On Thu, Jan 26, 2023 at 7:47 AM Mel Gorman <mgorman@xxxxxxxxxxxxxxxxxxx> wrote: > > On Wed, Jan 25, 2023 at 03:35:53PM -0800, Suren Baghdasaryan wrote: > > In cases when VMA flags are modified after VMA was isolated and mmap_lock > > was downgraded, flags modifications would result in an assertion because > > mmap write lock is not held. > > Add note that it's also used during exit when the locking of the VMAs > becomes irrelevant (mm users is 0, should be no VMA modifications taking > place other than zap). Ack. > > The typical naming pattern when a caller either knows it holds the necessary > lock or knows it does not matter is __mod_vm_flags() Ok. It sounds less explicit but plenty of examples, so I'm fine with such rename. Will apply in the next version. > > > Introduce mod_vm_flags_nolock to be used in such situation, when VMA is > > not part of VMA tree and locking it is not required. > > Instead of such situations, describe in as "used when the caller takes > responsibility for the required locking". Ack. > > > Pass a hint to untrack_pfn to conditionally use mod_vm_flags_nolock for > > flags modification and to avoid assertion. > > > > Signed-off-by: Suren Baghdasaryan <surenb@xxxxxxxxxx> > > Patch itself looks ok. It strays close to being "conditional locking" > though which might attract some complaints. The description seems to accurately describe what's done here but I'm open to better suggestions. Thanks! > > -- > Mel Gorman > SUSE Labs
