Am 25.11.2010 06:22, schrieb ronnie sahlberg: > Nicholas, > below. > > On Thu, Nov 25, 2010 at 3:32 PM, Nicholas A. Bellinger > <n...@linux-iscsi.org> wrote: > >> But existing code aside, I think having a small userspace iSCSI >> initiator built into QEMU that 'just works' across all host environments >> would be a pretty useful thing, even if the scalibility / scope is >> limited compared to existing kernel host level iSCSI initiator stacks, >> et al. I have not yet had a chance to look at Ronnie's code, but would >> be interested to understand how the threading model currently functions. >> >> Ronnie, I would recommending following Kevin's earlier advice and split >> your work into a reviewable series of commits (preferrably generated by >> git-format-patch) and repost the series for feedback to qemu-devel. You >> can read that as coded language for 'you will want to learn git to >> submit your patch', but it really does work. ;) > > Thanks, > > I will work on the suggestions over the weekend, so Ill resend either > this weekend or next weekend. > So don't spend/waste time reviewing now. > > As for the threading model. > Currently it is not threads safe, so all calls into the library would > have to be protected through a mutex if used from concurrent threads. > I couldn't see any such mutexes when looking at sheepdog as an > example, so do the block drivers need to be threads-safe in qemu?
No, block drivers are not threaded currently. You don't have to take care of that yourself, everything is already protected by a mutex. > One goal of the library is to be 100% async and to never make any > blocking syscalls. > So the library will never block and should be able to reach good > performance, even with one single thread. That would match what other block drivers do. Kevin
