Numerous deleted DRM mmaped objects in Xorg server memory mappings

[Laurent Bonnaud]

Hi,

the Xorg server keeps in its memory mappings a lot of deleted DRM objects:

# grep /drm /proc/$(pidof Xorg)/maps
7fc03d0bb000-7fc03d8bb000 rw-s 00000000 00:05 29858 /drm mm object (deleted)
7fc03f340000-7fc03f3c0000 rw-s 00000000 00:05 269000 /drm mm object (deleted)
7fc0404c0000-7fc0404e0000 rw-s 00000000 00:05 239479 /drm mm object (deleted)
7fc040558000-7fc040568000 rw-s 00000000 00:05 269836 /drm mm object (deleted)
[many similar lines]

# grep /drm /proc/$(pidof Xorg)/maps | wc
    159 1431 15582

This is a waste of memory and according to the analysis below (made with ksysguard) it amounts to 22MB.

Process 2082 - Xorg

Summary

The process Xorg (with pid 2082) is using approximately 73.3 MB of memory.
It is using 62.3 MB privately, and a further 32.6 MB that is, or could be, shared with other programs.
Dividing up the shared memory between all the processes sharing that memory we get a reduced shared memory usage of 11.1 MB. Adding that to the private usage, we get the above mentioned total memory footprint of 73.3 MB.
3.1 MB is swapped out to disk, probably due to a low amount of available memory left.
Library Usage

The memory usage of a process is found by adding up the memory usage of each of its libraries, plus the process's own heap, stack and any other mappings.

Private

37176 KB [heap]
22324 KB /drm mm object (deleted)
2152 KB /usr/lib/xorg/Xorg
372 KB /usr/lib/x86_64-linux-gnu/libepoxy.so.0.0.0
212 KB /usr/lib/xorg/modules/libglamoregl.so

Shared

19996 KB /SYSV00000000 (deleted)
4784 KB /usr/lib/x86_64-linux-gnu/dri/i965_dri.so
1544 KB /lib/x86_64-linux-gnu/libc-2.24.so
1160 KB /usr/lib/x86_64-linux-gnu/libstdc++.so.6.0.22
560 KB /usr/lib/x86_64-linux-gnu/libpixman-1.so.0.33.6

ProblemType: Bug
DistroRelease: Ubuntu 16.10
Package: xserver-xorg-core 2:1.18.4-1ubuntu6.1
Uname: Linux 4.9.8-040908-generic x86_64
.tmp.unity_support_test.0:

ApportVersion: 2.20.3-0ubuntu8.2
Architecture: amd64
BootLog: /dev/sda1: clean, 1129716/15376384 files, 41270535/61491456 blocks
CompizPlugins: [core,composite,opengl,compiztoolbox,decor,vpswitch,snap,mousepoll,resize,place,move,wall,grid,regex,imgpng,session,gnomecompat,animation,fade,staticswitcher,workarounds,scale,expo,ezoom,dbus]
CompositorRunning: None
CurrentDesktop: KDE
Date: Sun Feb 5 09:26:54 2017
DistUpgraded: Fresh install
DistroCodename: yakkety
DistroVariant: kubuntu
EcryptfsInUse: Yes
ExtraDebuggingInterest: Yes
GconfCompiz:
 /apps/compiz-1/general:
   /apps/compiz-1/general/screen0:
    /apps/compiz-1/general/screen0/options:
     active_plugins = [core,composite,opengl,compiztoolbox,decor,vpswitch,snap,mousepoll,resize,place,move,wall,grid,regex,imgpng,session,gnomecompat,animation,fade,staticswitcher,workarounds,scale,expo,ezoom,dbus]
GraphicsCard:
 Intel Corporation 2nd Generation Core Processor Family Integrated Graphics Controller [8086:0126] (rev 09) (prog-if 00 [VGA controller])
   Subsystem: Dell 2nd Generation Core Processor Family Integrated Graphics Controller [1028:0494]
MachineType: Dell Inc. Latitude E6520
ProcKernelCmdLine: BOOT_IMAGE=/boot/vmlinuz-4.9.8-040908-generic root=UUID=749a9901-bdd3-4b5f-b80e-69414667e058 ro enable_mtrr_cleanup mtrr_spare_reg_nr=1 mtrr_gran_size=32M mtrr_chunk_size=128M quiet splash vt.handoff=7
SourcePackage: xorg-server
UpgradeStatus: No upgrade log present (probably fresh install)
dmi.bios.date: 11/14/2013
dmi.bios.vendor: Dell Inc.
dmi.bios.version: A19
dmi.board.name: 0NVF5K
dmi.board.vendor: Dell Inc.
dmi.board.version: A01
dmi.chassis.type: 9
dmi.chassis.vendor: Dell Inc.
dmi.modalias: dmi:bvnDellInc.:bvrA19:bd11/14/2013:svnDellInc.:pnLatitudeE6520:pvr01:rvnDellInc.:rn0NVF5K:rvrA01:cvnDellInc.:ct9:cvr:
dmi.product.name: Latitude E6520
dmi.product.version: 01
dmi.sys.vendor: Dell Inc.
version.compiz: compiz 1:0.9.13.0+16.10.20160818.2-0ubuntu2
version.ia32-libs: ia32-libs N/A
version.libdrm2: libdrm2 2.4.70-1
version.libgl1-mesa-dri: libgl1-mesa-dri 12.0.6-0ubuntu0.16.10.1
version.libgl1-mesa-dri-experimental: libgl1-mesa-dri-experimental N/A
version.libgl1-mesa-glx: libgl1-mesa-glx 12.0.6-0ubuntu0.16.10.1
version.xserver-xorg-core: xserver-xorg-core 2:1.18.4-1ubuntu6.1
version.xserver-xorg-input-evdev: xserver-xorg-input-evdev 1:2.10.2-1ubuntu1
version.xserver-xorg-video-ati: xserver-xorg-video-ati 1:7.7.1-1
version.xserver-xorg-video-intel: xserver-xorg-video-intel 2:2.99.917+git20160706-1ubuntu1
version.xserver-xorg-video-nouveau: xserver-xorg-video-nouveau 1:1.0.12-2

[Laurent Bonnaud (laurent-bonnaud)]

In artful the deleted objects have a different name:

# grep i915 /proc/$(pidof Xorg)/maps
7f37ddb56000-7f37ddbd6000 rw-s 00000000 00:18 1268577 /i915 (deleted)
7f37de9ce000-7f37dedce000 rw-s 00000000 00:18 64439 /i915 (deleted)
7f37e3396000-7f37e3b96000 rw-s 00000000 00:18 37015 /i915 (deleted)
7f37ebeed000-7f37ebefd000 rw-s 00000000 00:18 104879 /i915 (deleted)
7f37ebf0d000-7f37ebf15000 rw-s 00000000 00:18 1263772 /i915 (deleted)
7f37f28d7000-7f37f28df000 rw-s 00000000 00:18 1262549 /i915 (deleted)
7f37f28e2000-7f37f28e3000 rw-s 00000000 00:18 54294 /i915 (deleted)
7f37f28e3000-7f37f28e4000 rw-s 00000000 00:18 38653 /i915 (deleted)
7f37f28e4000-7f37f28e5000 rw-s 00000000 00:18 40964 /i915 (deleted)
7f37f28e5000-7f37f28e6000 rw-s 00000000 00:18 40226 /i915 (deleted)
7f37f28e6000-7f37f28e7000 rw-s 00000000 00:18 40225 /i915 (deleted)
7f37f28e7000-7f37f28f7000 rw-s 00000000 00:18 38652 /i915 (deleted)
7f37f28f7000-7f37f28f8000 rw-s 00000000 00:18 1250238 /i915 (deleted)
7f37f28fb000-7f37f28fc000 rw-s 00000000 00:18 757881 /i915 (deleted)
7f37f28fc000-7f37f28fd000 rw-s 00000000 00:18 757880 /i915 (deleted)
7f37f28fd000-7f37f28fe000 rw-s 00000000 00:18 757879 /i915 (deleted)
7f37f28fe000-7f37f28ff000 rw-s 00000000 00:18 757878 /i915 (deleted)
7f37f28ff000-7f37f2907000 rw-s 00000000 00:18 1261547 /i915 (deleted)
7f37f2907000-7f37f290f000 rw-s 00000000 00:18 1263683 /i915 (deleted)
7f37f2910000-7f37f2911000 rw-s 00000000 00:18 757877 /i915 (deleted)
7f37f2911000-7f37f2912000 rw-s 00000000 00:18 45058 /i915 (deleted)
7f37f2a2f000-7f37f2a30000 rw-s 00000000 00:18 1254529 /i915 (deleted)
7f37f2a34000-7f37f2a35000 rw-s 00000000 00:18 38657 /i915 (deleted)
7f37f2a35000-7f37f2a36000 rw-s 00000000 00:18 38655 /i915 (deleted)
7f37f2a36000-7f37f2a37000 rw-s 00000000 00:18 757876 /i915 (deleted)
7f37f2a37000-7f37f2a38000 rw-s 00000000 00:18 757875 /i915 (deleted)
7f37f2a38000-7f37f2a39000 rw-s 00000000 00:18 757874 /i915 (deleted)
7f37f2a3e000-7f37f2a3f000 rw-s 00000000 00:18 866965 /i915 (deleted)
7f37f2a79000-7f37f2a81000 rw-s 00000000 00:18 36441 /i915 (deleted)

[Laurent Bonnaud (laurent-bonnaud)]

Closing per upstream comment.