Mismatch between SGA and HugePages

Oracle 18.5.0.0.0 on Exadata X-7

Inside Oracle, v$parameter and v$spparameter both show sga_target and sga_max_size as 81920M:

SQL> select value/1024/1024 from v$parameter where name in ('sga_max_size','sga_target');

VALUE/1024/1024

---------------

          81920

          81920

But alert.log shows:

2019-09-10T22:46:28.183947-05:00

  PAGESIZE  AVAILABLE_PAGES  EXPECTED_PAGES  ALLOCATED_PAGES  ERROR(s)

2019-09-10T22:46:28.184057-05:00

        4K       Configured               7               7        NONE

2019-09-10T22:46:28.184231-05:00

     2048K            41415           40914           40914        NONE

So, we see only 40914 pages or 81828M is allocated. This can be corroborated with the entries in x$ksmssinfo, or in the output of Linux command `ipcs -m':

SQL> select "AREA NAME", "SEGMENT SIZE"/1048576 SegmentSize, "SIZE"/1048576 ChunkSize, pagesize, shmid from x$ksmssinfo;