Zi Yan <ziy@xxxxxxxxxx> writes: > On 26 Dec 2022, at 19:28, Huang Ying wrote: > >> In this patch the _unmap and _move stage of the folio migration is >> batched. That for, previously, it is, >> >> for each folio >> _unmap() >> _move() >> >> Now, it is, >> >> for each folio >> _unmap() >> for each folio >> _move() > > Also worth adding some notes here, we need extra code to undo the _unmap() > if _move() fails. Andrew has asked for comments on *_undo_src/dst(), > but I think it would be better to provide a high level new workflow, > in the form of pseudo code, in git log and the comment for migrate_pages(). > The extra cleanup code for a failed _move() with a previously successful > _unmap() might not be obvious to everyone. Here, I removed the detailed error processing to make it easier to understand the basic flow changing. So, I would rather to keep the pseudo code here as simple as possible and keep the detailed flow in the diff below. Best Regards, Huang, Ying >> >> Based on this, we can batch the TLB flushing and use some hardware >> accelerator to copy folios between batched _unmap and batched _move >> stages. >> [snip]
