On Sat, Jan 11, 2025 at 3:45 PM Hillf Danton <hdanton@xxxxxxxx> wrote: > > On Sat, 11 Jan 2025 09:11:52 -0800 Suren Baghdasaryan <surenb@xxxxxxxxxx> > > I see your point. I think it's a strong argument to use atomic > > directly instead of refcount for this locking. I'll try that and see > > how it looks. Thanks for the feedback! > > > Better not before having a clear answer to why is it sane to invent > anything like rwsem in 2025. What, the 40 bytes? Nope it is the > fair price paid for finer locking granuality. It's not just about the 40 bytes. It allows us to fold the separate vma->detached flag nicely into the same refcounter, which consolidates the vma state in one place. Later that makes it much easier to add SLAB_TYPESAFE_BY_RCU because now we have to preserve only this refcounter during the vma reuse. > > BTW Vlastimil, the cc list is cut down because I have to walk around > the spam check on the mail agent side. >
