On Sun, 2013-03-17 at 17:40 +0900, Namjae Jeon wrote:
> From: Namjae Jeon <namjae.j...@samsung.com>
>
> Add tracepoints for page i/o operations and block allocation
> tracing during page read operation.
>
> Signed-off-by: Namjae Jeon <namjae.j...@samsung.com>
> Signed-off-by: Pankaj Kumar <pankaj...@samsung.com>
> ---
> fs/f2fs/data.c | 11 ++++++--
> include/trace/events/f2fs.h | 58
> +++++++++++++++++++++++++++++++++++++++++++
> 2 files changed, 67 insertions(+), 2 deletions(-)
>
> diff --git a/fs/f2fs/data.c b/fs/f2fs/data.c
> index 02ad450..bb9117b 100644
> --- a/fs/f2fs/data.c
> +++ b/fs/f2fs/data.c
> @@ -22,6 +22,7 @@
> #include "f2fs.h"
> #include "node.h"
> #include "segment.h"
> +#include <trace/events/f2fs.h>
>
> /*
> * Lock ordering for the change of data block address:
> @@ -335,6 +336,9 @@ int f2fs_readpage(struct f2fs_sb_info *sbi, struct page
> *page,
> bool sync = (type == READ_SYNC);
> struct bio *bio;
>
> + if (page->mapping)
> + trace_f2fs_readpage(page);
Since the only thing that happens whet page->mapping is set is to trace
the page, you can move that check into the tracepoint itself. That is,
move the branch into the tracepoint, making the branch a nop when the
tracepoint isn't active. That's what TRACE_EVENT_CONDITION() does. Make
this into:
trace_f2fs_readpage(page);
and then see below.
> +
> /* This page can be already read by other threads */
> if (PageUptodate(page)) {
> if (!sync)
> @@ -385,6 +389,7 @@ static int get_data_block_ro(struct inode *inode,
> sector_t iblock,
> pgoff_t pgofs;
> int err;
>
> + trace_f2fs_get_data_block_enter(inode, iblock, 0);
> /* Get the page offset from the block offset(iblock) */
> pgofs = (pgoff_t)(iblock >> (PAGE_CACHE_SHIFT - blkbits));
>
> @@ -394,9 +399,10 @@ static int get_data_block_ro(struct inode *inode,
> sector_t iblock,
> /* When reading holes, we need its node page */
> set_new_dnode(&dn, inode, NULL, NULL, 0);
> err = get_dnode_of_data(&dn, pgofs, LOOKUP_NODE_RA);
> - if (err)
> + if (err) {
> + trace_f2fs_get_data_block_exit(inode, iblock, err);
> return (err == -ENOENT) ? 0 : err;
> -
> + }
> /* It does not support data allocation */
> BUG_ON(create);
>
> @@ -420,6 +426,7 @@ static int get_data_block_ro(struct inode *inode,
> sector_t iblock,
> bh_result->b_size = (i << blkbits);
> }
> f2fs_put_dnode(&dn);
> + trace_f2fs_get_data_block_exit(inode, iblock, 0);
> return 0;
> }
>
> diff --git a/include/trace/events/f2fs.h b/include/trace/events/f2fs.h
> index 0d39f58..d60f3ed 100644
> --- a/include/trace/events/f2fs.h
> +++ b/include/trace/events/f2fs.h
> @@ -266,6 +266,64 @@ TRACE_EVENT(f2fs_truncate,
> (unsigned long) __entry->ino)
> );
>
> +TRACE_EVENT(f2fs_readpage,
TRACE_EVENT_CONDITIO(f2fs_readpage,
> + TP_PROTO(struct page *page),
> +
> + TP_ARGS(page),
TP_CONDITION(page->mapping),
That's it!
Now the tracepoint will only be called if page->mapping is set, but
checking page->mapping will be done only if the tracepoint is enabled.
Keeping the original code untouched.
-- Steve
> +
> + TP_STRUCT__entry(
> + __field(pgoff_t, index)
> + __field(ino_t, ino)
> + __field(dev_t, dev)
> +
> + ),
> +
> + TP_fast_assign(
> + __entry->index = page->index;
> + __entry->ino = page->mapping->host->i_ino;
> + __entry->dev = page->mapping->host->i_sb->s_dev;
> + ),
> +
> + TP_printk("dev %d,%d ino %lu page_index %lu",
> + MAJOR(__entry->dev), MINOR(__entry->dev),
> + (unsigned long) __entry->ino,
> + (unsigned long) __entry->index)
> +);
> +
> +DECLARE_EVENT_CLASS(f2fs_data_block,
> + TP_PROTO(struct inode *inode, sector_t block, int ret),
> +
> + TP_ARGS(inode, block, ret),
> +
> + TP_STRUCT__entry(
> + __field(dev_t, dev)
> + __field(ino_t, ino)
> + __field(sector_t, block)
> + __field(int, ret)
> + ),
> +
> + TP_fast_assign(
> + __entry->dev = inode->i_sb->s_dev;
> + __entry->ino = inode->i_ino;
> + __entry->block = block;
> + __entry->ret = ret;
> + ),
> +
> + TP_printk("dev %d,%d ino %lu block number %llu error %d",
> + MAJOR(__entry->dev), MINOR(__entry->dev),
> + (unsigned long) __entry->ino, (unsigned long long)
> __entry->block, __entry->ret)
> +);
> +
> +DEFINE_EVENT(f2fs_data_block, f2fs_get_data_block_enter,
> + TP_PROTO(struct inode *inode, sector_t block, int ret),
> + TP_ARGS(inode, block, ret)
> +);
> +
> +DEFINE_EVENT(f2fs_data_block, f2fs_get_data_block_exit,
> + TP_PROTO(struct inode *inode, sector_t block, int ret),
> + TP_ARGS(inode, block, ret)
> +);
> +
> #endif /* _TRACE_F2FS_H */
>
> /* This part must be outside protection */
--
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