HugePages は free コマンドで見ると used に計上される - ablog の続き。
Huge Page はユーザープロセスから使われる前はOSカーネル内に確保され、used に計上されるが、ユーザプロセスが使用すると cahched に計上されるぽい。
検証結果
# ulimit -l unlimited # ulimit -l unlimited # sysctl -w vm.nr_hugepages=200 vm.nr_hugepages = 200 # sysctl vm.nr_hugepages vm.nr_hugepages = 200 # gdb hugepage-shm GNU gdb (GDB) Red Hat Enterprise Linux (7.2-60.el6) Copyright (C) 2010 Free Software Foundation, Inc. License GPLv3+: GNU GPL version 3 or later <http://gnu.org/licenses/gpl.html> This is free software: you are free to change and redistribute it. There is NO WARRANTY, to the extent permitted by law. Type "show copying" and "show warranty" for details. This GDB was configured as "x86_64-redhat-linux-gnu". For bug reporting instructions, please see: <http://www.gnu.org/software/gdb/bugs/>... Reading symbols from /home/yazekats/Documents/github/yoheia/misc/hugepage_test/hugepage-shm...done. (gdb) b 89 Breakpoint 1 at 0x40086f: file hugepage-shm.c, line 89. (gdb) run Starting program: /home/yazekats/Documents/github/yoheia/misc/hugepage_test/hugepage-shm shmid: 0x150025 shmaddr: 0x2aaaaac00000 Starting the writes: ................................................................................................................................................................................................................................................................ Breakpoint 1, main () at hugepage-shm.c:89 89 dprintf("Done.\n"); Missing separate debuginfos, use: debuginfo-install glibc-2.12-1.132.el6.x86_64 (gdb)
System V IPC 共有メモリで 256MB 使われている
# ipcs -m ------ Shared Memory Segments -------- key shmid owner perms bytes nattch status (中略) 0x00000002 1376293 root 600 268435456 1 ★256MB
共有メモリを作成したプロセスの PID は 4500
# ipcs -p ------ Shared Memory Creator/Last-op -------- shmid owner cpid lpid (中略) 1376293 root 4500 4500 ★共有メモリを作成、操作したプロセスの PID は 4500
PID 4500 のメモリ使用量の内訳を pmap コマンドで確認する
# pmap -x 4500 4500: /home/yazekats/Documents/github/yoheia/misc/hugepage_test/hugepage-shm Address Kbytes RSS Dirty Mode Mapping 0000000000400000 4 4 4 r-x-- hugepage-shm 0000000000600000 4 4 4 rw--- hugepage-shm 0000003ba6200000 128 108 12 r-x-- ld-2.12.so 0000003ba641f000 4 4 4 r---- ld-2.12.so 0000003ba6420000 4 4 4 rw--- ld-2.12.so 0000003ba6421000 4 4 4 rw--- [ anon ] 0000003ba6600000 1580 236 0 r-x-- libc-2.12.so 0000003ba678b000 2044 0 0 ----- libc-2.12.so 0000003ba698a000 16 8 8 r---- libc-2.12.so 0000003ba698e000 4 4 4 rw--- libc-2.12.so 0000003ba698f000 20 12 12 rw--- [ anon ] 00002aaaaac00000 262144 0 0 rw-s- SYSV00000002 (deleted) ★ここが共有メモリ。RSSが0、本当に物理的に使われていないのか？ 00007ffff7fe0000 12 12 12 rw--- [ anon ] 00007ffff7ffc000 8 8 8 rw--- [ anon ] 00007ffff7ffe000 4 4 0 r-x-- [ anon ] 00007ffffffde000 132 8 8 rw--- [ stack ] ffffffffff600000 4 0 0 r-x-- [ anon ] ---------------- ------ ------ ------ total kB 266116 420 84
