On Wed, Aug 11, 2010 at 01:46:04AM -0400, Ben Blum wrote: > On Fri, Jul 30, 2010 at 07:56:49PM -0400, Ben Blum wrote: > > This patch series is a revision of http://lkml.org/lkml/2010/6/25/11 . > > > > This patch series implements a write function for the 'cgroup.procs' > > per-cgroup file, which enables atomic movement of multithreaded > > applications between cgroups. Writing the thread-ID of any thread in a > > threadgroup to a cgroup's procs file causes all threads in the group to > > be moved to that cgroup safely with respect to threads forking/exiting. > > (Possible usage scenario: If running a multithreaded build system that > > sucks up system resources, this lets you restrict it all at once into a > > new cgroup to keep it under control.) > > > > Example: Suppose pid 31337 clones new threads 31338 and 31339. > > > > # cat /dev/cgroup/tasks > > ... > > 31337 > > 31338 > > 31339 > > # mkdir /dev/cgroup/foo > > # echo 31337 > /dev/cgroup/foo/cgroup.procs > > # cat /dev/cgroup/foo/tasks > > 31337 > > 31338 > > 31339 > > > > A new lock, called threadgroup_fork_lock and living in signal_struct, is > > introduced to ensure atomicity when moving threads between cgroups. It's > > taken for writing during the operation, and taking for reading in fork() > > around the calls to cgroup_fork() and cgroup_post_fork(). I put calls to > > down_read/up_read directly in copy_process(), since new inline functions > > seemed like overkill. > > > > -- Ben > > > > --- > > Documentation/cgroups/cgroups.txt | 13 - > > include/linux/init_task.h | 9 > > include/linux/sched.h | 10 > > kernel/cgroup.c | 426 +++++++++++++++++++++++++++++++++----- > > kernel/cgroup_freezer.c | 4 > > kernel/cpuset.c | 4 > > kernel/fork.c | 16 + > > kernel/ns_cgroup.c | 4 > > kernel/sched.c | 4 > > 9 files changed, 440 insertions(+), 50 deletions(-) > > Here's an updated patchset. I've added an extra patch to implement the > callback scheme Paul suggested (note how there are twice as many deleted > lines of code as before :) ), and also moved the up_read/down_read calls > to static inline functions in sched.h near the other threadgroup-related > calls. One more go at this. I've refreshed the patches for some conflicts in cgroup_freezer.c, by adding an extra argument to the per_thread() call, "need_rcu", which makes the function take rcu_read_lock even around the single-task case (like freezer now requires). So no semantics have been changed. I also poked around at some attach() calls which also iterate over the threadgroup (blkiocg_attach, cpuset_attach, cpu_cgroup_attach). I was borderline about making another function, cgroup_attach_per_thread(), but decided against. There is a big issue in cpuset_attach, as explained in this email: http://www.spinics.net/lists/linux-containers/msg22223.html but the actual code/diffs for this patchset are independent of that getting fixed, so I'm putting this up for consideration now. -- Ben --- Documentation/cgroups/cgroups.txt | 13 - block/blk-cgroup.c | 31 ++ include/linux/cgroup.h | 14 + include/linux/init_task.h | 9 include/linux/sched.h | 35 ++ kernel/cgroup.c | 469 ++++++++++++++++++++++++++++++++++---- kernel/cgroup_freezer.c | 33 +- kernel/cpuset.c | 30 -- kernel/fork.c | 10 kernel/ns_cgroup.c | 25 -- kernel/sched.c | 24 - 11 files changed, 565 insertions(+), 128 deletions(-) _______________________________________________ Containers mailing list Containers@xxxxxxxxxxxxxxxxxxxxxxxxxx https://lists.linux-foundation.org/mailman/listinfo/containers
