writeback: add more tracepoints
Add tracepoints for page dirtying, writeback_single_inode start, inode
dirtying and writeback. For the latter two inode events, a pair of
events are defined to denote start and end of the operations (the
starting one has _start suffix and the one w/o suffix happens after
the operation is complete). These inode ops are FS specific and can
be non-trivial and having enclosing tracepoints is useful for external
tracers.
This is part of tracepoint additions to improve visiblity into
dirtying / writeback operations for io tracer and userland.
v2: writeback_dirty_inode[_start] TPs may be called for files on
pseudo FSes w/ unregistered bdi. Check whether bdi->dev is %NULL
before dereferencing.
v3: buffer dirtying moved to a block TP.
Signed-off-by: Tejun Heo <tj@kernel.org>
Reviewed-by: Jan Kara <jack@suse.cz>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
diff --git a/fs/fs-writeback.c b/fs/fs-writeback.c
index 310972b..359494e 100644
--- a/fs/fs-writeback.c
+++ b/fs/fs-writeback.c
@@ -318,8 +318,14 @@
static int write_inode(struct inode *inode, struct writeback_control *wbc)
{
- if (inode->i_sb->s_op->write_inode && !is_bad_inode(inode))
- return inode->i_sb->s_op->write_inode(inode, wbc);
+ int ret;
+
+ if (inode->i_sb->s_op->write_inode && !is_bad_inode(inode)) {
+ trace_writeback_write_inode_start(inode, wbc);
+ ret = inode->i_sb->s_op->write_inode(inode, wbc);
+ trace_writeback_write_inode(inode, wbc);
+ return ret;
+ }
return 0;
}
@@ -450,6 +456,8 @@
WARN_ON(!(inode->i_state & I_SYNC));
+ trace_writeback_single_inode_start(inode, wbc, nr_to_write);
+
ret = do_writepages(mapping, wbc);
/*
@@ -1150,8 +1158,12 @@
* dirty the inode itself
*/
if (flags & (I_DIRTY_SYNC | I_DIRTY_DATASYNC)) {
+ trace_writeback_dirty_inode_start(inode, flags);
+
if (sb->s_op->dirty_inode)
sb->s_op->dirty_inode(inode, flags);
+
+ trace_writeback_dirty_inode(inode, flags);
}
/*