- 19 Apr, 2013 1 commit
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Li Zefan authored
We should store file xattrs in struct cfent instead of struct cftype, because cftype is a type while cfent is object instance of cftype. For example each cgroup has a tasks file, and each tasks file is associated with a uniq cfent, but all those files share the same struct cftype. Alexey Kodanev reported a crash, which can be reproduced: # mount -t cgroup -o xattr /sys/fs/cgroup # mkdir /sys/fs/cgroup/test # setfattr -n trusted.value -v test_value /sys/fs/cgroup/tasks # rmdir /sys/fs/cgroup/test # umount /sys/fs/cgroup oops! In this case, simple_xattrs_free() will free the same struct simple_xattrs twice. tj: Dropped unused local variable @cft from cgroup_diput(). Cc: <stable@vger.kernel.org> # 3.8.x Reported-by:
Alexey Kodanev <alexey.kodanev@oracle.com> Signed-off-by:
Li Zefan <lizefan@huawei.com> Signed-off-by:
Tejun Heo <tj@kernel.org>
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- 18 Apr, 2013 1 commit
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Rami Rosen authored
In devcgroup_css_alloc(), there is no longer need for parent_cgroup. bd2953eb("devcg: propagate local changes down the hierarchy") made the variable parent_cgroup redundant. This patch removes parent_cgroup from devcgroup_css_alloc(). Signed-off-by:
Rami Rosen <ramirose@gmail.com> Acked-by:
Aristeu Rozanski <aris@redhat.com> Signed-off-by:
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- 15 Apr, 2013 5 commits
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Tejun Heo authored
Turn on use_hierarchy by default if sane_behavior is specified and don't create .use_hierarchy file. It is debatable whether to remove .use_hierarchy file or make it ro as the former could make transition easier in certain cases; however, the behavior changes which will be gated by sane_behavior are intensive including changing basic meaning of certain control knobs in a few controllers and I don't really think keeping this piece would make things easier in any noticeable way, so let's remove it. v2: Explain that mem_cgroup_bind() doesn't have to worry about children as suggested by Michal Hocko. Signed-off-by:Serge E. Hallyn <serge.hallyn@ubuntu.com> Acked-by:
Michal Hocko <mhocko@suse.cz> Acked-by:
KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
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Li Zefan authored
It's not used, and it can be retrieved via cgrp->root->top_cgroup. Signed-off-by:
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Tejun Heo authored
It's a sad fact that at this point various cgroup controllers are carrying so many idiosyncrasies and pure insanities that it simply isn't possible to reach any sort of sane consistent behavior while maintaining staying fully compatible with what already has been exposed to userland. As we can't break exposed userland interface, transitioning to sane behaviors can only be done in steps while maintaining backwards compatibility. This patch introduces a new mount option - __DEVEL__sane_behavior - which disables crazy features and enforces consistent behaviors in cgroup core proper and various controllers. As exactly which behaviors it changes are still being determined, the mount option, at this point, is useful only for development of the new behaviors. As such, the mount option is prefixed with __DEVEL__ and generates a warning message when used. Eventually, once we get to the point where all controller's behaviors are consistent enough to implement unified hierarchy, the __DEVEL__ prefix will be dropped, and more importantly, unified-hierarchy will enforce sane_behavior by default. Maybe we'll able to completely drop the crazy stuff after a while, maybe not, but we at least have a strategy to move on to saner behaviors. This patch introduces the mount option and changes the following behaviors in cgroup core. * Mount options "noprefix" and "clone_children" are disallowed. Also, cgroupfs file cgroup.clone_children is not created. * When mounting an existing superblock, mount options should match. This is currently pretty crazy. If one mounts a cgroup, creates a subdirectory, unmounts it and then mount it again with different option, it looks like the new options are applied but they aren't. * Remount is disallowed. The behaviors changes are documented in the comment above CGRP_ROOT_SANE_BEHAVIOR enum and will be expanded as different controllers are converted and planned improvements progress. v2: Dropped unnecessary explicit file permission setting sane_behavior cftype entry as suggested by Li Zefan. Signed-off-by: -
Tejun Heo authored
While controllers shouldn't be accessing cgroupfs_root directly, it being hidden inside kern/cgroup.c makes somethings pretty silly. This makes routing hierarchy-wide settings which need to be visible to controllers cumbersome. We're gonna add another hierarchy-wide setting which needs to be accessed from controllers. Move cgroupfs_root and its flags to the header file so that we can access root settings with inline helpers. Signed-off-by:
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Tejun Heo authored
There's no reason to be using bitops, which tends to be more cumbersome, to handle root flags. Convert them to masks. Also, as they'll be moved to include/linux/cgroup.h and it's generally a good idea, add CGRP_ prefix. Note that flags are assigned from (1 << 1). The first bit will be used by a flag which will be added soon. Signed-off-by:
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- 14 Apr, 2013 1 commit
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Tejun Heo authored
While reimplementing cgroup_path(), 65dff759 ("cgroup: fix cgroup_path() vs rename() race") introduced a bug where the path of a non-root cgroup would have two slahses at the beginning, which is caused by treating the root cgroup which has the name '/' like non-root cgroups. $ grep systemd /proc/self/cgroup 1:name=systemd://user/root/1 Fix it by special casing root cgroup case and not looping over it in the normal path. Signed-off-by:
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- 12 Apr, 2013 1 commit
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Tejun Heo authored
This reverts commit 84cfb6ab. There are scheduled changes which make use of the removed callback. Signed-off-by:
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- 10 Apr, 2013 4 commits
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Tejun Heo authored
perf_event is one of a couple remaining cgroup controllers with broken hierarchy support. Converting it to support hierarchy is almost trivial. The only thing necessary is to consider a task belonging to a descendant cgroup as a match. IOW, if the cgroup of the currently executing task (@cpuctx->cgrp) equals or is a descendant of the event's cgroup (@event->cgrp), then the event should be enabled. Implement hierarchy support and remove .broken_hierarchy tag along with the incorrect comment on what needs to be done for hierarchy support. Signed-off-by: -
Li Zefan authored
A couple controllers want to determine whether two cgroups are in ancestor/descendant relationship. As it's more likely that the descendant is the primary subject of interest and there are other operations focusing on the descendants, let's ask is_descendent rather than is_ancestor. Implementation is trivial as the previous patch guarantees that all ancestors of a cgroup stay accessible as long as the cgroup is accessible. tj: Removed depth optimization, renamed from cgroup_is_ancestor(), rewrote descriptions. Signed-off-by: -
Li Zefan authored
Suppose we rmdir a cgroup and there're still css refs, this cgroup won't be freed. Then we rmdir the parent cgroup, and the parent is freed immediately due to css ref draining to 0. Now it would be a disaster if the still-alive child cgroup tries to access its parent. Make sure this won't happen. Signed-off-by:
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Rami Rosen authored
The bind() method of cgroup_subsys is not used in any of the controllers (cpuset, freezer, blkio, net_cls, memcg, net_prio, devices, perf, hugetlb, cpu and cpuacct) tj: Removed the entry on ->bind() from Documentation/cgroups/cgroups.txt. Also updated a couple paragraphs which were suggesting that dynamic re-binding may be implemented. It's not gonna. Signed-off-by:
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- 08 Apr, 2013 1 commit
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Tejun Heo authored
bd2953eb ("devcg: propagate local changes down the hierarchy") implemented proper hierarchy support. Remove the broken tag. Signed-off-by:
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- 07 Apr, 2013 6 commits
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Tejun Heo authored
We don't want controllers to assume that the information is officially available and do funky things with it. The only user is task_subsys_state_check() which uses it to verify RCU access context. We can move cgroup_lock_is_held() inside CONFIG_PROVE_RCU but that doesn't add meaningful protection compared to conditionally exposing cgroup_mutex. Remove cgroup_lock_is_held(), export cgroup_mutex iff CONFIG_PROVE_RCU and use lockdep_is_held() directly on the mutex in task_subsys_state_check(). While at it, add parentheses around macro arguments in task_subsys_state_check(). Signed-off-by:
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Tejun Heo authored
Now that locking interface is unexported, there's no reason to keep around these thin wrappers. Kill them and use mutex operations directly. Signed-off-by:
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Tejun Heo authored
Now that all external cgroup_lock() users are gone, we can finally unexport the locking interface and prevent future abuse of cgroup_mutex. Make cgroup_[un]lock() and cgroup_lock_live_group() static. Also, cgroup_attach_task() doesn't have any user left and can't be used without locking interface anyway. Make it static too. Signed-off-by:
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Tejun Heo authored
cgroup_lock_live_group() and cgroup_attach_task() are scheduled to be made static. Relocate the former and cgroup_attach_task_all() so that we don't need forward declarations. This patch is pure relocation. Signed-off-by:
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Tejun Heo authored
When a cpuset becomes empty (no CPU or memory), its tasks are transferred with the nearest ancestor with execution resources. This is implemented using cgroup_scan_tasks() with a callback which grabs cgroup_mutex and invokes cgroup_attach_task() on each task. Both cgroup_mutex and cgroup_attach_task() are scheduled to be unexported. Implement cgroup_transfer_tasks() in cgroup proper which is essentially the same as move_member_tasks_to_cpuset() except that it takes cgroups instead of cpusets and @to comes before @from like normal functions with those arguments, and replace move_member_tasks_to_cpuset() with it. Signed-off-by:
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Michal Hocko authored
As cgroup supports rename, it's unsafe to dereference dentry->d_name without proper vfs locks. Fix this by using cgroup_name() rather than dentry directly. Also open code memcg_cache_name because it is called only from kmem_cache_dup which frees the returned name right after kmem_cache_create_memcg makes a copy of it. Such a short-lived allocation doesn't make too much sense. So replace it by a static buffer as kmem_cache_dup is called with memcg_cache_mutex. Signed-off-by:
Glauber Costa <glommer@parallels.com> Signed-off-by:
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- 03 Apr, 2013 2 commits
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Kevin Wilson authored
This patch removes unused parameter from cgroup_task_migrate(). Signed-off-by:
Kevin Wilson <wkevils@gmail.com> Acked-by:
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Rami Rosen authored
This trivial patch removes a word which appears twice in Documentation/cgroup/cgroup.txt. Signed-off-by:
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- 20 Mar, 2013 6 commits
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Li Zefan authored
These two functions share most of the code. Signed-off-by:
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Aristeu Rozanski authored
This patch makes exception changes to propagate down in hierarchy respecting when possible local exceptions. New exceptions allowing additional access to devices won't be propagated, but it'll be possible to add an exception to access all of part of the newly allowed device(s). New exceptions disallowing access to devices will be propagated down and the local group's exceptions will be revalidated for the new situation. Example: A / \ B group behavior exceptions A allow "b 8:* rwm", "c 116:1 rw" B deny "c 1:3 rwm", "c 116:2 rwm", "b 3:* rwm" If a new exception is added to group A: # echo "c 116:* r" > A/devices.deny it'll propagate down and after revalidating B's local exceptions, the exception "c 116:2 rwm" will be removed. In case parent's exceptions change and local exceptions are not allowed anymore, they'll be deleted. v7: - do not allow behavior change when the cgroup has children - update documentation v6: fixed issues pointed by Serge Hallyn - only copy parent's exceptions while propagating behavior if the local behavior is different - while propagating exceptions, do not clear and copy parent's: it'd be against the premise we don't propagate access to more devices v5: fixed issues pointed by Serge Hallyn - updated documentation - not propagating when an exception is written to devices.allow - when propagating a new behavior, clean the local exceptions list if they're for a different behavior v4: fixed issues pointed by Tejun Heo - separated function to walk the tree and collect valid propagation targets v3: fixed issues pointed by Tejun Heo - update documentation - move css_online/css_offline changes to a new patch - use cgroup_for_each_descendant_pre() instead of own descendant walk - move exception_copy rework to a separared patch - move exception_clean rework to a separated patch v2: fixed issues pointed by Tejun Heo - instead of keeping the local settings that won't apply anymore, remove them Cc: Tejun Heo <tj@kernel.org> Cc: Serge Hallyn <serge.hallyn@canonical.com> Signed-off-by: -
Aristeu Rozanski authored
Allocate resources and change behavior only when online. This is needed in order to determine if a node is suitable for hierarchy propagation or if it's being removed. Locking: Both functions take devcgroup_mutex to make changes to device_cgroup structure. Hierarchy propagation will also take devcgroup_mutex before walking the tree while walking the tree itself is protected by rcu lock. Acked-by:
Serge Hallyn <serge.hallyn@canonical.com> Cc: Tejun Heo <tj@kernel.org> Cc: Serge Hallyn <serge.hallyn@canonical.com> Signed-off-by:
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Aristeu Rozanski authored
Currently may_access() is only able to verify if an exception is valid for the current cgroup, which has the same behavior. With hierarchy, it'll be also used to verify if a cgroup local exception is valid towards its cgroup parent, which might have different behavior. v2: - updated patch description - rebased on top of a new patch to expand the may_access() logic to make it more clear - fixed argument description order in may_access() Acked-by:
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Aristeu Rozanski authored
In order to make the next patch more clear, expand may_access() logic. v2: may_access() returns bool now Acked-by:
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Li Zefan authored
The 3rd parameter of flex_array_prealloc() is the number of elements, not the index of the last element. The effect of the bug is, when opening cgroup.procs, a flex array will be allocated and all elements of the array is allocated with GFP_KERNEL flag, but the last one is GFP_ATOMIC, and if we fail to allocate memory for it, it'll trigger a BUG_ON(). Signed-off-by:
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- 12 Mar, 2013 6 commits
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Li Zefan authored
eventfd_poll() never returns POLLHUP. Signed-off-by:
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Li Zefan authored
When we open cgroup.procs, we'll allocate an buffer and store all tasks' tgid in it, and then duplicate entries will be stripped. If that results in a much smaller pid list, we'll re-allocate a smaller buffer. But we've already sucessfully allocated memory and reading the procs file is a short period and the memory will be freed very soon, so why bother to re-allocate memory. Signed-off-by:
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Li Zefan authored
cpuset no longer nests cgroup_mutex inside cpu_hotplug lock, so we don't have to release cgroup_mutex before calling css_offline(). Signed-off-by:
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Li Zefan authored
Signed-off-by:
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Li Zefan authored
It was used by ns cgroup, and ns cgroup was removed long ago. Signed-off-by:
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Li Zefan authored
Sasha reported a lockdep warning when OOM was triggered. The reason is cgroup_name() should be called with rcu_read_lock() held. Reported-by:
Sasha Levin <sasha.levin@oracle.com> Signed-off-by:
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- 05 Mar, 2013 3 commits
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Li Zefan authored
We don't need to include cgroup.h in cpuset.h. Signed-off-by:
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Li Zefan authored
It's not needed at all. Signed-off-by:
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Li Zefan authored
subsys[i] is set to NULL in cgroup_unload_subsys() at modular unload, and that's protected by cgroup_mutex, and then the memory *subsys[i] resides will be freed. So this is unsafe without any locking: if (!ss || ss->module) ... v2: - add a comment for enum cgroup_subsys_id - simplify the comment in cgroup_exit() Signed-off-by:
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- 04 Mar, 2013 3 commits
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Li Zefan authored
We no longer fail rmdir() when there're still css refs, so we don't need to check css refs in check_for_release(). This also voids a bug. cgroup_has_css_refs() accesses subsys[i] without cgroup_mutex, so it can race with cgroup_unload_subsys(). cgroup_has_css_refs() ... if (ss == NULL || ss->root != cgrp->root) if ss pointers to net_cls_subsys, and cls_cgroup module is unloaded right after the former check but before the latter, the memory that net_cls_subsys resides has become invalid. Signed-off-by:
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Li Zefan authored
Use cgroup_name() instead of cgrp->dentry->name. This makes the code a bit simpler. While at it, remove cpuset_name and make cpuset_nodelist a local variable to cpuset_print_task_mems_allowed(). Signed-off-by:
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Li Zefan authored
rename() will change dentry->d_name. The result of this race can be worse than seeing partially rewritten name, but we might access a stale pointer because rename() will re-allocate memory to hold a longer name. As accessing dentry->name must be protected by dentry->d_lock or parent inode's i_mutex, while on the other hand cgroup-path() can be called with some irq-safe spinlocks held, we can't generate cgroup path using dentry->d_name. Alternatively we make a copy of dentry->d_name and save it in cgrp->name when a cgroup is created, and update cgrp->name at rename(). v5: use flexible array instead of zero-size array. v4: - allocate root_cgroup_name and all root_cgroup->name points to it. - add cgroup_name() wrapper. v3: use kfree_rcu() instead of synchronize_rcu() in user-visible path. v2: make cgrp->name RCU safe. Signed-off-by:
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