[PATCH 22/23] readahead: debug traces showing accessed file names

[Wu Fengguang <wfg@mail.ustc.edu.cn>]

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Print file names on their first read-ahead, for tracing file access patterns.

Signed-off-by: Wu Fengguang <wfg@mail.ustc.edu.cn>
---

 mm/readahead.c |   14 ++++++++++++++
 1 files changed, 14 insertions(+)

--- linux-2.6.16-rc6-mm2.orig/mm/readahead.c
+++ linux-2.6.16-rc6-mm2/mm/readahead.c
@@ -1229,6 +1229,20 @@ static int ra_dispatch(struct file_ra_st
 		ra_account(ra, RA_EVENT_IO_CACHE_HIT, ra_size - actual);
 	ra_account(ra, RA_EVENT_READAHEAD, actual);
 
+	if (!ra->ra_index && filp->f_dentry->d_inode) {
+		char *fn;
+		static char path[1024];
+		unsigned long size;
+
+		size = (i_size_read(filp->f_dentry->d_inode)+1023)/1024;
+		fn = d_path(filp->f_dentry, filp->f_vfsmnt, path, 1000);
+		if (!IS_ERR(fn))
+			ddprintk("ino %lu is %s size %luK by %s(%d)\n",
+					filp->f_dentry->d_inode->i_ino,
+					fn, size,
+					current->comm, current->pid);
+	}
+
 	dprintk("readahead-%s(ino=%lu, index=%lu, ra=%lu+%lu-%lu) = %d\n",
 			ra_class_name[ra_class],
 			mapping->host->i_ino, ra->la_index,

--