From 1b6f6f27b77803727a523b4337cbad411e8321ed Mon Sep 17 00:00:00 2001 From: xie xingguo Date: Tue, 26 Apr 2016 11:13:32 +0800 Subject: [PATCH] mon/OSDMonitor: improve reweight_by_utilization() logic By calling reweight_by_utilization() method, we are aiming at an evener result of utilization among all osds. To achieve this, we shall decrease weights of osds which are currently overloaded, and try to increase weights of osds which are currently underloaded when it is possible. However, we can't do this all at a time in order to avoid a massive pg migrations between osds. Thus we introduce a max_osds limit to smooth the progress. The problem here is that we have sorted the utilization of all osds in a descending manner and we always try to decrease the weights of the most overloaded osds since they are most likely to encounter a nearfull/full transition soon, but we won't increase the weights from the most underloaded(least utilized by contrast) at the same time, which I think is not quite reasonable. Actually, the best thing would probably be to iterate over teh low and high osds in parallel, and do the ones that are furthest from the average first. Signed-off-by: xie xingguo (cherry picked from commit e7a32534ebc9e27f955ff2d7a8d1db511383301e) Conflicts: src/mon/OSDMonitor.cc Resolved by picking the lambda implemenation. NOTE: Because hammer does not support C++11, the lambda functionality from the current master has been moved into the "Sorter" function object. --- src/mon/OSDMonitor.cc | 19 +++++++++++++------ 1 file changed, 13 insertions(+), 6 deletions(-) diff --git a/src/mon/OSDMonitor.cc b/src/mon/OSDMonitor.cc index 1f08548fa54c6..c647c60017d6d 100644 --- a/src/mon/OSDMonitor.cc +++ b/src/mon/OSDMonitor.cc @@ -463,10 +463,16 @@ void OSDMonitor::update_logger() } struct Sorter { - bool operator()(std::pair l, - std::pair r) { - return l.second > r.second; - } + + double average_util; + + Sorter(const double average_util_) + : average_util(average_util_) + {} + + bool operator()(std::pair l, std::pair r) { + return abs(l.second - average_util) > abs(r.second - average_util); + } }; /* Assign a lower weight to overloaded OSDs. @@ -595,8 +601,9 @@ int OSDMonitor::reweight_by_utilization(int oload, util_by_osd.push_back(osd_util); } - // sort and iterate from most to least utilized - std::sort(util_by_osd.begin(), util_by_osd.end(), Sorter()); + // sort by absolute deviation from the mean utilization, + // in descending order. + std::sort(util_by_osd.begin(), util_by_osd.end(), Sorter(average_util)); OSDMap::Incremental newinc; -- 2.39.5