On Tue, Oct 8, 2024 at 7:52 PM Suren Baghdasaryan <surenb@xxxxxxxxxx> wrote: > On Tue, Oct 8, 2024 at 10:16 AM Jann Horn <jannh@xxxxxxxxxx> wrote: > > Is that code in a tree somewhere? > > > > What locking will those RCU walkers use when accessing VMAs? I guess > > they probably anyway have to take the VMA locks to ensure they see > > consistent state, though I guess with enough effort you could avoid it > > (seqlock-style) on some fastpaths when the vma is not concurrently > > modified and the fastpath doesn't need access to the VMA's file? > > Sorry, it's not posted upstream yet but yes, the idea is to walk the > tree under RCU and detect concurrent changes using seq-counters. A > prototype was posted here: > https://lore.kernel.org/all/20240123231014.3801041-3-surenb@xxxxxxxxxx/ > but it had some issues I'm yet to resolve. Ah, thanks for the pointer.
