GFS2: Average in only non-zero round-trip times for congestion stats
This patch changes function gfs2_rgrp_congested so that it only factors
in non-zero values into its average round trip time. If the round-trip
time is zero for a particular cpu, that cpu has obviously never dealt
with bouncing the resource group in question, so factoring in a zero
value will only skew the numbers. It also fixes a compile error on
some arches related to division.
Signed-off-by: Bob Peterson <rpeterso@redhat.com>
Acked-by: Steven Whitehouse <swhiteho@redhat.com>
diff --git a/fs/gfs2/rgrp.c b/fs/gfs2/rgrp.c
index f39eedc..cb27065 100644
--- a/fs/gfs2/rgrp.c
+++ b/fs/gfs2/rgrp.c
@@ -1854,15 +1854,19 @@
s64 srttb_diff;
s64 sqr_diff;
s64 var;
- int cpu;
+ int cpu, nonzero = 0;
preempt_disable();
for_each_present_cpu(cpu) {
st = &per_cpu_ptr(sdp->sd_lkstats, cpu)->lkstats[LM_TYPE_RGRP];
- a_srttb += st->stats[GFS2_LKS_SRTTB];
+ if (st->stats[GFS2_LKS_SRTTB]) {
+ a_srttb += st->stats[GFS2_LKS_SRTTB];
+ nonzero++;
+ }
}
st = &this_cpu_ptr(sdp->sd_lkstats)->lkstats[LM_TYPE_RGRP];
- a_srttb /= num_present_cpus();
+ if (nonzero)
+ do_div(a_srttb, nonzero);
r_dcount = st->stats[GFS2_LKS_DCOUNT];
var = st->stats[GFS2_LKS_SRTTVARB] +
gl->gl_stats.stats[GFS2_LKS_SRTTVARB];