Re: [PATCH] vfs: Add a trace point in the mark_inode_dirty function

[Arjan van de Ven <arjan@infradead.org>]

On Mon, 29 Nov 2010 10:41:51 +0900 (JST)
KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> wrote:

> > Signed-of-by: Arjan van de Ven <arjan@linux.intel.com>
> > ---
> >  fs/fs-writeback.c                |    3 +++
> >  include/linux/fs.h               |   12 ++++++++++++
> >  include/trace/events/writeback.h |   28
> > ++++++++++++++++++++++++++++ 3 files changed, 43 insertions(+), 0
> > deletions(-)
> > 
> > diff --git a/fs/fs-writeback.c b/fs/fs-writeback.c
> > index 3d06ccc..62e33cc 100644
> > --- a/fs/fs-writeback.c
> > +++ b/fs/fs-writeback.c
> > @@ -952,6 +952,9 @@ void __mark_inode_dirty(struct inode *inode,
> > int flags) if ((inode->i_state & flags) == flags)
> >  		return;
> >  
> > +	if (flags & (I_DIRTY_SYNC | I_DIRTY_DATASYNC |
> > I_DIRTY_PAGES))
> > +		trace_writeback_inode_dirty(inode, flags);
> > +
> 
> Why can't we move this branch into TP_fast_assign()?

not really because then the tracepoint is already in process of being
emitted... no way to retract it anymore.