Re: Spurious "apparent wraparound" via SimpleLruTruncate() rounding

Hi Noah!

I've found this thread in CF looking for something to review.

> 9 нояб. 2020 г., в 09:53, Noah Misch  написал(а):
> 
> Rebased both patches, necessitated by commit c732c3f (a repair of commit
> dee663f).  As I mentioned on another branch of the thread, I'd be content if
> someone reviews the slru-truncate-modulo patch and disclaims knowledge of the
> slru-truncate-insurance patch; I would then abandon the latter patch.
> 

Commit c732c3f adds some SYNC_FORGET_REQUESTs.
slru-truncate-modulo-v5.patch fixes off-by-one error in functions like *PagePrecedes(int page1, int page2).
slru-truncate-t-insurance-v4.patch ensures that off-by-one errors do not inflict data loss.

While I agree that fixing error is better than hiding it, I could not figure out how c732c3f is connected to these patches.
Can you please give me few pointers how to understand this connection?

Best regards, Andrey Borodin.