The starting situation, no swap is active. total: used: free: shared: buffers: cached: Mem: 528072704 503410688 24662016 0 115126272 115027968 Swap: 0 0 0 MemTotal: 515696 kB MemFree: 24084 kB MemShared: 0 kB Buffers: 112428 kB Cached: 112332 kB SwapCached: 0 kB Active: 135992 kB Inactive: 227328 kB HighTotal: 0 kB HighFree: 0 kB LowTotal: 515696 kB LowFree: 24084 kB SwapTotal: 0 kB SwapFree: 0 kB (used - buffers - cached = 260 MB) Starting the memeater process that tries to allocate (and use) 600MB. It gets killed (of course) by the kernel. The situation afterwards: much less memory used. total: used: free: shared: buffers: cached: Mem: 528072704 176635904 351436800 0 692224 14303232 Swap: 0 0 0 MemTotal: 515696 kB MemFree: 343200 kB MemShared: 0 kB Buffers: 676 kB Cached: 13968 kB SwapCached: 0 kB Active: 18204 kB Inactive: 135008 kB HighTotal: 0 kB HighFree: 0 kB LowTotal: 515696 kB LowFree: 343200 kB SwapTotal: 0 kB SwapFree: 0 kB (used - buffers - cached = 154 MB) Here is the question: apparently over 100 MB of non-buffer, non-cache information disappeared from the memory. What?