On 6/11/26 09:36, Miaohe Lin wrote: > On 2026/6/11 13:43, Michael S. Tsirkin wrote: >> On Thu, Jun 11, 2026 at 11:35:36AM +0800, Miaohe Lin wrote: >>> >>> Do you mean repeating SetPageHWPoison on every branch? >> >> Right. >> >>> Is it possible >>> to make __free_pages_prepare changes page->flags atomically or this race >>> is specified to memory_failure? >>> >>> Thanks. >>> . >> >> >> Adding an atomic op on every fast path page allocation is, I am >> guessing, going to slow down Linux measureably. >> >> Doing it for the benefit of memory_failure, which is the slowest of >> slow paths, seems unpalatable, to me. > > Agree, it's not worth to do so. > >> >> Neither am I sure it's the only racy place - >> grep for __SetPage and __ClearPage - all these have the same issue, I >> suspect. >> >> At the same time, I'm not an mm maintainer. If you disagree, try to >> upstream a change converting all non atomics in mm to atomics, and see >> what others say. > > Since memory_failure might be the only place, this change would be > unacceptable. > We should come up with a better solution. Maybe we can try repeating > SetPageHWPoison > and ClearPageHWPoison at a first attempt though it looks somewhat weird to me > and makes > code more complicated.
And I am fairly sure we could still have some remaining races ... it's shaky. Hm ... -- Cheers, David
