cifs: don't cap ra_pages at the same level as default_backing_dev_info
While testing, I've found that even when we are able to negotiate a
much larger rsize with the server, on-the-wire reads often end up being
capped at 128k because of ra_pages being capped at that level.
Lifting this restriction gave almost a twofold increase in sequential
read performance on my craptactular KVM test rig with a 1M rsize.
I think this is safe since the actual ra_pages that the VM requests
is run through max_sane_readahead() prior to submitting the I/O. Under
memory pressure we should end up with large readahead requests being
suppressed anyway.
Signed-off-by: Jeff Layton <jlayton@redhat.com>
Signed-off-by: Steve French <sfrench@us.ibm.com>
diff --git a/fs/cifs/connect.c b/fs/cifs/connect.c
index f4d381e..6ce888b 100644
--- a/fs/cifs/connect.c
+++ b/fs/cifs/connect.c
@@ -3614,22 +3614,6 @@
return volume_info;
}
-/* make sure ra_pages is a multiple of rsize */
-static inline unsigned int
-cifs_ra_pages(struct cifs_sb_info *cifs_sb)
-{
- unsigned int reads;
- unsigned int rsize_pages = cifs_sb->rsize / PAGE_CACHE_SIZE;
-
- if (rsize_pages >= default_backing_dev_info.ra_pages)
- return default_backing_dev_info.ra_pages;
- else if (rsize_pages == 0)
- return rsize_pages;
-
- reads = default_backing_dev_info.ra_pages / rsize_pages;
- return reads * rsize_pages;
-}
-
int
cifs_mount(struct cifs_sb_info *cifs_sb, struct smb_vol *volume_info)
{
@@ -3717,7 +3701,7 @@
cifs_sb->rsize = cifs_negotiate_rsize(tcon, volume_info);
/* tune readahead according to rsize */
- cifs_sb->bdi.ra_pages = cifs_ra_pages(cifs_sb);
+ cifs_sb->bdi.ra_pages = cifs_sb->rsize / PAGE_CACHE_SIZE;
remote_path_check:
#ifdef CONFIG_CIFS_DFS_UPCALL