Re: VirtualBox Hangs Pre-Init Due To Ext2FS Fault
Hello James :) Quoting James Clarke (2015-07-15 22:20:57) I had a look today at what's happening, and it's that the *file* pager is trying to read from disk. Any thoughts? There is another thing I forgot. libpager is special, it has its own demuxer (see libpager/demuxer.c) that writes requests into a queue, and a pool of workers that process requests from said queue. The thing is, when we inhibit the pager RPCs, we merely prevent new ones from being enqueued, but we don't prevent the workers from processing already enqueued requests. So we indeed need to add functions to inhibit and restart paging to libpager that know about the queue. Justus
Re: VirtualBox Hangs Pre-Init Due To Ext2FS Fault
Yeah, I tried inhibiting both buckets, but the paging RPCs still got through, so my guess was that libports's inhibit/resume methods weren't able to deal with libpager's own threads. The thing is I don't think we currently keep track of any reference to the main/worker threads, as pager_start_workers just takes a bucket and returns void. Is there a way we can instead make the main thread and/or workers able to block ports_inhibit_X_rpcs like normal RPC handlers and be cancelled etc? If possible I think that would be a cleaner solution. James On 19 Jul 2015, at 13:50, Justus Winter 4win...@informatik.uni-hamburg.de wrote: Hello James :) Quoting James Clarke (2015-07-15 22:20:57) I had a look today at what's happening, and it's that the *file* pager is trying to read from disk. Any thoughts? There is another thing I forgot. libpager is special, it has its own demuxer (see libpager/demuxer.c) that writes requests into a queue, and a pool of workers that process requests from said queue. The thing is, when we inhibit the pager RPCs, we merely prevent new ones from being enqueued, but we don't prevent the workers from processing already enqueued requests. So we indeed need to add functions to inhibit and restart paging to libpager that know about the queue. Justus
Re: VirtualBox Hangs Pre-Init Due To Ext2FS Fault
On Sun, Jul 19, 2015 at 02:25:14PM +0100, James Clarke wrote: Yeah, I tried inhibiting both buckets, but the paging RPCs still got through, so my guess was that libports's inhibit/resume methods weren't able to deal with libpager's own threads. The thing is I don't think we currently keep track of any reference to the main/worker threads, as pager_start_workers just takes a bucket and returns void. Is there a way we can instead make the main thread and/or workers able to block ports_inhibit_X_rpcs like normal RPC handlers and be cancelled etc? If possible I think that would be a cleaner solution. To continue our discussion on IRC: No, it would definitely not be a cleaner solution, just an ugly hack. Since paging doesn't occur as part of an RPC, you just can't use RPC stuff to manage it. I suggest building rwlock-based synrchonization functions specific to the pager workers. -- Richard Braun
