On Fri, Mar 04, 2022 at 07:36:46AM +0800, Miles Chen wrote:
Hi Robin,
For various reasons based on the allocator behaviour and typical use-cases at the time, when the max32_alloc_size optimisation was introduced it seemed reasonable to couple the reset of the tracked size to the update of cached32_node upon freeing a relevant IOVA. However, since subsequent optimisations focused on helping genuine 32-bit devices make best use of even more limited address spaces, it is now a lot more likely for cached32_node to be anywhere in a "full" 32-bit address space, and as such more likely for space to become available from IOVAs below that node being freed.
At this point, the short-cut in __cached_rbnode_delete_update() really doesn't hold up any more, and we need to fix the logic to reliably provide the expected behaviour. We still want cached32_node to only move upwards, but we should reset the allocation size if *any* 32-bit space has become available.
Reported-by: Yunfei Wang yf.wang@mediatek.com Signed-off-by: Robin Murphy robin.murphy@arm.com
Would you mind adding:
Applied without stable tag for now. If needed, please consider re-sending it for stable when this patch is merged upstream.
Regards,
Joerg