Some of memory regions can be reserved for a specific purpose. They are usually defined through reserved-memory in device tree. If only size without address is specified in device tree, the address of the region will be determined at boot time. We may find the address of the memory regions through booting log, but it does not show all. And it could be hard to catch the very beginning log. The memblock_dump_all shows all memblock status but it does not show region name and its information is difficult to summarize. This patch introduce a debugfs node, memblock/memsize, to see reserved memory easily. Here's an example $ cat debugfs/memblock/memsize 0x0000000000000000-0x0000000000000000 0x02000000 ( 32768 KB ) map reusable linux,cma 0x0000000000000000-0x0000000000000000 0x01000000 ( 16384 KB ) map reusable vxxxxx ... 0x0000000000000000-0x0000000000000000 0x004e0000 ( 4992 KB ) nomap unusable unknown 0x0000000000000000-0x0000000000000000 0x00400000 ( 4096 KB ) nomap unusable cxxxxx 0x0000000000000000-0x0000000000000000 0x00e00000 ( 14336 KB ) nomap unusable gxxxxx Reserved : 1223856 KB .kernel : 275208 KB .text : 16576 KB .rwdata : 1963 KB .rodata : 11920 KB .bss : 2450 KB .memmap : 186368 KB .etc : 55933 KB .unusable : 948648 KB System : 11359056 KB .common : 10306384 KB .reusable : 1052672 KB Total : 12582912 KB ( 12288.00 MB ) Jaewon Kim (10): memblock: introduce memsize showing reserved memory memblock: detect hidden memory hole size memblock: handle overlapped reserved memory region memblock: take a region intersecting an unknown region memblock: track memblock changed at early param memblock: recognize late freed size by checking PageReserved memblock: track kernel size on memsize memblock: print memsize summary information memblock: print kernel internal size memblock: support memsize reusable to consider as reusable drivers/of/fdt.c | 11 + drivers/of/of_reserved_mem.c | 12 +- include/linux/memblock.h | 29 ++ init/main.c | 13 +- kernel/dma/contiguous.c | 9 +- mm/Kconfig | 16 ++ mm/memblock.c | 502 ++++++++++++++++++++++++++++++++++- mm/mm_init.c | 6 +- mm/page_alloc.c | 10 +- 9 files changed, 597 insertions(+), 11 deletions(-) -- 2.25.1
