On Tue, 15 May 2007, Christoph Hellwig wrote: > On Tue, May 15, 2007 at 12:18:17PM -0400, Gregory Haskins wrote: > > >>> On Tue, May 15, 2007 at 11:40 AM, in message > > <[EMAIL PROTECTED]>, Davide Libenzi > > <[EMAIL PROTECTED]> wrote: > > > > > > I don't know how critical is the path where you will be doing check. The > > > eventfd_fget() is pretty fast, so if you're not looking at a performance > > > critical path, I'd suggest that. Otherwise you can do an early > > > eventfd_get, and keep the file*. If you have no the ways to know if the > > > userspace disconnected, an atomic_read(&file- >f_count)==1 will tell you > > > that you're the only owner of the file* (that is, userspace closed the > > > eventfd descriptor). I'd give preference to the former option though. > > > > Thanks for the insight, Davide. It sounds like we can probably stay with > > the way I have it for now, and keep the file->f_count idea in our back > > pocket should a performance problem arise. > > accessing file->f_count is not allowed for drivers. It took us quite a > bit of effort to clean up all users a while ago, and it turned out most > of them were rather buggy.
Right, you could use the file_count() macro :) Seriuosly, if this (doing an eventfd_fget+fput) becomes a problem, I can have the check done in eventfd_signal() and return a proper error code. - Davide ------------------------------------------------------------------------- This SF.net email is sponsored by DB2 Express Download DB2 Express C - the FREE version of DB2 express and take control of your XML. No limits. Just data. Click to get it now. http://sourceforge.net/powerbar/db2/ _______________________________________________ kvm-devel mailing list kvm-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/kvm-devel
