/proc/meminfo or show_free_areas does not show full system wide memory usage status. There seems to be huge hidden memory especially on embedded Android system. Because it usually have some HW IP which do not have internal memory and use common DRAM memory. In Android system, most of those hidden memory seems to be vmalloc pages , ion system heap memory, graphics memory, and memory for DRAM based compressed swap storage. They may be shown in other node but it seems to useful if /proc/meminfo shows all those extra memory information. And show_mem also need to print the info in oom situation. Fortunately vmalloc pages is alread shown by commit 97105f0ab7b8 ("mm: vmalloc: show number of vmalloc pages in /proc/meminfo"). Swap memory using zsmalloc can be seen through vmstat by commit 91537fee0013 ("mm: add NR_ZSMALLOC to vmstat") but not on /proc/meminfo. Memory usage of specific driver can be various so that showing the usage through upstream meminfo.c is not easy. To print the extra memory usage of a driver, introduce following APIs. Each driver needs to count as atomic_long_t. int register_extra_meminfo(atomic_long_t *val, int shift, const char *name); int unregister_extra_meminfo(atomic_long_t *val); Currently register ION system heap allocator and zsmalloc pages. Additionally tested on local graphics driver. i.e) cat /proc/meminfo | tail -3 IonSystemHeap: 242620 kB ZsPages: 203860 kB GraphicDriver: 196576 kB i.e.) show_mem on oom <6>[ 420.856428] Mem-Info: <6>[ 420.856433] IonSystemHeap:32813kB ZsPages:44114kB GraphicDriver::13091kB <6>[ 420.856450] active_anon:957205 inactive_anon:159383 isolated_anon:0 Jaewon Kim (3): proc/meminfo: introduce extra meminfo mm: zsmalloc: include zs page size in proc/meminfo android: ion: include system heap size in proc/meminfo drivers/staging/android/ion/ion.c | 2 + drivers/staging/android/ion/ion.h | 1 + drivers/staging/android/ion/ion_system_heap.c | 2 + fs/proc/meminfo.c | 103 ++++++++++++++++++++++++++ include/linux/mm.h | 4 + lib/show_mem.c | 1 + mm/zsmalloc.c | 2 + 7 files changed, 115 insertions(+) -- 2.13.7