On Fri 07-06-24 17:50:34, Jann Horn wrote: [...] > Or, from a different angle: You're trying to allocate memory, and you > can't make forward progress until that memory has been allocated > (unless the process is killed). That's what GFP_KERNEL is for. Stuff > like "__GFP_NOWARN | __GFP_NORETRY" is for when you have a backup plan > that lets you make progress (perhaps in a slightly less efficient way, > or by dropping some incoming data, or something like that), and it > hints to the page allocator that it doesn't have to try hard to > reclaim memory if it can't find free memory quickly. Correct. A psedu-busy wait for allocation to succeed sounds like a very bad idea to imprint into ABI. Is there really any design requirement to make these mappings to never cause the OOM killer? Making the content dropable under memory pressure because it is inherently recoverable is something else (this is essentially an implicit MADV_FREE semantic) but putting a requirement on the memory allocation on the fault sounds just wrong to me. -- Michal Hocko SUSE Labs
