https://bugzilla.kernel.org/show_bug.cgi?id=214425

Bug ID: 214425 Summary: [drm][amdgpu][TTM] Page pool memory never gets freed Product: Drivers Version: 2.5 Kernel Version: 5.14.3 Hardware: x86-64 OS: Linux Tree: Mainline Status: NEW Severity: normal Priority: P1 Component: Video(DRI - non Intel) Assignee: drivers_video-dri@kernel-bugs.osdl.org Reporter: doucha@swarmtech.cz Regression: No

Hello, while playing certain webGL games, I've noticed what appears to be a memory leak in the kernel. Further investigation revealed that after about an hour of gameplay, over 3GB of memory (half of all available RAM on my machine) will be taken by the TTM page pool.

While the excessive allocation may be caused by a resource leak in the game itself (I need to investigate that further), the larger problem is that TTM never releases the memory even after I quit the game. Closing the game only moves the allocated memory from active buffer objects to idle memory pool where it'll get stuck until I reboot the system. Shutting down X server doesn't release the memory either.

System specs: HP Probook 455 G7 AMD Ryzen 5 4500U CPU AMD Renoir GPU (Mesa 21.2.1, LLVM 12.0) Gentoo Linux

TTM statistics before quitting the game: /sys/kernel/debug/ttm/buffer_objects: 3116

/sys/kernel/debug/ttm/page_pool: --- 0--- --- 1--- --- 2--- --- 3--- --- 4--- --- 5--- --- 6--- --- 7--- --- 8--- --- 9--- ---10--- wc : 2 2 1 1 8 2 0 1 2 1 2 uc : 0 0 0 0 0 0 0 0 0 0 0 wc 32 : 0 0 0 0 0 0 0 0 0 0 0 uc 32 : 0 0 0 0 0 0 0 0 0 0 0

total : 3410 of 939433

/sys/kernel/debug/ttm/page_pool_shrink: 2898/512

=======================================

TTM statistics after quitting the game (until reboot): /sys/kernel/debug/ttm/buffer_objects: 403

/sys/kernel/debug/ttm/page_pool: --- 0--- --- 1--- --- 2--- --- 3--- --- 4--- --- 5--- --- 6--- --- 7--- --- 8--- --- 9--- ---10--- wc : 151 134 20 5 255 241 790 193 416 1121 83 uc : 0 0 0 0 0 0 0 0 0 0 0 wc 32 : 0 0 0 0 0 0 0 0 0 0 0 uc 32 : 0 0 0 0 0 0 0 0 0 0 0

total : 853035 of 939433

/sys/kernel/debug/ttm/page_pool_shrink: 853034/1