Estou tentando descobrir o que está comendo minha memória. Estou especulando que, se não for usado pelos processos userspace, pode ser do lado do kernel.
Existe a saída de alguns comandos. Eu sei que o Linux está usando o copy-on-write, portanto o uso de memória esperado deve ser de 514MB ou menos (os segmentos compartilhados têm apenas 7,75 MB no total). free -m está relatando que é usado 2804 MB. Eu tentei comê-lo com python e de fato começou a trocar quando foi usado mais de 7324 MB (reportado por free -m). Então, como posso descobrir o que está usando 2804-514 MB de RAM? Não encontrei nenhum método fácil para decompor a memória usada pelos módulos do kernel.
Informações básicas do sistema: Linux Mint 17, thinkpad T530 com sistema de arquivos BTRFS.
$ free -m
total used free shared buffers cached
Mem: 7669 4055 3614 66 0 1250
-/+ buffers/cache: 2804 4864
Swap: 5367 0 5367
$ ipcs -m|tail -n +4|awk '{sum+=$5} END {print sum / 1024/1024}'
7.75
$ sudo ps axo pid,rss,cmd | awk '{sum+=$2} END {print sum / 1024}'
514.43
$ smem -twk
Area Used Cache Noncache
firmware/hardware 0 0 0
kernel image 0 0 0
kernel dynamic memory 3.6G 1.2G 2.3G
userspace memory 412.3M 52.6M 359.7M
free memory 3.5G 3.5G 0
----------------------------------------------------------
7.5G 4.8G 2.7G
meminfo (note que os números estão em MB)
cat /proc/meminfo |awk '{print $1"\t"($2/1024)"\t"$3}'
MemTotal: 7669.72 kB
MemFree: 3615.05 kB
Buffers: 0.078125 kB
Cached: 1250.41 kB
SwapCached: 0 kB
Active: 825.223 kB
Inactive: 781.68 kB
Active(anon): 124.059 kB
Inactive(anon): 298.477 kB
Active(file): 701.164 kB
Inactive(file): 483.203 kB
Unevictable: 0 kB
Mlocked: 0 kB
SwapTotal: 5367.33 kB
SwapFree: 5367.33 kB
Dirty: 0 kB
Writeback: 0 kB
AnonPages: 356.391 kB
Mapped: 52.7031 kB
Shmem: 66.1211 kB
Slab: 100.266 kB
SReclaimable: 54.0039 kB
SUnreclaim: 46.2617 kB
KernelStack: 3.35156 kB
PageTables: 18.0586 kB
NFS_Unstable: 0 kB
Bounce: 0 kB
WritebackTmp: 0 kB
CommitLimit: 9202.19 kB
Committed_AS: 1343.93 kB
VmallocTotal: 3.35544e+07 kB
VmallocUsed: 352.312 kB
VmallocChunk: 3.35541e+07 kB
HardwareCorrupted: 0 kB
AnonHugePages: 58 kB
HugePages_Total: 0
HugePages_Free: 0
HugePages_Rsvd: 0
HugePages_Surp: 0
Hugepagesize: 2 kB
DirectMap4k: 294.938 kB
DirectMap2M: 7578 kB
meminfo inalterado e outras informações solicitadas (note que algum tempo se passou desde o primeiro lote da informação, mas eu tentei torná-lo o mais possível)
sudo ps axo pid,rss,cmd | awk '{sum+=$2} END {print sum / 1024}'
518.551
$ free -m
total used free shared buffers cached
Mem: 7669 4155 3513 68 0 1202
-/+ buffers/cache: 2953 4716
Swap: 5367 0 5367
$ sudo slabtop -o -s c
Active / Total Objects (% used) : 344353 / 409584 (84.1%)
Active / Total Slabs (% used) : 12149 / 12149 (100.0%)
Active / Total Caches (% used) : 80 / 112 (71.4%)
Active / Total Size (% used) : 92748.52K / 105317.22K (88.1%)
Minimum / Average / Maximum Object : 0.01K / 0.26K / 15.75K
OBJS ACTIVE USE OBJ SIZE SLABS OBJ/SLAB CACHE SIZE NAME
13371 13371 100% 1.04K 452 30 14464K btrfs_inode
56280 49088 87% 0.19K 2680 21 10720K dentry
17010 14121 83% 0.55K 627 28 10032K radix_tree_node
10175 9575 94% 0.63K 407 25 6512K proc_inode_cache
29652 19386 65% 0.19K 1412 21 5648K kmalloc-192
9856 9452 95% 0.57K 352 28 5632K inode_cache
745 481 64% 5.98K 149 5 4768K task_struct
1104 1068 96% 4.00K 138 8 4416K kmalloc-4096
11200 11018 98% 0.31K 448 25 3584K btrfs_extent_buffer
1746 1679 96% 2.00K 110 16 3520K kmalloc-2048
30096 30048 99% 0.11K 836 36 3344K sysfs_dir_cache
43456 23262 53% 0.06K 679 64 2716K kmalloc-64
10368 7228 69% 0.25K 324 32 2592K kmalloc-256
2144 1911 89% 1.00K 67 32 2144K kmalloc-1024
13650 9943 72% 0.15K 525 26 2100K btrfs_extent_map
2013 2013 100% 0.96K 61 33 1952K ext4_inode_cache
3040 2472 81% 0.50K 95 32 1520K kmalloc-512
2232 1938 86% 0.66K 93 24 1488K shmem_inode_cache
1755 1735 98% 0.81K 45 39 1440K task_xstate
1584 1584 100% 0.88K 44 36 1408K mm_struct
1026 886 86% 1.06K 36 30 1152K signal_cache
525 442 84% 2.06K 35 15 1120K sighand_cache
133 127 95% 8.00K 34 4 1088K kmalloc-8192
7744 6829 88% 0.12K 242 32 968K kmalloc-128
14720 14260 96% 0.06K 230 64 920K ext4_free_data
8610 6966 80% 0.09K 205 42 820K btrfs_extent_state
12736 6989 54% 0.06K 199 64 796K anon_vma
1225 1069 87% 0.62K 49 25 784K sock_inode_cache
345 345 100% 2.06K 23 15 736K idr_layer_cache
2254 1321 58% 0.29K 84 27 672K btrfs_delayed_node
18688 14340 76% 0.03K 146 128 584K kmalloc-32
3870 3870 100% 0.13K 129 30 516K ext4_allocation_context
4875 4647 95% 0.10K 125 39 500K buffer_head
6272 6272 100% 0.07K 112 56 448K Acpi-ParseExt
252 163 64% 1.75K 14 18 448K TCP
1155 1155 100% 0.37K 55 21 440K btrfs_ordered_extent
4116 4116 100% 0.09K 98 42 392K kmalloc-96
4140 4140 100% 0.09K 90 46 360K ext4_xattr
4539 4539 100% 0.08K 89 51 356K btrfs_prelim_ref
1050 907 86% 0.31K 42 25 336K mnt_cache
882 647 73% 0.38K 42 21 336K blkdev_requests
$ top -n 1 -o %MEM
top - 19:38:58 up 2 days, 4:48, 21 users, load average: 0.07, 0.09, 0.13
Tasks: 267 total, 1 running, 266 sleeping, 0 stopped, 0 zombie
%Cpu(s): 1.1 us, 0.8 sy, 0.0 ni, 97.5 id, 0.6 wa, 0.0 hi, 0.0 si, 0.0 st
KiB Mem: 7853796 total, 4270896 used, 3582900 free, 60 buffers
KiB Swap: 5496148 total, 0 used, 5496148 free. 1238332 cached Mem
PID USER PR NI VIRT RES SHR S %CPU %MEM TIME+ COMMAND
1710 root 20 0 450176 37480 23708 S 6.3 0.5 23:25.64 Xorg
3233 loj 20 0 564556 37128 8868 S 6.3 0.5 4:15.48 xfce4-terminal
1889 root 20 0 182980 33740 1500 S 0.0 0.4 0:04.07 puppet
2604 loj 20 0 457136 29468 3096 S 0.0 0.4 0:08.20 xfdesktop
2398 root 20 0 926976 28652 1244 S 0.0 0.4 1:01.01 docker.io
2605 loj 20 0 421612 24312 2612 S 0.0 0.3 1:00.18 redshift-gtk
2634 loj 20 0 568552 21900 5252 S 0.0 0.3 0:03.30 mintUpdate
2919 loj 20 0 483152 12052 4608 S 0.0 0.2 0:05.71 panel-7-indicat
2742 loj 20 0 545364 11548 5864 S 0.0 0.1 0:06.72 panel-1-whisker
2600 loj 20 0 487296 11444 5264 S 0.0 0.1 0:43.00 xfce4-panel
2645 loj 20 0 248504 10576 1408 S 0.0 0.1 0:00.92 applet.py
2596 loj 20 0 167352 9924 4176 S 0.0 0.1 2:47.19 xfwm4
2628 loj 20 0 683744 9776 3352 S 0.0 0.1 0:15.63 nm-applet
2616 loj 20 0 382528 6832 3388 S 0.0 0.1 0:11.27 xfce4-power-man
2872 loj 20 0 382416 5944 1636 S 0.0 0.1 0:02.91 gvfs-udisks2-vo
10166 root 20 0 358828 5840 1884 S 0.0 0.1 0:16.78 NetworkManager
1099 root 20 0 295828 5556 1272 S 0.0 0.1 0:01.56 polkitd
2923 loj 20 0 164404 5348 3008 S 0.0 0.1 0:02.78 panel-5-datetim
14257 loj 20 0 25384 5340 1768 S 0.0 0.1 0:00.12 bash
20503 loj 20 0 25380 5340 1772 S 0.0 0.1 0:00.16 bash
17690 loj 20 0 25396 5328 1748 S 0.0 0.1 0:00.05 bash
18732 loj 20 0 25396 5328 1744 S 0.0 0.1 0:00.05 bash
18538 loj 20 0 25396 5324 1740 S 0.0 0.1 0:00.04 bash
16501 loj 20 0 25380 5308 1744 S 0.0 0.1 0:00.06 bash
27045 loj 20 0 26316 5100 592 S 0.0 0.1 0:00.87 bash
2913 loj 20 0 149164 5096 3132 S 0.0 0.1 0:11.82 panel-4-genmon
28187 loj 20 0 25396 5028 1440 S 0.0 0.1 0:00.09 bash
2917 loj 20 0 149160 4996 3036 S 0.0 0.1 0:29.28 panel-9-genmon
16558 loj 20 0 26160 4948 592 S 0.0 0.1 0:01.02 bash
2641 loj 9 -11 371060 4940 2532 S 0.0 0.1 13:13.11 pulseaudio
2904 loj 20 0 26100 4884 592 S 0.0 0.1 0:00.21 bash
12720 loj 20 0 26076 4856 592 S 0.0 0.1 0:00.25 bash
19240 loj 20 0 25572 4844 1156 S 0.0 0.1 0:00.18 bash
11583 loj 20 0 25380 4708 1140 S 0.0 0.1 0:00.15 bash
18425 loj 20 0 25508 4692 1044 S 0.0 0.1 0:00.08 bash
4865 loj 20 0 25368 4556 996 S 0.0 0.1 0:00.30 bash
11552 loj 20 0 25384 4516 944 S 0.0 0.1 0:00.05 bash
6966 loj 20 0 51180 4332 1620 S 0.0 0.1 0:00.15 vim
2888 root 20 0 451912 4288 1624 S 0.0 0.1 0:28.69 udisksd
11310 loj 20 0 25452 4216 592 S 0.0 0.1 0:01.20 bash
2679 loj 20 0 343428 4196 1752 S 0.0 0.1 0:02.56 xfsettingsd
31494 loj 20 0 25380 4164 596 S 0.0 0.1 0:00.16 bash
$ cat /proc/meminfo
MemTotal: 7853796 kB
MemFree: 3593092 kB
Buffers: 60 kB
Cached: 1237532 kB
SwapCached: 0 kB
Active: 667844 kB
Inactive: 934244 kB
Active(anon): 28480 kB
Inactive(anon): 412756 kB
Active(file): 639364 kB
Inactive(file): 521488 kB
Unevictable: 0 kB
Mlocked: 0 kB
SwapTotal: 5496148 kB
SwapFree: 5496148 kB
Dirty: 0 kB
Writeback: 0 kB
AnonPages: 364556 kB
Mapped: 48308 kB
Shmem: 76740 kB
Slab: 107128 kB
SReclaimable: 61012 kB
SUnreclaim: 46116 kB
KernelStack: 3344 kB
PageTables: 18088 kB
NFS_Unstable: 0 kB
Bounce: 0 kB
WritebackTmp: 0 kB
CommitLimit: 9423044 kB
Committed_AS: 1382404 kB
VmallocTotal: 34359738367 kB
VmallocUsed: 360768 kB
VmallocChunk: 34359364252 kB
HardwareCorrupted: 0 kB
AnonHugePages: 61440 kB
HugePages_Total: 0
HugePages_Free: 0
HugePages_Rsvd: 0
HugePages_Surp: 0
Hugepagesize: 2048 kB
DirectMap4k: 304064 kB
DirectMap2M: 7757824 kB
$ sudo cat /proc/vmstat
nr_free_pages 807707
nr_alloc_batch 3485
nr_inactive_anon 103817
nr_active_anon 14695
nr_inactive_file 157126
nr_active_file 183051
nr_unevictable 0
nr_mlock 0
nr_anon_pages 96859
nr_mapped 19398
nr_file_pages 361889
nr_dirty 0
nr_writeback 0
nr_slab_reclaimable 16123
nr_slab_unreclaimable 11793
nr_page_table_pages 4772
nr_kernel_stack 429
nr_unstable 0
nr_bounce 0
nr_vmscan_write 100293
nr_vmscan_immediate_reclaim 3432
nr_writeback_temp 0
nr_isolated_anon 0
nr_isolated_file 0
nr_shmem 21712
nr_dirtied 55931244
nr_written 55847537
numa_hit 335064087
numa_miss 0
numa_foreign 0
numa_interleave 24522
numa_local 335064087
numa_other 0
nr_anon_transparent_hugepages 28
nr_free_cma 0
nr_dirty_threshold 111416
nr_dirty_background_threshold 55708
pgpgin 129334306
pgpgout 233190636
pswpin 80715
pswpout 100268
pgalloc_dma 0
pgalloc_dma32 159890087
pgalloc_normal 257522463
pgalloc_movable 0
pgfree 424750256
pgactivate 23419593
pgdeactivate 11177646
pgfault 508757717
pgmajfault 19562
pgrefill_dma 0
pgrefill_dma32 3369566
pgrefill_normal 7975279
pgrefill_movable 0
pgsteal_kswapd_dma 0
pgsteal_kswapd_dma32 20040131
pgsteal_kswapd_normal 34430518
pgsteal_kswapd_movable 0
pgsteal_direct_dma 0
pgsteal_direct_dma32 1161023
pgsteal_direct_normal 1344398
pgsteal_direct_movable 0
pgscan_kswapd_dma 0
pgscan_kswapd_dma32 20077734
pgscan_kswapd_normal 34646412
pgscan_kswapd_movable 0
pgscan_direct_dma 0
pgscan_direct_dma32 1164470
pgscan_direct_normal 1414283
pgscan_direct_movable 0
pgscan_direct_throttle 0
zone_reclaim_failed 0
pginodesteal 63
slabs_scanned 2262272
kswapd_inodesteal 168
kswapd_low_wmark_hit_quickly 107411
kswapd_high_wmark_hit_quickly 94396
pageoutrun 231397
allocstall 37862
pgrotated 113947
numa_pte_updates 0
numa_huge_pte_updates 0
numa_hint_faults 0
numa_hint_faults_local 0
numa_pages_migrated 0
pgmigrate_success 2038063
pgmigrate_fail 3670
compact_migrate_scanned 18509229
compact_free_scanned 464282669
compact_isolated 9111435
compact_stall 3146
compact_fail 2215
compact_success 931
htlb_buddy_alloc_success 0
htlb_buddy_alloc_fail 0
unevictable_pgs_culled 0
unevictable_pgs_scanned 0
unevictable_pgs_rescued 6
unevictable_pgs_mlocked 6
unevictable_pgs_munlocked 6
unevictable_pgs_cleared 0
unevictable_pgs_stranded 0
thp_fault_alloc 5220
thp_fault_fallback 7309
thp_collapse_alloc 2740
thp_collapse_alloc_failed 1229
thp_split 2320
thp_zero_page_alloc 3
thp_zero_page_alloc_failed 0
nr_tlb_remote_flush 1119474
nr_tlb_remote_flush_received 1416528
nr_tlb_local_flush_all 3215771
nr_tlb_local_flush_one 161032407
$ sudo cat /proc/loadavg
0.52 0.35 0.27 2/1124 22236
Parece muito com um vazamento de memória do kernel. Eu esperava que o File + Anon + Free + Slab adicionasse à sua RAM física total, mas ele é de 2 a 3 GB. Se você está fazendo um monte de trabalho intensivo em disco, talvez seja o BTRFS (exemplo aqui ). Você precisaria de um kernel com o kmemleak ativado para verificar.