCH] [XFS] Make xfs_ail_check check less by default Checking the entire AIL on every insert and remove is prohibitively expensive - the sustained sequntial create rate on a single disk drops from about 1800/s to 60/s because of this checking resulting in the xfslogd becoming cpu bound. By default on debug builds, only check the next and previous entries in the list to ensure they are ordered correctly. If you really want, define XFS_TRANS_DEBUG to use the old behaviour. SGI-PV: 972759 SGI-Modid: xfs-linux-melb:xfs-kern:30372a Signed-off-by: David Chinner Signed-off-by: Lachlan McIlroy --- fs/xfs/xfs_trans_ail.c | 37 ++++++++++++++++++++++++++++--------- 1 file changed, 28 insertions(+), 9 deletions(-) diff --git a/fs/xfs/xfs_trans_ail.c b/fs/xfs/xfs_trans_ail.c index 7ed7425478..4d6330eddc 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 */ @@ -563,7 +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; } @@ -577,12 +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; } @@ -626,13 +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. @@ -641,10 +641,28 @@ xfs_ail_check( return; } + /* + * 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) { @@ -659,5 +677,6 @@ xfs_ail_check( } ASSERT(lip == (xfs_log_item_t*)base); ASSERT(base->ail_back == prev_lip); +#endif /* XFS_TRANS_DEBUG */ } #endif /* DEBUG */ -- 2.39.5