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70612d0e12
Recently a regression was introduced which caused TTM's buffer eviction to attempt to evict already-pinned BOs, causing issues with buffer eviction under memory pressure along with suspend/resume: nouveau 0000:1f:00.0: DRM: evicting buffers... nouveau 0000:1f:00.0: DRM: Moving pinned object 00000000c428c3ff! nouveau 0000:1f:00.0: fifo: fault 00 [READ] at 0000000000200000 engine 04 [BAR1] client 07 [HUB/HOST_CPU] reason 02 [PTE] on channel -1 [00ffeaa000 unknown] nouveau 0000:1f:00.0: fifo: DROPPED_MMU_FAULT 00001000 nouveau 0000:1f:00.0: fifo: fault 01 [WRITE] at 0000000000020000 engine 0c [HOST6] client 07 [HUB/HOST_CPU] reason 02 [PTE] on channel 1 [00ffb28000 DRM] nouveau 0000:1f:00.0: fifo: channel 1: killed nouveau 0000:1f:00.0: fifo: runlist 0: scheduled for recovery [TTM] Buffer eviction failed nouveau 0000:1f:00.0: DRM: waiting for kernel channels to go idle... nouveau 0000:1f:00.0: DRM: failed to idle channel 1 [DRM] nouveau 0000:1f:00.0: DRM: resuming display... After some bisection and investigation, it appears this resulted from the recent changes to ttm_bo_move_to_lru_tail(). Previously when a buffer was pinned, the buffer would be removed from the LRU once ttm_bo_unreserve to maintain the LRU list when pinning or unpinning BOs. However, since: commit3d1a88e105("drm/ttm: cleanup LRU handling further") We've been exiting from ttm_bo_move_to_lru_tail() at the very beginning of the function if the bo we're looking at is pinned, resulting in the pinned BO never getting removed from the lru and as a result - causing issues when it eventually becomes time for eviction. So, let's fix this by calling ttm_bo_del_from_lru() from ttm_bo_move_to_lru_tail() in the event that we're dealing with a pinned buffer. v2 (chk): reduce to only the fixing one liner since we always want to call the callback whenever we would move on the LRU. Fixes:3d1a88e105("drm/ttm: cleanup LRU handling further") Cc: Dave Airlie <airlied@redhat.com> Reviewed-by: Christian König <christian.koenig@amd.com> Signed-off-by: Lyude Paul <lyude@redhat.com> Signed-off-by: Christian König <christian.koenig@amd.com> Link: https://patchwork.freedesktop.org/patch/msgid/20210105114505.38210-1-christian.koenig@amd.com
Linux kernel
============
There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.
In order to build the documentation, use ``make htmldocs`` or
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https://www.kernel.org/doc/html/latest/
There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.
Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.