linux 内存分析
内存分析：
条件：开移动侦测，车道校准，停车监控，智能算法，后拉uvc
执行cat /proc/meminfo:
MemTotal: 66204 kB
MemFree: 25356 kB //当前剩余内存为24M
Buffers: 1788 kB //该部分对于系统来说是占用的
Cached: 7380 kB //该部分对于系统来说是占用的
Active: 22384 kB
Inactive: 1260 kB
Active(anon): 16072 kB
Inactive(anon): 48 kB
Active(file): 6312 kB
Inactive(file): 1212 kB
Unevictable: 1588 kB
LowTotal: 66204 kB
LowFree: 25356 kB
AnonPages: 16064 kB
Mapped: 7420 kB
Shmem: 56 kB
Slab: 4416 kB
SReclaimable: 1416 kB
SUnreclaim: 3000 kB
KernelStack: 808 kB
PageTables: 360 kB
CommitLimit: 33100 kB
Committed_AS: 25560 kB
VmallocTotal: 892928 kB
VmallocUsed: 45068 kB
VmallocChunk: 610664 kB
执行root@android:/ # ./busybox free 得到结果如下：
root@android:/ # ./busybox free -m
total used free shared buffers
Mem: 64 39 24 0 1
-/+ buffers: 38 26
Swap: 0 0 0
从以上结果可知当前系统已使用内存为：约为39M 剩余内存为 24M
3,接下来执行统计所有进程消耗的内存：
PID Vss Rss Pss Uss cmdline
59 82712K 31828K 31617K 31508K /system/bin/mediaserver //内存消耗大户，潜在优化对象
58 3700K 3100K 2889K 2780K /system/bin/newcdr
347 408K 408K 303K 284K procrank
56 416K 416K 290K 264K /system/bin/vold
65 348K 348K 256K 240K /system/bin/sh
52 332K 332K 251K 208K /init
61 196K 196K 192K 192K /sbin/adbd
60 236K 236K 133K 112K /system/bin/debuggerd
51 188K 188K 115K 80K /sbin/ueventd
55 196K 196K 110K 96K /system/bin/servicemanager
1 180K 180K 99K 56K /init
------ ------ ------
36259K 35820K TOTAL
总共消耗：34.98M
那么问题来了：系统总的内存USED为39M ,进程消耗内存为：34.98M 中间有4M的差值？
我们在看cat/meminfo/这项里的Slab、PageTables这两项，首先slab是内核为了高性能每个需要重复使用的对象都会有个池，这个slab池会cache大量常用的对象，所以会消耗大量的内存
slab：4416 kB
命令查看：
echo `cat /proc/slabinfo |awk 'BEGIN{sum=0;}{sum=sum+$3*$4;}END{print sum/1024/1024}'` MB
PageTables：是系统boot的时候就会根据内存大小算出来分配出去的，18内核是1.56%左右，32内核由于cgroup的原因会在2.3%
命令查看：
echo `grep PageTables /proc/meminfo | awk '{print $2}'` KB
总结：内存的去向主要有3个：1. 进程消耗。 2. slab消耗 3.pagetable消耗
| SDV 内存分析(物理内存128M) 测试条件 | xxxdroid 内存项 | ||
| 启动应用未录像 1 | linux系统内核保留 | 约6.8M | |
| 2 | ION 内存 | 80M | |
| 3 | mediaserver 多媒体 | 3.97M（4060K） | |
| 5 | logger | 0.375M （384K） | |
| 6 | TCP/SOCKET | 74K | |
| 7 | Buffers | 12K | |
| 8 | sdv 应用 | 6.05 M (6188K) | |
| 9 | Cached | 4.63M（4744k） | |
| 10 | init | 184K | |
| 11 | ueventd | 188K | |
| 12 | servicemanager | 320K | |
| 13 | vold | 824K | |
| 14 | debuggerd | 388K | |
| 15 | adbd | 176K | |
| 16 | standbyservice | 1604K | |
| 17 | sh | 820K | |
| 18 | Slab | 5412K | |
| 19 | PageTables: | 336K | |
| 20 | MemFree | 约18.7M (19068K) |
| 测试条件： SDV 物理内存大小: 128M byte，通过 调试方法：在commandline中 memblock=debug |
|||
| memory layout | 内存范围 | 大小 byte | |
| kernel _stext代码段、data段 | [0x000000400081c0-0x000000405efe57] | 5.905M（0x5e7c98） | |
| kernel initrd 段 | [0x00000041000000-0x00000041037fe0] | 224K | |
| 页表内存 | [0x00000040004000-0x00000040007fff] | 16K | |
| android RAM_CONSOLE | [ 41f20800-41f307ff] | 64K | |
| sys_config.fex | [0x00000041f00000-0x00000041f20000] | 128K | |
| STANDBY_MEM_SIZE | [0x00000041f20000-0x00000041f20800] | 2K | |
| alloc_base_nid | 20.1K（0x5060） | ||
| 中断向量 | 4K | ||
| bootmem bitmap | 56KB | ||
| pmd表内存 | 8736byte | ||
| fixmap | 896 kB | ||
| ION | 80M | ||
cat proc/meminfo
top
cat proc/slabinfo
echo f > /proc/sysrq-trigger
130|root@camdroid:/ #
130|root@camdroid:/ # echo f > /proc/sysrq-trigger
[ 37.890423] SysRq : Manual OOM execution
[ 37.895297] kworker/0:0 invoked oom-killer: gfp_mask=0xd0, order=0, oom_adj=0, oom_score_adj=0
[ 37.905132] Backtrace:
[ 37.908097] [<c0013410>] (dump_backtrace+0x0/0x110) from [<c03158f8>] (dump_stack+0x18/0x1c)
[ 37.917666] r6:00000000 r5:000000d0 r4:c0e82080 r3:c0460740
[ 37.924466] [<c03158e0>] (dump_stack+0x0/0x1c) from [<c0070e64>] (dump_header.isra.15+0x54/0x124)
[ 37.934503] [VFE_WARN] Nobody is waiting on this video buffer,buf = 0xc0cd8640
[ 37.942730] [<c0070e10>] (dump_header.isra.15+0x0/0x124) from [<c007103c>] (oom_kill_process.part.18.constprop.19+0x44/0x1e4)
[ 37.955475] r6:00000000 r5:000000d0 r4:c0e82080
[ 37.961009] [<c0070ff8>] (oom_kill_process.part.18.constprop.19+0x0/0x1e4) from [<c00715d0>] (out_of_memory+0x2c4/0x33c)
[ 37.973267] [VFE_WARN] Nobody is waiting on this video buffer,buf = 0xc0cd86c0
[ 37.981499] [<c007130c>] (out_of_memory+0x0/0x33c) from [<c01831d0>] (moom_callback+0x2c/0x38)
[ 37.991261] [<c01831a4>] (moom_callback+0x0/0x38) from [<c004245c>] (process_one_work+0x1e0/0x338)
[ 38.001308] [VFE_WARN]Only two buffer left for csi
[ 38.006823] [<c004227c>] (process_one_work+0x0/0x338) from [<c004323c>] (worker_thread+0x1c0/0x2c8)
[ 38.017071] [<c004307c>] (worker_thread+0x0/0x2c8) from [<c0046aec>] (kthread+0x94/0xa0)
[ 38.026164] [<c0046a58>] (kthread+0x0/0xa0) from [<c0031df0>] (do_exit+0x0/0x660)
[ 38.034655] [VFE]capture video mode!
[ 38.043738] r6:c0031df0 r5:c0046a58 r4:c1821ed0
[ 38.049255] Mem-info:
[ 38.051880] Normal per-cpu:
[ 38.055071] CPU 0: hi: 18, btch: 3 usd: 17
[ 38.060591] active_anon:1073 inactive_anon:8 isolated_anon:0
[ 38.060597] active_file:244 inactive_file:1349 isolated_file:0
[ 38.060602] unevictable:0 dirty:0 writeback:0 unstable:0
[ 38.060607] free:3051 slab_reclaimable:292 slab_unreclaimable:837
[ 38.060613] mapped:1115 shmem:11 pagetables:69 bounce:0
[ 38.060618] free_cma:0
[ 38.095613] [VFE]capture video first frame done!
[ 38.100914] [VFE_WARN]Only two buffer left for csi
[ 38.106358] Normal free:12204kB min:1016kB low:1268kB high:1524kB active_anon:4292kB inactive_anon:32kB active_file:976kB inactive_file:5396kB unevictable:0kB isolated(anon):0kB isolated(file):0kB present:65024kB mlocked:0kB dirty:0kB writeback:0kB mapped:4460kB shmem:44kB slab_reclaimable:1168kB slab_unreclaimable:3348kB kernel_stack:816kB pagetables:276kB unstable:0kB bounce:0kB free_cma:0kB writeback_tmp:0kB pages_scanned:0 all_unreclaimable? no
[ 38.150896] [VFE]capture video mode!
[ 38.154961] lowmem_reserve[]: 0 0
[ 38.159029] Normal: 19*4kB (U) 104*8kB (UEM)
[ 38.164266] [VFE]capture video first frame done!
[ 38.169770] [VFE_WARN]Only two buffer left for csi
[ 38.175193] 124*16kB (UEM) 63*32kB (UEM) 34*64kB (UEM) 8*128kB (M) 0*256kB 0*512kB 0*1024kB 0*2048kB 1*4096kB (R) = 12204kB
[ 38.189138] 1604 total pagecache pages
[ 38.194127] 16384 pages of RAM
[ 38.197625] [VFE]capture video mode!
[ 38.201720] 3206 free pages
[ 38.205003] 8675 reserved pages
[ 38.208577] 1129 slab pages
[ 38.211782] 2319 pages shared
[ 38.215166] 0 pages swap cached
[ 38.218831] [ pid ] uid tgid total_vm rss cpu oom_adj oom_score_adj name
[ 38.227173] [ 54] 0 54 87 47 0 0 0 ueventd
[ 38.235858] [VFE]capture video first frame done!
[ 38.241073] [VFE_WARN]Only two buffer left for csi
[ 38.246591] [ 55] 0 55 98 60 0 0 0 init
[ 38.254907] [ 58] 1000 58 222 80 0 0 0 servicemanager
[ 38.264279] [ 59] 0 59 946 184 0 0 0 vold
[ 38.272685] [VFE]capture video mode!
[ 38.276760] [ 60] 0 60 9902 1004 0 0 0 mediaserver
[ 38.285840] [ 62] 0 62 6111 1122 0 0 0 ccdr 单位： 以页（4K）为单位， 1122 个页，即 （1122/256） M = 4.3828125 M
[ 38.294246] [ 63] 0 63 862 45 0 0 0 adbd
[ 38.302554] [VFE]capture video first frame done!
[ 38.307853] [VFE_WARN]Only two buffer left for csi
[ 38.313281] [ 64] 0 64 233 97 0 0 0 debuggerd
[ 38.322169] [ 65] 0 65 1075 401 0 0 0 standbyservice
[ 38.331441] [VFE]capture video mode!
[ 38.335605] [ 69] 0 69 204 116 0 0 0 sh
[ 38.348734] Out of memory: Kill process 62 (ccdr) score 117 or sacrifice child
[ 38.356954] Killed process 62 (ccdr) total-vm:24444kB, anon-rss:1760kB, file-rss:2728kB
[ 38.366026] [VFE]capture video first frame done!
[ 38.371239] [VFE_WARN]Only two buffer left for csi
[ 38.382458] init: waitpid returned pid 62, status = 00000009
[ 38.388866] init: process 'ccdr', pid 62 exited
[ 38.397783] [VFE]capture video mode!
root@camdroid:/ # [ 38.407329] [VFE]vfe_close
[ 38.410536] [h22_mipi Raw]CSI_SUBDEV_PWR_OFF!
[ 38.415468] [VFE]mclk off
[ 38.456069] [VFE]..........................vfe clk close!.......................
[ 38.464462] [VFE]vfe_close end
[ 44.693656] ****************Set_Rset_Cap=2***********
[ 75.998831] charger->usb_valid = 0
[ 76.002730] set usb vol-lim to 4000 mV, cur-lim to 0 mA