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| * | | | | | | | | | ftrace: Remove boolean of hash_enable and hash_disableSteven Rostedt (Red Hat)2014-05-141-6/+3
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Commit 4104d326b670 "ftrace: Remove global function list and call function directly" cleaned up the global_ops filtering and made the code simpler, but it left a variable "hash_enable" that was used to know if the hash functions should be updated or not. It was updated if the global_ops did not override them. As the global_ops are now no different than any other ftrace_ops, the hash always gets updated and there's no reason to use the hash_enable boolean. The same goes for hash_disable used in ftrace_shutdown(). Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
| * | | | | | | | | | tracing: Replace __get_cpu_var uses with this_cpu_ptrChristoph Lameter2014-05-062-3/+3
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Replace uses of &__get_cpu_var for address calculation with this_cpu_ptr. Link: http://lkml.kernel.org/p/alpine.DEB.2.10.1404291415560.18364@gentwo.org Acked-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com> Signed-off-by: Christoph Lameter <cl@linux.com> Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
| * | | | | | | | | | ftrace: Have function graph tracer use global_ops for filteringSteven Rostedt (Red Hat)2014-05-021-8/+6
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Commit 4104d326b670 "ftrace: Remove global function list and call function directly" cleaned up the global_ops filtering and made the code simpler. But it left out function graph filtering which also depended on that code. The function graph filtering still needs to use global_ops as the filter otherwise it wont filter at all. Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
| * | | | | | | | | | tracing: Remove mock up poll wait functionSteven Rostedt (Red Hat)2014-04-306-34/+4
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Now that the ring buffer has a built in way to wake up readers when there's data, using irq_work such that it is safe to do it in any context. But it was still using the old "poor man's" wait polling that checks every 1/10 of a second to see if it should wake up a waiter. This makes the latency for a wake up excruciatingly long. No need to do that anymore. Completely remove the different wait_poll types from the tracers and have them all use the default one now. Reported-by: Johannes Berg <johannes@sipsolutions.net> Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
| * | | | | | | | | | tracing: Break out of tracing_wait_pipe() before wait_pipe() is calledSteven Rostedt (Red Hat)2014-04-291-9/+9
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | When reading from trace_pipe, if tracing is off but nothing was read it should block. If something is read and tracing is off, then EOF is returned. If tracing is on and there's nothing to read, it will block. But because the check of whether tracing is off and something was read is done after the block on the pipe, it is hit or miss if the EOF is returned or not leading to inconsistent behavior. Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
| * | | | | | | | | | tracing: Fix documentation of ftrace_set_global_{filter,notrace}()Jiaxing Wang2014-04-241-4/+2
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The functions ftrace_set_global_filter() and ftrace_set_global_notrace() still have their old names in the kernel doc (ftrace_set_filter and ftrace_set_notrace respectively). Replace these with the real names. Link: http://lkml.kernel.org/p/1398006644-5935-3-git-send-email-wangjiaxing@insigma.com.cn Signed-off-by: Jiaxing Wang <wangjiaxing@insigma.com.cn> Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
| * | | | | | | | | | tracing/stack_trace: Skip 4 instead of 3 when using ftrace_ops_list_funcJiaxing Wang2014-04-243-2/+12
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | When using ftrace_ops_list_func, we should skip 4 instead of 3, to avoid ftrace_call+0x5/0xb appearing in the stack trace: Depth Size Location (110 entries) ----- ---- -------- 0) 2956 0 update_curr+0xe/0x1e0 1) 2956 68 ftrace_call+0x5/0xb 2) 2888 92 enqueue_entity+0x53/0xe80 3) 2796 80 enqueue_task_fair+0x47/0x7e0 4) 2716 28 enqueue_task+0x45/0x70 5) 2688 12 activate_task+0x22/0x30 Add a function using_ftrace_ops_list_func() to test for this while keeping ftrace_ops_list_func to remain static. Link: http://lkml.kernel.org/p/1398006644-5935-2-git-send-email-wangjiaxing@insigma.com.cn Signed-off-by: Jiaxing Wang <wangjiaxing@insigma.com.cn> Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
| * | | | | | | | | | tracing: Add static to local functionsFabian Frederick2014-04-212-5/+5
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | This patch adds static to the following functions: -cycle_t buffer_ftrace_now -void free_snapshot -int trace_selftest_startup_dynamic_tracing Link: http://lkml.kernel.org/p/20140417214442.d7abc7c0b0e4b90e7fedecc9@skynet.be Signed-off-by: Fabian Frederick <fabf@skynet.be> Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
| * | | | | | | | | | ftrace: Statically initialize pm notifier blockMathias Krause2014-04-211-2/+4
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Instead of initializing the pm notifier block in register_ftrace_graph(), initialize it statically. This safes us some code. Found in the PaX patch, written by the PaX Team. Link: http://lkml.kernel.org/p/1396186310-3156-1-git-send-email-minipli@googlemail.com Cc: Frederic Weisbecker <fweisbec@gmail.com> Cc: Ingo Molnar <mingo@redhat.com> Cc: PaX Team <pageexec@freemail.hu> Signed-off-by: Mathias Krause <minipli@googlemail.com> Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
| * | | | | | | | | | tracing: Allow irq/preempt tracers to be used by instancesSteven Rostedt (Red Hat)2014-04-211-7/+17
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The irqsoff, preemptoff and preemptirqsoff tracers can now be used by instances. But they may only be used by one instance at a time (including the top level directory). This allows multiple tracers to run while the irqsoff (and friends) tracer is running simultaneously. Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
| * | | | | | | | | | tracing: Allow wakeup tracers to be used by instancesSteven Rostedt (Red Hat)2014-04-211-0/+16
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The wakeup and wakeup_rt tracers can now be used by instances. But they may only be used by one instance at a time (including the top level directory). This allows multiple tracers to run while the wakeup tracer is running simultaneously. Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
| * | | | | | | | | | tracing: Move ftrace_max_lock into trace_arraySteven Rostedt (Red Hat)2014-04-213-28/+30
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | In preparation for having tracers enabled in instances, the max_lock should be unique as updating the max for one tracer is a separate operation than updating it for another tracer using a different max. Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
| * | | | | | | | | | tracing: Move tracing_max_latency into trace_arraySteven Rostedt (Red Hat)2014-04-215-36/+33
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | In preparation for letting the latency tracers be used by instances, remove the global tracing_max_latency variable and add a max_latency field to the trace_array that the latency tracers will now use. Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
| * | | | | | | | | | ftrace: Remove global function list and call function directlySteven Rostedt (Red Hat)2014-04-217-209/+125
| | |_|_|_|/ / / / / | |/| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Instead of having a list of global functions that are called, as only one global function is allow to be enabled at a time, there's no reason to have a list. Instead, simply have all the users of the global ops, use the global ops directly, instead of registering their own ftrace_ops. Just switch what function is used before enabling the function tracer. This removes a lot of code as well as the complexity involved with it. Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
* | | | | | | | | | Merge branch 'for-3.16' of ↵Linus Torvalds2014-06-106-684/+1220
|\ \ \ \ \ \ \ \ \ \ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup Pull cgroup updates from Tejun Heo: "A lot of activities on cgroup side. Heavy restructuring including locking simplification took place to improve the code base and enable implementation of the unified hierarchy, which currently exists behind a __DEVEL__ mount option. The core support is mostly complete but individual controllers need further work. To explain the design and rationales of the the unified hierarchy Documentation/cgroups/unified-hierarchy.txt is added. Another notable change is css (cgroup_subsys_state - what each controller uses to identify and interact with a cgroup) iteration update. This is part of continuing updates on css object lifetime and visibility. cgroup started with reference count draining on removal way back and is now reaching a point where csses behave and are iterated like normal refcnted objects albeit with some complexities to allow distinguishing the state where they're being deleted. The css iteration update isn't taken advantage of yet but is planned to be used to simplify memcg significantly" * 'for-3.16' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup: (77 commits) cgroup: disallow disabled controllers on the default hierarchy cgroup: don't destroy the default root cgroup: disallow debug controller on the default hierarchy cgroup: clean up MAINTAINERS entries cgroup: implement css_tryget() device_cgroup: use css_has_online_children() instead of has_children() cgroup: convert cgroup_has_live_children() into css_has_online_children() cgroup: use CSS_ONLINE instead of CGRP_DEAD cgroup: iterate cgroup_subsys_states directly cgroup: introduce CSS_RELEASED and reduce css iteration fallback window cgroup: move cgroup->serial_nr into cgroup_subsys_state cgroup: link all cgroup_subsys_states in their sibling lists cgroup: move cgroup->sibling and ->children into cgroup_subsys_state cgroup: remove cgroup->parent device_cgroup: remove direct access to cgroup->children memcg: update memcg_has_children() to use css_next_child() memcg: remove tasks/children test from mem_cgroup_force_empty() cgroup: remove css_parent() cgroup: skip refcnting on normal root csses and cgrp_dfl_root self css cgroup: use cgroup->self.refcnt for cgroup refcnting ...
| * | | | | | | | | | cgroup: disallow disabled controllers on the default hierarchyLi Zefan2014-06-051-5/+9
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | After booting with cgroup_disable=memory, I still saw memcg files in the default hierarchy, and I can write to them, though it won't take effect. # dmesg ... Disabling memory control group subsystem ... # mount -t cgroup -o __DEVEL__sane_behavior xxx /cgroup # ls /cgroup ... memory.failcnt memory.move_charge_at_immigrate memory.force_empty memory.numa_stat memory.limit_in_bytes memory.oom_control ... # cat /cgroup/memory.usage_in_bytes 0 tj: Minor comment update. Signed-off-by: Li Zefan <lizefan@huawei.com> Signed-off-by: Tejun Heo <tj@kernel.org>
| * | | | | | | | | | cgroup: don't destroy the default rootLi Zefan2014-06-051-1/+4
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The default root is allocated and initialized at boot phase, so we shouldn't destroy the default root when it's umounted, otherwise it will lead to disaster. Just try mount and then umount the default root, and the kernel will crash immediately. v2: - No need to check for CSS_NO_REF in cgroup_get/put(). (Tejun) - Better call cgroup_put() for the default root in kill_sb(). (Tejun) - Add a comment. Signed-off-by: Li Zefan <lizefan@huawei.com> Signed-off-by: Tejun Heo <tj@kernel.org>
| * | | | | | | | | | cgroup: disallow debug controller on the default hierarchyTejun Heo2014-05-191-3/+18
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The debug controller, as its name suggests, exposes cgroup core internals to userland to aid debugging. Unfortunately, except for the name, there's no provision to prevent its usage in production configurations and the controller is widely enabled and mounted leaking internal details to userland. Like most other debug information, the information exposed by debug isn't interesting even for debugging itself once the related parts are working reliably. This controller has no reason for existing. This patch implements cgrp_dfl_root_inhibit_ss_mask which can suppress specific subsystems on the default hierarchy and adds the debug subsystem to it so that it can be gradually deprecated as usages move towards the unified hierarchy. Signed-off-by: Tejun Heo <tj@kernel.org>
| * | | | | | | | | | cgroup: convert cgroup_has_live_children() into css_has_online_children()Tejun Heo2014-05-161-12/+20
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Now that cgroup liveliness and css onliness are the same state, convert cgroup_has_live_children() into css_has_online_children() so that it can be used for actual csses too. The function now uses css_for_each_child() for iteration and is published. Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Li Zefan <lizefan@huawei.com>
| * | | | | | | | | | cgroup: use CSS_ONLINE instead of CGRP_DEADTejun Heo2014-05-161-3/+4
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Use CSS_ONLINE on the self css to indicate whether a cgroup has been killed instead of CGRP_DEAD. This will allow re-using css online test for cgroup liveliness test. This doesn't introduce any functional change. Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Li Zefan <lizefan@huawei.com>
| * | | | | | | | | | cgroup: iterate cgroup_subsys_states directlyTejun Heo2014-05-161-25/+37
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Currently, css_next_child() is implemented as finding the next child cgroup which has the css enabled, which used to be the only way to do it as only cgroups participated in sibling lists and thus could be iteratd. This works as long as what's required during iteration is not missing online csses; however, it turns out that there are use cases where offlined but not yet released csses need to be iterated. This is difficult to implement through cgroup iteration the unified hierarchy as there may be multiple dying csses for the same subsystem associated with single cgroup. After the recent changes, the cgroup self and regular csses behave identically in how they're linked and unlinked from the sibling lists including assertion of CSS_RELEASED and css_next_child() can simply switch to iterating csses directly. This both simplifies the logic and ensures that all visible non-released csses are included in the iteration whether there are multiple dying csses for a subsystem or not. As all other iterators depend on css_next_child() for sibling iteration, this changes behaviors of all css iterators. Add and update explanations on the css states which are included in traversal to all iterators. As css iteration could always contain offlined csses, this shouldn't break any of the current users and new usages which need iteration of all on and offline csses can make use of the new semantics. Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Li Zefan <lizefan@huawei.com> Cc: Johannes Weiner <hannes@cmpxchg.org>
| * | | | | | | | | | cgroup: introduce CSS_RELEASED and reduce css iteration fallback windowTejun Heo2014-05-161-21/+20
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | css iterations allow the caller to drop RCU read lock. As long as the caller keeps the current position accessible, it can simply re-grab RCU read lock later and continue iteration. This is achieved by using CGRP_DEAD to detect whether the current positions next pointer is safe to dereference and if not re-iterate from the beginning to the next position using ->serial_nr. CGRP_DEAD is used as the marker to invalidate the next pointer and the only requirement is that the marker is set before the next sibling starts its RCU grace period. Because CGRP_DEAD is set at the end of cgroup_destroy_locked() but the cgroup is unlinked when the reference count reaches zero, we currently have a rather large window where this fallback re-iteration logic can be triggered. This patch introduces CSS_RELEASED which is set when a css is unlinked from its sibling list. This still keeps the re-iteration logic working while drastically reducing the window of its activation. While at it, rewrite the comment in css_next_child() to reflect the new flag and better explain the synchronization. This will also enable iterating csses directly instead of through cgroups. v2: CSS_RELEASED now assigned to 1 << 2 as 1 << 0 is used by CSS_NO_REF. Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Li Zefan <lizefan@huawei.com>
| * | | | | | | | | | cgroup: move cgroup->serial_nr into cgroup_subsys_stateTejun Heo2014-05-161-9/+11
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | We're moving towards using cgroup_subsys_states as the fundamental structural blocks. All csses including the cgroup->self and actual ones now form trees through css->children and ->sibling which follow the same rules as what cgroup->children and ->sibling followed. This patch moves cgroup->serial_nr which is used to implement css iteration into css. Note that all csses, regardless of their types, allocate their serial numbers from the same monotonically increasing counter. This doesn't affect the ordering needed by css iteration or cause any other material behavior changes. This will be used to update css iteration. Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Li Zefan <lizefan@huawei.com>
| * | | | | | | | | | cgroup: link all cgroup_subsys_states in their sibling listsTejun Heo2014-05-161-7/+12
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Currently, while all csses have ->children and ->sibling, only the self csses of cgroups make use of them. This patch makes all other csses to link themselves on the sibling lists too. This will be used to update css iteration. Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Li Zefan <lizefan@huawei.com>
| * | | | | | | | | | cgroup: move cgroup->sibling and ->children into cgroup_subsys_stateTejun Heo2014-05-161-18/+20
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | We're moving towards using cgroup_subsys_states as the fundamental structural blocks. Let's move cgroup->sibling and ->children into cgroup_subsys_state. This is pure move without functional change and only cgroup->self's fields are actually used. Other csses will make use of the fields later. While at it, update init_and_link_css() so that it zeroes the whole css before initializing it and remove explicit zeroing of ->flags. Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Li Zefan <lizefan@huawei.com>
| * | | | | | | | | | cgroup: remove cgroup->parentTejun Heo2014-05-161-22/+30
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | cgroup->parent is redundant as cgroup->self.parent can also be used to determine the parent cgroup and we're moving towards using cgroup_subsys_states as the fundamental structural blocks. This patch introduces cgroup_parent() which follows cgroup->self.parent and removes cgroup->parent. Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Li Zefan <lizefan@huawei.com>
| * | | | | | | | | | cgroup: remove css_parent()Tejun Heo2014-05-165-8/+8
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | cgroup in general is moving towards using cgroup_subsys_state as the fundamental structural component and css_parent() was introduced to convert from using cgroup->parent to css->parent. It was quite some time ago and we're moving forward with making css more prominent. This patch drops the trivial wrapper css_parent() and let the users dereference css->parent. While at it, explicitly mark fields of css which are public and immutable. v2: New usage from device_cgroup.c converted. Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Michal Hocko <mhocko@suse.cz> Acked-by: Neil Horman <nhorman@tuxdriver.com> Acked-by: "David S. Miller" <davem@davemloft.net> Acked-by: Li Zefan <lizefan@huawei.com> Cc: Vivek Goyal <vgoyal@redhat.com> Cc: Jens Axboe <axboe@kernel.dk> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Johannes Weiner <hannes@cmpxchg.org>
| * | | | | | | | | | cgroup: skip refcnting on normal root csses and cgrp_dfl_root self cssTejun Heo2014-05-161-2/+9
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | 9395a4500404 ("cgroup: enable refcnting for root csses") enabled reference counting for root csses (cgroup_subsys_states) so that cgroup's self csses can be used to manage the lifetime of the containing cgroups. Unfortunately, this change was incorrect. During early init, cgrp_dfl_root self css refcnt is used. percpu_ref can't initialized during early init and its initialization is deferred till cgroup_init() time. This means that cpu was using percpu_ref which wasn't properly initialized. Due to the way percpu variables are laid out on x86, this didn't blow up immediately on x86 but ended up incrementing and decrementing the percpu variable at offset zero, whatever it may be; however, on other archs, this caused fault and early boot failure. As cgroup self csses for root cgroups of non-dfl hierarchies need working refcounting, we can't revert 9395a4500404. This patch adds CSS_NO_REF which explicitly inhibits reference counting on the css and sets it on all normal (non-self) csses and cgroup_dfl_root self css. v2: cgrp_dfl_root.self is the offending one. Set the flag on it. Signed-off-by: Tejun Heo <tj@kernel.org> Reported-by: Stephen Warren <swarren@nvidia.com> Tested-by: Stephen Warren <swarren@nvidia.com> Fixes: 9395a4500404 ("cgroup: enable refcnting for root csses")
| * | | | | | | | | | cgroup: use cgroup->self.refcnt for cgroup refcntingTejun Heo2014-05-141-66/+80
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Currently cgroup implements refcnting separately using atomic_t cgroup->refcnt. The destruction paths of cgroup and css are rather complex and bear a lot of similiarities including the use of RCU and bouncing to a work item. This patch makes cgroup use the refcnt of self css for refcnting instead of using its own. This makes cgroup refcnting use css's percpu refcnt and share the destruction mechanism. * css_release_work_fn() and css_free_work_fn() are updated to handle both csses and cgroups. This is a bit messy but should do until we can make cgroup->self a full css, which currently can't be done thanks to multiple hierarchies. * cgroup_destroy_locked() now performs percpu_ref_kill(&cgrp->self.refcnt) instead of cgroup_put(cgrp). * Negative refcnt sanity check in cgroup_get() is no longer necessary as percpu_ref already handles it. * Similarly, as a cgroup which hasn't been killed will never be released regardless of its refcnt value and percpu_ref has sanity check on kill, cgroup_is_dead() sanity check in cgroup_put() is no longer necessary. * As whether a refcnt reached zero or not can only be decided after the reference count is killed, cgroup_root->cgrp's refcnting can no longer be used to decide whether to kill the root or not. Let's make cgroup_kill_sb() explicitly initiate destruction if the root doesn't have any children. This makes sense anyway as unmounted cgroup hierarchy without any children should be destroyed. While this is a bit messy, this will allow pushing more bookkeeping towards cgroup->self and thus handling cgroups and csses in more uniform way. In the very long term, it should be possible to introduce a base subsystem and convert the self css to a proper one making things whole lot simpler and unified. Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Li Zefan <lizefan@huawei.com>
| * | | | | | | | | | cgroup: enable refcnting for root cssesTejun Heo2014-05-141-3/+3
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Currently, css_get(), css_tryget() and css_tryget_online() are noops for root csses as an optimization; however, we're planning to use css refcnts to track of cgroup lifetime too and root cgroups also need to be reference counted. Since css has been converted to percpu_refcnt, the overhead of refcnting is miniscule and this optimization isn't too meaningful anymore. Furthermore, controllers which optimize the root cgroup often never even invoke these functions in their hot paths. This patch enables refcnting for root csses too. This makes CSS_ROOT flag unused and removes it. Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Li Zefan <lizefan@huawei.com>
| * | | | | | | | | | cgroup: bounce css release through css->destroy_workTejun Heo2014-05-141-2/+11
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | css release is planned to do more and would require process context. Bounce it through css->destroy_work. Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Li Zefan <lizefan@huawei.com>
| * | | | | | | | | | cgroup: remove cgroup_destory_css_killed()Tejun Heo2014-05-141-56/+6
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | cgroup_destroy_css_killed() is cgroup destruction stage which happens after all csses are offlined. After the recent updates, it no longer does anything other than putting the base reference. This patch removes the function and makes cgroup_destroy_locked() put the base ref at the end isntead. This also makes cgroup->nr_css unnecessary. Removed. Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Li Zefan <lizefan@huawei.com>
| * | | | | | | | | | cgroup: move cgroup->sibling unlinking to cgroup_put()Tejun Heo2014-05-141-3/+5
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Move cgroup->sibling unlinking from cgroup_destroy_css_killed() to cgroup_put(). This is later but still before the RCU grace period, so it doesn't break css_next_child() although there now is a larger window in which a dead cgroup is visible during css iteration. As css iteration always could have included offline csses, this doesn't affect correctness; however, it does make css_next_child() fall back to reiterting mode more often. This also makes cgroup_put() directly take cgroup_mutex, which limits where it can be called from. These are not immediately problematic and will be dealt with later. This change enables simplification of cgroup destruction path. Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Li Zefan <lizefan@huawei.com>
| * | | | | | | | | | cgroup: move check_for_release(parent) call to the end of ↵Tejun Heo2014-05-141-6/+4
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | cgroup_destroy_locked() Currently, check_for_release() on the parent of a destroyed cgroup is invoked from cgroup_destroy_css_killed(). This is because this is where the destroyed cgroup can be removed from the parent's children list. check_for_release() tests the emptiness of the list directly, so invoking it before removing the cgroup from the list makes it think that the parent still has children even when it no longer does. This patch updates check_for_release() to use cgroup_has_live_children() instead of directly testing ->children emptiness and moves check_for_release(parent) earlier to the end of cgroup_destroy_locked(). As cgroup_has_live_children() ignores cgroups marked DEAD, check_for_release() functions correctly as long as it's called after asserting DEAD. This makes release notification slightly more timely and more importantly enables further simplification of cgroup destruction path. Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Li Zefan <lizefan@huawei.com>
| * | | | | | | | | | cgroup: separate out cgroup_has_live_children() from cgroup_destroy_locked()Tejun Heo2014-05-141-10/+16
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | We're expecting another user. Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Li Zefan <lizefan@huawei.com>
| * | | | | | | | | | cgroup: rename cgroup->dummy_css to ->self and move it to the topTejun Heo2014-05-141-10/+10
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | cgroup->dummy_css is used as the placeholder css when performing css oriended operations on the cgroup. We're gonna shift more cgroup management to this css. Let's rename it to ->self and move it to the top. This is pure rename and field relocation. Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Li Zefan <lizefan@huawei.com>
| * | | | | | | | | | cgroup: use restart_syscall() for mount retriesTejun Heo2014-05-141-4/+4
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | cgroup_mount() uses dumb delay-and-retry logic to wait for cgroup_root which is being destroyed. The retry currently loops inside cgroup_mount() proper. This patch makes it return with restart_syscall() instead so that retry travels out to userland boundary. This slightly simplifies the logic and more importantly makes the retry logic behave better when the wait for some reason becomes lengthy or infinite by allowing the operation to be suspended or terminated from userland. v2: The original patch forgot to free memory allocated for @opts. Fixed. Caught by Li Zefan. Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Li Zefan <lizefan@huawei.com>
| * | | | | | | | | | cgroup: remove cgroup_tree_mutexTejun Heo2014-05-131-55/+9
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | cgroup_tree_mutex was introduced to work around the circular dependency between cgroup_mutex and kernfs active protection - some kernfs file and directory operations needed cgroup_mutex putting cgroup_mutex under active protection but cgroup also needs to be able to access cgroup hierarchies and cftypes to determine which kernfs_nodes need to be removed. cgroup_tree_mutex nested above both cgroup_mutex and kernfs active protection and used to protect the hierarchy and cftypes. While this worked, it added a lot of double lockings and was generally cumbersome. kernfs provides a mechanism to opt out of active protection and cgroup was already using it for removal and subtree_control. There's no reason to mix both methods of avoiding circular locking dependency and the preceding cgroup_kn_lock_live() changes applied it to all relevant cgroup kernfs operations making it unnecessary to nest cgroup_mutex under kernfs active protection. The previous patch reversed the original lock ordering and put cgroup_mutex above kernfs active protection. After these changes, all cgroup_tree_mutex usages are now accompanied by cgroup_mutex making the former completely redundant. This patch removes cgroup_tree_mutex and all its usages. Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Li Zefan <lizefan@huawei.com>
| * | | | | | | | | | cgroup: nest kernfs active protection under cgroup_mutexTejun Heo2014-05-131-11/+16
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | After the recent cgroup_kn_lock_live() changes, cgroup_mutex is no longer nested below kernfs active protection. The two don't have any relationship now. This patch nests kernfs active protection under cgroup_mutex. All cftype operations now require both cgroup_tree_mutex and cgroup_mutex, temporary cgroup_mutex releases over kernfs operations are removed, and cgroup_add/rm_cftypes() grab both mutexes. This makes cgroup_tree_mutex redundant, which will be removed by the next patch. Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Li Zefan <lizefan@huawei.com>
| * | | | | | | | | | cgroup: use cgroup_kn_lock_live() in other cgroup kernfs methodsTejun Heo2014-05-131-27/+12
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Make __cgroup_procs_write() and cgroup_release_agent_write() use cgroup_kn_lock_live() and cgroup_kn_unlock() instead of cgroup_lock_live_group(). This puts the operations under both cgroup_tree_mutex and cgroup_mutex protection without circular dependency from kernfs active protection. Also, this means that cgroup_mutex is no longer nested below kernfs active protection. There is no longer any place where the two locks interact. This leaves cgroup_lock_live_group() without any user. Removed. This will help simplifying cgroup locking. Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Li Zefan <lizefan@huawei.com>
| * | | | | | | | | | cgroup: factor out cgroup_kn_lock_live() and cgroup_kn_unlock()Tejun Heo2014-05-131-67/+90
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | cgroup_mkdir(), cgroup_rmdir() and cgroup_subtree_control_write() share the logic to break active protection so that they can grab cgroup_tree_mutex which nests above active protection and/or remove self. Factor out this logic into cgroup_kn_lock_live() and cgroup_kn_unlock(). This patch doesn't introduce any functional changes. Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Li Zefan <lizefan@huawei.com>
| * | | | | | | | | | cgroup: move cgroup->kn->priv clearing to cgroup_rmdir()Tejun Heo2014-05-131-11/+12
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The ->priv field of a cgroup directory kernfs_node points back to the cgroup. This field is RCU cleared in cgroup_destroy_locked() for non-kernfs accesses from css_tryget_from_dir() and cgroupstats_build(). As these are only applicable to cgroups which finished creation successfully and fully initialized cgroups are always removed by cgroup_rmdir(), this can be safely moved to the end of cgroup_rmdir(). This will help simplifying cgroup locking and shouldn't introduce any behavior difference. Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Li Zefan <lizefan@huawei.com>
| * | | | | | | | | | cgroup: grab cgroup_mutex earlier in cgroup_subtree_control_write()Tejun Heo2014-05-131-8/+8
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Move cgroup_lock_live_group() invocation upwards to right below cgroup_tree_mutex in cgroup_subtree_control_write(). This is to help the planned locking simplification. This doesn't make any userland-visible behavioral changes. Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Li Zefan <lizefan@huawei.com>
| * | | | | | | | | | cgroup: collapse cgroup_create() into croup_mkdir()Tejun Heo2014-05-131-39/+13
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | cgroup_mkdir() is the sole user of cgroup_create(). Let's collapse the latter into the former. This will help simplifying locking. While at it, remove now stale comment about inode locking. This patch doesn't introduce any functional changes. Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Li Zefan <lizefan@huawei.com>
| * | | | | | | | | | cgroup: reorganize cgroup_create()Tejun Heo2014-05-131-35/+34
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Reorganize cgroup_create() so that all paths share unlock out path. * All err_* labels are renamed to out_* as they're now shared by both success and failure paths. * @err renamed to @ret for the similar reason as above and so that it's more consistent with other functions. * cgroup memory allocation moved after locking so that freeing failed cgroup happens before unlocking. While this moves more code inside critical section, memory allocations inside cgroup locking are already pretty common and this is unlikely to make any noticeable difference. * While at it, replace a stray @parent->root dereference with @root. This reorganization will help simplifying locking. Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Li Zefan <lizefan@huawei.com>
| * | | | | | | | | | cgroup: remove cgroup->control_knTejun Heo2014-05-131-5/+3
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Now that cgroup_subtree_control_write() has access to the associated kernfs_open_file and thus the kernfs_node, there's no need to cache it in cgroup->control_kn on creation. Remove cgroup->control_kn and use @of->kn directly. Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Li Zefan <lizefan@huawei.com>
| * | | | | | | | | | cgroup: convert "tasks" and "cgroup.procs" handle to use cftype->write()Tejun Heo2014-05-131-10/+16
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | cgroup_tasks_write() and cgroup_procs_write() are currently using cftype->write_u64(). This patch converts them to use cftype->write() instead. This allows access to the associated kernfs_open_file which will be necessary to implement the planned kernfs active protection manipulation for these files. This shifts buffer parsing to attach_task_by_pid() and makes it return @nbytes on success. Let's rename it to __cgroup_procs_write() to clearly indicate that this is a write handler implementation. This patch doesn't introduce any visible behavior changes. Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Li Zefan <lizefan@huawei.com>
| * | | | | | | | | | cgroup: replace cftype->trigger() with cftype->write()Tejun Heo2014-05-131-4/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | cftype->trigger() is pointless. It's trivial to ignore the input buffer from a regular ->write() operation. Convert all ->trigger() users to ->write() and remove ->trigger(). This patch doesn't introduce any visible behavior changes. Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Li Zefan <lizefan@huawei.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Michal Hocko <mhocko@suse.cz>
| * | | | | | | | | | cgroup: replace cftype->write_string() with cftype->write()Tejun Heo2014-05-133-37/+37
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Convert all cftype->write_string() users to the new cftype->write() which maps directly to kernfs write operation and has full access to kernfs and cgroup contexts. The conversions are mostly mechanical. * @css and @cft are accessed using of_css() and of_cft() accessors respectively instead of being specified as arguments. * Should return @nbytes on success instead of 0. * @buf is not trimmed automatically. Trim if necessary. Note that blkcg and netprio don't need this as the parsers already handle whitespaces. cftype->write_string() has no user left after the conversions and removed. While at it, remove unnecessary local variable @p in cgroup_subtree_control_write() and stale comment about CGROUP_LOCAL_BUFFER_SIZE in cgroup_freezer.c. This patch doesn't introduce any visible behavior changes. v2: netprio was missing from conversion. Converted. Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Aristeu Rozanski <arozansk@redhat.com> Acked-by: Vivek Goyal <vgoyal@redhat.com> Acked-by: Li Zefan <lizefan@huawei.com> Cc: Jens Axboe <axboe@kernel.dk> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Michal Hocko <mhocko@suse.cz> Cc: Neil Horman <nhorman@tuxdriver.com> Cc: "David S. Miller" <davem@davemloft.net>
| * | | | | | | | | | cgroup: implement cftype->write()Tejun Heo2014-05-131-6/+8
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | During the recent conversion to kernfs, cftype's seq_file operations are updated so that they are directly mapped to kernfs operations and thus can fully access the associated kernfs and cgroup contexts; however, write path hasn't seen similar updates and none of the existing write operations has access to, for example, the associated kernfs_open_file. Let's introduce a new operation cftype->write() which maps directly to the kernfs write operation and has access to all the arguments and contexts. This will replace ->write_string() and ->trigger() and ease manipulation of kernfs active protection from cgroup file operations. Two accessors - of_cft() and of_css() - are introduced to enable accessing the associated cgroup context from cftype->write() which only takes kernfs_open_file for the context information. The accessors for seq_file operations - seq_cft() and seq_css() - are rewritten to wrap the of_ accessors. Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Li Zefan <lizefan@huawei.com>