On Sun, Oct 29 2006, Blaisorblade wrote: > Add some comments about requirements for ubd_io_lock and expand its use. > > When an irq signals that the "controller" (i.e. another thread on the host, > which does the actual requests and is the only one blocked on I/O on the > host) has done some work, we call again the request function ourselves > (do_ubd_request). > > We now do that with ubd_io_lock held - that's useful to protect against > concurrent calls to elv_next_request and so on.
Not only useful, required, as I think I complained about a year or more ago :-) > XXX: Maybe we shouldn't call at all the request function. Input needed on > this. Are we supposed to plug and unplug the queue? That code "indirectly" > does that by setting a flag, called do_ubd, which makes the request function > return (it's a residual of 2.4 block layer interface). Sometimes you need to. I'd probably just remove the do_ubd check and always recall the request function when handling completions, it's easier and safe. -- Jens Axboe ------------------------------------------------------------------------- Using Tomcat but need to do more? Need to support web services, security? Get stuff done quickly with pre-integrated technology to make your job easier Download IBM WebSphere Application Server v.1.0.1 based on Apache Geronimo http://sel.as-us.falkag.net/sel?cmd=lnk&kid=120709&bid=263057&dat=121642 _______________________________________________ User-mode-linux-devel mailing list User-mode-linux-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/user-mode-linux-devel
