Rockchip Linux 内存调试常用命令
:::info 文档信息
文档标识：RK-KF-YF-140 · 发布版本：V1.0.0 · 发布日期：2021-01-06 · 页数：13 · 语言：中文
原始文档：Rockchip_Developer_Guide_Linux_Meminfo_CN.pdf
:::
章节大纲
- Rockchip Linux 内存调试常用命令（P1）
- total内存信息（P3）
- meminfo（P3）
- sysrq-trigger（P4）
- kernel内存信息（P5）
- slab（P5）
- kernfs_node_cache（P5）
- inode_cache（P6）
- memblock（P6）
- memory（P8）
- reserved（P8）
- zoneinfo（P9）
- slab（P5）
- 空闲内存（P11）
- free（P11）
- 清除缓存（P12）
- drop_caches（P12）
- 虚拟内存使用情况（P12）
- vmallocinfo（P12）
- vmstat（P13）
- 内存压力（P13）
- pressure（P13）
- total内存信息（P3）
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目录
Rockchip Linux 内存调试常用命令1. total内存信息1.1 meminfo 1.2 sysrq-trigger 2. kernel内存信息2.1 slab 2.1.1 kernfs_node_cache 2.1.2 inode_cache 2.2 memblock 2.2.1 memory 2.2.2 reserved 2.3 zoneinfo 3. 空闲内存3.1 free 4. 清除缓存4.1 drop_caches 5. 虚拟内存使用情况5.1 vmallocinfo 5.2 vmstat 6. 内存压力6.1 pressure
1. total内存信息
1.1 meminfo
cat /proc/meminfo
MemTotal: 1497696 kB
MemFree: 590524 kB
MemAvailable: 773252 kB
Buffers: 768 kB
Cached: 216892 kB
SwapCached: 14204 kB
Active: 260884 kB
Inactive: 176744 kB
Active(anon): 120620 kB
Inactive(anon): 106688 kB
Active(file): 140264 kB
Inactive(file): 70056 kB
Unevictable: 3224 kB
Mlocked: 3224 kB
SwapTotal: 748844 kB
SwapFree: 346156 kB
Dirty: 776 kB
Writeback: 0 kB
AnonPages: 220804 kB
Mapped: 194276 kB
Shmem: 4968 kB
KReclaimable: 43900 kB
Slab: 111060 kB
SReclaimable: 40648 kB
SUnreclaim: 70412 kB
KernelStack: 18496 kB
PageTables: 42096 kB
NFS_Unstable: 0 kB
Bounce: 0 kB
WritebackTmp: 0 kB
CommitLimit: 1497692 kB
Committed_AS: 41751048 kB
VmallocTotal: 263061440 kB
VmallocUsed: 30368 kB
VmallocChunk: 0 kB
Percpu: 2528 kB
CmaTotal: 532480 kB
CmaFree: 0 kB
MemTotal = MemFree + Buffers + Cached
Swap：SwapTotal/SwapFree，是系统脚本中通过swap命令启用、分配
swap 分区通常被称为交换分区，这是一块特殊的硬盘空间，即当实际内存不够用的时候，操作系统会从内存中取出一部分暂时不用的数据，放在交换分区中，从而为当前运行的程序腾出足够的内存空间
Slab：Slab当前使用大小，其中可回收SReclaimable:，不可回收SUnreclaim，如果增长太大，可能内存泄漏
Vmalloc：VmallocTotal是总的大小，VmallocUsed已用大小
Cma：CmaTotal总大小，CmaFree空闲大小。
CMA被系统借用，也属于被使用，CmaFree会减小。
1.2 sysrq-trigger
echo m > /proc/sysrq-trigger
Mem-Info:
active_anon:43194 inactive_anon:26284 isolated_anon:0
active_file:35286 inactive_file:17959 isolated_file:0
unevictable:806 dirty:0 writeback:0 unstable:0
slab_reclaimable:10164 slab_unreclaimable:17630
mapped:48836 shmem:1280 pagetables:10550 bounce:0
free:134653 free_pcp:717 free_cma:0
Node 0 active_anon:172776kB inactive_anon:105136kB active_file:141144kB
inactive_file:71836kB unevictable:3224kB isolated(anon):0kB
isolated(file):0kB mapped:195344kB dirty:0kB writeback:0kB shmeo
DMA32 free:538612kB min:4884kB low:24024kB high:25520kB active_anon:172776kB
inactive_anon:105136kB active_file:141144kB inactive_file:71836kB
unevictable:3224kB writepending:0kB present:2095104kB
lowmem_reserve[]: 0 0 0
DMA32: 13625*4kB (UEH) 12210*8kB (UEH) 8286*16kB (UMEH) 4151*32kB (UMEH)
1157*64kB (UMEH) 223*128kB (UM) 46*256kB (U) 9*512kB (U) 2*1024kB (U)
0*2048kB 0*4096kB = 538612kB
58687 total pagecache pages
3564 pages in swap cache
Swap cache stats: add 155134, delete 151579, find 11930/52536
Free swap = 346412kB
Total swap = 748844kB
523776 pages RAM
0 pages HighMem/MovableOnly
149352 pages reserved
133120 pages cma reserved
2. kernel内存信息
2.1 slab
内核申请的内存调试接口，编译需要打开两个宏定义
CONFIG_SLUB_SYSFS=y
CONFIG_SLUB_DEBUG=y
统计slab总大小命令
echo `cat /proc/slabinfo |awk 'BEGIN{sum=0;}{sum=sum+$3*$4;}END{print
sum/1024/1024}'` MB
2.1.1 kernfs_node_cache
如下命令看到kernfs使用了2.5M，655 pages = 2.55859375 MBytes
[root@RV1126_RV1109:/]# cat /proc/slabinfo |grep kernfs_node_cache
kernfs_node_cache 18319 18340 144 28 1 : tunables 0 0 0 :
slabdata 655 655 0
代码位置在 fs/kernfs/mount.c
void __init kernfs_init(void)
{
/*
* the slab is freed in RCU context, so kernfs_find_and_get_node_by_ino
* can access the slab lock free. This could introduce stale nodes,
* please see how kernfs_find_and_get_node_by_ino filters out stale
* nodes.
*/
kernfs_node_cache = kmem_cache_create("kernfs_node_cache",
sizeof(struct kernfs_node),
0,
SLAB_PANIC | SLAB_TYPESAFE_BY_RCU,
NULL);
}
2.1.2 inode_cache
如下命令看到inode cache使用了3.2M，816 pages = 3.1875 MBytes
[root@RV1126_RV1109:/]# cat /proc/slabinfo |grep inode_cache
inode_cache 6282 6340 408 20 2 : tunables 0 0 0 :
slabdata 317 317 0
代码位置在 fs/inode.c
void __init inode_init(void)
{
/* inode slab cache */
inode_cachep = kmem_cache_create("inode_cache",
sizeof(struct inode),
0,
(SLAB_RECLAIM_ACCOUNT|SLAB_PANIC|
SLAB_MEM_SPREAD|SLAB_ACCOUNT),
init_once);
}
2.2 memblock
系统预留内存调试接口，编译需要在bootargs中添加 memblock=debug
chosen {
bootargs = "earlycon=uart8250,mmio32,0xff570000 console=ttyFIQ0
memblock=debug";
};
[ 0.000000] MEMBLOCK configuration:
[ 0.000000] memory size = 0x3fdb8000 reserved size = 0x11706eb8
[ 0.000000] memory.cnt = 0x2
[ 0.000000] memory[0x0] [0x00000000-0x083fffff], 0x08400000 bytes flags:
0x0
[ 0.000000] memory[0x1] [0x08648000-0x3fffffff], 0x379b8000 bytes flags:
0x0
[ 0.000000] reserved.cnt = 0x7
[ 0.000000] reserved[0x0] [0x00004000-0x00007fff], 0x00004000 bytes flags:
0x0
[ 0.000000] reserved[0x1] [0x00100000-0x00e32b2f], 0x00d32b30 bytes flags:
0x0
[ 0.000000] reserved[0x2] [0x08000000-0x080fffff], 0x00100000 bytes flags:
0x0
[ 0.000000] reserved[0x3] [0x08300000-0x08318fff], 0x00019000 bytes flags:
0x0
[ 0.000000] reserved[0x4] [0x2dc00000-0x3dbfffff], 0x10000000 bytes flags:
0x0 CMA
[ 0.000000] reserved[0x5] [0x3df00000-0x3dfb7387], 0x000b7388 bytes flags:
0x0
[ 0.000000] reserved[0x6] [0x3f800000-0x3fffffff], 0x00800000 bytes flags:
0x0 CMA
其中预留比较大的有initrd（加载root使用）和node memmap（管理页内存使用）
initrd预留13MBytes
void __init arm_memblock_init(const struct machine_desc *mdesc)
{
arm_initrd_init();
}
node memmap预留8MBytes
[ 0.000000] On node 0 totalpages: 262006
[ 0.000000] memblock_reserve: [0x3ef75000-0x3f774fff]
memblock_virt_alloc_internal+0x108/0x1a4
[ 0.000000] alloc_node_mem_map: node 0, pgdat b0d4bd00, node_mem_map eef75000
[ 0.000000] Normal zone: 2048 pages used for memmap
[ 0.000000] Normal zone: 0 pages reserved
[ 0.000000] Normal zone: 262006 pages, LIFO batch:63
设备内存情况开机打印：
[ 0.000000] Virtual kernel memory layout:
[ 0.000000] vector : 0xffff0000 - 0xffff1000 ( 4 kB)
[ 0.000000] fixmap : 0xffc00000 - 0xfff00000 (3072 kB)
[ 0.000000] vmalloc : 0xf0800000 - 0xff800000 ( 240 MB)
[ 0.000000] lowmem : 0xb0000000 - 0xf0000000 (1024 MB)
[ 0.000000] pkmap : 0xafe00000 - 0xb0000000 ( 2 MB)
[ 0.000000] modules : 0xaf000000 - 0xafe00000 ( 14 MB)
[ 0.000000] .text : 0x(ptrval) - 0x(ptrval) (9184 kB)
[ 0.000000] .init : 0x(ptrval) - 0x(ptrval) (1024 kB)
[ 0.000000] .data : 0x(ptrval) - 0x(ptrval) ( 332 kB)
[ 0.000000] .bss : 0x(ptrval) - 0x(ptrval) ( 896 kB)
[ 0.000000] Memory: 752320K/1048024K available (8192K kernel code, 331K
rwdata, 1900K rodata, 1024K init, 895K bss, 25368K reserved, 270336K cma-
reserved, 0K highmem)
752320K: 空闲页可用内存， nr_free_pages() << (PAGE_SHIFT - 10)
1048024K：总共可见物理内存， physpages << (PAGE_SHIFT - 10)
kernel code：内核代码， codesize = _etext - _stext
rwdata：可读可写数据段， datasize = _edata - _sdata
rodata：只读数据段， rosize = __end_rodata - __start_rodata
init：包括 init_data_size = __init_end - __init_begin 和 init_code_size = _einittext -
_sinittext
bss：用来存放程序中未初始化的全局变量的一块内存区域， bss_size = __bss_stop - __bss_start
reserved：memblock预留内存， physpages -totalram_pages- totalcma_pages
cma-reserved：CMA预留内存， totalcma_pages
[ 0.000000] Reserved memory: created CMA memory pool at 0x3f800000, size 8 MiB
[ 0.000000] OF: reserved mem: initialized node linux,cma, compatible id
shared-dma-pool
[ 0.000000] Reserved memory: created CMA memory pool at 0x2dc00000, size 256
MiB
[ 0.000000] OF: reserved mem: initialized node isp, compatible id shared-dma-
pool
2.2.1 memory
内核的内存支持多个block，Rockchip平台在进入内核前，会有部分内存作特殊用途，例如OPTEE/ATF的代码，需要放在132M～135M，如下大小为0x248000的内存块被用于OPTEE存放代码
[root@RV1126_RV1109:/]# cat /sys/kernel/debug/memblock/memory
0: 0x00000000..0x083fffff
1: 0x08648000..0x3fffffff
2.2.2 reserved
[root@RV1126_RV1109:/]# cat /sys/kernel/debug/memblock/reserved
0: 0x00004000..0x00007fff
1: 0x00100000..0x00e32b2f
2: 0x08000000..0x080fffff
3: 0x08300000..0x08318fff
4: 0x083ff000..0x083fffff
5: 0x2dc00000..0x3dbfffff
6: 0x3df00000..0x3dfb7387
7: 0x3ee41000..0x3ef3cfff
8: 0x3ef3f480..0x3ef3f4f7
9: 0x3ef3f500..0x3ef3f803
10: 0x3ef3f834..0x3f7fefff
11: 0x3f7ff040..0x3f7ff384
12: 0x3f7ff3c0..0x3f7ff3fb
13: 0x3f7ff400..0x3f7ff583
14: 0x3f7ff5c0..0x3f7ff784
15: 0x3f7ff7c0..0x3f7ff837
16: 0x3f7ff840..0x3f7ff84f
17: 0x3f7ff880..0x3f7ff88f
18: 0x3f7ff8c0..0x3f7ff8c3
19: 0x3f7ff900..0x3f7ff903
20: 0x3f7ff940..0x3f7ffa4b
21: 0x3f7ffa80..0x3f7ffb8b
22: 0x3f7ffbc0..0x3f7ffccb
23: 0x3f7ffcf0..0x3f7ffd08
24: 0x3f7ffd0c..0x3f7ffd24
25: 0x3f7ffd28..0x3f7ffd72
26: 0x3f7ffd74..0x3f7ffd8e
27: 0x3f7ffd90..0x3f7ffdaa
28: 0x3f7ffdac..0x3f7ffdc6
29: 0x3f7ffdc8..0x3f7ffde2
30: 0x3f7ffde4..0x3f7ffdfe
31: 0x3f7ffe00..0x3f7ffedf
32: 0x3f7ffee8..0x3f7fff9f
33: 0x3f7fffb0..0x3fffffff
2.3 zoneinfo
cat /proc/zoneinfo
Node 0, zone DMA32
per-node stats
nr_inactive_anon 28250
nr_active_anon 34245
nr_inactive_file 29724
nr_active_file 33943
nr_unevictable 806
nr_slab_reclaimable 10088
nr_slab_unreclaimable 17495
nr_isolated_anon 0
nr_isolated_file 0
workingset_refault 258089
workingset_activate 54883
workingset_restore 35120
workingset_nodereclaim 4574
nr_anon_pages 59384
nr_mapped 65408
nr_file_pages 70824
nr_dirty 31
nr_writeback 0
nr_writeback_temp 0
nr_shmem 1581
nr_shmem_hugepages 0
nr_shmem_pmdmapped 0
nr_anon_transparent_hugepages 0
nr_unstable 0
nr_vmscan_write 148946
nr_vmscan_immediate_reclaim 2540
nr_dirtied 798484
nr_written 938957
nr_kernel_misc_reclaimable 0
nr_unreclaimable_pages 0
nr_ion_heap 0
nr_ion_heap_pool 0
nr_gpu_heap 0
pages free 133183
min 1221
low 6006
high 6380
spanned 523776
present 523776
managed 374424
protection: (0, 0, 0)
nr_free_pages 133183
nr_zone_inactive_anon 28250
nr_zone_active_anon 34245
nr_zone_inactive_file 29724
nr_zone_active_file 33943
nr_zone_unevictable 806
nr_zone_write_pending 31
nr_mlock 806
nr_page_table_pages 10425
nr_kernel_stack 18256
nr_bounce 0
nr_zspages 26061
nr_free_cma 0
pagesets
cpu: 0
count: 342
high: 378
batch: 63
vm stats threshold: 30
cpu: 1
count: 301
high: 378
batch: 63
vm stats threshold: 30
cpu: 2
count: 32
high: 378
batch: 63
vm stats threshold: 30
cpu: 3
count: 296
high: 378
batch: 63
vm stats threshold: 30
node_unreclaimable: 0
start_pfn: 512
Node 0, zone Normal
pages free 0
min 0
low 0
high 0
spanned 0
present 0
managed 0
protection: (0, 0, 0)
Node 0, zone Movable
pages free 0
min 0
low 0
high 0
spanned 0
present 0
managed 0
protection: (0, 0, 0)
3. 空闲内存
3.1 free
total：是内核页管理的总内存；
used：是指正在被使用的内存；
free：是指空闲的内存；
shared：是指共享的内存，如匿名页；
buffers：是指缓冲内存数；
cached：是指缓存内存数；
buffers（缓冲）和 cached（缓存）的区别。cached 是给读取数据时加速的，buffers 是给写入数据加速的。cached 是指把读取出来的数据保存在内存中，当再次读取时，不用读取硬盘而直接从内存中读取，加速了数据的读取过程；buffers 是指在写入数据时，先把分散的写入操作保存到内存中，当达到一定程度后再集中写入硬盘，减少了磁盘碎片和硬盘的反复寻道，加速了数据的写入过程。
free
total used free shared buffers
Mem: 1533640704 1308901376 224739328 6422528 921600
-/+ buffers/cache: 1307979776 225660928
Swap: 766816256 401342464 365473792
free -m
total used free shared buffers
Mem: 1462 1249 213 6 0
-/+ buffers/cache: 1248 214
Swap: 731 382 348
free -h
total used free shared buffers
Mem: 1.4G 1.2G 212M 6.1M 900K
-/+ buffers/cache: 1.2G 213M
Swap: 731M 383M 349M
4. 清除缓存
4.1 drop_caches
echo x > /proc/sys/vm/drop_caches
清空 pagecache
echo 1 > /proc/sys/vm/drop_caches
清空 dentries 和 inodes
echo 2 > /proc/sys/vm/drop_caches
清空所有缓存（pagecache、dentries 和 inodes）
echo 3 > /proc/sys/vm/drop_caches
5. 虚拟内存使用情况
5.1 vmallocinfo
cat /proc/vmallocinfo
0x0000000000000000-0x0000000000000000 8192 bpf_jit_binary_alloc+0x70/0x110
pages=1 vmalloc
...
0x0000000000000000-0x0000000000000000 20480 start_kernel+0x330/0x4f0
pages=4 vmalloc
0x0000000000000000-0x0000000000000000 8192 of_iomap+0x4c/0xb8
phys=0x00000000fdd00000 ioremap
0x0000000000000000-0x0000000000000000 20480 start_kernel+0x330/0x4f0
pages=4 vmalloc
0x0000000000000000-0x0000000000000000 8192 of_iomap+0x4c/0xb8
phys=0x00000000fdd20000 ioremap
0x0000000000000000-0x0000000000000000 20480 start_kernel+0x330/0x4f0
pages=4 vmalloc
5.2 vmstat
cat /proc/vmstat
6. 内存压力
6.1 pressure
cat /proc/pressure/memory
VSS- Virtual Set Size 虚拟耗用内存（包含共享库占用的内存）RSS- Resident Set Size 实际使用物理内存（包含共享库占用的内存）PSS- Proportional Set Size 实际使用的物理内存（比例分配共享库占用的内存）USS- Unique Set Size 进程独自占用的物理内存（不包含共享库占用的内存）
一般来说内存占用大小有如下规律：VSS >= RSS >= PSS >= USS