packages: kernel/kernel-small_fixes.patch - speedup deletion of files on xfs
arekm
arekm at pld-linux.org
Thu Sep 8 17:54:13 CEST 2011
Author: arekm Date: Thu Sep 8 15:54:13 2011 GMT
Module: packages Tag: HEAD
---- Log message:
- speedup deletion of files on xfs
---- Files affected:
packages/kernel:
kernel-small_fixes.patch (1.34 -> 1.35)
---- Diffs:
================================================================
Index: packages/kernel/kernel-small_fixes.patch
diff -u packages/kernel/kernel-small_fixes.patch:1.34 packages/kernel/kernel-small_fixes.patch:1.35
--- packages/kernel/kernel-small_fixes.patch:1.34 Thu Aug 25 21:27:49 2011
+++ packages/kernel/kernel-small_fixes.patch Thu Sep 8 17:54:07 2011
@@ -446,3 +446,300 @@
exit
fi
done
+commit 1d8c95a363bf8cd4d4182dd19c01693b635311c2
+Author: Dave Chinner <dchinner at redhat.com>
+Date: Mon Jul 18 03:40:16 2011 +0000
+
+ xfs: use a cursor for bulk AIL insertion
+
+ Delayed logging can insert tens of thousands of log items into the
+ AIL at the same LSN. When the committing of log commit records
+ occur, we can get insertions occurring at an LSN that is not at the
+ end of the AIL. If there are thousands of items in the AIL on the
+ tail LSN, each insertion has to walk the AIL to find the correct
+ place to insert the new item into the AIL. This can consume large
+ amounts of CPU time and block other operations from occurring while
+ the traversals are in progress.
+
+ To avoid this repeated walk, use a AIL cursor to record
+ where we should be inserting the new items into the AIL without
+ having to repeat the walk. The cursor infrastructure already
+ provides this functionality for push walks, so is a simple extension
+ of existing code. While this will not avoid the initial walk, it
+ will avoid repeating it tens of thousands of times during a single
+ checkpoint commit.
+
+ This version includes logic improvements from Christoph Hellwig.
+
+ Signed-off-by: Dave Chinner <dchinner at redhat.com>
+ Reviewed-by: Christoph Hellwig <hch at lst.de>
+ Signed-off-by: Alex Elder <aelder at sgi.com>
+
+diff --git a/fs/xfs/xfs_trans.c b/fs/xfs/xfs_trans.c
+index c83f63b..efc147f 100644
+--- a/fs/xfs/xfs_trans.c
++++ b/fs/xfs/xfs_trans.c
+@@ -1426,6 +1426,7 @@ xfs_trans_committed(
+ static inline void
+ xfs_log_item_batch_insert(
+ struct xfs_ail *ailp,
++ struct xfs_ail_cursor *cur,
+ struct xfs_log_item **log_items,
+ int nr_items,
+ xfs_lsn_t commit_lsn)
+@@ -1434,7 +1435,7 @@ xfs_log_item_batch_insert(
+
+ spin_lock(&ailp->xa_lock);
+ /* xfs_trans_ail_update_bulk drops ailp->xa_lock */
+- xfs_trans_ail_update_bulk(ailp, log_items, nr_items, commit_lsn);
++ xfs_trans_ail_update_bulk(ailp, cur, log_items, nr_items, commit_lsn);
+
+ for (i = 0; i < nr_items; i++)
+ IOP_UNPIN(log_items[i], 0);
+@@ -1452,6 +1453,13 @@ xfs_log_item_batch_insert(
+ * as an iclog write error even though we haven't started any IO yet. Hence in
+ * this case all we need to do is IOP_COMMITTED processing, followed by an
+ * IOP_UNPIN(aborted) call.
++ *
++ * The AIL cursor is used to optimise the insert process. If commit_lsn is not
++ * at the end of the AIL, the insert cursor avoids the need to walk
++ * the AIL to find the insertion point on every xfs_log_item_batch_insert()
++ * call. This saves a lot of needless list walking and is a net win, even
++ * though it slightly increases that amount of AIL lock traffic to set it up
++ * and tear it down.
+ */
+ void
+ xfs_trans_committed_bulk(
+@@ -1463,8 +1471,13 @@ xfs_trans_committed_bulk(
+ #define LOG_ITEM_BATCH_SIZE 32
+ struct xfs_log_item *log_items[LOG_ITEM_BATCH_SIZE];
+ struct xfs_log_vec *lv;
++ struct xfs_ail_cursor cur;
+ int i = 0;
+
++ spin_lock(&ailp->xa_lock);
++ xfs_trans_ail_cursor_last(ailp, &cur, commit_lsn);
++ spin_unlock(&ailp->xa_lock);
++
+ /* unpin all the log items */
+ for (lv = log_vector; lv; lv = lv->lv_next ) {
+ struct xfs_log_item *lip = lv->lv_item;
+@@ -1493,7 +1506,9 @@ xfs_trans_committed_bulk(
+ /*
+ * Not a bulk update option due to unusual item_lsn.
+ * Push into AIL immediately, rechecking the lsn once
+- * we have the ail lock. Then unpin the item.
++ * we have the ail lock. Then unpin the item. This does
++ * not affect the AIL cursor the bulk insert path is
++ * using.
+ */
+ spin_lock(&ailp->xa_lock);
+ if (XFS_LSN_CMP(item_lsn, lip->li_lsn) > 0)
+@@ -1507,7 +1522,7 @@ xfs_trans_committed_bulk(
+ /* Item is a candidate for bulk AIL insert. */
+ log_items[i++] = lv->lv_item;
+ if (i >= LOG_ITEM_BATCH_SIZE) {
+- xfs_log_item_batch_insert(ailp, log_items,
++ xfs_log_item_batch_insert(ailp, &cur, log_items,
+ LOG_ITEM_BATCH_SIZE, commit_lsn);
+ i = 0;
+ }
+@@ -1515,7 +1530,11 @@ xfs_trans_committed_bulk(
+
+ /* make sure we insert the remainder! */
+ if (i)
+- xfs_log_item_batch_insert(ailp, log_items, i, commit_lsn);
++ xfs_log_item_batch_insert(ailp, &cur, log_items, i, commit_lsn);
++
++ spin_lock(&ailp->xa_lock);
++ xfs_trans_ail_cursor_done(ailp, &cur);
++ spin_unlock(&ailp->xa_lock);
+ }
+
+ /*
+diff --git a/fs/xfs/xfs_trans_ail.c b/fs/xfs/xfs_trans_ail.c
+index 5fc2380..9a69dc0 100644
+--- a/fs/xfs/xfs_trans_ail.c
++++ b/fs/xfs/xfs_trans_ail.c
+@@ -272,9 +272,9 @@ 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().
++ * Initialise the cursor to the first item in the AIL with the given @lsn.
++ * This searches the list from lowest LSN to highest. Pass a @lsn of zero
++ * to initialise the cursor to the first item in the AIL.
+ */
+ xfs_log_item_t *
+ xfs_trans_ail_cursor_first(
+@@ -300,31 +300,97 @@ out:
+ }
+
+ /*
+- * splice the log item list into the AIL at the given LSN.
++ * Initialise the cursor to the last item in the AIL with the given @lsn.
++ * This searches the list from highest LSN to lowest. 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.
++ */
++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;
++}
++
++/*
++ * Initialise the cursor to the last item in the AIL with the given @lsn.
++ * This searches the list from highest LSN to lowest.
++ */
++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.
+ */
+ static void
+ xfs_ail_splice(
+- struct xfs_ail *ailp,
+- struct list_head *list,
+- xfs_lsn_t lsn)
++ struct xfs_ail *ailp,
++ struct xfs_ail_cursor *cur,
++ struct list_head *list,
++ xfs_lsn_t lsn)
+ {
+- xfs_log_item_t *next_lip;
++ struct xfs_log_item *lip = cur ? cur->item : NULL;
++ struct xfs_log_item *next_lip;
+
+- /* If the list is empty, just insert the item. */
+- if (list_empty(&ailp->xa_ail)) {
+- list_splice(list, &ailp->xa_ail);
+- return;
++ /*
++ * Get a new cursor if we don't have a placeholder or the existing one
++ * has been invalidated.
++ */
++ if (!lip || (__psint_t)lip & 1) {
++ lip = __xfs_trans_ail_cursor_last(ailp, lsn);
++
++ if (!lip) {
++ /* The list is empty, so just splice and return. */
++ if (cur)
++ cur->item = NULL;
++ 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, lsn) <= 0)
+- break;
++ /*
++ * Our cursor points to the item we want to insert _after_, so we have
++ * to update the cursor to point to the end of the list we are splicing
++ * in so that it points to the correct location for the next splice.
++ * i.e. before the splice
++ *
++ * lsn -> lsn -> lsn + x -> lsn + x ...
++ * ^
++ * | cursor points here
++ *
++ * After the splice we have:
++ *
++ * lsn -> lsn -> lsn -> lsn -> .... -> lsn -> lsn + x -> lsn + x ...
++ * ^ ^
++ * | cursor points here | needs to move here
++ *
++ * So we set the cursor to the last item in the list to be spliced
++ * before we execute the splice, resulting in the cursor pointing to
++ * the correct item after the splice occurs.
++ */
++ if (cur) {
++ next_lip = list_entry(list->prev, struct xfs_log_item, li_ail);
++ cur->item = next_lip;
+ }
+-
+- ASSERT(&next_lip->li_ail == &ailp->xa_ail ||
+- XFS_LSN_CMP(next_lip->li_lsn, lsn) <= 0);
+-
+- list_splice_init(list, &next_lip->li_ail);
++ list_splice(list, &lip->li_ail);
+ }
+
+ /*
+@@ -645,6 +711,7 @@ xfs_trans_unlocked_item(
+ void
+ 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)
+@@ -674,7 +741,7 @@ xfs_trans_ail_update_bulk(
+ list_add(&lip->li_ail, &tmp);
+ }
+
+- xfs_ail_splice(ailp, &tmp, lsn);
++ xfs_ail_splice(ailp, cur, &tmp, lsn);
+
+ if (!mlip_changed) {
+ spin_unlock(&ailp->xa_lock);
+diff --git a/fs/xfs/xfs_trans_priv.h b/fs/xfs/xfs_trans_priv.h
+index 6b164e9..c0cb408 100644
+--- a/fs/xfs/xfs_trans_priv.h
++++ b/fs/xfs/xfs_trans_priv.h
+@@ -82,6 +82,7 @@ struct xfs_ail {
+ extern struct workqueue_struct *xfs_ail_wq; /* AIL workqueue */
+
+ void 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);
+ static inline void
+@@ -90,7 +91,7 @@ xfs_trans_ail_update(
+ struct xfs_log_item *lip,
+ xfs_lsn_t lsn) __releases(ailp->xa_lock)
+ {
+- xfs_trans_ail_update_bulk(ailp, &lip, 1, lsn);
++ xfs_trans_ail_update_bulk(ailp, NULL, &lip, 1, lsn);
+ }
+
+ void xfs_trans_ail_delete_bulk(struct xfs_ail *ailp,
+@@ -111,10 +112,13 @@ xfs_lsn_t xfs_ail_min_lsn(struct xfs_ail *ailp);
+ void xfs_trans_unlocked_item(struct xfs_ail *,
+ xfs_log_item_t *);
+
+-struct xfs_log_item *xfs_trans_ail_cursor_first(struct xfs_ail *ailp,
++struct xfs_log_item * xfs_trans_ail_cursor_first(struct xfs_ail *ailp,
+ struct xfs_ail_cursor *cur,
+ xfs_lsn_t lsn);
+-struct xfs_log_item *xfs_trans_ail_cursor_next(struct xfs_ail *ailp,
++struct xfs_log_item * xfs_trans_ail_cursor_last(struct xfs_ail *ailp,
++ struct xfs_ail_cursor *cur,
++ xfs_lsn_t lsn);
++struct xfs_log_item * xfs_trans_ail_cursor_next(struct xfs_ail *ailp,
+ struct xfs_ail_cursor *cur);
+ void xfs_trans_ail_cursor_done(struct xfs_ail *ailp,
+ struct xfs_ail_cursor *cur);
================================================================
---- CVS-web:
http://cvs.pld-linux.org/cgi-bin/cvsweb.cgi/packages/kernel/kernel-small_fixes.patch?r1=1.34&r2=1.35&f=u
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