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* cgroup: remove hierarchy_mutexLi Zefan2012-06-061-15/+2
| | | | | | | | | | | It was introduced for memcg to iterate cgroup hierarchy without holding cgroup_mutex, but soon after that it was replaced with a lockless way in memcg. No one used hierarchy_mutex since that, so remove it. Signed-off-by: Li Zefan <lizefan@huawei.com> Signed-off-by: Tejun Heo <tj@kernel.org>
* cgroup: remove cgroup_subsys->populate()Tejun Heo2012-04-111-1/+0
| | | | | | | | With memcg converted, cgroup_subsys->populate() doesn't have any user left. Remove it. Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Li Zefan <lizefan@huawei.com>
* cgroup: make css->refcnt clearing on cgroup removal optionalTejun Heo2012-04-011-0/+17
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Currently, cgroup removal tries to drain all css references. If there are active css references, the removal logic waits and retries ->pre_detroy() until either all refs drop to zero or removal is cancelled. This semantics is unusual and adds non-trivial complexity to cgroup core and IMHO is fundamentally misguided in that it couples internal implementation details (references to internal data structure) with externally visible operation (rmdir). To userland, this is a behavior peculiarity which is unnecessary and difficult to expect (css refs is otherwise invisible from userland), and, to policy implementations, this is an unnecessary restriction (e.g. blkcg wants to hold css refs for caching purposes but can't as that becomes visible as rmdir hang). Unfortunately, memcg currently depends on ->pre_destroy() retrials and cgroup removal vetoing and can't be immmediately switched to the new behavior. This patch introduces the new behavior of not waiting for css refs to drain and maintains the old behavior for subsystems which have __DEPRECATED_clear_css_refs set. Once, memcg is updated, we can drop the code paths for the old behavior as proposed in the following patch. Note that the following patch is incorrect in that dput work item is in cgroup and may lose some of dputs when multiples css's are released back-to-back, and __css_put() triggers check_for_release() when refcnt reaches 0 instead of 1; however, it shows what part can be removed. http://thread.gmane.org/gmane.linux.kernel.containers/22559/focus=75251 Note that, in not-too-distant future, cgroup core will start emitting warning messages for subsys which require the old behavior, so please get moving. Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Li Zefan <lizf@cn.fujitsu.com> Cc: Vivek Goyal <vgoyal@redhat.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Michal Hocko <mhocko@suse.cz> Cc: Balbir Singh <bsingharora@gmail.com> Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
* cgroup: use negative bias on css->refcnt to block css_tryget()Tejun Heo2012-04-011-8/+4
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | When a cgroup is about to be removed, cgroup_clear_css_refs() is called to check and ensure that there are no active css references. This is currently achieved by dropping the refcnt to zero iff it has only the base ref. If all css refs could be dropped to zero, ref clearing is successful and CSS_REMOVED is set on all css. If not, the base ref is restored. While css ref is zero w/o CSS_REMOVED set, any css_tryget() attempt on it busy loops so that they are atomic w.r.t. the whole css ref clearing. This does work but dropping and re-instating the base ref is somewhat hairy and makes it difficult to add more logic to the put path as there are two of them - the regular css_put() and the reversible base ref clearing. This patch updates css ref clearing such that blocking new css_tryget() and putting the base ref are separate operations. CSS_DEACT_BIAS, defined as INT_MIN, is added to css->refcnt and css_tryget() busy loops while refcnt is negative. After all css refs are deactivated, if they were all one, ref clearing succeeded and CSS_REMOVED is set and the base ref is put using the regular css_put(); otherwise, CSS_DEACT_BIAS is subtracted from the refcnts and the original postive values are restored. css_refcnt() accessor which always returns the unbiased positive reference counts is added and used to simplify refcnt usages. While at it, relocate and reformat comments in cgroup_has_css_refs(). This separates css->refcnt deactivation and putting the base ref, which enables the next patch to make ref clearing optional. Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Li Zefan <lizf@cn.fujitsu.com>
* cgroup: implement cgroup_rm_cftypes()Tejun Heo2012-04-011-0/+1
| | | | | | | | | | | | | Implement cgroup_rm_cftypes() which removes an array of cftypes from a subsystem. It can be called whether the target subsys is attached or not. cgroup core will remove the specified file from all existing cgroups. This will be used to improve sub-subsys modularity and will be helpful for unified hierarchy. Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Li Zefan <lizf@cn.fujitsu.com>
* cgroup: introduce struct cfentTejun Heo2012-04-011-0/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | This patch adds cfent (cgroup file entry) which is the association between a cgroup and a file. This is in-cgroup representation of files under a cgroup directory. This simplifies walking walking cgroup files and thus cgroup_clear_directory(), which is now implemented in two parts - cgroup_rm_file() and a loop around it. cgroup_rm_file() will be used to implement cftype removal and cfent is scheduled to serve cgroup specific per-file data (e.g. for sysfs-like "sever" semantics). v2: - cfe was freed from cgroup_rm_file() which led to use-after-free if the file had openers at the time of removal. Moved to cgroup_diput(). - cgroup_clear_directory() triggered WARN_ON_ONCE() if d_subdirs wasn't empty after removing all files. This triggered spuriously if some files were open during directory clearing. Removed. v3: - In cgroup_diput(), WARN_ONCE(!list_empty(&cfe->node)) could be spuriously triggered for root cgroups because they don't go through cgroup_clear_directory() on unmount. Don't trigger WARN for root cgroups. Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Li Zefan <lizf@cn.fujitsu.com> Cc: Glauber Costa <glommer@parallels.com>
* cgroup: remove cgroup_add_file[s]()Tejun Heo2012-04-011-16/+0
| | | | | | | | | | No controller is using cgroup_add_files[s](). Unexport them, and convert cgroup_add_files() to handle NULL entry terminated array instead of taking count explicitly and continue creation on failure for internal use. Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Li Zefan <lizf@cn.fujitsu.com>
* cgroup: implement cgroup_add_cftypes() and friendsTejun Heo2012-04-011-2/+31
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Currently, cgroup directories are populated by subsys->populate() callback explicitly creating files on each cgroup creation. This level of flexibility isn't needed or desirable. It provides largely unused flexibility which call for abuses while severely limiting what the core layer can do through the lack of structure and conventions. Per each cgroup file type, the only distinction that cgroup users is making is whether a cgroup is root or not, which can easily be expressed with flags. This patch introduces cgroup_add_cftypes(). These deal with cftypes instead of individual files - controllers indicate that certain types of files exist for certain subsystem. Newly added CFTYPE_*_ON_ROOT flags indicate whether a cftype should be excluded or created only on the root cgroup. cgroup_add_cftypes() can be called any time whether the target subsystem is currently attached or not. cgroup core will create files on the existing cgroups as necessary. Also, cgroup_subsys->base_cftypes is added to ease registration of the base files for the subsystem. If non-NULL on subsys init, the cftypes pointed to by ->base_cftypes are automatically registered on subsys init / load. Further patches will convert the existing users and remove the file based interface. Note that this interface allows dynamic addition of files to an active controller. This will be used for sub-controller modularity and unified hierarchy in the longer term. This patch implements the new mechanism but doesn't apply it to any user. v2: replaced DECLARE_CGROUP_CFTYPES[_COND]() with cgroup_subsys->base_cftypes, which works better for cgroup_subsys which is loaded as module. Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Li Zefan <lizf@cn.fujitsu.com>
* cgroup: build list of all cgroups under a given cgroupfs_rootTejun Heo2012-04-011-0/+2
| | | | | | | | | Build a list of all cgroups anchored at cgroupfs_root->allcg_list and going through cgroup->allcg_node. The list is protected by cgroup_mutex and will be used to improve cgroup file handling. Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Li Zefan <lizf@cn.fujitsu.com>
* cgroup: revert ss_id_lock to spinlockHugh Dickins2012-03-211-1/+1
| | | | | | | | | | | | | | | | | | Commit c1e2ee2dc436 ("memcg: replace ss->id_lock with a rwlock") has now been seen to cause the unfair behavior we should have expected from converting a spinlock to an rwlock: softlockup in cgroup_mkdir(), whose get_new_cssid() is waiting for the wlock, while there are 19 tasks using the rlock in css_get_next() to get on with their memcg workload (in an artificial test, admittedly). Yet lib/idr.c was made suitable for RCU way back: revert that commit, restoring ss->id_lock to a spinlock. Signed-off-by: Hugh Dickins <hughd@google.com> Acked-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Acked-by: Li Zefan <lizf@cn.fujitsu.com> Cc: Eric Dumazet <eric.dumazet@gmail.com> Acked-by: Tejun Heo <tj@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* cgroup: remove cgroup_subsys argument from callbacksLi Zefan2012-02-021-17/+12
| | | | | | | | | | | | | | | | | | | | | The argument is not used at all, and it's not necessary, because a specific callback handler of course knows which subsys it belongs to. Now only ->pupulate() takes this argument, because the handlers of this callback always call cgroup_add_file()/cgroup_add_files(). So we reduce a few lines of code, though the shrinking of object size is minimal. 16 files changed, 113 insertions(+), 162 deletions(-) text data bss dec hex filename 5486240 656987 7039960 13183187 c928d3 vmlinux.o.orig 5486170 656987 7039960 13183117 c9288d vmlinux.o Signed-off-by: Li Zefan <lizf@cn.fujitsu.com> Signed-off-by: Tejun Heo <tj@kernel.org>
* cgroup: move struct cgroup_pidlist out from the header fileLi Zefan2012-01-201-32/+0
| | | | | | | It's internally used only. Signed-off-by: Li Zefan <lizf@cn.fujitsu.com> Signed-off-by: Tejun Heo <tj@kernel.org>
* cgroup: remove cgroup_attach_task_current_cg()Li Zefan2012-01-201-9/+0
| | | | | | | | | It's just a wrapper of cgroup_attach_task_all(), and it's no longer used after commit 87d6a412bd1ed82c14cabd4b408003b23bbd2880 (vhost: fix attach to cgroups regression) Signed-off-by: Li Zefan <lizf@cn.fujitsu.com> Signed-off-by: Tejun Heo <tj@kernel.org>
* Merge branch 'for-3.3' of ↵Linus Torvalds2012-01-091-6/+25
|\ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup * 'for-3.3' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup: (21 commits) cgroup: fix to allow mounting a hierarchy by name cgroup: move assignement out of condition in cgroup_attach_proc() cgroup: Remove task_lock() from cgroup_post_fork() cgroup: add sparse annotation to cgroup_iter_start() and cgroup_iter_end() cgroup: mark cgroup_rmdir_waitq and cgroup_attach_proc() as static cgroup: only need to check oldcgrp==newgrp once cgroup: remove redundant get/put of task struct cgroup: remove redundant get/put of old css_set from migrate cgroup: Remove unnecessary task_lock before fetching css_set on migration cgroup: Drop task_lock(parent) on cgroup_fork() cgroups: remove redundant get/put of css_set from css_set_check_fetched() resource cgroups: remove bogus cast cgroup: kill subsys->can_attach_task(), pre_attach() and attach_task() cgroup, cpuset: don't use ss->pre_attach() cgroup: don't use subsys->can_attach_task() or ->attach_task() cgroup: introduce cgroup_taskset and use it in subsys->can_attach(), cancel_attach() and attach() cgroup: improve old cgroup handling in cgroup_attach_proc() cgroup: always lock threadgroup during migration threadgroup: extend threadgroup_lock() to cover exit and exec threadgroup: rename signal->threadgroup_fork_lock to ->group_rwsem ... Fix up conflict in kernel/cgroup.c due to commit e0197aae59e5: "cgroups: fix a css_set not found bug in cgroup_attach_proc" that already mentioned that the bug is fixed (differently) in Tejun's cgroup patchset. This one, in other words.
| * cgroup: kill subsys->can_attach_task(), pre_attach() and attach_task()Tejun Heo2011-12-121-3/+0
| | | | | | | | | | | | | | | | | | | | These three methods are no longer used. Kill them. Signed-off-by: Tejun Heo <tj@kernel.org> Reviewed-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Reviewed-by: Frederic Weisbecker <fweisbec@gmail.com> Acked-by: Paul Menage <paul@paulmenage.org> Cc: Li Zefan <lizf@cn.fujitsu.com>
| * cgroup: introduce cgroup_taskset and use it in subsys->can_attach(), ↵Tejun Heo2011-12-121-3/+25
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | cancel_attach() and attach() Currently, there's no way to pass multiple tasks to cgroup_subsys methods necessitating the need for separate per-process and per-task methods. This patch introduces cgroup_taskset which can be used to pass multiple tasks and their associated cgroups to cgroup_subsys methods. Three methods - can_attach(), cancel_attach() and attach() - are converted to use cgroup_taskset. This unifies passed parameters so that all methods have access to all information. Conversions in this patchset are identical and don't introduce any behavior change. -v2: documentation updated as per Paul Menage's suggestion. Signed-off-by: Tejun Heo <tj@kernel.org> Reviewed-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Reviewed-by: Frederic Weisbecker <fweisbec@gmail.com> Acked-by: Paul Menage <paul@paulmenage.org> Acked-by: Li Zefan <lizf@cn.fujitsu.com> Cc: Balbir Singh <bsingharora@gmail.com> Cc: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp> Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Cc: James Morris <jmorris@namei.org>
* | cgroup: propagate mode_tAl Viro2012-01-031-1/+1
|/ | | | Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
* memcg: replace ss->id_lock with a rwlockAndrew Bresticker2011-11-021-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | While back-porting Johannes Weiner's patch "mm: memcg-aware global reclaim" for an internal effort, we noticed a significant performance regression during page-reclaim heavy workloads due to high contention of the ss->id_lock. This lock protects idr map, and serializes calls to idr_get_next() in css_get_next() (which is used during the memcg hierarchy walk). Since idr_get_next() is just doing a look up, we need only serialize it with respect to idr_remove()/idr_get_new(). By making the ss->id_lock a rwlock, contention is greatly reduced and performance improves. Tested: cat a 256m file from a ramdisk in a 128m container 50 times on each core (one file + container per core) in parallel on a NUMA machine. Result is the time for the test to complete in 1 of the containers. Both kernels included Johannes' memcg-aware global reclaim patches. Before rwlock patch: 1710.778s After rwlock patch: 152.227s Signed-off-by: Andrew Bresticker <abrestic@google.com> Cc: Paul Menage <menage@gmail.com> Cc: Li Zefan <lizf@cn.fujitsu.com> Acked-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Cc: Ying Han <yinghan@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* rcu: treewide: Do not use rcu_read_lock_held when calling rcu_dereference_checkMichal Hocko2011-07-081-1/+0
| | | | | | | | | | Since ca5ecddf (rcu: define __rcu address space modifier for sparse) rcu_dereference_check use rcu_read_lock_held as a part of condition automatically so callers do not have to do that as well. Signed-off-by: Michal Hocko <mhocko@suse.cz> Acked-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Signed-off-by: Jiri Kosina <jkosina@suse.cz>
* cgroup: remove the ns_cgroupDaniel Lezcano2011-05-261-3/+0
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The ns_cgroup is an annoying cgroup at the namespace / cgroup frontier and leads to some problems: * cgroup creation is out-of-control * cgroup name can conflict when pids are looping * it is not possible to have a single process handling a lot of namespaces without falling in a exponential creation time * we may want to create a namespace without creating a cgroup The ns_cgroup was replaced by a compatibility flag 'clone_children', where a newly created cgroup will copy the parent cgroup values. The userspace has to manually create a cgroup and add a task to the 'tasks' file. This patch removes the ns_cgroup as suggested in the following thread: https://lists.linux-foundation.org/pipermail/containers/2009-June/018616.html The 'cgroup_clone' function is removed because it is no longer used. This is a userspace-visible change. Commit 45531757b45c ("cgroup: notify ns_cgroup deprecated") (merged into 2.6.27) caused the kernel to emit a printk warning users that the feature is planned for removal. Since that time we have heard from XXX users who were affected by this. Signed-off-by: Daniel Lezcano <daniel.lezcano@free.fr> Signed-off-by: Serge E. Hallyn <serge.hallyn@canonical.com> Cc: Eric W. Biederman <ebiederm@xmission.com> Cc: Jamal Hadi Salim <hadi@cyberus.ca> Reviewed-by: Li Zefan <lizf@cn.fujitsu.com> Acked-by: Paul Menage <menage@google.com> Acked-by: Matt Helsley <matthltc@us.ibm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* cgroups: add per-thread subsystem callbacksBen Blum2011-05-261-4/+6
| | | | | | | | | | | | | | | | | | | | | | | | | | | | Add cgroup subsystem callbacks for per-thread attachment in atomic contexts Add can_attach_task(), pre_attach(), and attach_task() as new callbacks for cgroups's subsystem interface. Unlike can_attach and attach, these are for per-thread operations, to be called potentially many times when attaching an entire threadgroup. Also, the old "bool threadgroup" interface is removed, as replaced by this. All subsystems are modified for the new interface - of note is cpuset, which requires from/to nodemasks for attach to be globally scoped (though per-cpuset would work too) to persist from its pre_attach to attach_task and attach. This is a pre-patch for cgroup-procs-writable.patch. Signed-off-by: Ben Blum <bblum@andrew.cmu.edu> Cc: "Eric W. Biederman" <ebiederm@xmission.com> Cc: Li Zefan <lizf@cn.fujitsu.com> Cc: Matt Helsley <matthltc@us.ibm.com> Reviewed-by: Paul Menage <menage@google.com> Cc: Oleg Nesterov <oleg@redhat.com> Cc: David Rientjes <rientjes@google.com> Cc: Miao Xie <miaox@cn.fujitsu.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* Fix common misspellingsLucas De Marchi2011-03-311-1/+1
| | | | | | Fixes generated by 'codespell' and manually reviewed. Signed-off-by: Lucas De Marchi <lucas.demarchi@profusion.mobi>
* perf: Add cgroup supportStephane Eranian2011-02-161-0/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | This kernel patch adds the ability to filter monitoring based on container groups (cgroups). This is for use in per-cpu mode only. The cgroup to monitor is passed as a file descriptor in the pid argument to the syscall. The file descriptor must be opened to the cgroup name in the cgroup filesystem. For instance, if the cgroup name is foo and cgroupfs is mounted in /cgroup, then the file descriptor is opened to /cgroup/foo. Cgroup mode is activated by passing PERF_FLAG_PID_CGROUP in the flags argument to the syscall. For instance to measure in cgroup foo on CPU1 assuming cgroupfs is mounted under /cgroup: struct perf_event_attr attr; int cgroup_fd, fd; cgroup_fd = open("/cgroup/foo", O_RDONLY); fd = perf_event_open(&attr, cgroup_fd, 1, -1, PERF_FLAG_PID_CGROUP); close(cgroup_fd); Signed-off-by: Stephane Eranian <eranian@google.com> [ added perf_cgroup_{exit,attach} ] Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> LKML-Reference: <4d590250.114ddf0a.689e.4482@mx.google.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
* cgroup: Fix cgroup_subsys::exit callbackPeter Zijlstra2011-02-161-1/+2
| | | | | | | | | | | | | Make the ::exit method act like ::attach, it is after all very nearly the same thing. The bug had no effect on correctness - fixing it is an optimization for the scheduler. Also, later perf-cgroups patches rely on it. Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Acked-by: Paul Menage <menage@google.com> LKML-Reference: <1297160655.13327.92.camel@laptop> Signed-off-by: Ingo Molnar <mingo@elte.hu>
* tree-wide: fix comment/printk typosUwe Kleine-König2010-11-011-1/+1
| | | | | | | | | | "gadget", "through", "command", "maintain", "maintain", "controller", "address", "between", "initiali[zs]e", "instead", "function", "select", "already", "equal", "access", "management", "hierarchy", "registration", "interest", "relative", "memory", "offset", "already", Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de> Signed-off-by: Jiri Kosina <jkosina@suse.cz>
* cgroup: add clone_children control fileDaniel Lezcano2010-10-271-0/+4
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The ns_cgroup is a control group interacting with the namespaces. When a new namespace is created, a corresponding cgroup is automatically created too. The cgroup name is the pid of the process who did 'unshare' or the child of 'clone'. This cgroup is tied with the namespace because it prevents a process to escape the control group and use the post_clone callback, so the child cgroup inherits the values of the parent cgroup. Unfortunately, the more we use this cgroup and the more we are facing problems with it: (1) when a process unshares, the cgroup name may conflict with a previous cgroup with the same pid, so unshare or clone return -EEXIST (2) the cgroup creation is out of control because there may have an application creating several namespaces where the system will automatically create several cgroups in his back and let them on the cgroupfs (eg. a vrf based on the network namespace). (3) the mix of (1) and (2) force an administrator to regularly check and clean these cgroups. This patchset removes the ns_cgroup by adding a new flag to the cgroup and the cgroupfs mount option. It enables the copy of the parent cgroup when a child cgroup is created. We can then safely remove the ns_cgroup as this flag brings a compatibility. We have now to manually create and add the task to a cgroup, which is consistent with the cgroup framework. This patch: Sent as an answer to a previous thread around the ns_cgroup. https://lists.linux-foundation.org/pipermail/containers/2009-June/018627.html It adds a control file 'clone_children' for a cgroup. This control file is a boolean specifying if the child cgroup should be a clone of the parent cgroup or not. The default value is 'false'. This flag makes the child cgroup to call the post_clone callback of all the subsystem, if it is available. At present, the cpuset is the only one which had implemented the post_clone callback. The option can be set at mount time by specifying the 'clone_children' mount option. Signed-off-by: Daniel Lezcano <daniel.lezcano@free.fr> Signed-off-by: Serge E. Hallyn <serge.hallyn@canonical.com> Cc: Eric W. Biederman <ebiederm@xmission.com> Acked-by: Paul Menage <menage@google.com> Reviewed-by: Li Zefan <lizf@cn.fujitsu.com> Cc: Jamal Hadi Salim <hadi@cyberus.ca> Cc: Matt Helsley <matthltc@us.ibm.com> Acked-by: Balbir Singh <balbir@linux.vnet.ibm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* Merge branch 'rcu/urgent' of ↵Ingo Molnar2010-10-071-1/+11
|\ | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/paulmck/linux-2.6-rcu into core/rcu
| * cgroups: fix API thinkoMichael S. Tsirkin2010-09-091-1/+11
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Add cgroup_attach_task_all() The existing cgroup_attach_task_current_cg() API is called by a thread to attach another thread to all of its cgroups; this is unsuitable for cases where a privileged task wants to attach itself to the cgroups of a less privileged one, since the call must be made from the context of the target task. This patch adds a more generic cgroup_attach_task_all() API that allows both the source task and to-be-moved task to be specified. cgroup_attach_task_current_cg() becomes a specialization of the more generic new function. [menage@google.com: rewrote changelog] [akpm@linux-foundation.org: address reviewer comments] Signed-off-by: Michael S. Tsirkin <mst@redhat.com> Tested-by: Alex Williamson <alex.williamson@redhat.com> Acked-by: Paul Menage <menage@google.com> Cc: Li Zefan <lizf@cn.fujitsu.com> Cc: Ben Blum <bblum@google.com> Cc: Sridhar Samudrala <sri@us.ibm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* | cgroups: __rcu annotationsArnd Bergmann2010-08-191-2/+2
|/ | | | | | | | Signed-off-by: Arnd Bergmann <arnd@arndb.de> Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Acked-by: Paul Menage <menage@google.com> Cc: Li Zefan <lizf@cn.fujitsu.com> Reviewed-by: Josh Triplett <josh@joshtriplett.org>
* Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net-next-2.6Linus Torvalds2010-08-041-0/+7
|\ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | * git://git.kernel.org/pub/scm/linux/kernel/git/davem/net-next-2.6: (1443 commits) phy/marvell: add 88ec048 support igb: Program MDICNFG register prior to PHY init e1000e: correct MAC-PHY interconnect register offset for 82579 hso: Add new product ID can: Add driver for esd CAN-USB/2 device l2tp: fix export of header file for userspace can-raw: Fix skb_orphan_try handling Revert "net: remove zap_completion_queue" net: cleanup inclusion phy/marvell: add 88e1121 interface mode support u32: negative offset fix net: Fix a typo from "dev" to "ndev" igb: Use irq_synchronize per vector when using MSI-X ixgbevf: fix null pointer dereference due to filter being set for VLAN 0 e1000e: Fix irq_synchronize in MSI-X case e1000e: register pm_qos request on hardware activation ip_fragment: fix subtracting PPPOE_SES_HLEN from mtu twice net: Add getsockopt support for TCP thin-streams cxgb4: update driver version cxgb4: add new PCI IDs ... Manually fix up conflicts in: - drivers/net/e1000e/netdev.c: due to pm_qos registration infrastructure changes - drivers/net/phy/marvell.c: conflict between adding 88ec048 support and cleaning up the IDs - drivers/net/wireless/ipw2x00/ipw2100.c: trivial ipw2100_pm_qos_req conflict (registration change vs marking it static)
| * cgroups: Add an API to attach a task to current task's cgroupSridhar Samudrala2010-07-281-0/+7
| | | | | | | | | | | | | | | | | | | | Add a new kernel API to attach a task to current task's cgroup in all the active hierarchies. Signed-off-by: Sridhar Samudrala <sri@us.ibm.com> Signed-off-by: Michael S. Tsirkin <mst@redhat.com> Reviewed-by: Paul Menage <menage@google.com> Acked-by: Li Zefan <lizf@cn.fujitsu.com>
* | sched: Fix PROVE_RCU vs cpu_cgroupPeter Zijlstra2010-06-081-6/+14
|/ | | | | | | | | | | | | | | | | | | | | | | | PROVE_RCU has a few issues with the cpu_cgroup because the scheduler typically holds rq->lock around the css rcu derefs but the generic cgroup code doesn't (and can't) know about that lock. Provide means to add extra checks to the css dereference and use that in the scheduler to annotate its users. The addition of rq->lock to these checks is correct because the cgroup_subsys::attach() method takes the rq->lock for each task it moves, therefore by holding that lock, we ensure the task is pinned to the current cgroup and the RCU derefence is valid. That leaves one genuine race in __sched_setscheduler() where we used task_group() without holding any of the required locks and thus raced with the cgroup code. Solve this by moving the check under the appropriate lock. Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com> LKML-Reference: <new-submission> Signed-off-by: Ingo Molnar <mingo@elte.hu>
* cgroups: make cftype.unregister_event() void-returningKirill A. Shutemov2010-05-271-1/+1
| | | | | | | | | | | | | | | | | | | | | Since we are unable to handle an error returned by cftype.unregister_event() properly, let's make the callback void-returning. mem_cgroup_unregister_event() has been rewritten to be a "never fail" function. On mem_cgroup_usage_register_event() we save old buffer for thresholds array and reuse it in mem_cgroup_usage_unregister_event() to avoid allocation. Signed-off-by: Kirill A. Shutemov <kirill@shutemov.name> Acked-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Cc: Phil Carmody <ext-phil.2.carmody@nokia.com> Cc: Balbir Singh <balbir@linux.vnet.ibm.com> Cc: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp> Cc: Paul Menage <menage@google.com> Cc: Li Zefan <lizf@cn.fujitsu.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* cgroup: Check task_lock in task_subsys_state()Li Zefan2010-05-041-0/+1
| | | | | | | | | | | | | Expand task_subsys_state()'s rcu_dereference_check() to include the full locking rule as documented in Documentation/cgroups/cgroups.txt by adding a check for task->alloc_lock being held. This fixes an RCU false positive when resuming from suspend. The warning comes from freezer cgroup in cgroup_freezing_or_frozen(). Signed-off-by: Li Zefan <lizf@cn.fujitsu.com> Acked-by: Matt Helsley <matthltc@us.ibm.com> Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
* cgroups: remove events before destroying subsystem state objectsKirill A. Shutemov2010-03-121-3/+0
| | | | | | | | | | | | | | | | | Events should be removed after rmdir of cgroup directory, but before destroying subsystem state objects. Let's take reference to cgroup directory dentry to do that. Signed-off-by: Kirill A. Shutemov <kirill@shutemov.name> Acked-by: KAMEZAWA Hiroyuki <kamezawa.hioryu@jp.fujitsu.com> Cc: Paul Menage <menage@google.com> Acked-by: Li Zefan <lizf@cn.fujitsu.com> Cc: Balbir Singh <balbir@linux.vnet.ibm.com> Cc: Pavel Emelyanov <xemul@openvz.org> Cc: Dan Malek <dan@embeddedalley.com> Cc: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* cgroup: implement eventfd-based generic API for notificationsKirill A. Shutemov2010-03-121-0/+24
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | This patchset introduces eventfd-based API for notifications in cgroups and implements memory notifications on top of it. It uses statistics in memory controler to track memory usage. Output of time(1) on building kernel on tmpfs: Root cgroup before changes: make -j2 506.37 user 60.93s system 193% cpu 4:52.77 total Non-root cgroup before changes: make -j2 507.14 user 62.66s system 193% cpu 4:54.74 total Root cgroup after changes (0 thresholds): make -j2 507.13 user 62.20s system 193% cpu 4:53.55 total Non-root cgroup after changes (0 thresholds): make -j2 507.70 user 64.20s system 193% cpu 4:55.70 total Root cgroup after changes (1 thresholds, never crossed): make -j2 506.97 user 62.20s system 193% cpu 4:53.90 total Non-root cgroup after changes (1 thresholds, never crossed): make -j2 507.55 user 64.08s system 193% cpu 4:55.63 total This patch: Introduce the write-only file "cgroup.event_control" in every cgroup. To register new notification handler you need: - create an eventfd; - open a control file to be monitored. Callbacks register_event() and unregister_event() must be defined for the control file; - write "<event_fd> <control_fd> <args>" to cgroup.event_control. Interpretation of args is defined by control file implementation; eventfd will be woken up by control file implementation or when the cgroup is removed. To unregister notification handler just close eventfd. If you need notification functionality for a control file you have to implement callbacks register_event() and unregister_event() in the struct cftype. [kamezawa.hiroyu@jp.fujitsu.com: Kconfig fix] Signed-off-by: Kirill A. Shutemov <kirill@shutemov.name> Reviewed-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Paul Menage <menage@google.com> Cc: Li Zefan <lizf@cn.fujitsu.com> Cc: Balbir Singh <balbir@linux.vnet.ibm.com> Cc: Pavel Emelyanov <xemul@openvz.org> Cc: Dan Malek <dan@embeddedalley.com> Cc: Vladislav Buzov <vbuzov@embeddedalley.com> Cc: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp> Cc: Alexander Shishkin <virtuoso@slind.org> Cc: Davide Libenzi <davidel@xmailserver.org> Signed-off-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* cgroups: subsystem module unloadingBen Blum2010-03-121-1/+3
| | | | | | | | | | | | | | | | | | | Provides support for unloading modular subsystems. This patch adds a new function cgroup_unload_subsys which is to be used for removing a loaded subsystem during module deletion. Reference counting of the subsystems' modules is moved from once (at load time) to once per attached hierarchy (in parse_cgroupfs_options and rebind_subsystems) (i.e., 0 or 1). Signed-off-by: Ben Blum <bblum@andrew.cmu.edu> Acked-by: Li Zefan <lizf@cn.fujitsu.com> Cc: Paul Menage <menage@google.com> Cc: "David S. Miller" <davem@davemloft.net> Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Cc: Lai Jiangshan <laijs@cn.fujitsu.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* cgroups: subsystem module loading interfaceBen Blum2010-03-121-0/+4
| | | | | | | | | | | | | | | | | | | | | Add interface between cgroups subsystem management and module loading This patch implements rudimentary module-loading support for cgroups - namely, a cgroup_load_subsys (similar to cgroup_init_subsys) for use as a module initcall, and a struct module pointer in struct cgroup_subsys. Several functions that might be wanted by modules have had EXPORT_SYMBOL added to them, but it's unclear exactly which functions want it and which won't. Signed-off-by: Ben Blum <bblum@andrew.cmu.edu> Acked-by: Li Zefan <lizf@cn.fujitsu.com> Cc: Paul Menage <menage@google.com> Cc: "David S. Miller" <davem@davemloft.net> Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Cc: Lai Jiangshan <laijs@cn.fujitsu.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* cgroups: revamp subsys arrayBen Blum2010-03-121-2/+8
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | This patch series provides the ability for cgroup subsystems to be compiled as modules both within and outside the kernel tree. This is mainly useful for classifiers and subsystems that hook into components that are already modules. cls_cgroup and blkio-cgroup serve as the example use cases for this feature. It provides an interface cgroup_load_subsys() and cgroup_unload_subsys() which modular subsystems can use to register and depart during runtime. The net_cls classifier subsystem serves as the example for a subsystem which can be converted into a module using these changes. Patch #1 sets up the subsys[] array so its contents can be dynamic as modules appear and (eventually) disappear. Iterations over the array are modified to handle when subsystems are absent, and the dynamic section of the array is protected by cgroup_mutex. Patch #2 implements an interface for modules to load subsystems, called cgroup_load_subsys, similar to cgroup_init_subsys, and adds a module pointer in struct cgroup_subsys. Patch #3 adds a mechanism for unloading modular subsystems, which includes a more advanced rework of the rudimentary reference counting introduced in patch 2. Patch #4 modifies the net_cls subsystem, which already had some module declarations, to be configurable as a module, which also serves as a simple proof-of-concept. Part of implementing patches 2 and 4 involved updating css pointers in each css_set when the module appears or leaves. In doing this, it was discovered that css_sets always remain linked to the dummy cgroup, regardless of whether or not any subsystems are actually bound to it (i.e., not mounted on an actual hierarchy). The subsystem loading and unloading code therefore should keep in mind the special cases where the added subsystem is the only one in the dummy cgroup (and therefore all css_sets need to be linked back into it) and where the removed subsys was the only one in the dummy cgroup (and therefore all css_sets should be unlinked from it) - however, as all css_sets always stay attached to the dummy cgroup anyway, these cases are ignored. Any fix that addresses this issue should also make sure these cases are addressed in the subsystem loading and unloading code. This patch: Make subsys[] able to be dynamically populated to support modular subsystems This patch reworks the way the subsys[] array is used so that subsystems can register themselves after boot time, and enables the internals of cgroups to be able to handle when subsystems are not present or may appear/disappear. Signed-off-by: Ben Blum <bblum@andrew.cmu.edu> Acked-by: Li Zefan <lizf@cn.fujitsu.com> Cc: Paul Menage <menage@google.com> Cc: "David S. Miller" <davem@davemloft.net> Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Cc: Lai Jiangshan <laijs@cn.fujitsu.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* cgroup: introduce coalesce css_get() and css_put()Daisuke Nishimura2010-03-121-3/+9
| | | | | | | | | | | | | | | | | | | | | | | | | Current css_get() and css_put() increment/decrement css->refcnt one by one. This patch add a new function __css_get(), which takes "count" as a arg and increment the css->refcnt by "count". And this patch also add a new arg("count") to __css_put() and change the function to decrement the css->refcnt by "count". These coalesce version of __css_get()/__css_put() will be used to improve performance of memcg's moving charge feature later, where instead of calling css_get()/css_put() repeatedly, these new functions will be used. No change is needed for current users of css_get()/css_put(). Signed-off-by: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp> Acked-by: Paul Menage <menage@google.com> Cc: Balbir Singh <balbir@linux.vnet.ibm.com> Acked-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Cc: Li Zefan <lizf@cn.fujitsu.com> Cc: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* cgroup: introduce cancel_attach()Daisuke Nishimura2010-03-121-0/+2
| | | | | | | | | | | | | | | | Add cancel_attach() operation to struct cgroup_subsys. cancel_attach() can be used when can_attach() operation prepares something for the subsys, but we should rollback what can_attach() operation has prepared if attach task fails after we've succeeded in can_attach(). Signed-off-by: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp> Acked-by: Li Zefan <lizf@cn.fujitsu.com> Reviewed-by: Paul Menage <menage@google.com> Cc: Balbir Singh <balbir@linux.vnet.ibm.com> Acked-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Cc: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* sched: Use lockdep-based checking on rcu_dereference()Paul E. McKenney2010-02-251-1/+4
| | | | | | | | | | | | | | | | | | | | Update the rcu_dereference() usages to take advantage of the new lockdep-based checking. Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Cc: laijs@cn.fujitsu.com Cc: dipankar@in.ibm.com Cc: mathieu.desnoyers@polymtl.ca Cc: josh@joshtriplett.org Cc: dvhltc@us.ibm.com Cc: niv@us.ibm.com Cc: peterz@infradead.org Cc: rostedt@goodmis.org Cc: Valdis.Kletnieks@vt.edu Cc: dhowells@redhat.com LKML-Reference: <1266887105-1528-6-git-send-email-paulmck@linux.vnet.ibm.com> [ -v2: fix allmodconfig missing symbol export build failure on x86 ] Signed-off-by: Ingo Molnar <mingo@elte.hu>
* const: constify remaining file_operationsAlexey Dobriyan2009-10-011-1/+1
| | | | | | | | [akpm@linux-foundation.org: fix KVM] Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com> Acked-by: Mike Frysinger <vapier@gentoo.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* cgroups: let ss->can_attach and ss->attach do whole threadgroups at a timeBen Blum2009-09-241-3/+4
| | | | | | | | | | | | | | | | | | | | | | | | | | Alter the ss->can_attach and ss->attach functions to be able to deal with a whole threadgroup at a time, for use in cgroup_attach_proc. (This is a pre-patch to cgroup-procs-writable.patch.) Currently, new mode of the attach function can only tell the subsystem about the old cgroup of the threadgroup leader. No subsystem currently needs that information for each thread that's being moved, but if one were to be added (for example, one that counts tasks within a group) this bit would need to be reworked a bit to tell the subsystem the right information. [hidave.darkstar@gmail.com: fix build] Signed-off-by: Ben Blum <bblum@google.com> Signed-off-by: Paul Menage <menage@google.com> Acked-by: Li Zefan <lizf@cn.fujitsu.com> Reviewed-by: Matt Helsley <matthltc@us.ibm.com> Cc: "Eric W. Biederman" <ebiederm@xmission.com> Cc: Oleg Nesterov <oleg@redhat.com> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Ingo Molnar <mingo@elte.hu> Cc: Dave Young <hidave.darkstar@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* cgroups: change css_set freeing mechanism to be under RCUBen Blum2009-09-241-0/+3
| | | | | | | | | | | | | | | | | | | Changes css_set freeing mechanism to be under RCU This is a prepatch for making the procs file writable. In order to free the old css_sets for each task to be moved as they're being moved, the freeing mechanism must be RCU-protected, or else we would have to have a call to synchronize_rcu() for each task before freeing its old css_set. Signed-off-by: Ben Blum <bblum@google.com> Signed-off-by: Paul Menage <menage@google.com> Cc: "Paul E. McKenney" <paulmck@us.ibm.com> Acked-by: Li Zefan <lizf@cn.fujitsu.com> Cc: Matt Helsley <matthltc@us.ibm.com> Cc: "Eric W. Biederman" <ebiederm@xmission.com> Cc: Oleg Nesterov <oleg@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* cgroups: ensure correct concurrent opening/reading of pidlists across pid ↵Ben Blum2009-09-241-5/+29
| | | | | | | | | | | | | | | | | | | | | | namespaces Previously there was the problem in which two processes from different pid namespaces reading the tasks or procs file could result in one process seeing results from the other's namespace. Rather than one pidlist for each file in a cgroup, we now keep a list of pidlists keyed by namespace and file type (tasks versus procs) in which entries are placed on demand. Each pidlist has its own lock, and that the pidlists themselves are passed around in the seq_file's private pointer means we don't have to touch the cgroup or its master list except when creating and destroying entries. Signed-off-by: Ben Blum <bblum@google.com> Signed-off-by: Paul Menage <menage@google.com> Cc: Li Zefan <lizf@cn.fujitsu.com> Cc: Matt Helsley <matthltc@us.ibm.com> Cc: "Eric W. Biederman" <ebiederm@xmission.com> Cc: Oleg Nesterov <oleg@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* cgroups: add a read-only "procs" file similar to "tasks" that shows only ↵Ben Blum2009-09-241-8/+14
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | unique tgids struct cgroup used to have a bunch of fields for keeping track of the pidlist for the tasks file. Those are now separated into a new struct cgroup_pidlist, of which two are had, one for procs and one for tasks. The way the seq_file operations are set up is changed so that just the pidlist struct gets passed around as the private data. Interface example: Suppose a multithreaded process has pid 1000 and other threads with ids 1001, 1002, 1003: $ cat tasks 1000 1001 1002 1003 $ cat cgroup.procs 1000 $ Signed-off-by: Ben Blum <bblum@google.com> Signed-off-by: Paul Menage <menage@google.com> Acked-by: Li Zefan <lizf@cn.fujitsu.com> Cc: Matt Helsley <matthltc@us.ibm.com> Cc: "Eric W. Biederman" <ebiederm@xmission.com> Cc: Oleg Nesterov <oleg@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* cgroups: revert "cgroups: fix pid namespace bug"Paul Menage2009-09-241-4/+7
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The following series adds a "cgroup.procs" file to each cgroup that reports unique tgids rather than pids, and allows all threads in a threadgroup to be atomically moved to a new cgroup. The subsystem "attach" interface is modified to support attaching whole threadgroups at a time, which could introduce potential problems if any subsystem were to need to access the old cgroup of every thread being moved. The attach interface may need to be revised if this becomes the case. Also added is functionality for read/write locking all CLONE_THREAD fork()ing within a threadgroup, by means of an rwsem that lives in the sighand_struct, for per-threadgroup-ness and also for sharing a cacheline with the sighand's atomic count. This scheme should introduce no extra overhead in the fork path when there's no contention. The final patch reveals potential for a race when forking before a subsystem's attach function is called - one potential solution in case any subsystem has this problem is to hang on to the group's fork mutex through the attach() calls, though no subsystem yet demonstrates need for an extended critical section. This patch: Revert commit 096b7fe012d66ed55e98bc8022405ede0cc80e96 Author: Li Zefan <lizf@cn.fujitsu.com> AuthorDate: Wed Jul 29 15:04:04 2009 -0700 Commit: Linus Torvalds <torvalds@linux-foundation.org> CommitDate: Wed Jul 29 19:10:35 2009 -0700 cgroups: fix pid namespace bug This is in preparation for some clashing cgroups changes that subsume the original commit's functionaliy. The original commit fixed a pid namespace bug which Ben Blum fixed independently (in the same way, but with different code) as part of a series of patches. I played around with trying to reconcile Ben's patch series with Li's patch, but concluded that it was simpler to just revert Li's, given that Ben's patch series contained essentially the same fix. Signed-off-by: Paul Menage <menage@google.com> Cc: Li Zefan <lizf@cn.fujitsu.com> Cc: Matt Helsley <matthltc@us.ibm.com> Cc: "Eric W. Biederman" <ebiederm@xmission.com> Cc: Oleg Nesterov <oleg@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* cgroup avoid permanent sleep at rmdirKAMEZAWA Hiroyuki2009-07-291-0/+17
| | | | | | | | | | | | | | | | | | | | | After commit ec64f51545fffbc4cb968f0cea56341a4b07e85a ("cgroup: fix frequent -EBUSY at rmdir"), cgroup's rmdir (especially against memcg) doesn't return -EBUSY by temporary ref counts. That commit expects all refs after pre_destroy() is temporary but...it wasn't. Then, rmdir can wait permanently. This patch tries to fix that and change followings. - set CGRP_WAIT_ON_RMDIR flag before pre_destroy(). - clear CGRP_WAIT_ON_RMDIR flag when the subsys finds racy case. if there are sleeping ones, wakes them up. - rmdir() sleeps only when CGRP_WAIT_ON_RMDIR flag is set. Tested-by: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp> Reported-by: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp> Reviewed-by: Paul Menage <menage@google.com> Acked-by: Balbir Sigh <balbir@linux.vnet.ibm.com> Signed-off-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* cgroups: fix pid namespace bugLi Zefan2009-07-291-7/+4
| | | | | | | | | | | | | | | | | | | | | The bug was introduced by commit cc31edceee04a7b87f2be48f9489ebb72d264844 ("cgroups: convert tasks file to use a seq_file with shared pid array"). We cache a pid array for all threads that are opening the same "tasks" file, but the pids in the array are always from the namespace of the last process that opened the file, so all other threads will read pids from that namespace instead of their own namespaces. To fix it, we maintain a list of pid arrays, which is keyed by pid_ns. The list will be of length 1 at most time. Reported-by: Paul Menage <menage@google.com> Idea-by: Paul Menage <menage@google.com> Signed-off-by: Li Zefan <lizf@cn.fujitsu.com> Reviewed-by: Serge Hallyn <serue@us.ibm.com> Cc: Balbir Singh <balbir@in.ibm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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