From 8f71465c19ffefbfd0da3c1f5dc172b4bce05e93 Mon Sep 17 00:00:00 2001 From: Jeff Layton Date: Tue, 1 May 2012 17:41:49 -0400 Subject: [PATCH] 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 Signed-off-by: Steve French --- fs/cifs/connect.c | 18 +----------------- 1 file changed, 1 insertion(+), 17 deletions(-) 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 @@ cifs_get_volume_info(char *mount_data, const char *devname) 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 @@ try_mount_again: 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 -- 2.7.4