On Sat, Feb 18, 2023 at 09:23:06AM +0100, Martin Pieuchot wrote: > On 24/01/23(Tue) 04:40, Renato Aguiar wrote: > > Hi Martin, > > > > "David Hill" <[email protected]> writes: > > > > > > > > Yes, same result as before. This patch does not seem to help. > > > > > > > I could also reproduce it with patched 'current' :( > > Here's another possible fix I came up with. The idea is to deliberately > allow readers to starve writers for the VM map lock. > > My previous fix didn't work because a writer could already be waiting on > the lock before calling vm_map_busy() and there's currently no way to > tell it to back out and stop preventing readers from making progress. > > I don't see any simpler solution without rewriting the vm_map_lock() > primitive. > > Could you confirm this work for you? If so I'll document the new > RW_FORCEREAD flag and add a comment to explain why we need it in this > case. > > Thanks, > Martin
I'm no longer able to reproduce the hang with this anymore on my 8-core cpu.
