On Thu, Jul 23, 2009 at 08:22:00PM -0700, Ben Blum wrote: > Makes procs file writable to move all threads by tgid at once > > This patch adds functionality that enables users to move all threads in a > threadgroup at once to a cgroup by writing the tgid to the 'cgroup.procs' > file. This current implementation makes use of a rwsem that's taken for > reading in the fork() path to prevent newly forking threads within the There is much ado about not taking additional "global locks" in fork() paths. * The fork and exit callbacks cgroup_fork() and cgroup_exit(), don't * (usually) take cgroup_mutex. These are the two most performance * critical pieces of code here. ... and as I recall cgroup_fork() doesn't ever take cgroup_mutex because it is so performance critical. Assuming the above comments in kernel/cgroup.c are correct then this patch adds a performance regression by introducing a global mutex in the fork path, doesn't it? Cheers, -Matt Helsley _______________________________________________ Containers mailing list Containers@xxxxxxxxxxxxxxxxxxxxxxxxxx https://lists.linux-foundation.org/mailman/listinfo/containers
