Public bug reported:
After prolonged GPU activity (e.g. YouTube video playback, games, WebGL
applications), a large amount of system RAM becomes unavailable to
userspace even though it is not accounted for by processes, page cache,
slab, or shared memory.
This causes the kernel to reclaim page cache and swap application memory
while several gigabytes remain effectively unavailable until the kernel
eventually invokes memory shrinkers.
System
Ubuntu 24.04
Kernel: 7.0.0-28-generic
AMD APU/GPU: VGA compatible controller: Advanced Micro Devices, Inc. [AMD/ATI]
Lucienne (rev c2)
Wayland session
After several hours of GPU usage:
- free reports approximately 11–12 GiB used out of 16 GiB.
- smem reports only about 3.6 GiB PSS across all processes.
- /proc/meminfo shows:
- normal page cache
- normal slab usage
- no unusually large shared memory
- Memory pressure (/proc/pressure/memory) remains near zero.
Despite this, applications begin to experience cache eviction and
swapping. For example, YouTube playback starts buffering and interactive
performance degrades while several gigabytes of RAM remain unaccounted
for.
While investigating, I manually triggered memory reclaim:
sudo sh -c 'echo 2 > /proc/sys/vm/drop_caches'
awk '/MemTotal/{t=$2} /MemFree/{f=$2} /^Cached/{c=$2} /^Buffers/{b=$2}
/SReclaimable/{sr=$2} /
AnonPages/{a=$2} /SUnreclaim/{su=$2}
END{printf "gap: %.2f GiB\n",(t-f-c-b-sr-a-su)/1048576}' /proc/meminfo
And the gap went from 5.66 GiB to 1.96 GiB.
The behaviour appears consistent with the TTM page pool used by amdgpu
and to fix that i capped ttm to 512 Mb:
echo 'options ttm page_pool_size=131072' | sudo tee
/etc/modprobe.d/ttm.conf
Please let me know if additional debugging.
Best regards,
Lorenzo
ProblemType: Bug
DistroRelease: Ubuntu 24.04
Package: linux-image-7.0.0-28-generic 7.0.0-28.28~24.04.1
ProcVersionSignature: Ubuntu 7.0.0-28.28~24.04.1-generic 7.0.12
Uname: Linux 7.0.0-28-generic x86_64
ApportVersion: 2.28.2-0ubuntu0.1
Architecture: amd64
CasperMD5CheckResult: pass
CurrentDesktop: ubuntu:GNOME
Date: Mon Aug 3 11:58:24 2026
InstallationDate: Installed on 2023-07-26 (1104 days ago)
InstallationMedia: Ubuntu 22.04.2 LTS "Jammy Jellyfish" - Release amd64
(20230223)
MachineType: Acer Aspire A515-45
ProcFB: 0 amdgpudrmfb
ProcKernelCmdLine: BOOT_IMAGE=/boot/vmlinuz-7.0.0-28-generic
root=UUID=9f94ee82-4ce1-4e25-bc27-fb995e04e6fb ro
PulseList: Error: command ['pacmd', 'list'] failed with exit code 1: No
PulseAudio daemon running, or not running as session daemon.
RelatedPackageVersions:
linux-restricted-modules-7.0.0-28-generic N/A
linux-backports-modules-7.0.0-28-generic N/A
linux-firmware 20240318.git3b128b60-0ubuntu2.27
SourcePackage: linux-hwe-7.0
UpgradeStatus: Upgraded to noble on 2024-09-23 (679 days ago)
dmi.bios.date: 10/24/2023
dmi.bios.release: 1.52
dmi.bios.vendor: INSYDE Corp.
dmi.bios.version: V1.52
dmi.board.asset.tag: Base Board Asset Tag
dmi.board.name: Calla_LC
dmi.board.vendor: LN
dmi.board.version: V1.52
dmi.chassis.type: 10
dmi.chassis.vendor: Chassis Manufacturer
dmi.chassis.version: Chassis Version
dmi.ec.firmware.release: 1.8
dmi.modalias:
dmi:bvnINSYDECorp.:bvrV1.52:bd10/24/2023:br1.52:efr1.8:svnAcer:pnAspireA515-45:pvrV1.52:rvnLN:rnCalla_LC:rvrV1.52:cvnChassisManufacturer:ct10:cvrChassisVersion:sku0000000000000000:pfaAspire5:
dmi.product.family: Aspire 5
dmi.product.name: Aspire A515-45
dmi.product.sku: 0000000000000000
dmi.product.version: V1.52
dmi.sys.vendor: Acer
** Affects: linux-hwe-7.0 (Ubuntu)
Importance: Undecided
Status: New
** Tags: amd64 apport-bug noble wayland-session
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https://bugs.launchpad.net/bugs/2162724
Title:
TTM page pool grows to 25% of RAM, causing page-cache thrashing on a
16 GB APU system
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