Michal Hocko <mhocko@xxxxxxxxxx> writes: > On Thu 02-04-20 16:10:29, Huang, Ying wrote: >> Michal Hocko <mhocko@xxxxxxxxxx> writes: >> >> > On Thu 02-04-20 15:03:23, Huang, Ying wrote: > [...] >> >> > Could you explain why do we need this WARN_ON? I haven't really checked >> >> > the swap support for THP but cannot we have normal swap pmd entries? >> >> >> >> I have some patches to add the swap pmd entry support, but they haven't >> >> been merged yet. >> >> >> >> Similar checks are for all THP migration code paths, so I follow the >> >> same style. >> > >> > I haven't checked other migration code paths but what is the reason to >> > add the warning here? Even if this shouldn't happen, smaps is perfectly >> > fine to ignore that situation, no? >> >> Yes. smaps itself is perfectly fine to ignore it. I think this is used >> to find bugs in other code paths such as THP migration related. > > Please do not add new warnings without a good an strong reasons. As a > matter of fact there are people running with panic_on_warn and each > warning is fatal for them. Please also note that this is a user trigable > path and that requires even more care. OK for me. Best Regards, Huang, Ying
