1. Use top Check memory usage , Then type. "M" The commands are sorted in descending order according to memory usage ("P" yes CPU Occupancy is in descending order )
2. Shut down unnecessary processes ,
3. Reuse top Check the memory usage , I found that the memory usage has dropped , however free -g But there are others 100G occupied （ Total memory 128G),vmstat Found to be cache It takes up a lot of memory .
4. Use echo 1 > /proc/sys/vm/drop_caches Release cache
The common command to release the cache is as follows
To free pagecache: Clear page cache only （PageCache）
echo 1 > /proc/sys/vm/drop_caches
To free dentries and inodes: Clear directory entries and inode
echo 2 > /proc/sys/vm/drop_caches
To free pagecache, dentries and inodes: Clear page cache , Catalog entries and inode
echo 3 > /proc/sys/vm/drop_caches
5. Reuse free -g View memory usage , Found that memory usage is normal .