A memória é ocupada por encadeamentos “invisíveis”

Question

Xubuntu Saucy com 4 GB de RAM. Quando o computador é reiniciado e imediatamente após o login, cerca de 500 MB de RAM são obtidos de acordo com free -m . Então eu corro alguns programas e uso de memória vai acima de 3 GM.

Agora aqui está o problema: Se eu fechar todos os aplicativos abertos, ainda assim, cerca de 2,5 GB de memória serão usados, mas nenhum thread será responsável por toda essa memória. Aqui está o resultado de ps aux :

USER       PID %CPU %MEM    VSZ   RSS TTY      STAT START   TIME COMMAND  
root         1  0.0  0.0  27092  2680 ?        Ss   mar27   0:02 /sbin/init  
root         2  0.0  0.0      0     0 ?        S    mar27   0:00 [kthreadd]  
root         3  0.0  0.0      0     0 ?        S    mar27   0:25 [ksoftirqd/0]  
root         5  0.0  0.0      0     0 ?        S<   mar27   0:00 [kworker/0:0H]  
root         7  0.0  0.0      0     0 ?        S    mar27   0:15 [migration/0]  
root         8  0.0  0.0      0     0 ?        S    mar27   0:00 [rcu_bh]  
root         9  0.0  0.0      0     0 ?        S    mar27   0:00 [rcuob/0]  
root        10  0.0  0.0      0     0 ?        S    mar27   0:00 [rcuob/1]  
root        11  0.0  0.0      0     0 ?        S    mar27   0:24 [rcu_sched]  
root        12  0.0  0.0      0     0 ?        S    mar27   0:11 [rcuos/0]  
root        13  0.0  0.0      0     0 ?        S    mar27   0:12 [rcuos/1]  
root        14  0.0  0.0      0     0 ?        S    mar27   0:01 [watchdog/0]  
root        15  0.0  0.0      0     0 ?        S    mar27   0:01 [watchdog/1]  
root        16  0.0  0.0      0     0 ?        S    mar27   0:11 [migration/1]  
root        17  0.0  0.0      0     0 ?        S    mar27   0:22 [ksoftirqd/1]  
root        19  0.0  0.0      0     0 ?        S<   mar27   0:00 [kworker/1:0H]  
root        20  0.0  0.0      0     0 ?        S<   mar27   0:00 [khelper]  
root        21  0.0  0.0      0     0 ?        S    mar27   0:00 [kdevtmpfs]  
root        22  0.0  0.0      0     0 ?        S<   mar27   0:00 [netns]  
root        23  0.0  0.0      0     0 ?        S<   mar27   0:00 [writeback]  
root        24  0.0  0.0      0     0 ?        S<   mar27   0:00 [kintegrityd]  
root        25  0.0  0.0      0     0 ?        S<   mar27   0:00 [bioset]  
root        27  0.0  0.0      0     0 ?        S<   mar27   0:00 [kblockd]  
root        29  0.0  0.0      0     0 ?        S<   mar27   0:00 [ata_sff]  
root        30  0.0  0.0      0     0 ?        S    mar27   0:00 [khubd]  
root        31  0.0  0.0      0     0 ?        S<   mar27   0:00 [md]  
root        32  0.0  0.0      0     0 ?        S<   mar27   0:00 [devfreq_wq]  
root        35  0.0  0.0      0     0 ?        S    mar27   0:00 [khungtaskd]  
root        36  0.0  0.0      0     0 ?        S    mar27   0:05 [kswapd0]  
root        37  0.0  0.0      0     0 ?        SN   mar27   0:00 [ksmd]  
root        38  0.0  0.0      0     0 ?        SN   mar27   0:00 [khugepaged]  
root        39  0.0  0.0      0     0 ?        S    mar27   0:00 [fsnotify_mark]  
root        40  0.0  0.0      0     0 ?        S    mar27   0:00 [ecryptfs-kthrea]  
root        41  0.0  0.0      0     0 ?        S<   mar27   0:00 [crypto]  
root        53  0.0  0.0      0     0 ?        S<   mar27   0:00 [kthrotld]  
root        74  0.0  0.0      0     0 ?        S<   mar27   0:00 [deferwq]  
root        75  0.0  0.0      0     0 ?        S<   mar27   0:00 [charger_manager]  
root       122  0.0  0.0      0     0 ?        S<   mar27   0:00 [firewire]  
root       124  0.0  0.0      0     0 ?        S    mar27   0:00 [scsi_eh_0]  
root       125  0.0  0.0      0     0 ?        S    mar27   0:00 [scsi_eh_1]  
root       126  0.0  0.0      0     0 ?        S    mar27   0:00 [scsi_eh_2]  
root       127  0.0  0.0      0     0 ?        S    mar27   0:00 [scsi_eh_3]  
root       144  0.0  0.0      0     0 ?        S    mar27   0:03 [jbd2/sda6-8]  
root       145  0.0  0.0      0     0 ?        S<   mar27   0:00 [ext4-rsv-conver]  
root       146  0.0  0.0      0     0 ?        S<   mar27   0:00 [ext4-unrsv-conv]  
root       346  0.0  0.0      0     0 ?        S<   mar27   0:00 [cfg80211]  
root       347  0.0  0.0      0     0 ?        S<   mar27   0:00 [kpsmoused]  
root       392  0.0  0.0      0     0 ?        S<   mar27   0:00 [hd-audio0]  
102        531  0.0  0.0  31640  2500 ?        Ss   mar27   0:13 dbus-daemon --system --fork  
root       590  0.0  0.0  37140  1580 ?        Ss   mar27   0:00 /lib/systemd/systemd-logind  
root       591  0.0  0.0  83484  3324 ?        Ss   mar27   0:02 /usr/sbin/modem-manager  
root       592  0.0  0.0  19396  2116 ?        Ss   mar27   0:00 /usr/sbin/bluetoothd  
root       625  0.0  0.0      0     0 ?        S<   mar27   0:00 [krfcommd]  
root       636  0.0  0.1 271524  5588 ?        Ssl  mar27   0:21 NetworkManager  
root       659  0.0  0.1 284248  5392 ?        Sl   mar27   0:03 /usr/lib/policykit-1/polkitd --no-debug  
syslog     692  0.0  0.0 247476  1304 ?        Sl   mar27   0:19 rsyslogd -c5  
root       797  0.0  0.0  16056   548 ?        S    mar27   0:00 upstart-socket-bridge --daemon  
root       800  0.0  0.0  15668   516 ?        S    mar27   0:00 upstart-file-bridge --daemon  
root       851  0.0  0.0  24236   748 tty4     Ss+  mar27   0:00 /sbin/getty -8 38400 tty4  
root       854  0.0  0.0  24236   748 tty5     Ss+  mar27   0:00 /sbin/getty -8 38400 tty5  
root       860  0.0  0.0  24236   748 tty2     Ss+  mar27   0:00 /sbin/getty -8 38400 tty2  
root       863  0.0  0.0  24236   748 tty3     Ss+  mar27   0:00 /sbin/getty -8 38400 tty3  
root       872  0.0  0.0  24236   748 tty6     Ss+  mar27   0:00 /sbin/getty -8 38400 tty6  
root       932  0.0  0.0   4376   612 ?        Ss   mar27   0:00 acpid -c /etc/acpi/events -s /var/run/acpid.socket  
root       933  0.0  0.0  25804   900 ?        Ss   mar27   0:00 cron  
root       951  0.0  0.0 275628  3052 ?        SLsl mar27   0:00 lightdm  
root       994  1.4  2.7 300936 113208 tty7    Ss+  mar27 112:27 /usr/bin/X -core :0 -auth /var/run/lightdm/root/:0 -nolisten tcp vt7 -novtswitch  
root       997  0.0  0.0  24236   752 tty1     Ss+  mar27   0:00 /sbin/getty -8 38400 tty1  
root      1021  0.0  0.0 279004  4008 ?        Sl   mar27   0:06 /usr/lib/accountsservice/accounts-daemon  
root      1035  0.0  0.0      0     0 ?        S    mar27   0:00 [kauditd]  
root      1085  0.0  0.0 163808  2988 ?        Sl   mar27   0:00 lightdm --session-child 12 19  
root      1094  0.0  0.0  32692  2836 ?        Ss   mar27   0:11 /sbin/wpa_supplicant -B -P /run/sendsigs.omit.d/wpasupplicant.pid -u -s -O /var/run/wpa_supplicant  
rez       1144  0.0  0.0  37560  1848 ?        Ss   mar27   0:01 init --user  
rez       1195  0.0  0.0  12624    92 ?        Ss   mar27   0:00 ssh-agent  
rez       1200  0.0  0.0  32716  2572 ?        Ss   mar27   0:08 dbus-daemon --fork --session --address=unix:abstract=/tmp/dbus-S88cKKbWgL  
rez       1205  0.0  0.0  26516  1044 ?        Ss   mar27   0:00 upstart-event-bridge  
rez       1216  0.0  0.0   4440   576 ?        Ss   mar27   0:00 /bin/sh /etc/xdg/xfce4/xinitrc -- /etc/X11/xinit/xserverrc  
rez       1224  0.0  0.2 328460 11808 ?        Sl   mar27   0:11 xfce4-session  
rez       1229  0.0  0.0  34996   760 ?        S    mar27   0:00 upstart-file-bridge --daemon --user  
rez       1230  0.0  0.0  26520   528 ?        S    mar27   0:01 upstart-dbus-bridge --daemon --session --user --bus-name session  
rez       1232  0.0  0.0  26520   532 ?        S    mar27   0:01 upstart-dbus-bridge --daemon --system --user --bus-name system  
rez       1235  0.0  0.0  39360  2432 ?        S    mar27   0:00 /usr/lib/x86_64-linux-gnu/xfce4/xfconf/xfconfd  
rez       1238  0.0  0.4 320204 16784 ?        Sl   mar27   3:51 xfwm4 --replace --display :0.0 --sm-client-id 273d07c4e-c10c-41ee-8cf9-2374cb32777e  
rez       1240  0.0  1.2 1151052 50204 ?       Sl   mar27   2:10 Thunar --sm-client-id 20caa2dc4-4174-44d3-82ef-fbb67bffe778 --daemon  
nobody    1242  0.0  0.0  39412  1340 ?        S    mar27   0:01 /usr/sbin/dnsmasq --no-resolv --keep-in-foreground --no-hosts --bind-interfaces --pid-file=/var/run/NetworkManager/dnsmasq.pid --listen-address=127.0.1.1 --conf-file=/var/run/NetworkManager/dnsmasq.conf --cache-size=0 --proxy-dnssec --enable-dbus=org.freedesktop.NetworkManager.dnsmasq --conf-dir=/etc/NetworkManager/dnsmasq.d  
rez       1266  0.0  0.7 526112 31824 ?        Sl   mar27   0:19 xfdesktop --display :0.0 --sm-client-id 2da06fe80-f4ae-4839-8b3b-91600fe2eb68  
rez       1267  0.0  0.6 348032 24372 ?        Ssl  mar27   0:20 xfsettingsd --display :0.0 --sm-client-id 2ba6a0c3b-f588-4771-9570-4b877c7f8c7f  
rez       1300  0.0  0.0 200876  2908 ?        Sl   mar27   0:00 /usr/lib/gvfs/gvfsd  
rez       1304  0.0  0.0 336860  2484 ?        Sl   mar27   0:00 /usr/lib/gvfs//gvfsd-fuse -f /run/user/1000/gvfs  
rez       1322  0.0  0.3 311836 12852 ?        Ssl  mar27   0:07 xfce4-power-manager --restart --sm-client-id 2ad69ea99-5f8a-4c94-afef-b10023557baf  
rez       1324  0.0  0.3 453000 15768 ?        Sl   mar27   0:01 /usr/lib/policykit-1-gnome/polkit-gnome-authentication-agent-1  
rez       1334  0.0  0.0 337356  2724 ?        Sl   mar27   0:00 /usr/lib/at-spi2-core/at-spi-bus-launcher  
rez       1340  0.0  0.0  30488  1612 ?        S    mar27   0:00 /bin/dbus-daemon --config-file=/etc/at-spi2/accessibility.conf --nofork --print-address 3  
rez       1344  0.0  0.0 124920  2956 ?        Sl   mar27   0:01 /usr/lib/at-spi2-core/at-spi2-registryd --use-gnome-session  
rez       1347  0.0  0.7 958552 29336 ?        SLl  mar27   1:28 nm-applet  
rez       1352  0.0  0.9 344436 39920 ?        Ssl  mar27   0:25 xfce4-volumed  
rez       1355  0.0  0.0 368400  3804 ?        Sl   mar27   0:06 /usr/lib/x86_64-linux-gnu/indicator-application-service  
rez       1363  0.0  0.0  74664  2804 ?        S    mar27   0:21 xscreensaver -no-splash  
rez       1372  0.6  0.1 365508  5072 ?        Sl   mar27  49:29 /usr/bin/pulseaudio --start --log-target=syslog  
rtkit     1374  0.0  0.0 168920  1176 ?        SNl  mar27   0:02 /usr/lib/rtkit/rtkit-daemon  
root      1399  0.0  0.1 298576  4396 ?        Sl   mar27   0:07 /usr/lib/upower/upowerd  
rez       1497  0.0  0.1 450192  5196 ?        Sl   mar27   0:02 /usr/lib/gvfs/gvfs-udisks2-volume-monitor  
root      1500  0.0  0.1 436580  5668 ?        Sl   mar27   0:30 /usr/lib/udisks2/udisksd --no-debug  
rez       1536  0.0  0.0 200212  3276 ?        Sl   mar27   0:00 /usr/lib/gvfs/gvfs-mtp-volume-monitor  
rez       1624  0.0  0.0 289908  2892 ?        Sl   mar27   0:00 /usr/lib/gvfs/gvfs-afc-volume-monitor  
rez       1637  0.0  0.0 207980  2776 ?        Sl   mar27   0:00 /usr/lib/gvfs/gvfs-gphoto2-volume-monitor  
rez       1639  0.0  0.0  61360  2336 ?        S    mar27   0:00 /usr/lib/x86_64-linux-gnu/gconf/gconfd-2  
rez       1655  0.0  0.0  64324  2628 ?        S    mar27   0:01 /usr/bin/obex-data-server --no-daemon   
rez       1832  0.0  0.3 476124 15004 ?        Ssl  mar27   0:05 xfrun4  
rez       1943  0.0  0.7 450508 28392 ?        Sl   mar27   0:15 /usr/lib/gvfs/gvfsd-trash --spawner :1.9 /org/gtk/gvfs/exec_spaw/0  
root      1997  0.0  0.0  24444   596 ?        S    mar27   0:00 dbus-launch --autolaunch=42613f7aae1f969ac75e6e7252f27376 --binary-syntax --close-stderr  
root      1998  0.0  0.0  30652  1188 ?        Ss   mar27   0:00 //bin/dbus-daemon --fork --print-pid 5 --print-address 7 --session  
rez       2942  0.0  0.0 302736  3708 ?        Sl   mar27   0:00 /usr/lib/gvfs/gvfsd-http --spawner :1.9 /org/gtk/gvfs/exec_spaw/1  
root      4058  0.0  0.0  39204  2312 ?        S    13:54   0:00 /usr/lib/x86_64-linux-gnu/xfce4/xfconf/xfconfd  
root      4067  0.0  0.0 200752  2952 ?        Sl   13:54   0:00 /usr/lib/gvfs/gvfsd  
root      4071  0.0  0.0 271324  3000 ?        Sl   13:54   0:00 /usr/lib/gvfs//gvfsd-fuse -f /root/.gvfs  
root      4443  0.0  0.1 515556  5524 ?        Sl   13:54   0:00 /usr/lib/gvfs/gvfs-udisks2-volume-monitor  
root      4451  0.0  0.0 200344  3384 ?        Sl   13:54   0:00 /usr/lib/gvfs/gvfs-mtp-volume-monitor  
root      4455  0.0  0.0 289908  3296 ?        Sl   13:54   0:00 /usr/lib/gvfs/gvfs-afc-volume-monitor  
root      4460  0.0  0.0 207980  3344 ?        Sl   13:54   0:00 /usr/lib/gvfs/gvfs-gphoto2-volume-monitor  
root      5845  0.0  0.0  17320   632 ?        S    14:20   0:00 upstart-udev-bridge --daemon  
root      5848  0.0  0.0  42964  1952 ?        Ss   14:20   0:00 /lib/systemd/systemd-udevd --daemon  
root      7073  0.0  0.0 128452  2276 ?        Ss   mar27   0:01 smbd -F  
root      7076  0.0  0.0 129096  1124 ?        S    mar27   0:00 smbd -F  
root      7112  0.0  0.0  91400  1348 ?        Ss   mar27   0:16 nmbd -D  
root      9236  0.0  0.0  25248  1396 ?        Ss   mar30   0:03 hostapd -B /etc/hostapd-hotspot.conf -f /tmp/hostapd.log  
root     10401  0.0  0.0  25248  1368 ?        Ss   mar30   0:04 hostapd -B /etc/hostapd-hotspot.conf -f /tmp/hostapd.log  
rez      12137  0.0  0.1 125468  4216 ?        Sl   mar27   0:02 /usr/lib/gvfs/gvfsd-metadata  
root     12267  0.0  0.0      0     0 ?        S    14:42   0:00 [kworker/1:3]  
rez      12435  0.0  0.0 178216  2648 ?        Sl   mar27   0:00 /usr/lib/dconf/dconf-service  
root     13050  0.0  0.0      0     0 ?        S<   14:44   0:00 [hci0]  
root     13051  0.0  0.0      0     0 ?        S<   14:44   0:00 [hci0]  
dnsmasq  13805  0.0  0.0  39416  1028 ?        S    15:24   0:00 /usr/sbin/dnsmasq -x /var/run/dnsmasq/dnsmasq.pid -u dnsmasq -r /var/run/dnsmasq/resolv.conf -7 /etc/dnsmasq.d,.dpkg-dist,.dpkg-old,.dpkg-new  
root     13873  0.0  0.0      0     0 ?        S    15:24   0:07 [irq/18-b43]  
root     13875  0.0  0.0  25248  1344 ?        Ss   15:24   0:01 hostapd -B /etc/hostapd-hotspot.conf -f /tmp/hostapd.log  
root     13884  0.0  0.0  20944   988 ?        S    15:24   0:02 /bin/bash /usr/bin/ap-hotspot start  
rez      14672  0.0  0.1 684664  6128 ?        Sl   mar27   0:01 /usr/lib/indicator-sound-gtk2/indicator-sound-service  
root     15097  0.0  0.0 195828  3936 ?        Sl   mar27   0:03 /usr/lib/udisks/udisks-daemon  
root     15098  0.0  0.0  47844   528 ?        S    mar27   0:00 udisks-daemon: not polling any devices  
rez      15264  0.0  0.0 374624  3600 ?        SLl  mar27   0:00 /usr/bin/gnome-keyring-daemon --start --foreground --components=secrets  
root     15913  0.0  0.0      0     0 ?        S    16:17   0:04 [kworker/0:2]  
root     16432  0.0  0.0      0     0 ?        S<   mar27   0:00 [kworker/1:1H]  
root     16733  0.0  0.0      0     0 ?        S    16:37   0:00 [kworker/u4:0]  
rez      16991  0.0  0.7 544484 30484 ?        Sl   mar30   0:00 /usr/bin/python /usr/bin/blueman-applet  
root     17133  0.0  0.0  10244  3736 ?        S    16:46   0:00 /sbin/dhclient -d -sf /usr/lib/NetworkManager/nm-dhcp-client.action -pf /run/sendsigs.omit.d/network-manager.dhclient-eth0.pid -lf /var/lib/NetworkManager/dhclient-1d839b90-39a2-4362-9cb0-0cba8724ef39-eth0.lease -cf /var/lib/NetworkManager/dhclient-eth0.conf eth0  
root     17918  0.0  0.0  72940  2636 ?        Ss   mar27   0:00 /usr/sbin/cups-browsed  
rez      18213  0.0  0.5 462292 22604 ?        Sl   mar27   0:01 artha  
root     18672  0.0  0.0  25248  1356 ?        Ss   mar27   0:03 hostapd -B /etc/hostapd-hotspot.conf -f /tmp/hostapd.log  
rez      18679  0.0  0.0  24444   596 ?        S    mar27   0:00 dbus-launch --autolaunch=42613f7aae1f969ac75e6e7252f27376 --binary-syntax --close-stderr  
rez      18680  0.0  0.0  30524  1128 ?        Ss   mar27   0:00 //bin/dbus-daemon --fork --print-pid 5 --print-address 7 --session  
rez      18685  0.0  0.0  39232  2208 ?        S    mar27   0:00 /usr/lib/x86_64-linux-gnu/xfce4/xfconf/xfconfd  
rez      18688  0.0  0.0 200752  2856 ?        Sl   mar27   0:00 /usr/lib/gvfs/gvfsd  
root     19329  0.0  0.0      0     0 ?        S    17:35   0:00 [kworker/0:1]  
root     19677  0.0  0.0      0     0 ?        S    mar30   0:00 [jbd2/sda1-8]  
root     19678  0.0  0.0      0     0 ?        S<   mar30   0:00 [ext4-rsv-conver]  
root     19679  0.0  0.0      0     0 ?        S<   mar30   0:00 [ext4-unrsv-conv]  
root     19967  0.0  0.0      0     0 ?        S    17:52   0:00 [kworker/u4:1]  
root     19996  0.0  0.0  61356  2576 ?        S    mar30   0:00 /usr/lib/x86_64-linux-gnu/gconf/gconfd-2  
root     20457  0.0  0.0      0     0 ?        S    18:03   0:00 [kworker/u4:2]  
root     20532  0.0  0.0  25248  1396 ?        Ss   mar31   0:03 hostapd -B /etc/hostapd-hotspot.conf -f /tmp/hostapd.log  
rez      20659  1.3  0.3 456460 15952 ?        Sl   18:07   0:00 xfce4-terminal  
rez      20663  0.0  0.0  14832   816 ?        S    18:07   0:00 gnome-pty-helper  
rez      20664  0.1  0.0  30540  3372 pts/5    Ss   18:07   0:00 bash  
root     20727  0.0  0.0  15612   624 ?        S    18:07   0:00 sleep 5  
root     20728  0.6  0.0  69172  2292 pts/5    S+   18:07   0:00 sudo ps aux  
root     20729  0.0  0.0  26856  1348 pts/5    R+   18:08   0:00 ps aux  
root     22673  0.0  0.0  74436  2912 ?        Ss   mar28   0:00 /usr/sbin/cupsd -F  
root     22880  0.0  0.0  25248  1372 ?        Ss   mar28   0:03 hostapd -B /etc/hostapd-hotspot.conf -f /tmp/hostapd.log  
root     26957  0.0  0.0      0     0 ?        S<   mar31   0:00 [kworker/u5:2]  
rez      28053  0.0  0.5 440980 22640 ?        Sl   mar30   1:41 xfce4-panel  
rez      28057  0.0  0.2 168856 10340 ?        S    mar30   0:00 /usr/lib/x86_64-linux-gnu/xfce4/panel/wrapper /usr/lib/x86_64-linux-gnu/xfce4/panel/plugins/libactions.so 9 14680107 actions Action Buttons Log out, lock or other system actions   
rez      28059  0.0  0.1 158580  7540 ?        S    mar30   0:00 /usr/lib/x86_64-linux-gnu/xfce4/panel/wrapper /usr/lib/x86_64-linux-gnu/xfce4/panel/plugins/libsystray.so 4 14680108 systray Notification Area Area where notification icons appear   
rez      28060  0.0  0.5 517992 23188 ?        Sl   mar30   0:07 /usr/lib/x86_64-linux-gnu/xfce4/panel-plugins/xfce4-indicator-plugin  5 14680109 indicator Indicator Plugin An indicator of something that needs your attention on the desktop   
rez      28062  0.0  0.4 452116 17196 ?        Sl   mar30   0:06 /usr/lib/x86_64-linux-gnu/xfce4/panel/wrapper /usr/lib/x86_64-linux-gnu/xfce4/panel-plugins/libnotes.so 12 14680121 xfce4-notes-plugin Notes Ideal for your quick notes   
rez      28063  0.0  0.5 260536 21088 ?        Sl   mar30   0:15 /usr/lib/x86_64-linux-gnu/xfce4/panel-plugins/xfce4-xkb-plugin  28 14680122 xkb-plugin Keyboard Layouts Keyboard layouts setup and switch plugin   
root     28891  0.0  0.0      0     0 ?        S    mar31   0:20 [kworker/1:1]  
root     29208  0.0  0.0      0     0 ?        S<   09:43   0:00 [kworker/u5:1]  
avahi    29548  0.0  0.0  32348  1584 ?        S    mar28   0:00 avahi-daemon: registering [rez-Vostro.local]  
avahi    29550  0.0  0.0  32228   420 ?        S    mar28   0:00 avahi-daemon: chroot helper  
root     30645  0.0  0.0  25248  1356 ?        Ss   mar29   0:03 hostapd -B /etc/hostapd-hotspot.conf -f /tmp/hostapd.log  

e aqui a saída de free -m

           total       used       free     shared    buffers     cached
Mem:          3949       2512       1436          0        241       1164
-/+ buffers/cache:       1106       2842
Swap:         1715         55       1660

Como você pode ver (mesmo que nem todos os tópicos sejam mostrados na figura), a memória ocupada pelas threads não irá adicionar nada perto de 2512/3949 = 64%.

Então, o que está ocupando toda essa memória? Podem ser os rastros do kernel (cuja quantidade de memória não é exibida) ou um vazamento no próprio Ubuntu?

Algo que pode ser relevante é que a quantidade de memória usada mostrada pelo gerenciador de tarefas XFCE é significativamente menor do que a que o free -m mostra.

    

Answer 1

Por padrão, free mostra também a memória usada pelo cache e pelos buffers

Na saída free -m , como já foi dito nos comentários, você precisa olhar para a linha

-/+ buffers/cache:       1106       2842

para ver exatamente a quantidade de memória usada pelos aplicativos, kernel e módulos. Nesse caso, você está usando 1106 MB, o que representa quase 28% da memória total. O resto é tomado pelos buffers e cache habituais que ajudam o kernel a acessar os arquivos mais rapidamente.

A saída ps mostra a memória usada pelo processo

Na saída ps , vejo que ainda há toda a área de trabalho gráfica em execução, com muitos componentes em execução. Eles levam cerca de 13% da memória.

E os módulos ...

O delta entre o cálculo ps e o free é constituído da memória do kernel e dos módulos carregados. Como a coluna tamanho da saída lsmod exibe apenas o tamanho do módulo no sistema de arquivos (portanto, o arquivo syse do arquivo .ko a partir do qual este módulo é carregado) não é confiável medir o memória usada por eles. Uma abordagem mais confiável para medir a memória usada pelos módulos é usar os utilitários slabtop (instalados a partir do pacote procps .

Veja também o conteúdo de /proc/meminfo , ele fornece o uso total da memória Slab, a memória usada para alocar memória de forma eficiente aos objetos do kernel. (Veja Wikipedia para mais detalhes sobre Slab).

Em conclusão

O uso da memória é um domínio complexo, e você precisará de mais de uma ferramenta para ver em detalhes qual parte da memória é usada por quê. free , ps , slabtop , /proc/meminfo conteúdo, top , vmstat , htop , ... todos eles podem trazer uma informação útil para construir a imagem completa em sua memória particular uso.