[SNIP]
My approach was basically to not only lock the current BO, but also the next one. Since only a locked BO can move on the LRU we effectively created an anchor. Before I dig into the code a couple of questions:These are described in the patches but brief comments inline.1. How do you distinct BOs and iteration anchors on the LRU?Using a struct ttm_lru_item, containing a struct list_head and the type. List nodes embeds this instead of a struct list_head. This is larger than the list head but makes it explicit what we're doing.
Need to look deeper into the code of this, but it would be nice if we could abstract that better somehow.
2. How do you detect that a bulk list moved on the LRU?An age u64 counter on the bulk move that we're comparing against. It's updated each time it moves.3. How do you remove the iteration anchors from the bulk list?A function call at the end of iteration, that the function iterating is requried to call.
Thinking quite a bit about that in the last week and I came to the conclusion that this might be overkill.
All BOs in a bulk share the same reservation object. So when you acquired one you can just keep the dma-resv locked even after evicting the BO.
Since moving BOs requires locking the dma-resv object the whole problem then just boils down to a list_for_each_element_safe().
That's probably a bit simpler than doing the add/remove dance.
Regards,
Christian.
/ThomasRegards, Christian.The restartable property is used in patch 4 to restart swapout if needed, but the main purpose is this paves the way for shrinker- and exhaustive eviction. Cc: Christian König <christian.koenig@xxxxxxx> Cc: <dri-devel@xxxxxxxxxxxxxxxxxxxxx> Thomas Hellström (4): drm/ttm: Allow TTM LRU list nodes of different types drm/ttm: Use LRU hitches drm/ttm: Consider hitch moves within bulk sublist moves drm/ttm: Allow continued swapout after -ENOSPC falure drivers/gpu/drm/ttm/ttm_bo.c | 1 + drivers/gpu/drm/ttm/ttm_device.c | 33 +++-- drivers/gpu/drm/ttm/ttm_resource.c | 202 +++++++++++++++++++++++- ----- include/drm/ttm/ttm_resource.h | 91 +++++++++++-- 4 files changed, 267 insertions(+), 60 deletions(-)
