Messages in this thread | | | From | "Luck, Tony" <> | Subject | RE: [PATCH v2 0/2] Replace and improve "mcsafe" with copy_safe() | Date | Mon, 4 May 2020 20:05:13 +0000 |
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> When a copy function hits a bad page and the page is not yet known to > be bad, what does it do? (I.e. the page was believed to be fine but > the copy function gets #MC.) Does it unmap it right away? What does > it return?
I suspect that we will only ever find a handful of situations where the kernel can recover from memory that has gone bad that are worth fixing (got to be some code path that touches a meaningful fraction of memory, otherwise we get code complexity without any meaningful payoff).
I don't think we'd want different actions for the cases of "we just found out now that this page is bad" and "we got a notification an hour ago that this page had gone bad". Currently we treat those the same for application errors ... SIGBUS either way[1].
-Tony
[1] well there are options both globally and at the per-process level to have the "early" notifications delivered right away.
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