As a result of discussion in the thread [0], Robert Haas proposed to focus on making SLRU 64 bit, as a first step towards 64 bit XIDs.
Here is the patch set.
In overall, code of this patch set is based on the existing code from [0] and may be simplified, due to the fact, that SLRU_PAGES_PER_SEGMENT is not meant to be changed now.
But I decided to leave it that way. At least for now.
As always, reviews and opinions are very welcome.
Should we change status for this thread to "need review"?