On Tue, Nov 23, 2021 at 9:47 AM Shakeel Butt <shakeelb@xxxxxxxxxx> wrote: > > The deferred THPs are split on memory pressure through shrinker > callback and splitting of THP during reclaim can fail for several > reasons like unable to lock the THP, under writeback or unexpected > number of pins on the THP. Such pages are put back on the deferred split > list for consideration later. However kernel does not update the > deferred queue size on putting back the pages whose split was failed. > This patch fixes that. I forgot to add the user visible impact. "Without this patch the split_queue_len can underflow. Shrinker will always get that there are some THPs to split even if there are not and waste some cpu to scan the empty list."
