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authorDavid Chinner <dgc@sgi.com>2008-02-05 12:13:38 +1100
committerLachlan McIlroy <lachlan@redback.melbourne.sgi.com>2008-02-07 18:23:05 +1100
commitde08dbc1977419efa47eb71f10d96a98eb5bb111 (patch)
tree178aab8a805b8b44d593f9e96eae5fd3cb792ff9
parent249a8c1124653fa90f3a3afff869095a31bc229f (diff)
[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 <dgc@sgi.com> Signed-off-by: Lachlan McIlroy <lachlan@sgi.com>
-rw-r--r--fs/xfs/xfs_trans_ail.c37
1 files changed, 28 insertions, 9 deletions
diff --git a/fs/xfs/xfs_trans_ail.c b/fs/xfs/xfs_trans_ail.c
index 7ed7425478d..4d6330eddc8 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.
@@ -642,9 +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) {
@@ -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 */