High memory usage on director

Issue

• High memory usage is reported on director node.

# free -m
              total        used        free      shared  buff/cache   available
Mem:          48111       46479         442         208        1189         917
Swap:          3999        3999           0

• Why director node is having high memory utilization ?
• heat-engine processes are consuming major chunk of memory on undercloud node

top - 11:25:22 up 6 days, 21:25,  1 user,  load average: 0.61, 0.78, 0.60
Tasks: 860 total,   2 running, 857 sleeping,   0 stopped,   1 zombie
%Cpu(s):  1.0 us,  0.6 sy,  0.0 ni, 98.2 id,  0.2 wa,  0.0 hi,  0.0 si,  0.0 st
KiB Mem : 49265972 total,   477224 free, 47564436 used,  1224312 buff/cache
KiB Swap:  4095996 total,      796 free,  4095200 used.   970108 avail Mem

  PID USER      PR  NI    VIRT    RES    SHR S  %CPU %MEM     TIME+ COMMAND
10944 heat      20   0 1627004 1.207g   2808 S   0.3  2.6  16:27.93 heat-engine
10919 heat      20   0 1421592 1.003g   2764 S   0.3  2.1  16:19.71 heat-engine
10921 heat      20   0 1700796 982.3m   2844 S   0.3  2.0  24:41.77 heat-engine
10936 heat      20   0 1365944 981.7m   2784 S   0.3  2.0  24:38.14 heat-engine
10930 heat      20   0 1345444 984816   2780 S   0.0  2.0  25:42.15 heat-engine
10924 heat      20   0 1338844 978280   2792 S   0.0  2.0  19:12.36 heat-engine
10915 heat      20   0 1319528 958544   2832 S   0.0  1.9  27:09.51 heat-engine
10925 heat      20   0 1318260 954488   2776 S   0.3  1.9  15:12.01 heat-engine
10933 heat      20   0 1310580 949592   2780 S   0.3  1.9  14:44.41 heat-engine
10937 heat      20   0 1301868 941072   2792 S   0.0  1.9  14:33.21 heat-engine
10916 heat      20   0 1292476 931072   2820 S   0.0  1.9  24:43.97 heat-engine
10945 heat      20   0 1290424 929168   2800 S   0.3  1.9  24:43.70 heat-engine
10938 heat      20   0 1288476 927832   2784 S   0.0  1.9  24:43.47 heat-engine
10917 heat      20   0 1288008 925572   2856 S   0.0  1.9  24:27.35 heat-engine
10927 heat      20   0 1277592 916976   2736 S   0.3  1.9  23:35.90 heat-engine
10932 heat      20   0 1270116 893920   2800 S   0.0  1.8  14:37.24 heat-engine
10934 heat      20   0 1243460 882308   2776 S   0.0  1.8  14:26.17 heat-engine
10928 heat      20   0 1229276 865248   2776 S   0.3  1.8  14:21.28 heat-engine
10931 heat      20   0 1207864 842488   2784 S   0.3  1.7  30:39.84 heat-engine
10926 heat      20   0 1190316 829588   2780 S   0.0  1.7  22:53.10 heat-engine
10922 heat      20   0 1189616 827964   2800 S   0.0  1.7  14:33.42 heat-engine
10929 heat      20   0 1188300 826872   2756 S   0.3  1.7  22:20.35 heat-engine
10920 heat      20   0 1175476 814408   2800 S   0.0  1.7  29:12.20 heat-engine
10941 heat      20   0 1156700 796332   2932 S   0.3  1.6  22:57.35 heat-engine
10923 heat      20   0 1157468 793340   2816 S   0.0  1.6  13:51.06 heat-engine
10943 heat      20   0 1152120 791352   2820 S   0.3  1.6  26:50.90 heat-engine
10918 heat      20   0 1150156 789180   2808 S   0.0  1.6  52:16.08 heat-engine
10940 heat      20   0 1147016 785004   2756 S   0.3  1.6  16:35.08 heat-engine
10935 heat      20   0 1138932 777548   2864 S   0.0  1.6  25:35.17 heat-engine
10914 heat      20   0 1133040 771956   2756 S   0.3  1.6  13:36.58 heat-engine
10942 heat      20   0 1127356 766800   2848 S   0.0  1.6  65:15.52 heat-engine
10939 heat      20   0 1124920 763132   2760 S   0.0  1.5  15:41.09 heat-engine