Add back cached memory code logic.

openbsd/OpenBSDMachine.c

@@ -141,7 +141,18 @@ static void OpenBSDMachine_scanMemoryInfo(OpenBSDMachine* this) {
    }
 
    super->totalMem = uvmexp.npages * this->pageSizeKB;
-   super->usedMem = (uvmexp.npages - uvmexp.free) * this->pageSizeKB;
+   super->usedMem = (uvmexp.npages - uvmexp.free - uvmexp.paging) * this->pageSizeKB;
+
+   // Taken from OpenBSD systat/iostat.c, top/machine.c and uvm_sysctl(9)
+   const int bcache_mib[] = { CTL_VFS, VFS_GENERIC, VFS_BCACHESTAT };
+   struct bcachestats bcstats;
+   size_t size_bcstats = sizeof(bcstats);
+
+   if (sysctl(bcache_mib, 3, &bcstats, &size_bcstats, NULL, 0) < 0) {
+      CRT_fatalError("cannot get vfs.bcachestat");
+   }
+
+   super->cachedMem = bcstats.numbufpages * this->pageSizeKB;
 
    /*
     * Copyright (c) 1994 Thorsten Lockert <[email protected]>