Total installed memory in bytes.

Unused memory in bytes.

Estimation of how much memory, in bytes, is available for starting new applications, without swapping. Unlike the data provided by the cache or free fields, this field takes into account page cache and also that not all reclaimable memory will be reclaimed due to items being in use.

Memory used by kernel buffers.

Memory used by the page cache and slabs.

Total swap memory.

Unused swap memory.