On Thu, Jan 26, 2023 at 9:32 AM Mel Gorman <mgorman@xxxxxxxxxxxxxxxxxxx> wrote: > > On Thu, Jan 26, 2023 at 08:18:31AM -0800, Suren Baghdasaryan wrote: > > 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. > > > > It might be a personal thing. nolock to me is ambigious because it might > mean "lock is already held", "no lock is necessary" or "no lock is acquired" > where as *for me*, calling foo vs __foo *usually* means "direct callers of > __foo take care of the locking, memory ordering, per-cpu pinning details etc" > depending on the context. Of course, this convention is not universally true. > > > > > 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. > > I don't have alternative suggestions but if someone else reads the patch and > says "this is conditional locking", you can at least claim that someone > else considered "conditional locking" and didn't think it was a major > problem in this specific patch. Perfect. Thanks! > > -- > Mel Gorman > SUSE Labs
