Hi Kim,
> -----Original Message-----
> From: Jaegeuk Kim [mailto:jaegeuk....@samsung.com]
> Sent: Wednesday, May 07, 2014 8:30 AM
> To: Chao Yu
> Cc: linux-f2fs-de...@lists.sourceforge.net; linux-fsde...@vger.kernel.org;
> linux-kernel@vger.kernel.org
> Subject: Re: [f2fs-dev][PATCH 6/6] f2fs: add a tracepoint for
> f2fs_read_data_pages
>
> Hi Chao,
>
> 2014-05-06 (화), 16:54 +0800, Chao Yu:
> > This patch adds a tracepoint for f2fs_read_data_pages to trace when pages
> > are
> > readahead by VFS.
> >
> > Signed-off-by: Chao Yu <chao2...@samsung.com>
> > ---
> > fs/f2fs/data.c | 3 +++
> > include/trace/events/f2fs.h | 26 ++++++++++++++++++++++++++
> > 2 files changed, 29 insertions(+)
> >
> > diff --git a/fs/f2fs/data.c b/fs/f2fs/data.c
> > index 8c250a5..f2d1e8a 100644
> > --- a/fs/f2fs/data.c
> > +++ b/fs/f2fs/data.c
> > @@ -729,6 +729,9 @@ static int f2fs_read_data_pages(struct file *file,
> > struct list_head *pages, unsigned nr_pages)
> > {
> > struct inode *inode = file->f_mapping->host;
> > + struct page *page = list_entry(pages->prev, struct page, lru);
>
> IMO, it needs to avoid the above line.
Maybe it’s not safe to access page directly in lru list here.
Let's ignore this patch.
Thanks.
> Thanks,
>
> > +
> > + trace_f2fs_readpages(inode, page, nr_pages);
> >
> > /* If the file has inline data, skip readpages */
> > if (f2fs_has_inline_data(inode))
> > diff --git a/include/trace/events/f2fs.h b/include/trace/events/f2fs.h
> > index b983990..7fbaaaa 100644
> > --- a/include/trace/events/f2fs.h
> > +++ b/include/trace/events/f2fs.h
> > @@ -847,6 +847,32 @@ TRACE_EVENT(f2fs_writepages,
> > __entry->for_sync)
> > );
> >
> > +TRACE_EVENT(f2fs_readpages,
> > +
> > + TP_PROTO(struct inode *inode, struct page *page, unsigned int nrpage),
> > +
> > + TP_ARGS(inode, page, nrpage),
> > +
> > + TP_STRUCT__entry(
> > + __field(dev_t, dev)
> > + __field(ino_t, ino)
> > + __field(pgoff_t, start)
> > + __field(unsigned int, nrpage)
> > + ),
> > +
> > + TP_fast_assign(
> > + __entry->dev = inode->i_sb->s_dev;
> > + __entry->ino = inode->i_ino;
> > + __entry->start = page->index;
> > + __entry->nrpage = nrpage;
> > + ),
> > +
> > + TP_printk("dev = (%d,%d), ino = %lu, start = %lu nrpage = %u",
> > + show_dev_ino(__entry),
> > + (unsigned long)__entry->start,
> > + __entry->nrpage)
> > +);
> > +
> > TRACE_EVENT(f2fs_submit_page_mbio,
> >
> > TP_PROTO(struct page *page, int rw, int type, block_t blk_addr),
>
> --
> Jaegeuk Kim
> Samsung
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