xfs: add tracepoints to readpage calls

This allows us to see page cache driven readahead in action as it
passes through XFS. This helps to understand buffered read
throughput problems such as readahead IO IO sizes being too small
for the underlying device to reach max throughput.

Signed-off-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Brian Foster <bfoster@redhat.com>
Signed-off-by: Dave Chinner <david@fromorbit.com>

1 files changed, 2 insertions, 0 deletions

diff --git a/fs/xfs/xfs_aops.c b/fs/xfs/xfs_aops.c
index 29e7e5d..379c089 100644
--- a/fs/xfs/xfs_aops.c
+++ b/fs/xfs/xfs_aops.c
@@ -1917,6 +1917,7 @@ xfs_vm_readpage(
 	struct file		*unused,
 	struct page		*page)
 {
+	trace_xfs_vm_readpage(page->mapping->host, 1);
 	return mpage_readpage(page, xfs_get_blocks);
 }
 
@@ -1927,6 +1928,7 @@ xfs_vm_readpages(
 	struct list_head	*pages,
 	unsigned		nr_pages)
 {
+	trace_xfs_vm_readpages(mapping->host, nr_pages);
 	return mpage_readpages(mapping, pages, nr_pages, xfs_get_blocks);
 }