On Wed, May 07, 2008 at 08:25:58AM -0400, Daniel Veillard wrote: > On Tue, May 06, 2008 at 12:51:08AM -0700, Dave Leskovec wrote: > > This patch changes the lxc tty forwarding process to use epoll instead of > > poll. > > This is done to avoid a cpu consuming loop when a user disconnects from the > > container console. > > > > During some testing, we found that when the slave end of a tty is closed, > > calls > > to poll() on the master end will return immediately with POLLHUP until the > > slave > > end is opened again. The result of this is that if you connect to the > > container > > console using virsh and then ctrl-] out of it, the container tty process > > will > > chew up the processor handling POLLHUP. This event can't be disabled > > regardless > > of what is set in the events field. > > > > This can be avoided by using epoll. When used in edge triggered mode, you > > see > > the initial EPOLLHUP but will not see another one until someone connects and > > then disconnects from the console again. This also drove some changes into > > how > > the regular input data is handled. Once an EPOLLIN is seen from an fd, > > another > > one will not be surfaced until all data has been read from the file (EAGAIN > > is > > returned by read). > > Sounds fine in principle but i have a couple of questions with the patch > > > +#include <stdbool.h> > > err ... what is that ? looks like a linux specific header, do we really > need this ? epoll is linux specific I think but #include <sys/epoll.h> > should be sufficient no ?
It is kinda academic whether epool is linux specific - the entire LXC driver is Linux specific, so you're not compiling it on Solaris/Windows anyway. So any Linux-isms in LXC driver code is fine Dan. -- |: Red Hat, Engineering, Boston -o- http://people.redhat.com/berrange/ :| |: http://libvirt.org -o- http://virt-manager.org -o- http://ovirt.org :| |: http://autobuild.org -o- http://search.cpan.org/~danberr/ :| |: GnuPG: 7D3B9505 -o- F3C9 553F A1DA 4AC2 5648 23C1 B3DF F742 7D3B 9505 :| -- Libvir-list mailing list Libvir-list@redhat.com https://www.redhat.com/mailman/listinfo/libvir-list
