Memory usage on macOS?

[thenktor]

Hi,

what exactly does the memory usage graph on macOS show?

Currently:

• btm shows 11.9GiB/16.OGiB.
• top shows MemRegions: 0 total, 0B resident, 0B private, 2086M shared. PhysMem: 15G used (2970M wired, 5276M compressor), 165M unused.
• htop shows 12.8G/16.0G

Mach Virtual Memory Statistics: (page size of 16384 bytes)
Pages free:                                4342.
Pages active:                            247448.
Pages inactive:                          242953.
Pages speculative:                         3936.
Pages throttled:                              0.
Pages wired down:                        189730.
Pages purgeable:                           7433.
"Translation faults":                2051037981.
Pages copy-on-write:                  402327622.
Pages zero filled:                    750839767.
Pages reactivated:                    152158216.
Pages purged:                          42535163.
File-backed pages:                       172457.
Anonymous pages:                         321880.
Pages stored in compressor:             1291940.
Pages occupied by compressor:            319748.
Decompressions:                       195424560.
Compressions:                         241607596.
Pageins:                               62842188.
Pageouts:                                611719.
Swapins:                                 457186.
Swapouts:                                808821.

EDIT: pages to MB:

Pages free                      7998 pages    124.97 MB
Pages active                  245524 pages   3836.31 MB
Pages inactive                243231 pages   3800.48 MB
Pages speculative                887 pages     13.86 MB
Pages throttled                    0 pages      0.00 MB
Pages wired down              190101 pages   2970.33 MB
Pages purgeable                18700 pages    292.19 MB

[ClementTsang]

Sorry for the late reply! It mostly just reports what https://crates.io/crates/sysinfo is reporting, which should now match https://github.com/apple-oss-distributions/xnu/blob/main/doc/vm/memorystatus_notify.md#available-memory. In particular (see here):

                    self.mem_available = u64::from(stat.active_count)
                        .saturating_add(u64::from(stat.inactive_count))
                        .saturating_add(u64::from(stat.free_count))
                        .saturating_mul(self.page_size_b);
                    self.mem_used = u64::from(stat.internal_page_count)
                        .saturating_sub(u64::from(stat.purgeable_count))
                        .saturating_add(u64::from(stat.wire_count))
                        .saturating_add(u64::from(stat.compressor_page_count))
                        .saturating_mul(self.page_size_b);
                    self.mem_free = u64::from(stat.free_count)
                        .saturating_sub(u64::from(stat.speculative_count))
                        .saturating_mul(self.page_size_b);