LU-7990 llite: increase whole-file readahead to RPC size

Increase the default whole-file readahead limit to match the current
RPC size.  That ensures that files smaller than the RPC size will be
read in a single round-trip instead of sending multiple smaller RPCs.

Lustre-change: https://review.whamcloud.com/26955
Lustre-commit: 627d0133d9d7bef908544537a8a2b2093719fc72

Signed-off-by: Andreas Dilger <andreas.dilger@intel.com>
Change-Id: I3bdb1c7f92c546d58951a9e6b783af23c83ebbe5
Reviewed-by: Patrick Farrell <paf@cray.com>
Reviewed-by: Dmitry Eremin <dmitry.eremin@intel.com>
Signed-off-by: Minh Diep <minh.diep@intel.com>
Reviewed-on: https://review.whamcloud.com/29738
Tested-by: Jenkins
Tested-by: Maloo <hpdd-maloo@intel.com>
Reviewed-by: John L. Hammond <john.hammond@intel.com>

diff --git a/lustre/llite/llite_lib.c b/lustre/llite/llite_lib.c
index ba305aa..0824fa2 100644 (file)
--- a/lustre/llite/llite_lib.c
+++ b/lustre/llite/llite_lib.c
@@ -99,8 +99,7 @@ static struct ll_sb_info *ll_init_sbi(void)
        sbi->ll_ra_info.ra_max_pages_per_file = min(pages / 32,
                                           SBI_DEFAULT_READAHEAD_MAX);
        sbi->ll_ra_info.ra_max_pages = sbi->ll_ra_info.ra_max_pages_per_file;
-       sbi->ll_ra_info.ra_max_read_ahead_whole_pages =
-                                          SBI_DEFAULT_READAHEAD_WHOLE_MAX;
+       sbi->ll_ra_info.ra_max_read_ahead_whole_pages = -1;
 
         ll_generate_random_uuid(uuid);
         class_uuid_unparse(uuid, &sbi->ll_sb_uuid);
@@ -449,6 +448,12 @@ static int client_common_fill_super(struct super_block *sb, char *md, char *dt,
 
        sbi->ll_dt_exp->exp_connect_data = *data;
 
+       /* Don't change value if it was specified in the config log */
+       if (sbi->ll_ra_info.ra_max_read_ahead_whole_pages == -1)
+               sbi->ll_ra_info.ra_max_read_ahead_whole_pages =
+                       max_t(unsigned long, SBI_DEFAULT_READAHEAD_WHOLE_MAX,
+                             (data->ocd_brw_size >> PAGE_SHIFT));
+
        err = obd_fid_init(sbi->ll_dt_exp->exp_obd, sbi->ll_dt_exp,
                           LUSTRE_SEQ_METADATA);
        if (err) {