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authorJeff Layton <jlayton@redhat.com>2011-03-25 16:25:57 -0400
committerSteve French <sfrench@us.ibm.com>2011-04-12 00:56:00 +0000
commit2b6c26a0a62cc0bab0ad487533d5581d7c293fef (patch)
tree9d1d9b7c3313c43ac580432dbd5ffcceef825d24 /fs
parent8679b0dba7cb98842cbe37f61ef05ef64106334c (diff)
downloadlinux-2b6c26a0a62cc0bab0ad487533d5581d7c293fef.tar.gz
cifs: set ra_pages in backing_dev_info
Commit 522440ed made cifs set backing_dev_info on the mapping attached
to new inodes. This change caused a fairly significant read performance
regression, as cifs started doing page-sized reads exclusively.

By virtue of the fact that they're allocated as part of cifs_sb_info by
kzalloc, the ra_pages on cifs BDIs get set to 0, which prevents any
readahead. This forces the normal read codepaths to use readpage instead
of readpages causing a four-fold increase in the number of read calls
with the default rsize.

Fix it by setting ra_pages in the BDI to the same value as that in the
default_backing_dev_info.

Fixes https://bugzilla.kernel.org/show_bug.cgi?id=31662

Cc: stable@kernel.org
Reported-and-Tested-by: Till <till2.schaefer@uni-dortmund.de>
Signed-off-by: Jeff Layton <jlayton@redhat.com>
Signed-off-by: Steve French <sfrench@us.ibm.com>
Diffstat (limited to 'fs')
-rw-r--r--fs/cifs/cifsfs.c1
1 files changed, 1 insertions, 0 deletions
diff --git a/fs/cifs/cifsfs.c b/fs/cifs/cifsfs.c
index 0e0cc60dbde0..e3352a1ac479 100644
--- a/fs/cifs/cifsfs.c
+++ b/fs/cifs/cifsfs.c
@@ -130,6 +130,7 @@ cifs_read_super(struct super_block *sb, void *data,
 		kfree(cifs_sb);
 		return rc;
 	}
+	cifs_sb->bdi.ra_pages = default_backing_dev_info.ra_pages;
 
 #ifdef CONFIG_CIFS_DFS_UPCALL
 	/* copy mount params to sb for use in submounts */