diff options
| author | Bob Peterson <rpeterso@redhat.com> | 2014-11-19 12:27:11 -0600 |
|---|---|---|
| committer | Bob Peterson <rpeterso@redhat.com> | 2015-04-24 07:57:08 -0500 |
| commit | f4a3ae9308e34bcd704325a08879b2c1cfb74686 (patch) | |
| tree | 2002df7eacb9f6d17fedc46057eae3159d9cd68c | |
| parent | bb0fd7ab0986105765d11baa82e619c618a235aa (diff) | |
GFS2: Use average srttb value in congestion calculations
This patch changes function gfs2_rgrp_congested so that it uses an
average srttb (smoothed round trip time for blocking rgrp glocks)
rather than the CPU-specific value. If we use the CPU-specific value
it can incorrectly report no contention when there really is contention
due to the glock processing occurring on a different CPU.
Signed-off-by: Bob Peterson <rpeterso@redhat.com>
Acked-by: Steven Whitehouse <swhiteho@redhat.com>
| -rw-r--r-- | fs/gfs2/rgrp.c | 13 |
1 files changed, 9 insertions, 4 deletions
diff --git a/fs/gfs2/rgrp.c b/fs/gfs2/rgrp.c index 6af2396a317c..f39eedc1af76 100644 --- a/fs/gfs2/rgrp.c +++ b/fs/gfs2/rgrp.c @@ -1850,14 +1850,19 @@ static bool gfs2_rgrp_congested(const struct gfs2_rgrpd *rgd, int loops) const struct gfs2_sbd *sdp = gl->gl_sbd; struct gfs2_lkstats *st; s64 r_dcount, l_dcount; - s64 r_srttb, l_srttb; + s64 l_srttb, a_srttb = 0; s64 srttb_diff; s64 sqr_diff; s64 var; + int cpu; 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]; + } st = &this_cpu_ptr(sdp->sd_lkstats)->lkstats[LM_TYPE_RGRP]; - r_srttb = st->stats[GFS2_LKS_SRTTB]; + a_srttb /= num_present_cpus(); r_dcount = st->stats[GFS2_LKS_DCOUNT]; var = st->stats[GFS2_LKS_SRTTVARB] + gl->gl_stats.stats[GFS2_LKS_SRTTVARB]; @@ -1866,10 +1871,10 @@ static bool gfs2_rgrp_congested(const struct gfs2_rgrpd *rgd, int loops) l_srttb = gl->gl_stats.stats[GFS2_LKS_SRTTB]; l_dcount = gl->gl_stats.stats[GFS2_LKS_DCOUNT]; - if ((l_dcount < 1) || (r_dcount < 1) || (r_srttb == 0)) + if ((l_dcount < 1) || (r_dcount < 1) || (a_srttb == 0)) return false; - srttb_diff = r_srttb - l_srttb; + srttb_diff = a_srttb - l_srttb; sqr_diff = srttb_diff * srttb_diff; var *= 2; |