Quoting Matthew Auld (2020-11-27 12:06:41)
From: Venkata Sandeep Dhanalakota venkata.s.dhanalakota@intel.com
when allocating pages to lmem object of size 4G or greater we allocate memory blocks from buddy system.
Any lmem object is from the buddy system.
In this scenario buddy sytem can allocate blocks that can have size >= 4G and these blocks require >32b to represent block size with these blocks we run into an issue with sg list construction because sg->length field is only 32b wide.
Just say the when using scatterlist, the maximum segment size is 4G. In fact, we can ask sg what the backend maximum is, and use that as our max order.
The only question is whether this merits a flag, or we just assume that the buddy allocator is only used for objects and so always presented via sg? -Chris