On 2024/2/2 01:55, Johannes Weiner wrote: > On Thu, Feb 01, 2024 at 03:49:04PM +0000, Chengming Zhou wrote: >> cat /sys/kernel/debug/zswap/duplicate_entry >> 2086447 >> >> When testing, the duplicate_entry value is very high, but no warning >> message in the kernel log. From the comment of duplicate_entry >> "Duplicate store was encountered (rare)", it seems something goes wrong. >> >> Actually it's incremented in the beginning of zswap_store(), which found >> its zswap entry has already on the tree. And this is a normal case, >> since the folio could leave zswap entry on the tree after swapin, >> later it's dirtied and swapout/zswap_store again, found its original >> zswap entry. (Maybe we can reuse it instead of invalidating it?) > > Probably not worth it, especially after the next patch. You are right, not worth it. > >> So duplicate_entry should be only incremented in the real bug case, >> which already have "WARN_ON(1)", it looks redundant to count bug case, >> so this patch just remove it. >> >> Signed-off-by: Chengming Zhou <zhouchengming@xxxxxxxxxxxxx> > > Either way, I agree that the WARN_ON() is more useful to point out a > bug than a counter. > > Acked-by: Johannes Weiner <hannes@xxxxxxxxxxx> Thanks!
