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| * | cgroup: hold cgroup_mutex before calling css_offline()Li Zefan2013-03-121-10/+1
| | | | | | | | | | | | | | | | | | | | | | | | 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: Li Zefan <lizefan@huawei.com> Signed-off-by: Tejun Heo <tj@kernel.org>
| * | cgroup: remove unused variables in cgroup_destroy_locked()Li Zefan2013-03-121-2/+0
| | | | | | | | | | | | | | | Signed-off-by: Li Zefan <lizefan@huawei.com> Signed-off-by: Tejun Heo <tj@kernel.org>
| * | cgroup: remove cgroup_is_descendant()Li Zefan2013-03-121-28/+0
| | | | | | | | | | | | | | | | | | | | | It was used by ns cgroup, and ns cgroup was removed long ago. Signed-off-by: Li Zefan <lizefan@huawei.com> Signed-off-by: Tejun Heo <tj@kernel.org>
| * | cgroup: avoid accessing modular cgroup subsys structure without lockingLi Zefan2013-03-051-14/+14
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | 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: Li Zefan <lizefan@huawei.com> Signed-off-by: Tejun Heo <tj@kernel.org>
| * | cgroup: no need to check css refs for release notificationLi Zefan2013-03-041-59/+8
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | 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: Li Zefan <lizefan@huawei.com> Signed-off-by: Tejun Heo <tj@kernel.org>
| * | cgroup: fix cgroup_path() vs rename() raceLi Zefan2013-03-041-30/+76
| |/ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | 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: Li Zefan <lizefan@huawei.com> Signed-off-by: Tejun Heo <tj@kernel.org>
* | Merge branch 'for-3.10' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/wqLinus Torvalds2013-04-291-2/+2
|\ \ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Pull workqueue updates from Tejun Heo: "A lot of activities on workqueue side this time. The changes achieve the followings. - WQ_UNBOUND workqueues - the workqueues which are per-cpu - are updated to be able to interface with multiple backend worker pools. This involved a lot of churning but the end result seems actually neater as unbound workqueues are now a lot closer to per-cpu ones. - The ability to interface with multiple backend worker pools are used to implement unbound workqueues with custom attributes. Currently the supported attributes are the nice level and CPU affinity. It may be expanded to include cgroup association in future. The attributes can be specified either by calling apply_workqueue_attrs() or through /sys/bus/workqueue/WQ_NAME/* if the workqueue in question is exported through sysfs. The backend worker pools are keyed by the actual attributes and shared by any workqueues which share the same attributes. When attributes of a workqueue are changed, the workqueue binds to the worker pool with the specified attributes while leaving the work items which are already executing in its previous worker pools alone. This allows converting custom worker pool implementations which want worker attribute tuning to use workqueues. The writeback pool is already converted in block tree and there are a couple others are likely to follow including btrfs io workers. - WQ_UNBOUND's ability to bind to multiple worker pools is also used to make it NUMA-aware. Because there's no association between work item issuer and the specific worker assigned to execute it, before this change, using unbound workqueue led to unnecessary cross-node bouncing and it couldn't be helped by autonuma as it requires tasks to have implicit node affinity and workers are assigned randomly. After these changes, an unbound workqueue now binds to multiple NUMA-affine worker pools so that queued work items are executed in the same node. This is turned on by default but can be disabled system-wide or for individual workqueues. Crypto was requesting NUMA affinity as encrypting data across different nodes can contribute noticeable overhead and doing it per-cpu was too limiting for certain cases and IO throughput could be bottlenecked by one CPU being fully occupied while others have idle cycles. While the new features required a lot of changes including restructuring locking, it didn't complicate the execution paths much. The unbound workqueue handling is now closer to per-cpu ones and the new features are implemented by simply associating a workqueue with different sets of backend worker pools without changing queue, execution or flush paths. As such, even though the amount of change is very high, I feel relatively safe in that it isn't likely to cause subtle issues with basic correctness of work item execution and handling. If something is wrong, it's likely to show up as being associated with worker pools with the wrong attributes or OOPS while workqueue attributes are being changed or during CPU hotplug. While this creates more backend worker pools, it doesn't add too many more workers unless, of course, there are many workqueues with unique combinations of attributes. Assuming everything else is the same, NUMA awareness costs an extra worker pool per NUMA node with online CPUs. There are also a couple things which are being routed outside the workqueue tree. - block tree pulled in workqueue for-3.10 so that writeback worker pool can be converted to unbound workqueue with sysfs control exposed. This simplifies the code, makes writeback workers NUMA-aware and allows tuning nice level and CPU affinity via sysfs. - The conversion to workqueue means that there's no 1:1 association between a specific worker, which makes writeback folks unhappy as they want to be able to tell which filesystem caused a problem from backtrace on systems with many filesystems mounted. This is resolved by allowing work items to set debug info string which is printed when the task is dumped. As this change involves unifying implementations of dump_stack() and friends in arch codes, it's being routed through Andrew's -mm tree." * 'for-3.10' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/wq: (84 commits) workqueue: use kmem_cache_free() instead of kfree() workqueue: avoid false negative WARN_ON() in destroy_workqueue() workqueue: update sysfs interface to reflect NUMA awareness and a kernel param to disable NUMA affinity workqueue: implement NUMA affinity for unbound workqueues workqueue: introduce put_pwq_unlocked() workqueue: introduce numa_pwq_tbl_install() workqueue: use NUMA-aware allocation for pool_workqueues workqueue: break init_and_link_pwq() into two functions and introduce alloc_unbound_pwq() workqueue: map an unbound workqueues to multiple per-node pool_workqueues workqueue: move hot fields of workqueue_struct to the end workqueue: make workqueue->name[] fixed len workqueue: add workqueue->unbound_attrs workqueue: determine NUMA node of workers accourding to the allowed cpumask workqueue: drop 'H' from kworker names of unbound worker pools workqueue: add wq_numa_tbl_len and wq_numa_possible_cpumask[] workqueue: move pwq_pool_locking outside of get/put_unbound_pool() workqueue: fix memory leak in apply_workqueue_attrs() workqueue: fix unbound workqueue attrs hashing / comparison workqueue: fix race condition in unbound workqueue free path workqueue: remove pwq_lock which is no longer used ...
| * | sched: replace PF_THREAD_BOUND with PF_NO_SETAFFINITYTejun Heo2013-03-191-2/+2
| |/ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | PF_THREAD_BOUND was originally used to mark kernel threads which were bound to a specific CPU using kthread_bind() and a task with the flag set allows cpus_allowed modifications only to itself. Workqueue is currently abusing it to prevent userland from meddling with cpus_allowed of workqueue workers. What we need is a flag to prevent userland from messing with cpus_allowed of certain kernel tasks. In kernel, anyone can (incorrectly) squash the flag, and, for worker-type usages, restricting cpus_allowed modification to the task itself doesn't provide meaningful extra proection as other tasks can inject work items to the task anyway. This patch replaces PF_THREAD_BOUND with PF_NO_SETAFFINITY. sched_setaffinity() checks the flag and return -EINVAL if set. set_cpus_allowed_ptr() is no longer affected by the flag. This will allow simplifying workqueue worker CPU affinity management. Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Ingo Molnar <mingo@kernel.org> Reviewed-by: Lai Jiangshan <laijs@cn.fujitsu.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de>
* / cgroup: remove css_get_nextMichal Hocko2013-04-291-49/+0
|/ | | | | | | | | | | | | | | Now that we have generic and well ordered cgroup tree walkers there is no need to keep css_get_next in the place. Signed-off-by: Michal Hocko <mhocko@suse.cz> Acked-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Acked-by: Li Zefan <lizefan@huawei.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Ying Han <yinghan@google.com> Cc: Tejun Heo <htejun@gmail.com> Cc: Glauber Costa <glommer@parallels.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* hlist: drop the node parameter from iteratorsSasha Levin2013-02-271-7/+5
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | I'm not sure why, but the hlist for each entry iterators were conceived list_for_each_entry(pos, head, member) The hlist ones were greedy and wanted an extra parameter: hlist_for_each_entry(tpos, pos, head, member) Why did they need an extra pos parameter? I'm not quite sure. Not only they don't really need it, it also prevents the iterator from looking exactly like the list iterator, which is unfortunate. Besides the semantic patch, there was some manual work required: - Fix up the actual hlist iterators in linux/list.h - Fix up the declaration of other iterators based on the hlist ones. - A very small amount of places were using the 'node' parameter, this was modified to use 'obj->member' instead. - Coccinelle didn't handle the hlist_for_each_entry_safe iterator properly, so those had to be fixed up manually. The semantic patch which is mostly the work of Peter Senna Tschudin is here: @@ iterator name hlist_for_each_entry, hlist_for_each_entry_continue, hlist_for_each_entry_from, hlist_for_each_entry_rcu, hlist_for_each_entry_rcu_bh, hlist_for_each_entry_continue_rcu_bh, for_each_busy_worker, ax25_uid_for_each, ax25_for_each, inet_bind_bucket_for_each, sctp_for_each_hentry, sk_for_each, sk_for_each_rcu, sk_for_each_from, sk_for_each_safe, sk_for_each_bound, hlist_for_each_entry_safe, hlist_for_each_entry_continue_rcu, nr_neigh_for_each, nr_neigh_for_each_safe, nr_node_for_each, nr_node_for_each_safe, for_each_gfn_indirect_valid_sp, for_each_gfn_sp, for_each_host; type T; expression a,c,d,e; identifier b; statement S; @@ -T b; <+... when != b ( hlist_for_each_entry(a, - b, c, d) S | hlist_for_each_entry_continue(a, - b, c) S | hlist_for_each_entry_from(a, - b, c) S | hlist_for_each_entry_rcu(a, - b, c, d) S | hlist_for_each_entry_rcu_bh(a, - b, c, d) S | hlist_for_each_entry_continue_rcu_bh(a, - b, c) S | for_each_busy_worker(a, c, - b, d) S | ax25_uid_for_each(a, - b, c) S | ax25_for_each(a, - b, c) S | inet_bind_bucket_for_each(a, - b, c) S | sctp_for_each_hentry(a, - b, c) S | sk_for_each(a, - b, c) S | sk_for_each_rcu(a, - b, c) S | sk_for_each_from -(a, b) +(a) S + sk_for_each_from(a) S | sk_for_each_safe(a, - b, c, d) S | sk_for_each_bound(a, - b, c) S | hlist_for_each_entry_safe(a, - b, c, d, e) S | hlist_for_each_entry_continue_rcu(a, - b, c) S | nr_neigh_for_each(a, - b, c) S | nr_neigh_for_each_safe(a, - b, c, d) S | nr_node_for_each(a, - b, c) S | nr_node_for_each_safe(a, - b, c, d) S | - for_each_gfn_sp(a, c, d, b) S + for_each_gfn_sp(a, c, d) S | - for_each_gfn_indirect_valid_sp(a, c, d, b) S + for_each_gfn_indirect_valid_sp(a, c, d) S | for_each_host(a, - b, c) S | for_each_host_safe(a, - b, c, d) S | for_each_mesh_entry(a, - b, c, d) S ) ...+> [akpm@linux-foundation.org: drop bogus change from net/ipv4/raw.c] [akpm@linux-foundation.org: drop bogus hunk from net/ipv6/raw.c] [akpm@linux-foundation.org: checkpatch fixes] [akpm@linux-foundation.org: fix warnings] [akpm@linux-foudnation.org: redo intrusive kvm changes] Tested-by: Peter Senna Tschudin <peter.senna@gmail.com> Acked-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Signed-off-by: Sasha Levin <sasha.levin@oracle.com> Cc: Wu Fengguang <fengguang.wu@intel.com> Cc: Marcelo Tosatti <mtosatti@redhat.com> Cc: Gleb Natapov <gleb@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* cgroup: convert to idr_alloc()Tejun Heo2013-02-271-19/+8
| | | | | | | | | Convert to the much saner new idr interface. Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Li Zefan <lizefan@huawei.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* cgroup: don't use idr_remove_all()Tejun Heo2013-02-271-3/+1
| | | | | | | | | | idr_destroy() can destroy idr by itself and idr_remove_all() is being deprecated. Drop its usage. Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Li Zefan <lizefan@huawei.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* Merge branch 'for-linus' of ↵Linus Torvalds2013-02-261-3/+3
|\ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs Pull vfs pile (part one) from Al Viro: "Assorted stuff - cleaning namei.c up a bit, fixing ->d_name/->d_parent locking violations, etc. The most visible changes here are death of FS_REVAL_DOT (replaced with "has ->d_weak_revalidate()") and a new helper getting from struct file to inode. Some bits of preparation to xattr method interface changes. Misc patches by various people sent this cycle *and* ocfs2 fixes from several cycles ago that should've been upstream right then. PS: the next vfs pile will be xattr stuff." * 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs: (46 commits) saner proc_get_inode() calling conventions proc: avoid extra pde_put() in proc_fill_super() fs: change return values from -EACCES to -EPERM fs/exec.c: make bprm_mm_init() static ocfs2/dlm: use GFP_ATOMIC inside a spin_lock ocfs2: fix possible use-after-free with AIO ocfs2: Fix oops in ocfs2_fast_symlink_readpage() code path get_empty_filp()/alloc_file() leave both ->f_pos and ->f_version zero target: writev() on single-element vector is pointless export kernel_write(), convert open-coded instances fs: encode_fh: return FILEID_INVALID if invalid fid_type kill f_vfsmnt vfs: kill FS_REVAL_DOT by adding a d_weak_revalidate dentry op nfsd: handle vfs_getattr errors in acl protocol switch vfs_getattr() to struct path default SET_PERSONALITY() in linux/elf.h ceph: prepopulate inodes only when request is aborted d_hash_and_lookup(): export, switch open-coded instances 9p: switch v9fs_set_create_acl() to inode+fid, do it before d_instantiate() 9p: split dropping the acls from v9fs_set_create_acl() ...
| * new helper: file_inode(file)Al Viro2013-02-221-3/+3
| | | | | | | | Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
* | cgroup: fail if monitored file and event_control are in different cgroupLi Zefan2013-02-181-0/+11
| | | | | | | | | | | | | | | | | | | | | | | | | | | | If we pass fd of memory.usage_in_bytes of cgroup A to cgroup.event_control of cgroup B, then we won't get memory usage notification from A but B! What's worse, if A and B are in different mount hierarchy, we'll end up accessing NULL pointer! Disallow this kind of invalid usage. Signed-off-by: Li Zefan <lizefan@huawei.com> Acked-by: Kirill A. Shutemov <kirill@shutemov.name> Signed-off-by: Tejun Heo <tj@kernel.org>
* | cgroup: fix cgroup_rmdir() vs close(eventfd) raceLi Zefan2013-02-181-16/+25
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | commit 205a872bd6f9a9a09ef035ef1e90185a8245cc58 ("cgroup: fix lockdep warning for event_control") solved a deadlock by introducing a new bug. Move cgrp->event_list to a temporary list doesn't mean you can traverse this list locklessly, because at the same time cgroup_event_wake() can be called and remove the event from the list. The result of this race is disastrous. We adopt the way how kvm irqfd code implements race-free event removal, which is now described in the comments in cgroup_event_wake(). v3: - call eventfd_signal() no matter it's eventfd close or cgroup removal that removes the cgroup event. Acked-by: Kirill A. Shutemov <kirill@shutemov.name> Signed-off-by: Li Zefan <lizefan@huawei.com> Signed-off-by: Tejun Heo <tj@kernel.org>
* | cgroup: fix exit() vs rmdir() raceLi Zefan2013-02-181-0/+8
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | In cgroup_exit() put_css_set_taskexit() is called without any lock, which might lead to accessing a freed cgroup: thread1 thread2 --------------------------------------------- exit() cgroup_exit() put_css_set_taskexit() atomic_dec(cgrp->count); rmdir(); /* not safe !! */ check_for_release(cgrp); rcu_read_lock() can be used to make sure the cgroup is alive. Signed-off-by: Li Zefan <lizefan@huawei.com> Signed-off-by: Tejun Heo <tj@kernel.org> Cc: stable@vger.kernel.org
* | cgroup: remove bogus comments in cgroup_diput()Li Zefan2013-01-241-6/+0
| | | | | | | | | | | | | | | | | | | | Since commit 48ddbe194623ae089cc0576e60363f2d2e85662a ("cgroup: make css->refcnt clearing on cgroup removal optional"), each css holds a ref on cgroup's dentry, so cgroup_diput() won't be called until all css' refs go down to 0, which invalids the comments. Signed-off-by: Li Zefan <lizefan@huawei.com> Signed-off-by: Tejun Heo <tj@kernel.org>
* | cgroup: remove synchronize_rcu() from cgroup_diput()Li Zefan2013-01-241-29/+43
| | | | | | | | | | | | | | | | Free cgroup via call_rcu(). The actual work is done through workqueue. Signed-off-by: Li Zefan <lizefan@huawei.com> Signed-off-by: Tejun Heo <tj@kernel.org>
* | cgroup: remove duplicate RCU free on struct cgroupLi Zefan2013-01-241-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | When destroying a cgroup, though in cgroup_diput() we've called synchronize_rcu(), we then still have to free it via call_rcu(). The story is, long ago to fix a race between reading /proc/sched_debug and freeing cgroup, the code was changed to utilize call_rcu(). See commit a47295e6bc42ad35f9c15ac66f598aa24debd4e2 ("cgroups: make cgroup_path() RCU-safe") As we've fixed cpu cgroup that cpu_cgroup_offline_css() is used to unregister a task_group so there won't be concurrent access to this task_group after synchronize_rcu() in diput(). Now we can just kfree(cgrp). Signed-off-by: Li Zefan <lizefan@huawei.com> Signed-off-by: Tejun Heo <tj@kernel.org>
* | cgroup: initialize cgrp->dentry before css_alloc()Li Zefan2013-01-241-3/+4
| | | | | | | | | | | | | | | | | | | | | | With this change, we're guaranteed that cgroup_path() won't see NULL cgrp->dentry, and thus we can remove the NULL check in it. (Well, it's not strictly true, because dummptop.dentry is always NULL but we already handle that separately.) Signed-off-by: Li Zefan <lizefan@huawei.com> Signed-off-by: Tejun Heo <tj@kernel.org>
* | cgroup: remove a NULL check in cgroup_exit()Li Zefan2013-01-241-2/+1
| | | | | | | | | | | | | | | | | | init_task.cgroups is initialized at boot phase, and whenver a ask is forked, it's cgroups pointer is inherited from its parent, and it's never set to NULL afterwards. Signed-off-by: Li Zefan <lizefan@huawei.com> Signed-off-by: Tejun Heo <tj@kernel.org>
* | cgroup: fix bogus kernel warnings when cgroup_create() failedLi Zefan2013-01-221-9/+12
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | If cgroup_create() failed and cgroup_destroy_locked() is called to do cleanup, we'll see a bunch of warnings: cgroup_addrm_files: failed to remove 2MB.limit_in_bytes, err=-2 cgroup_addrm_files: failed to remove 2MB.usage_in_bytes, err=-2 cgroup_addrm_files: failed to remove 2MB.max_usage_in_bytes, err=-2 cgroup_addrm_files: failed to remove 2MB.failcnt, err=-2 cgroup_addrm_files: failed to remove prioidx, err=-2 cgroup_addrm_files: failed to remove ifpriomap, err=-2 ... We failed to remove those files, because cgroup_create() has failed before creating those cgroup files. To fix this, we simply don't warn if cgroup_rm_file() can't find the cft entry. Signed-off-by: Li Zefan <lizefan@huawei.com> Signed-off-by: Tejun Heo <tj@kernel.org>
* | cgroup: remove synchronize_rcu() from rebind_subsystems()Li Zefan2013-01-141-1/+0
| | | | | | | | | | | | | | | | Nothing's protected by RCU in rebind_subsystems(), and I can't think of a reason why it is needed. Signed-off-by: Li Zefan <lizefan@huawei.com> Signed-off-by: Tejun Heo <tj@kernel.org>
* | cgroup: remove synchronize_rcu() from cgroup_attach_{task|proc}()Li Zefan2013-01-141-2/+0
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | These 2 syncronize_rcu()s make attaching a task to a cgroup quite slow, and it can't be ignored in some situations. A real case from Colin Cross: Android uses cgroups heavily to manage thread priorities, putting threads in a background group with reduced cpu.shares when they are not visible to the user, and in a foreground group when they are. Some RPCs from foreground threads to background threads will temporarily move the background thread into the foreground group for the duration of the RPC. This results in many calls to cgroup_attach_task. In cgroup_attach_task() it's task->cgroups that is protected by RCU, and put_css_set() calls kfree_rcu() to free it. If we remove this synchronize_rcu(), there can be threads in RCU-read sections accessing their old cgroup via current->cgroups with concurrent rmdir operation, but this is safe. # time for ((i=0; i<50; i++)) { echo $$ > /mnt/sub/tasks; echo $$ > /mnt/tasks; } real 0m2.524s user 0m0.008s sys 0m0.004s With this patch: real 0m0.004s user 0m0.004s sys 0m0.000s tj: These synchronize_rcu()s are utterly confused. synchornize_rcu() necessarily has to come between two operations to guarantee that the changes made by the former operation are visible to all rcu readers before proceeding to the latter operation. Here, synchornize_rcu() are at the end of attach operations with nothing beyond it. Its only effect would be delaying completion of write(2) to sysfs tasks/procs files until all rcu readers see the change, which doesn't mean anything. Signed-off-by: Li Zefan <lizefan@huawei.com> Signed-off-by: Tejun Heo <tj@kernel.org> Reported-by: Colin Cross <ccross@google.com>
* | cgroup: use new hashtable implementationLi Zefan2013-01-101-53/+39
| | | | | | | | | | | | | | Switch cgroup to use the new hashtable implementation. No functional changes. Signed-off-by: Li Zefan <lizefan@huawei.com> Signed-off-by: Tejun Heo <tj@kernel.org>
* | cgroup: implement cgroup_rightmost_descendant()Tejun Heo2013-01-071-0/+26
|/ | | | | | | | | | | Implement cgroup_rightmost_descendant() which returns the right most descendant of the specified cgroup. This can be used to skip the cgroup's subtree while iterating with cgroup_for_each_descendant_pre(). Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Michal Hocko <mhocko@suse.cz> Acked-by: Li Zefan <lizefan@huawei.com>
* Merge branch 'akpm' (Andrew's patch-bomb)Linus Torvalds2012-12-171-1/+0
|\ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Merge misc patches from Andrew Morton: "Incoming: - lots of misc stuff - backlight tree updates - lib/ updates - Oleg's percpu-rwsem changes - checkpatch - rtc - aoe - more checkpoint/restart support I still have a pile of MM stuff pending - Pekka should be merging later today after which that is good to go. A number of other things are twiddling thumbs awaiting maintainer merges." * emailed patches from Andrew Morton <akpm@linux-foundation.org>: (180 commits) scatterlist: don't BUG when we can trivially return a proper error. docs: update documentation about /proc/<pid>/fdinfo/<fd> fanotify output fs, fanotify: add @mflags field to fanotify output docs: add documentation about /proc/<pid>/fdinfo/<fd> output fs, notify: add procfs fdinfo helper fs, exportfs: add exportfs_encode_inode_fh() helper fs, exportfs: escape nil dereference if no s_export_op present fs, epoll: add procfs fdinfo helper fs, eventfd: add procfs fdinfo helper procfs: add ability to plug in auxiliary fdinfo providers tools/testing/selftests/kcmp/kcmp_test.c: print reason for failure in kcmp_test breakpoint selftests: print failure status instead of cause make error kcmp selftests: print fail status instead of cause make error kcmp selftests: make run_tests fix mem-hotplug selftests: print failure status instead of cause make error cpu-hotplug selftests: print failure status instead of cause make error mqueue selftests: print failure status instead of cause make error vm selftests: print failure status instead of cause make error ubifs: use prandom_bytes mtd: nandsim: use prandom_bytes ...
| * kernel: remove reference to feature-removal-schedule.txtTao Ma2012-12-171-1/+0
| | | | | | | | | | | | | | | | | | | | In commit 9c0ece069b32 ("Get rid of Documentation/feature-removal.txt"), Linus removed feature-removal-schedule.txt from Documentation, but there is still some reference to this file. So remove them. Signed-off-by: Tao Ma <boyu.mt@taobao.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* | Merge branch 'for-linus' of ↵Linus Torvalds2012-12-171-1/+1
|\ \ | |/ |/| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/user-namespace Pull user namespace changes from Eric Biederman: "While small this set of changes is very significant with respect to containers in general and user namespaces in particular. The user space interface is now complete. This set of changes adds support for unprivileged users to create user namespaces and as a user namespace root to create other namespaces. The tyranny of supporting suid root preventing unprivileged users from using cool new kernel features is broken. This set of changes completes the work on setns, adding support for the pid, user, mount namespaces. This set of changes includes a bunch of basic pid namespace cleanups/simplifications. Of particular significance is the rework of the pid namespace cleanup so it no longer requires sending out tendrils into all kinds of unexpected cleanup paths for operation. At least one case of broken error handling is fixed by this cleanup. The files under /proc/<pid>/ns/ have been converted from regular files to magic symlinks which prevents incorrect caching by the VFS, ensuring the files always refer to the namespace the process is currently using and ensuring that the ptrace_mayaccess permission checks are always applied. The files under /proc/<pid>/ns/ have been given stable inode numbers so it is now possible to see if different processes share the same namespaces. Through the David Miller's net tree are changes to relax many of the permission checks in the networking stack to allowing the user namespace root to usefully use the networking stack. Similar changes for the mount namespace and the pid namespace are coming through my tree. Two small changes to add user namespace support were commited here adn in David Miller's -net tree so that I could complete the work on the /proc/<pid>/ns/ files in this tree. Work remains to make it safe to build user namespaces and 9p, afs, ceph, cifs, coda, gfs2, ncpfs, nfs, nfsd, ocfs2, and xfs so the Kconfig guard remains in place preventing that user namespaces from being built when any of those filesystems are enabled. Future design work remains to allow root users outside of the initial user namespace to mount more than just /proc and /sys." * 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/user-namespace: (38 commits) proc: Usable inode numbers for the namespace file descriptors. proc: Fix the namespace inode permission checks. proc: Generalize proc inode allocation userns: Allow unprivilged mounts of proc and sysfs userns: For /proc/self/{uid,gid}_map derive the lower userns from the struct file procfs: Print task uids and gids in the userns that opened the proc file userns: Implement unshare of the user namespace userns: Implent proc namespace operations userns: Kill task_user_ns userns: Make create_new_namespaces take a user_ns parameter userns: Allow unprivileged use of setns. userns: Allow unprivileged users to create new namespaces userns: Allow setting a userns mapping to your current uid. userns: Allow chown and setgid preservation userns: Allow unprivileged users to create user namespaces. userns: Ignore suid and sgid on binaries if the uid or gid can not be mapped userns: fix return value on mntns_install() failure vfs: Allow unprivileged manipulation of the mount namespace. vfs: Only support slave subtrees across different user namespaces vfs: Add a user namespace reference from struct mnt_namespace ...
| * pidns: Use task_active_pid_ns where appropriateEric W. Biederman2012-11-191-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The expressions tsk->nsproxy->pid_ns and task_active_pid_ns aka ns_of_pid(task_pid(tsk)) should have the same number of cache line misses with the practical difference that ns_of_pid(task_pid(tsk)) is released later in a processes life. Furthermore by using task_active_pid_ns it becomes trivial to write an unshare implementation for the the pid namespace. So I have used task_active_pid_ns everywhere I can. In fork since the pid has not yet been attached to the process I use ns_of_pid, to achieve the same effect. Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
* | cgroup_rm_file: don't delete the uncreated filesGao feng2012-12-061-6/+6
| | | | | | | | | | | | | | | | | | | | | | | | | | | | in cgroup_add_file,when creating files for cgroup, some of creation may be skipped. So we need to avoid deleting these uncreated files in cgroup_rm_file, otherwise the warning msg will be triggered. "cgroup_addrm_files: failed to remove memory_pressure_enabled, err=-2" Signed-off-by: Gao feng <gaofeng@cn.fujitsu.com> Acked-by: Li Zefan <lizefan@huawei.com> Signed-off-by: Tejun Heo <tj@redhat.com> Cc: stable@vger.kernel.org
* | cgroup: remove subsystem files when remounting cgroupGao feng2012-12-031-2/+9
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | cgroup_clear_directroy is called by cgroup_d_remove_dir and cgroup_remount. when we call cgroup_remount to remount the cgroup,the subsystem may be unlinked from cgroupfs_root->subsys_list in rebind_subsystem,this subsystem's files will not be removed in cgroup_clear_directroy. And the system will panic when we try to access these files. this patch removes subsystems's files before rebind_subsystems, if rebind_subsystems failed, repopulate these removed files. With help from Tejun. Signed-off-by: Gao feng <gaofeng@cn.fujitsu.com> Signed-off-by: Tejun Heo <tj@kernel.org>
* | cgroup: use cgroup_addrm_files() in cgroup_clear_directory()Gao feng2012-11-301-1/+3
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | cgroup_clear_directory() incorrectly invokes cgroup_rm_file() on each cftset of the target subsystems, which only removes the first file of each set. This leaves dangling files after subsystems are removed from a cgroup root via remount. Use cgroup_addrm_files() to remove all files of target subsystems. tj: Move cgroup_addrm_files() prototype decl upwards next to other global declarations. Commit message updated. Signed-off-by: Gao feng <gaofeng@cn.fujitsu.com> Signed-off-by: Tejun Heo <tj@kernel.org>
* | cgroup: warn about broken hierarchies only after css_onlineGlauber Costa2012-11-301-9/+9
| | | | | | | | | | | | | | | | | | | | | | | | | | If everything goes right, it shouldn't really matter if we are spitting this warning after css_alloc or css_online. If we fail between then, there are some ill cases where we would previously see the message and now we won't (like if the files fail to be created). I believe it really shouldn't matter: this message is intended in spirit to be shown when creation succeeds, but with insane settings. Signed-off-by: Glauber Costa <glommer@parallels.com> Signed-off-by: Tejun Heo <tj@kernel.org>
* | cgroup: list_del_init() on removed eventsGreg Thelen2012-11-281-2/+2
| | | | | | | | | | | | | | | | | | Use list_del_init() rather than list_del() to remove events from cgrp->event_list. No functional change. This is just defensive coding. Signed-off-by: Greg Thelen <gthelen@google.com> Signed-off-by: Tejun Heo <tj@kernel.org>
* | cgroup: fix lockdep warning for event_controlGreg Thelen2012-11-281-3/+8
| | | | | | | | | | | | | | | | | | | | | | | | The cgroup_event_wake() function is called with the wait queue head locked and it takes cgrp->event_list_lock. However, in cgroup_rmdir() remove_wait_queue() was being called after taking cgrp->event_list_lock. Correct the lock ordering by using a temporary list to obtain the event list to remove from the wait queue. Signed-off-by: Greg Thelen <gthelen@google.com> Signed-off-by: Aaron Durbin <adurbin@google.com> Signed-off-by: Tejun Heo <tj@kernel.org>
* | cgroup: move list add after list head initilizationLi Zhong2012-11-281-1/+1
| | | | | | | | | | | | | | | | | | | | | | 2243076ad1 ("cgroup: initialize cgrp->allcg_node in init_cgroup_housekeeping()") initializes cgrp->allcg_node in init_cgroup_housekeeping(). Then in init_cgroup_root(), we should call init_cgroup_housekeeping() before adding it to &root->allcg_list; otherwise, we are initializing an entry already in a list. Signed-off-by: Li Zhong <zhong@linux.vnet.ibm.com> Signed-off-by: Tejun Heo <tj@kernel.org>
* | cgroup: remove obsolete guarantee from cgroup_task_migrate.Tao Ma2012-11-201-5/+3
| | | | | | | | | | | | | | | | | | | | | | 'guarantee' is already removed from cgroup_task_migrate, so remove the corresponding comments. Some other typos in cgroup are also changed. Cc: Tejun Heo <tj@kernel.org> Cc: Li Zefan <lizefan@huawei.com> Signed-off-by: Tao Ma <boyu.mt@taobao.com> Signed-off-by: Tejun Heo <tj@kernel.org>
* | cgroup: add cgroup->idTejun Heo2012-11-191-1/+14
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | With the introduction of generic cgroup hierarchy iterators, css_id is being phased out. It was unnecessarily complex, id'ing the wrong thing (cgroups need IDs, not CSSes) and has other oddities like not being available at ->css_alloc(). This patch adds cgroup->id, which is a simple per-hierarchy ida-allocated ID which is assigned before ->css_alloc() and released after ->css_free(). Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Li Zefan <lizefan@huawei.com> Acked-by: Neil Horman <nhorman@tuxdriver.com>
* | cgroup, cpuset: remove cgroup_subsys->post_clone()Tejun Heo2012-11-191-4/+0
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Currently CGRP_CPUSET_CLONE_CHILDREN triggers ->post_clone(). Now that clone_children is cpuset specific, there's no reason to have this rather odd option activation mechanism in cgroup core. cpuset can check the flag from its ->css_allocate() and take the necessary action. Move cpuset_post_clone() logic to the end of cpuset_css_alloc() and remove cgroup_subsys->post_clone(). Loosely based on Glauber's "generalize post_clone into post_create" patch. Signed-off-by: Tejun Heo <tj@kernel.org> Original-patch-by: Glauber Costa <glommer@parallels.com> Original-patch: <1351686554-22592-2-git-send-email-glommer@parallels.com> Acked-by: Serge E. Hallyn <serge.hallyn@ubuntu.com> Acked-by: Li Zefan <lizefan@huawei.com> Cc: Glauber Costa <glommer@parallels.com>
* | cgroup: s/CGRP_CLONE_CHILDREN/CGRP_CPUSET_CLONE_CHILDREN/Tejun Heo2012-11-191-16/+12
| | | | | | | | | | | | | | | | | | | | | | | | clone_children is only meaningful for cpuset and will stay that way. Rename the flag to reflect that and update documentation. Also, drop clone_children() wrapper in cgroup.c. The thin wrapper is used only a few times and one of them will go away soon. Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Serge E. Hallyn <serge.hallyn@ubuntu.com> Acked-by: Li Zefan <lizefan@huawei.com> Cc: Glauber Costa <glommer@parallels.com>
* | cgroup: rename ->create/post_create/pre_destroy/destroy() to ↵Tejun Heo2012-11-191-25/+26
| | | | | | | | | | | | | | | | | | | | ->css_alloc/online/offline/free() Rename cgroup_subsys css lifetime related callbacks to better describe what their roles are. Also, update documentation. Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Li Zefan <lizefan@huawei.com>
* | cgroup: allow ->post_create() to failTejun Heo2012-11-191-10/+19
| | | | | | | | | | | | | | | | | | | | | | There could be cases where controllers want to do initialization operations which may fail from ->post_create(). This patch makes ->post_create() return -errno to indicate failure and online_css() relay such failures. Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Li Zefan <lizefan@huawei.com> Cc: Glauber Costa <glommer@parallels.com>
* | cgroup: update cgroup_create() failure pathTejun Heo2012-11-191-7/+14
| | | | | | | | | | | | | | | | | | | | | | | | cgroup_create() was ignoring failure of cgroupfs files. Update it such that, if file creation fails, it rolls back by calling cgroup_destroy_locked() and returns failure. Note that error out goto labels are renamed. The labels are a bit confusing but will become better w/ later cgroup operation renames. Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Li Zefan <lizefan@huawei.com>
* | cgroup: use mutex_trylock() when grabbing i_mutex of a new cgroup directoryTejun Heo2012-11-191-3/+9
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | All cgroup directory i_mutexes nest outside cgroup_mutex; however, new directory creation is a special case. A new cgroup directory is created while holding cgroup_mutex. Populating the new directory requires both the new directory's i_mutex and cgroup_mutex. Because all directory i_mutexes nest outside cgroup_mutex, grabbing both requires releasing cgroup_mutex first, which isn't a good idea as the new cgroup isn't yet ready to be manipulated by other cgroup opreations. This is worked around by grabbing the new directory's i_mutex while holding cgroup_mutex before making it visible. As there's no other user at that point, grabbing the i_mutex under cgroup_mutex can't lead to deadlock. cgroup_create_file() was using I_MUTEX_CHILD to tell lockdep not to worry about the reverse locking order; however, this creates pseudo locking dependency cgroup_mutex -> I_MUTEX_CHILD, which isn't true - all directory i_mutexes are still nested outside cgroup_mutex. This pseudo locking dependency can lead to spurious lockdep warnings. Use mutex_trylock() instead. This will always succeed and lockdep doesn't create any locking dependency for it. Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Li Zefan <lizefan@huawei.com>
* | cgroup: simplify cgroup_load_subsys() failure pathTejun Heo2012-11-191-11/+10
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Now that cgroup_unload_subsys() can tell whether the root css is online or not, we can safely call cgroup_unload_subsys() after idr init failure in cgroup_load_subsys(). Replace the manual unrolling and invoke cgroup_unload_subsys() on failure. This drops cgroup_mutex inbetween but should be safe as the subsystem will fail try_module_get() and thus can't be mounted inbetween. As this means that cgroup_unload_subsys() can be called before css_sets are rehashed, remove BUG_ON() on %NULL css_set->subsys[] from cgroup_unload_subsys(). Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Li Zefan <lizefan@huawei.com>
* | cgroup: introduce CSS_ONLINE flag and on/offline_css() helpersTejun Heo2012-11-191-23/+42
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | New helpers on/offline_css() respectively wrap ->post_create() and ->pre_destroy() invocations. online_css() sets CSS_ONLINE after ->post_create() is complete and offline_css() invokes ->pre_destroy() iff CSS_ONLINE is set and clears it while also handling the temporary dropping of cgroup_mutex. This patch doesn't introduce any behavior change at the moment but will be used to improve cgroup_create() failure path and allow ->post_create() to fail. Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Li Zefan <lizefan@huawei.com>
* | cgroup: separate out cgroup_destroy_locked()Tejun Heo2012-11-191-15/+25
| | | | | | | | | | | | | | | | | | | | | | | | | | Separate out cgroup_destroy_locked() from cgroup_destroy(). This will be later used in cgroup_create() failure path. While at it, add lockdep asserts on i_mutex and cgroup_mutex, and move @d and @parent assignments to their declarations. This patch doesn't introduce any functional difference. Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Li Zefan <lizefan@huawei.com>
* | cgroup: fix harmless bugs in cgroup_load_subsys() fail path and ↵Tejun Heo2012-11-191-1/+14
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | cgroup_unload_subsys() * If idr init fails, cgroup_load_subsys() cleared dummytop->subsys[] before calilng ->destroy() making CSS inaccessible to the callback, and didn't unlink ss->sibling. As no modular controller uses ->use_id, this doesn't cause any actual problems. * cgroup_unload_subsys() was forgetting to free idr, call ->pre_destroy() and clear ->active. As there currently is no modular controller which uses ->use_id, ->pre_destroy() or ->active, this doesn't cause any actual problems. Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Li Zefan <lizefan@huawei.com>