f2fs: add tracepoint for tracing the page i/o

Add tracepoints for page i/o operations and block allocation
tracing during page read operation.
Signed-off-by: Namjae Jeon <namjae.jeon@samsung.com>
Signed-off-by: Pankaj Kumar <pankaj.km@samsung.com>
Acked-by: Steven Rostedt <rostedt@goodmis.org>
[Jaegeuk: combine and modify the tracepoint structures]
Signed-off-by: Jaegeuk Kim <jaegeuk.kim@samsung.com>

fs/f2fs/data.c

@@ -21,6 +21,7 @@
 #include "f2fs.h"
 #include "node.h"
 #include "segment.h"
+#include <trace/events/f2fs.h>
 
 /*
  * Lock ordering for the change of data block address:
@@ -348,6 +349,8 @@ int f2fs_readpage(struct f2fs_sb_info *sbi, struct page *page,
 	struct block_device *bdev = sbi->sb->s_bdev;
 	struct bio *bio;
 
+	trace_f2fs_readpage(page, blk_addr, type);
+
 	down_read(&sbi->bio_sem);
 
 	/* Allocate a new bio */
@@ -388,14 +391,18 @@ static int get_data_block_ro(struct inode *inode, sector_t iblock,
 	/* Get the page offset from the block offset(iblock) */
 	pgofs =	(pgoff_t)(iblock >> (PAGE_CACHE_SHIFT - blkbits));
 
-	if (check_extent_cache(inode, pgofs, bh_result))
+	if (check_extent_cache(inode, pgofs, bh_result)) {
+		trace_f2fs_get_data_block(inode, iblock, bh_result, 0);
 		return 0;
+	}
 
 	/* 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(inode, iblock, bh_result, err);
 		return (err == -ENOENT) ? 0 : err;
+	}
 
 	/* It does not support data allocation */
 	BUG_ON(create);
@@ -420,6 +427,7 @@ 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(inode, iblock, bh_result, 0);
 	return 0;
 }
 

include/trace/events/f2fs.h

@@ -8,6 +8,15 @@
 
 #define show_dev(entry)		MAJOR(entry->dev), MINOR(entry->dev)
 #define show_dev_ino(entry)	show_dev(entry), (unsigned long)entry->ino
+#define show_bio_type(type)						\
+	__print_symbolic(type,						\
+		{ READ, 	"READ" },				\
+		{ READA, 	"READAHEAD" },				\
+		{ READ_SYNC, 	"READ_SYNC" },				\
+		{ WRITE, 	"WRITE" },				\
+		{ WRITE_SYNC, 	"WRITE_SYNC" },				\
+		{ WRITE_FLUSH,	"WRITE_FLUSH" },			\
+		{ WRITE_FUA, 	"WRITE_FUA" })
 
 DECLARE_EVENT_CLASS(f2fs__inode,
 
@@ -365,6 +374,71 @@ TRACE_EVENT(f2fs_truncate_partial_nodes,
 		__entry->err)
 );
 
+TRACE_EVENT_CONDITION(f2fs_readpage,
+
+	TP_PROTO(struct page *page, sector_t blkaddr, int type),
+
+	TP_ARGS(page, blkaddr, type),
+
+	TP_CONDITION(page->mapping),
+
+	TP_STRUCT__entry(
+		__field(dev_t,	dev)
+		__field(ino_t,	ino)
+		__field(pgoff_t,	index)
+		__field(sector_t,	blkaddr)
+		__field(int,	type)
+	),
+
+	TP_fast_assign(
+		__entry->dev		= page->mapping->host->i_sb->s_dev;
+		__entry->ino		= page->mapping->host->i_ino;
+		__entry->index		= page->index;
+		__entry->blkaddr	= blkaddr;
+		__entry->type		= type;
+	),
+
+	TP_printk("dev = (%d,%d), ino = %lu, page_index = 0x%lx, "
+		"blkaddr = 0x%llx, bio_type = %s",
+		show_dev_ino(__entry),
+		(unsigned long)__entry->index,
+		(unsigned long long)__entry->blkaddr,
+		show_bio_type(__entry->type))
+);
+
+TRACE_EVENT(f2fs_get_data_block,
+	TP_PROTO(struct inode *inode, sector_t iblock,
+				struct buffer_head *bh, int ret),
+
+	TP_ARGS(inode, iblock, bh, ret),
+
+	TP_STRUCT__entry(
+		__field(dev_t,	dev)
+		__field(ino_t,	ino)
+		__field(sector_t,	iblock)
+		__field(sector_t,	bh_start)
+		__field(size_t,	bh_size)
+		__field(int,	ret)
+	),
+
+	TP_fast_assign(
+		__entry->dev		= inode->i_sb->s_dev;
+		__entry->ino		= inode->i_ino;
+		__entry->iblock		= iblock;
+		__entry->bh_start	= bh->b_blocknr;
+		__entry->bh_size	= bh->b_size;
+		__entry->ret		= ret;
+	),
+
+	TP_printk("dev = (%d,%d), ino = %lu, file offset = %llu, "
+		"start blkaddr = 0x%llx, len = 0x%llx bytes, err = %d",
+		show_dev_ino(__entry),
+		(unsigned long long)__entry->iblock,
+		(unsigned long long)__entry->bh_start,
+		(unsigned long long)__entry->bh_size,
+		__entry->ret)
+);
+
 #endif /* _TRACE_F2FS_H */
 
  /* This part must be outside protection */