The per-sb inode writeback list tracks inodes currently under writeback
to facilitate efficient sync processing. In particular, it ensures that
sync only needs to walk through a list of inodes affected by the sync.
Add a couple tracepoints to help identify when inodes are added/removed
to and from the writeback lists. Piggyback off of the writeback lazytime
tracepoint template as it already tracks the relevant inode information.
Signed-off-by: Brian Foster <bfoster@xxxxxxxxxx>
---
fs/fs-writeback.c | 17 +++++++++++++----
include/trace/events/writeback.h | 22 ++++++++++++++++++----
2 files changed, 31 insertions(+), 8 deletions(-)
diff --git a/fs/fs-writeback.c b/fs/fs-writeback.c
index 6821347..672664b 100644
--- a/fs/fs-writeback.c
+++ b/fs/fs-writeback.c
@@ -954,8 +954,10 @@ void sb_mark_inode_writeback(struct inode *inode)
if (list_empty(&inode->i_wb_list)) {
spin_lock_irqsave(&sb->s_inode_wblist_lock, flags);
- if (list_empty(&inode->i_wb_list))
+ if (list_empty(&inode->i_wb_list)) {
list_add_tail(&inode->i_wb_list, &sb->s_inodes_wb);
+ trace_sb_mark_inode_writeback(inode);
+ }
spin_unlock_irqrestore(&sb->s_inode_wblist_lock, flags);
}
}
@@ -970,7 +972,10 @@ void sb_clear_inode_writeback(struct inode *inode)
if (!list_empty(&inode->i_wb_list)) {
spin_lock_irqsave(&sb->s_inode_wblist_lock, flags);
- list_del_init(&inode->i_wb_list);
+ if (!list_empty(&inode->i_wb_list)) {
+ list_del_init(&inode->i_wb_list);
+ trace_sb_clear_inode_writeback(inode);
+ }
spin_unlock_irqrestore(&sb->s_inode_wblist_lock, flags);
}
}
@@ -2202,8 +2207,10 @@ static void wait_sb_inodes(struct super_block *sb)
* The mapping can be cleaned before we wait on the inode since
* we do not have the mapping lock.
*/
- if (!mapping_tagged(mapping, PAGECACHE_TAG_WRITEBACK))
+ if (!mapping_tagged(mapping, PAGECACHE_TAG_WRITEBACK)) {
+ trace_sb_clear_inode_writeback(inode);
continue;
+ }
spin_unlock_irq(&sb->s_inode_wblist_lock);
@@ -2239,8 +2246,10 @@ static void wait_sb_inodes(struct super_block *sb)
if (list_empty(&inode->i_wb_list))
list_add_tail(&inode->i_wb_list, &sb->s_inodes_wb);
spin_unlock(&sb->s_inode_wblist_lock);
- } else
+ } else {
WARN_ON(!list_empty(&inode->i_wb_list));
+ trace_sb_clear_inode_writeback(inode);
+ }
spin_unlock_irq(&mapping->tree_lock);
iput(inode);
diff --git a/include/trace/events/writeback.h b/include/trace/events/writeback.h
index fff846b..962a7f1 100644
--- a/include/trace/events/writeback.h
+++ b/include/trace/events/writeback.h
@@ -727,7 +727,7 @@ DEFINE_EVENT(writeback_single_inode_template, writeback_single_inode,
TP_ARGS(inode, wbc, nr_to_write)
);
-DECLARE_EVENT_CLASS(writeback_lazytime_template,
+DECLARE_EVENT_CLASS(writeback_inode_template,
TP_PROTO(struct inode *inode),
TP_ARGS(inode),
@@ -754,25 +754,39 @@ DECLARE_EVENT_CLASS(writeback_lazytime_template,
show_inode_state(__entry->state), __entry->mode)
);
-DEFINE_EVENT(writeback_lazytime_template, writeback_lazytime,
+DEFINE_EVENT(writeback_inode_template, writeback_lazytime,
TP_PROTO(struct inode *inode),
TP_ARGS(inode)
);
-DEFINE_EVENT(writeback_lazytime_template, writeback_lazytime_iput,
+DEFINE_EVENT(writeback_inode_template, writeback_lazytime_iput,
TP_PROTO(struct inode *inode),
TP_ARGS(inode)
);
-DEFINE_EVENT(writeback_lazytime_template, writeback_dirty_inode_enqueue,
+DEFINE_EVENT(writeback_inode_template, writeback_dirty_inode_enqueue,
TP_PROTO(struct inode *inode),
TP_ARGS(inode)
);
+/*
+ * Inode writeback list tracking.
+ */
+
+DEFINE_EVENT(writeback_inode_template, sb_mark_inode_writeback,
+ TP_PROTO(struct inode *inode),
+ TP_ARGS(inode)
+);
+
+DEFINE_EVENT(writeback_inode_template, sb_clear_inode_writeback,
+ TP_PROTO(struct inode *inode),
+ TP_ARGS(inode)
+);
+
#endif /* _TRACE_WRITEBACK_H */
/* This part must be outside protection */
--
2.4.3
--
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