- 02 1月, 2018 1 次提交
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由 Matt Roper 提交于
The cgroup_subsys structure references a documentation file that has been renamed after the v1/v2 split. Since the v2 documentation doesn't currently contain any information on kernel interfaces for controllers, point the user to the v1 docs. Cc: Tejun Heo <tj@kernel.org> Cc: linux-doc@vger.kernel.org Signed-off-by: NMatt Roper <matthew.d.roper@intel.com> Signed-off-by: NTejun Heo <tj@kernel.org>
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- 02 11月, 2017 1 次提交
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由 Greg Kroah-Hartman 提交于
Many source files in the tree are missing licensing information, which makes it harder for compliance tools to determine the correct license. By default all files without license information are under the default license of the kernel, which is GPL version 2. Update the files which contain no license information with the 'GPL-2.0' SPDX license identifier. The SPDX identifier is a legally binding shorthand, which can be used instead of the full boiler plate text. This patch is based on work done by Thomas Gleixner and Kate Stewart and Philippe Ombredanne. How this work was done: Patches were generated and checked against linux-4.14-rc6 for a subset of the use cases: - file had no licensing information it it. - file was a */uapi/* one with no licensing information in it, - file was a */uapi/* one with existing licensing information, Further patches will be generated in subsequent months to fix up cases where non-standard license headers were used, and references to license had to be inferred by heuristics based on keywords. The analysis to determine which SPDX License Identifier to be applied to a file was done in a spreadsheet of side by side results from of the output of two independent scanners (ScanCode & Windriver) producing SPDX tag:value files created by Philippe Ombredanne. Philippe prepared the base worksheet, and did an initial spot review of a few 1000 files. The 4.13 kernel was the starting point of the analysis with 60,537 files assessed. Kate Stewart did a file by file comparison of the scanner results in the spreadsheet to determine which SPDX license identifier(s) to be applied to the file. She confirmed any determination that was not immediately clear with lawyers working with the Linux Foundation. Criteria used to select files for SPDX license identifier tagging was: - Files considered eligible had to be source code files. - Make and config files were included as candidates if they contained >5 lines of source - File already had some variant of a license header in it (even if <5 lines). All documentation files were explicitly excluded. The following heuristics were used to determine which SPDX license identifiers to apply. - when both scanners couldn't find any license traces, file was considered to have no license information in it, and the top level COPYING file license applied. For non */uapi/* files that summary was: SPDX license identifier # files ---------------------------------------------------|------- GPL-2.0 11139 and resulted in the first patch in this series. If that file was a */uapi/* path one, it was "GPL-2.0 WITH Linux-syscall-note" otherwise it was "GPL-2.0". Results of that was: SPDX license identifier # files ---------------------------------------------------|------- GPL-2.0 WITH Linux-syscall-note 930 and resulted in the second patch in this series. - if a file had some form of licensing information in it, and was one of the */uapi/* ones, it was denoted with the Linux-syscall-note if any GPL family license was found in the file or had no licensing in it (per prior point). Results summary: SPDX license identifier # files ---------------------------------------------------|------ GPL-2.0 WITH Linux-syscall-note 270 GPL-2.0+ WITH Linux-syscall-note 169 ((GPL-2.0 WITH Linux-syscall-note) OR BSD-2-Clause) 21 ((GPL-2.0 WITH Linux-syscall-note) OR BSD-3-Clause) 17 LGPL-2.1+ WITH Linux-syscall-note 15 GPL-1.0+ WITH Linux-syscall-note 14 ((GPL-2.0+ WITH Linux-syscall-note) OR BSD-3-Clause) 5 LGPL-2.0+ WITH Linux-syscall-note 4 LGPL-2.1 WITH Linux-syscall-note 3 ((GPL-2.0 WITH Linux-syscall-note) OR MIT) 3 ((GPL-2.0 WITH Linux-syscall-note) AND MIT) 1 and that resulted in the third patch in this series. - when the two scanners agreed on the detected license(s), that became the concluded license(s). - when there was disagreement between the two scanners (one detected a license but the other didn't, or they both detected different licenses) a manual inspection of the file occurred. - In most cases a manual inspection of the information in the file resulted in a clear resolution of the license that should apply (and which scanner probably needed to revisit its heuristics). - When it was not immediately clear, the license identifier was confirmed with lawyers working with the Linux Foundation. - If there was any question as to the appropriate license identifier, the file was flagged for further research and to be revisited later in time. In total, over 70 hours of logged manual review was done on the spreadsheet to determine the SPDX license identifiers to apply to the source files by Kate, Philippe, Thomas and, in some cases, confirmation by lawyers working with the Linux Foundation. Kate also obtained a third independent scan of the 4.13 code base from FOSSology, and compared selected files where the other two scanners disagreed against that SPDX file, to see if there was new insights. The Windriver scanner is based on an older version of FOSSology in part, so they are related. Thomas did random spot checks in about 500 files from the spreadsheets for the uapi headers and agreed with SPDX license identifier in the files he inspected. For the non-uapi files Thomas did random spot checks in about 15000 files. In initial set of patches against 4.14-rc6, 3 files were found to have copy/paste license identifier errors, and have been fixed to reflect the correct identifier. Additionally Philippe spent 10 hours this week doing a detailed manual inspection and review of the 12,461 patched files from the initial patch version early this week with: - a full scancode scan run, collecting the matched texts, detected license ids and scores - reviewing anything where there was a license detected (about 500+ files) to ensure that the applied SPDX license was correct - reviewing anything where there was no detection but the patch license was not GPL-2.0 WITH Linux-syscall-note to ensure that the applied SPDX license was correct This produced a worksheet with 20 files needing minor correction. This worksheet was then exported into 3 different .csv files for the different types of files to be modified. These .csv files were then reviewed by Greg. Thomas wrote a script to parse the csv files and add the proper SPDX tag to the file, in the format that the file expected. This script was further refined by Greg based on the output to detect more types of files automatically and to distinguish between header and source .c files (which need different comment types.) Finally Greg ran the script using the .csv files to generate the patches. Reviewed-by: NKate Stewart <kstewart@linuxfoundation.org> Reviewed-by: NPhilippe Ombredanne <pombredanne@nexb.com> Reviewed-by: NThomas Gleixner <tglx@linutronix.de> Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>
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- 27 10月, 2017 1 次提交
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由 Tejun Heo 提交于
The basic cpu stat is currently shown with "cpu." prefix in cgroup.stat, and the same information is duplicated in cpu.stat when cpu controller is enabled. This is ugly and not very scalable as we want to expand the coverage of stat information which is always available. This patch makes cgroup core always create "cpu.stat" file and show the basic cpu stat there and calls the cpu controller to show the extra stats when enabled. This ensures that the same information isn't presented in multiple places and makes future expansion of basic stats easier. Signed-off-by: NTejun Heo <tj@kernel.org> Acked-by: NPeter Zijlstra (Intel) <peterz@infradead.org>
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- 25 9月, 2017 1 次提交
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由 Tejun Heo 提交于
In cgroup1, while cpuacct isn't actually controlling any resources, it is a separate controller due to combination of two factors - 1. enabling cpu controller has significant side effects, and 2. we have to pick one of the hierarchies to account CPU usages on. cpuacct controller is effectively used to designate a hierarchy to track CPU usages on. cgroup2's unified hierarchy removes the second reason and we can account basic CPU usages by default. While we can use cpuacct for this purpose, both its interface and implementation leave a lot to be desired - it collects and exposes two sources of truth which don't agree with each other and some of the exposed statistics don't make much sense. Also, it propagates all the way up the hierarchy on each accounting event which is unnecessary. This patch adds basic resource accounting mechanism to cgroup2's unified hierarchy and accounts CPU usages using it. * All accountings are done per-cpu and don't propagate immediately. It just bumps the per-cgroup per-cpu counters and links to the parent's updated list if not already on it. * On a read, the per-cpu counters are collected into the global ones and then propagated upwards. Only the per-cpu counters which have changed since the last read are propagated. * CPU usage stats are collected and shown in "cgroup.stat" with "cpu." prefix. Total usage is collected from scheduling events. User/sys breakdown is sourced from tick sampling and adjusted to the usage using cputime_adjust(). This keeps the accounting side hot path O(1) and per-cpu and the read side O(nr_updated_since_last_read). v2: Minor changes and documentation updates as suggested by Waiman and Roman. Signed-off-by: NTejun Heo <tj@kernel.org> Acked-by: NPeter Zijlstra <peterz@infradead.org> Cc: Ingo Molnar <mingo@redhat.com> Cc: Li Zefan <lizefan@huawei.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Waiman Long <longman@redhat.com> Cc: Roman Gushchin <guro@fb.com>
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- 18 8月, 2017 1 次提交
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由 Waiman Long 提交于
A new mount option "cpuset_v2_mode" is added to the v1 cgroupfs filesystem to enable cpuset controller to use v2 behavior in a v1 cgroup. This mount option applies only to cpuset controller and have no effect on other controllers. Signed-off-by: NWaiman Long <longman@redhat.com> Signed-off-by: NTejun Heo <tj@kernel.org>
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- 03 8月, 2017 2 次提交
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由 Roman Gushchin 提交于
Creating cgroup hierearchies of unreasonable size can affect overall system performance. A user might want to limit the size of cgroup hierarchy. This is especially important if a user is delegating some cgroup sub-tree. To address this issue, introduce an ability to control the size of cgroup hierarchy. The cgroup.max.descendants control file allows to set the maximum allowed number of descendant cgroups. The cgroup.max.depth file controls the maximum depth of the cgroup tree. Both are single value r/w files, with "max" default value. The control files exist on each hierarchy level (including root). When a new cgroup is created, we check the total descendants and depth limits on each level, and if none of them are exceeded, a new cgroup is created. Only alive cgroups are counted, removed (dying) cgroups are ignored. Signed-off-by: NRoman Gushchin <guro@fb.com> Suggested-by: NTejun Heo <tj@kernel.org> Signed-off-by: NTejun Heo <tj@kernel.org> Cc: Zefan Li <lizefan@huawei.com> Cc: Waiman Long <longman@redhat.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: kernel-team@fb.com Cc: cgroups@vger.kernel.org Cc: linux-doc@vger.kernel.org Cc: linux-kernel@vger.kernel.org
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由 Roman Gushchin 提交于
Keep track of the number of online and dying descent cgroups. This data will be used later to add an ability to control cgroup hierarchy (limit the depth and the number of descent cgroups) and display hierarchy stats. Signed-off-by: NRoman Gushchin <guro@fb.com> Suggested-by: NTejun Heo <tj@kernel.org> Signed-off-by: NTejun Heo <tj@kernel.org> Cc: Zefan Li <lizefan@huawei.com> Cc: Waiman Long <longman@redhat.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: kernel-team@fb.com Cc: cgroups@vger.kernel.org Cc: linux-doc@vger.kernel.org Cc: linux-kernel@vger.kernel.org
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- 21 7月, 2017 2 次提交
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由 Tejun Heo 提交于
This patch implements cgroup v2 thread support. The goal of the thread mode is supporting hierarchical accounting and control at thread granularity while staying inside the resource domain model which allows coordination across different resource controllers and handling of anonymous resource consumptions. A cgroup is always created as a domain and can be made threaded by writing to the "cgroup.type" file. When a cgroup becomes threaded, it becomes a member of a threaded subtree which is anchored at the closest ancestor which isn't threaded. The threads of the processes which are in a threaded subtree can be placed anywhere without being restricted by process granularity or no-internal-process constraint. Note that the threads aren't allowed to escape to a different threaded subtree. To be used inside a threaded subtree, a controller should explicitly support threaded mode and be able to handle internal competition in the way which is appropriate for the resource. The root of a threaded subtree, the nearest ancestor which isn't threaded, is called the threaded domain and serves as the resource domain for the whole subtree. This is the last cgroup where domain controllers are operational and where all the domain-level resource consumptions in the subtree are accounted. This allows threaded controllers to operate at thread granularity when requested while staying inside the scope of system-level resource distribution. As the root cgroup is exempt from the no-internal-process constraint, it can serve as both a threaded domain and a parent to normal cgroups, so, unlike non-root cgroups, the root cgroup can have both domain and threaded children. Internally, in a threaded subtree, each css_set has its ->dom_cset pointing to a matching css_set which belongs to the threaded domain. This ensures that thread root level cgroup_subsys_state for all threaded controllers are readily accessible for domain-level operations. This patch enables threaded mode for the pids and perf_events controllers. Neither has to worry about domain-level resource consumptions and it's enough to simply set the flag. For more details on the interface and behavior of the thread mode, please refer to the section 2-2-2 in Documentation/cgroup-v2.txt added by this patch. v5: - Dropped silly no-op ->dom_cgrp init from cgroup_create(). Spotted by Waiman. - Documentation updated as suggested by Waiman. - cgroup.type content slightly reformatted. - Mark the debug controller threaded. v4: - Updated to the general idea of marking specific cgroups domain/threaded as suggested by PeterZ. v3: - Dropped "join" and always make mixed children join the parent's threaded subtree. v2: - After discussions with Waiman, support for mixed thread mode is added. This should address the issue that Peter pointed out where any nesting should be avoided for thread subtrees while coexisting with other domain cgroups. - Enabling / disabling thread mode now piggy backs on the existing control mask update mechanism. - Bug fixes and cleanup. Signed-off-by: NTejun Heo <tj@kernel.org> Cc: Waiman Long <longman@redhat.com> Cc: Peter Zijlstra <peterz@infradead.org>
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由 Tejun Heo 提交于
cgroup v2 is in the process of growing thread granularity support. A threaded subtree is composed of a thread root and threaded cgroups which are proper members of the subtree. The root cgroup of the subtree serves as the domain cgroup to which the processes (as opposed to threads / tasks) of the subtree conceptually belong and domain-level resource consumptions not tied to any specific task are charged. Inside the subtree, threads won't be subject to process granularity or no-internal-task constraint and can be distributed arbitrarily across the subtree. This patch introduces cgroup->dom_cgrp along with threaded css_set handling. * cgroup->dom_cgrp points to self for normal and thread roots. For proper thread subtree members, points to the dom_cgrp (the thread root). * css_set->dom_cset points to self if for normal and thread roots. If threaded, points to the css_set which belongs to the cgrp->dom_cgrp. The dom_cgrp serves as the resource domain and keeps the matching csses available. The dom_cset holds those csses and makes them easily accessible. * All threaded csets are linked on their dom_csets to enable iteration of all threaded tasks. * cgroup->nr_threaded_children keeps track of the number of threaded children. This patch adds the above but doesn't actually use them yet. The following patches will build on top. v4: ->nr_threaded_children added. v3: ->proc_cgrp/cset renamed to ->dom_cgrp/cset. Updated for the new enable-threaded-per-cgroup behavior. v2: Added cgroup_is_threaded() helper. Signed-off-by: NTejun Heo <tj@kernel.org>
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- 17 7月, 2017 1 次提交
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由 Tejun Heo 提交于
cgrp->populated_cnt counts both local (the cgroup's populated css_sets) and subtree proper (populated children) so that it's only zero when the whole subtree, including self, is empty. This patch splits the counter into two so that local and children populated states are tracked separately. It allows finer-grained tests on the state of the hierarchy which will be used to replace css_set walking local populated test. Signed-off-by: NTejun Heo <tj@kernel.org>
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- 29 6月, 2017 1 次提交
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由 Tejun Heo 提交于
Currently, cgroup only supports delegation to !root users and cgroup namespaces don't get any special treatments. This limits the usefulness of cgroup namespaces as they by themselves can't be safe delegation boundaries. A process inside a cgroup can change the resource control knobs of the parent in the namespace root and may move processes in and out of the namespace if cgroups outside its namespace are visible somehow. This patch adds a new mount option "nsdelegate" which makes cgroup namespaces delegation boundaries. If set, cgroup behaves as if write permission based delegation took place at namespace boundaries - writes to the resource control knobs from the namespace root are denied and migration crossing the namespace boundary aren't allowed from inside the namespace. This allows cgroup namespace to function as a delegation boundary by itself. v2: Silently ignore nsdelegate specified on !init mounts. Signed-off-by: NTejun Heo <tj@kernel.org> Cc: Aravind Anbudurai <aru7@fb.com> Cc: Serge Hallyn <serge@hallyn.com> Cc: Eric Biederman <ebiederm@xmission.com>
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- 15 6月, 2017 1 次提交
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由 Waiman Long 提交于
The reference count in the css_set data structure was used as a proxy of the number of tasks attached to that css_set. However, that count is actually not an accurate measure especially with thread mode support. So a new variable nr_tasks is added to the css_set to keep track of the actual task count. This new variable is protected by the css_set_lock. Functions that require the actual task count are updated to use the new variable. tj: s/task_count/nr_tasks/ for consistency with cgroup_root->nr_cgrps. Refreshed on top of cgroup/for-v4.13 which dropped on css_set_populated() -> nr_tasks conversion. Signed-off-by: NWaiman Long <longman@redhat.com> Signed-off-by: NTejun Heo <tj@kernel.org>
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- 18 5月, 2017 1 次提交
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由 Waiman Long 提交于
The kill_css() function may be called more than once under the condition that the css was killed but not physically removed yet followed by the removal of the cgroup that is hosting the css. This patch prevents any harmm from being done when that happens. Signed-off-by: NWaiman Long <longman@redhat.com> Signed-off-by: NTejun Heo <tj@kernel.org> Cc: stable@vger.kernel.org # v4.5+
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- 11 4月, 2017 1 次提交
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由 Todd Poynor 提交于
Various structures embed a struct cgroup_subsys_state, typically at the top of the containing structure. It is common for code that accesses the structures to perform operations that iterate over the chain of parent css pointers, also accessing data in each containing structure. In particular, struct cpuacct is used by fairly hot code paths in the scheduler such as cpuacct_charge(). Move the parent css pointer field to the end of the structure to increase the chances of residing in the same cache line as the data from the containing structure. Signed-off-by: NTodd Poynor <toddpoynor@google.com> Signed-off-by: NTejun Heo <tj@kernel.org>
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- 09 3月, 2017 1 次提交
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由 Elena Reshetova 提交于
refcount_t type and corresponding API should be used instead of atomic_t when the variable is used as a reference counter. This allows to avoid accidental refcounter overflows that might lead to use-after-free situations. Signed-off-by: NElena Reshetova <elena.reshetova@intel.com> Signed-off-by: NHans Liljestrand <ishkamiel@gmail.com> Signed-off-by: NKees Cook <keescook@chromium.org> Signed-off-by: NDavid Windsor <dwindsor@gmail.com> Signed-off-by: NTejun Heo <tj@kernel.org>
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- 02 3月, 2017 1 次提交
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由 Ingo Molnar 提交于
threadgroup_change_begin()/end() is a pointless wrapper around cgroup_threadgroup_change_begin()/end(), minus a might_sleep() in the !CONFIG_CGROUPS=y case. Remove the wrappery, move the might_sleep() (the down_read() already has a might_sleep() check). This debloats <linux/sched.h> a bit and simplifies this API. Update all call sites. No change in functionality. Acked-by: NLinus Torvalds <torvalds@linux-foundation.org> Cc: Mike Galbraith <efault@gmx.de> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: linux-kernel@vger.kernel.org Signed-off-by: NIngo Molnar <mingo@kernel.org>
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- 28 12月, 2016 2 次提交
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由 Tejun Heo 提交于
Reorder css_set fields so that they're roughly in the order of how hot they are. The rough order is 1. the actual csses 2. reference counter and the default cgroup pointer. 3. task lists and iterations 4. fields used during merge including css_set lookup 5. the rest Signed-off-by: NTejun Heo <tj@kernel.org> Acked-by: NAcked-by: Zefan Li <lizefan@huawei.com>
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由 Tejun Heo 提交于
Pipe the newly added kernfs->open/release() callbacks through cftype. While at it, as cleanup operations now can be performed from ->release() instead of ->seq_stop(), make the latter optional. Signed-off-by: NTejun Heo <tj@kernel.org> Acked-by: NAcked-by: Zefan Li <lizefan@huawei.com>
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- 26 11月, 2016 1 次提交
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由 Daniel Mack 提交于
This patch adds two sets of eBPF program pointers to struct cgroup. One for such that are directly pinned to a cgroup, and one for such that are effective for it. To illustrate the logic behind that, assume the following example cgroup hierarchy. A - B - C \ D - E If only B has a program attached, it will be effective for B, C, D and E. If D then attaches a program itself, that will be effective for both D and E, and the program in B will only affect B and C. Only one program of a given type is effective for a cgroup. Attaching and detaching programs will be done through the bpf(2) syscall. For now, ingress and egress inet socket filtering are the only supported use-cases. Signed-off-by: NDaniel Mack <daniel@zonque.org> Acked-by: NAlexei Starovoitov <ast@kernel.org> Signed-off-by: NDavid S. Miller <davem@davemloft.net>
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- 26 4月, 2016 1 次提交
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由 Tejun Heo 提交于
Since e93ad19d ("cpuset: make mm migration asynchronous"), cpuset kicks off asynchronous NUMA node migration if necessary during task migration and flushes it from cpuset_post_attach_flush() which is called at the end of __cgroup_procs_write(). This is to avoid performing migration with cgroup_threadgroup_rwsem write-locked which can lead to deadlock through dependency on kworker creation. memcg has a similar issue with charge moving, so let's convert it to an official callback rather than the current one-off cpuset specific function. This patch adds cgroup_subsys->post_attach callback and makes cpuset register cpuset_post_attach_flush() as its ->post_attach. The conversion is mostly one-to-one except that the new callback is called under cgroup_mutex. This is to guarantee that no other migration operations are started before ->post_attach callbacks are finished. cgroup_mutex is one of the outermost mutex in the system and has never been and shouldn't be a problem. We can add specialized synchronization around __cgroup_procs_write() but I don't think there's any noticeable benefit. Signed-off-by: NTejun Heo <tj@kernel.org> Cc: Li Zefan <lizefan@huawei.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Michal Hocko <mhocko@kernel.org> Cc: <stable@vger.kernel.org> # 4.4+ prerequisite for the next patch
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- 17 3月, 2016 1 次提交
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由 Tejun Heo 提交于
Before 2e91fa7f ("cgroup: keep zombies associated with their original cgroups"), all dead tasks were associated with init_css_set. If a zombie task is requested for migration, while migration prep operations would still be performed on init_css_set, the actual migration would ignore zombie tasks. As init_css_set is always valid, this worked fine. However, after 2e91fa7f, zombie tasks stay with the css_set it was associated with at the time of death. Let's say a task T associated with cgroup A on hierarchy H-1 and cgroup B on hiearchy H-2. After T becomes a zombie, it would still remain associated with A and B. If A only contains zombie tasks, it can be removed. On removal, A gets marked offline but stays pinned until all zombies are drained. At this point, if migration is initiated on T to a cgroup C on hierarchy H-2, migration path would try to prepare T's css_set for migration and trigger the following. WARNING: CPU: 0 PID: 1576 at kernel/cgroup.c:474 cgroup_get+0x121/0x160() CPU: 0 PID: 1576 Comm: bash Not tainted 4.4.0-work+ #289 ... Call Trace: [<ffffffff8127e63c>] dump_stack+0x4e/0x82 [<ffffffff810445e8>] warn_slowpath_common+0x78/0xb0 [<ffffffff810446d5>] warn_slowpath_null+0x15/0x20 [<ffffffff810c33e1>] cgroup_get+0x121/0x160 [<ffffffff810c349b>] link_css_set+0x7b/0x90 [<ffffffff810c4fbc>] find_css_set+0x3bc/0x5e0 [<ffffffff810c5269>] cgroup_migrate_prepare_dst+0x89/0x1f0 [<ffffffff810c7547>] cgroup_attach_task+0x157/0x230 [<ffffffff810c7a17>] __cgroup_procs_write+0x2b7/0x470 [<ffffffff810c7bdc>] cgroup_tasks_write+0xc/0x10 [<ffffffff810c4790>] cgroup_file_write+0x30/0x1b0 [<ffffffff811c68fc>] kernfs_fop_write+0x13c/0x180 [<ffffffff81151673>] __vfs_write+0x23/0xe0 [<ffffffff81152494>] vfs_write+0xa4/0x1a0 [<ffffffff811532d4>] SyS_write+0x44/0xa0 [<ffffffff814af2d7>] entry_SYSCALL_64_fastpath+0x12/0x6f It doesn't make sense to prepare migration for css_sets pointing to dead cgroups as they are guaranteed to contain only zombies which are ignored later during migration. This patch makes cgroup destruction path mark all affected css_sets as dead and updates the migration path to ignore them during preparation. Signed-off-by: NTejun Heo <tj@kernel.org> Fixes: 2e91fa7f ("cgroup: keep zombies associated with their original cgroups") Cc: stable@vger.kernel.org # v4.4+
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- 09 3月, 2016 2 次提交
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由 Tejun Heo 提交于
Some controllers, perf_event for now and possibly freezer in the future, don't really make sense to control explicitly through "cgroup.subtree_control". For example, the primary role of perf_event is identifying the cgroups of tasks; however, because the controller also keeps a small amount of state per cgroup, it can't be replaced with simple cgroup membership tests. This patch implements cgroup_subsys->implicit_on_dfl flag. When set, the controller is implicitly enabled on all cgroups on the v2 hierarchy so that utility type controllers such as perf_event can be enabled and function transparently. An implicit controller doesn't show up in "cgroup.controllers" or "cgroup.subtree_control", is exempt from no internal process rule and can be stolen from the default hierarchy even if there are non-root csses. v2: Reimplemented on top of the recent updates to css handling and subsystem rebinding. Rebinding implicit subsystems is now a simple matter of exempting it from the busy subsystem check. Signed-off-by: NTejun Heo <tj@kernel.org>
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由 Tejun Heo 提交于
Migration can be multi-target on the default hierarchy when a controller is enabled - processes belonging to each child cgroup have to be moved to the child cgroup itself to refresh css association. This isn't a problem for cgroup_migrate_add_src() as each source css_set still maps to single source and target cgroups; however, cgroup_migrate_prepare_dst() is called once after all source css_sets are added and thus might not have a single destination cgroup. This is currently worked around by specifying NULL for @dst_cgrp and using the source's default cgroup as destination as the only multi-target migration in use is self-targetting. While this works, it's subtle and clunky. As all taget cgroups are already specified while preparing the source css_sets, this clunkiness can easily be removed by recording the target cgroup in each source css_set. This patch adds css_set->mg_dst_cgrp which is recorded on cgroup_migrate_src() and used by cgroup_migrate_prepare_dst(). This also makes migration code ready for arbitrary multi-target migration. Signed-off-by: NTejun Heo <tj@kernel.org>
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- 03 3月, 2016 2 次提交
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由 Tejun Heo 提交于
While controllers are being enabled and disabled in cgroup_subtree_control_write(), the original subsystem masks are stashed in local variables so that they can be restored if the operation fails in the middle. This patch adds dedicated fields to struct cgroup to be used instead of the local variables and implements functions to stash the current values, propagate the changes and restore them recursively. Combined with the previous changes, this makes subsystem management operations fully recursive and modularlized. This will be used to expand cgroup core functionalities. While at it, remove now unused @css_enable and @css_disable from cgroup_subtree_control_write(). Signed-off-by: NTejun Heo <tj@kernel.org> Acked-by: NZefan Li <lizefan@huawei.com>
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由 Tejun Heo 提交于
Currently, whether a css (cgroup_subsys_state) has its interface files created is not tracked and assumed to change together with the owning cgroup's lifecycle. cgroup directory and interface creation is being separated out from internal object creation to help refactoring and eventually allow cgroups which are not visible through cgroupfs. This patch adds CSS_VISIBLE to track whether a css has its interface files created and perform management operations only when necessary which helps decoupling interface file handling from internal object lifecycle. After this patch, all css interface file management functions can be called regardless of the current state and will achieve the expected result. Signed-off-by: NTejun Heo <tj@kernel.org> Acked-by: NZefan Li <lizefan@huawei.com>
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- 23 2月, 2016 4 次提交
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由 Tejun Heo 提交于
Signed-off-by: NTejun Heo <tj@kernel.org> Cc: Li Zefan <lizefan@huawei.com> Cc: Ingo Molnar <mingo@redhat.com> Cc: Peter Zijlstra <peterz@infradead.org>
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由 Tejun Heo 提交于
After the recent do_each_subsys_mask() conversion, there's no reason to use ulong for subsystem masks. We'll be adding more subsystem masks to persistent data structures, let's reduce its size to u16 which should be enough for now and the foreseeable future. This doesn't create any noticeable behavior differences. v2: Johannes spotted that the initial patch missed cgroup_no_v1_mask. Converted. Signed-off-by: NTejun Heo <tj@kernel.org> Acked-by: NJohannes Weiner <hannes@cmpxchg.org>
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由 Tejun Heo 提交于
For consistency with cgroup->subtree_control. * cgroup->child_subsys_mask -> cgroup->subtree_ss_mask * cgroup_calc_child_subsys_mask() -> cgroup_calc_subtree_ss_mask() * cgroup_refresh_child_subsys_mask() -> cgroup_refresh_subtree_ss_mask() No functional changes. Signed-off-by: NTejun Heo <tj@kernel.org> Acked-by: NJohannes Weiner <hannes@cmpxchg.org>
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由 Tejun Heo 提交于
This reverts commit 56c807ba. cgroup_subsys->css_e_css_changed() was supposed to be used by cgroup writeback support; however, the change to per-inode cgroup association made it unnecessary and the callback doesn't have any user. Remove it. Signed-off-by: NTejun Heo <tj@kernel.org> Acked-by: NJohannes Weiner <hannes@cmpxchg.org>
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- 22 1月, 2016 1 次提交
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由 Tejun Heo 提交于
There are three subsystem callbacks in css shutdown path - css_offline(), css_released() and css_free(). Except for css_released(), cgroup core didn't guarantee the order of invocation. css_offline() or css_free() could be called on a parent css before its children. This behavior is unexpected and led to bugs in cpu and memory controller. This patch updates offline path so that a parent css is never offlined before its children. Each css keeps online_cnt which reaches zero iff itself and all its children are offline and offline_css() is invoked only after online_cnt reaches zero. This fixes the memory controller bug and allows the fix for cpu controller. Signed-off-by: NTejun Heo <tj@kernel.org> Reported-and-tested-by: NChristian Borntraeger <borntraeger@de.ibm.com> Reported-by: NBrian Christiansen <brian.o.christiansen@gmail.com> Link: http://lkml.kernel.org/g/5698A023.9070703@de.ibm.com Link: http://lkml.kernel.org/g/CAKB58ikDkzc8REt31WBkD99+hxNzjK4+FBmhkgS+NVrC9vjMSg@mail.gmail.com Cc: Heiko Carstens <heiko.carstens@de.ibm.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: stable@vger.kernel.org
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- 10 12月, 2015 1 次提交
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由 Tejun Heo 提交于
sock_cgroup_data is a struct containing an anonymous union. sock_cgroup_set_prioidx() and sock_cgroup_set_classid() were initializing a field inside the anonymous union as follows. struct sock_ccgroup_data skcd_buf = { .val = VAL }; While this is fine on more recent compilers, gcc-4.4.7 triggers the following errors. include/linux/cgroup-defs.h: In function ‘sock_cgroup_set_prioidx’: include/linux/cgroup-defs.h:619: error: unknown field ‘val’ specified in initializer include/linux/cgroup-defs.h:619: warning: missing braces around initializer include/linux/cgroup-defs.h:619: warning: (near initialization for ‘skcd_buf.<anonymous>’) This is because .val belongs to the anonymous union nested inside the struct but the initializer is missing the nesting. Fix it by adding an extra pair of braces. Signed-off-by: NTejun Heo <tj@kernel.org> Reported-by: NAlaa Hleihel <alaa@dev.mellanox.co.il> Fixes: bd1060a1 ("sock, cgroup: add sock->sk_cgroup") Signed-off-by: NDavid S. Miller <davem@davemloft.net>
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- 09 12月, 2015 2 次提交
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由 Tejun Heo 提交于
In cgroup v1, dealing with cgroup membership was difficult because the number of membership associations was unbound. As a result, cgroup v1 grew several controllers whose primary purpose is either tagging membership or pull in configuration knobs from other subsystems so that cgroup membership test can be avoided. net_cls and net_prio controllers are examples of the latter. They allow configuring network-specific attributes from cgroup side so that network subsystem can avoid testing cgroup membership; unfortunately, these are not only cumbersome but also problematic. Both net_cls and net_prio aren't properly hierarchical. Both inherit configuration from the parent on creation but there's no interaction afterwards. An ancestor doesn't restrict the behavior in its subtree in anyway and configuration changes aren't propagated downwards. Especially when combined with cgroup delegation, this is problematic because delegatees can mess up whatever network configuration implemented at the system level. net_prio would allow the delegatees to set whatever priority value regardless of CAP_NET_ADMIN and net_cls the same for classid. While it is possible to solve these issues from controller side by implementing hierarchical allowable ranges in both controllers, it would involve quite a bit of complexity in the controllers and further obfuscate network configuration as it becomes even more difficult to tell what's actually being configured looking from the network side. While not much can be done for v1 at this point, as membership handling is sane on cgroup v2, it'd be better to make cgroup matching behave like other network matches and classifiers than introducing further complications. In preparation, this patch updates sock->sk_cgrp_data handling so that it points to the v2 cgroup that sock was created in until either net_prio or net_cls is used. Once either of the two is used, sock->sk_cgrp_data reverts to its previous role of carrying prioidx and classid. This is to avoid adding yet another cgroup related field to struct sock. As the mode switching can happen at most once per boot, the switching mechanism is aimed at lowering hot path overhead. It may leak a finite, likely small, number of cgroup refs and report spurious prioidx or classid on switching; however, dynamic updates of prioidx and classid have always been racy and lossy - socks between creation and fd installation are never updated, config changes don't update existing sockets at all, and prioidx may index with dead and recycled cgroup IDs. Non-critical inaccuracies from small race windows won't make any noticeable difference. This patch doesn't make use of the pointer yet. The following patch will implement netfilter match for cgroup2 membership. v2: Use sock_cgroup_data to avoid inflating struct sock w/ another cgroup specific field. v3: Add comments explaining why sock_data_prioidx() and sock_data_classid() use different fallback values. Signed-off-by: NTejun Heo <tj@kernel.org> Cc: Daniel Borkmann <daniel@iogearbox.net> Cc: Daniel Wagner <daniel.wagner@bmw-carit.de> CC: Neil Horman <nhorman@tuxdriver.com> Signed-off-by: NDavid S. Miller <davem@davemloft.net>
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由 Tejun Heo 提交于
Introduce sock->sk_cgrp_data which is a struct sock_cgroup_data. ->sk_cgroup_prioidx and ->sk_classid are moved into it. The struct and its accessors are defined in cgroup-defs.h. This is to prepare for overloading the fields with a cgroup pointer. This patch mostly performs equivalent conversions but the followings are noteworthy. * Equality test before updating classid is removed from sock_update_classid(). This shouldn't make any noticeable difference and a similar test will be implemented on the helper side later. * sock_update_netprioidx() now takes struct sock_cgroup_data and can be moved to netprio_cgroup.h without causing include dependency loop. Moved. * The dummy version of sock_update_netprioidx() converted to a static inline function while at it. Signed-off-by: NTejun Heo <tj@kernel.org> Signed-off-by: NDavid S. Miller <davem@davemloft.net>
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- 03 12月, 2015 2 次提交
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由 Oleg Nesterov 提交于
Now that nobody use the "priv" arg passed to can_fork/cancel_fork/fork we can kill CGROUP_CANFORK_COUNT/SUBSYS_TAG/etc and cgrp_ss_priv[] in copy_process(). Signed-off-by: NOleg Nesterov <oleg@redhat.com> Signed-off-by: NTejun Heo <tj@kernel.org>
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由 Tejun Heo 提交于
Consider the following v2 hierarchy. P0 (+memory) --- P1 (-memory) --- A \- B P0 has memory enabled in its subtree_control while P1 doesn't. If both A and B contain processes, they would belong to the memory css of P1. Now if memory is enabled on P1's subtree_control, memory csses should be created on both A and B and A's processes should be moved to the former and B's processes the latter. IOW, enabling controllers can cause atomic migrations into different csses. The core cgroup migration logic has been updated accordingly but the controller migration methods haven't and still assume that all tasks migrate to a single target css; furthermore, the methods were fed the css in which subtree_control was updated which is the parent of the target csses. pids controller depends on the migration methods to move charges and this made the controller attribute charges to the wrong csses often triggering the following warning by driving a counter negative. WARNING: CPU: 1 PID: 1 at kernel/cgroup_pids.c:97 pids_cancel.constprop.6+0x31/0x40() Modules linked in: CPU: 1 PID: 1 Comm: systemd Not tainted 4.4.0-rc1+ #29 ... ffffffff81f65382 ffff88007c043b90 ffffffff81551ffc 0000000000000000 ffff88007c043bc8 ffffffff810de202 ffff88007a752000 ffff88007a29ab00 ffff88007c043c80 ffff88007a1d8400 0000000000000001 ffff88007c043bd8 Call Trace: [<ffffffff81551ffc>] dump_stack+0x4e/0x82 [<ffffffff810de202>] warn_slowpath_common+0x82/0xc0 [<ffffffff810de2fa>] warn_slowpath_null+0x1a/0x20 [<ffffffff8118e031>] pids_cancel.constprop.6+0x31/0x40 [<ffffffff8118e0fd>] pids_can_attach+0x6d/0xf0 [<ffffffff81188a4c>] cgroup_taskset_migrate+0x6c/0x330 [<ffffffff81188e05>] cgroup_migrate+0xf5/0x190 [<ffffffff81189016>] cgroup_attach_task+0x176/0x200 [<ffffffff8118949d>] __cgroup_procs_write+0x2ad/0x460 [<ffffffff81189684>] cgroup_procs_write+0x14/0x20 [<ffffffff811854e5>] cgroup_file_write+0x35/0x1c0 [<ffffffff812e26f1>] kernfs_fop_write+0x141/0x190 [<ffffffff81265f88>] __vfs_write+0x28/0xe0 [<ffffffff812666fc>] vfs_write+0xac/0x1a0 [<ffffffff81267019>] SyS_write+0x49/0xb0 [<ffffffff81bcef32>] entry_SYSCALL_64_fastpath+0x12/0x76 This patch fixes the bug by removing @css parameter from the three migration methods, ->can_attach, ->cancel_attach() and ->attach() and updating cgroup_taskset iteration helpers also return the destination css in addition to the task being migrated. All controllers are updated accordingly. * Controllers which don't care whether there are one or multiple target csses can be converted trivially. cpu, io, freezer, perf, netclassid and netprio fall in this category. * cpuset's current implementation assumes that there's single source and destination and thus doesn't support v2 hierarchy already. The only change made by this patchset is how that single destination css is obtained. * memory migration path already doesn't do anything on v2. How the single destination css is obtained is updated and the prep stage of mem_cgroup_can_attach() is reordered to accomodate the change. * pids is the only controller which was affected by this bug. It now correctly handles multi-destination migrations and no longer causes counter underflow from incorrect accounting. Signed-off-by: NTejun Heo <tj@kernel.org> Reported-and-tested-by: NDaniel Wagner <daniel.wagner@bmw-carit.de> Cc: Aleksa Sarai <cyphar@cyphar.com>
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- 21 11月, 2015 1 次提交
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由 Tejun Heo 提交于
cgroup_is_descendant() currently walks up the hierarchy and compares each ancestor to the cgroup in question. While enough for cgroup core usages, this can't be used in hot paths to test cgroup membership. This patch adds cgroup->ancestor_ids[] which records the IDs of all ancestors including self and cgroup->level for the nesting level. This allows testing whether a given cgroup is a descendant of another in three finite steps - testing whether the two belong to the same hierarchy, whether the descendant candidate is at the same or a higher level than the ancestor and comparing the recorded ancestor_id at the matching level. cgroup_is_descendant() is accordingly reimplmented and made inline. Signed-off-by: NTejun Heo <tj@kernel.org>
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- 17 11月, 2015 1 次提交
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由 Tejun Heo 提交于
With major controllers - cpu, memory and io - shaping up for the unified hierarchy, cgroup2 is about ready to be, gradually, released into the wild. Replace __DEVEL__sane_behavior flag which was used to select the unified hierarchy with a separate filesystem type "cgroup2" so that unified hierarchy can be mounted as follows. mount -t cgroup2 none $MOUNT_POINT The cgroup2 fs has its own magic number - 0x63677270 ("cgrp"). v2: Assign a different magic number to cgroup2 fs. Signed-off-by: NTejun Heo <tj@kernel.org> Acked-by: NLi Zefan <lizefan@huawei.com> Cc: Johannes Weiner <hannes@cmpxchg.org>
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- 16 11月, 2015 1 次提交
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由 Tejun Heo 提交于
6f60eade ("cgroup: generalize obtaining the handles of and notifying cgroup files") introduced cftype->file_offset so that the handles for per-css file instances can be recorded. These handles then can be used, for example, to generate file modified notifications. Unfortunately, it made the wrong assumption that files are created once for a given css and removed on its destruction. Due to the dependencies among subsystems, a css may be hidden from userland and then later shown again. This is implemented by removing and re-creating the affected files, so the associated kernfs_node for a given cgroup file may change over time. This incorrect assumption led to the corruption of css->files lists. Reimplement cftype->file_offset handling so that cgroup_file->kn is protected by a lock and updated as files are created and destroyed. This also makes keeping them on per-cgroup list unnecessary. Signed-off-by: NTejun Heo <tj@kernel.org> Reported-by: NJames Sedgwick <jsedgwick@fb.com> Fixes: 6f60eade ("cgroup: generalize obtaining the handles of and notifying cgroup files") Acked-by: NJohannes Weiner <hannes@cmpxchg.org> Acked-by: NZefan Li <lizefan@huawei.com>
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- 16 10月, 2015 2 次提交
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由 Tejun Heo 提交于
pids controller is completely broken in that it uncharges when a task exits allowing zombies to escape resource control. With the recent updates, cgroup core now maintains cgroup association till task free and pids controller can be fixed by uncharging on free instead of exit. This patch adds cgroup_subsys->free() method and update pids controller to use it instead of ->exit() for uncharging. Signed-off-by: NTejun Heo <tj@kernel.org> Cc: Aleksa Sarai <cyphar@cyphar.com>
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由 Tejun Heo 提交于
cgroup_exit() is called when a task exits and disassociates the exiting task from its cgroups and half-attach it to the root cgroup. This is unnecessary and undesirable. No controller actually needs an exiting task to be disassociated with non-root cgroups. Both cpu and perf_event controllers update the association to the root cgroup from their exit callbacks just to keep consistent with the cgroup core behavior. Also, this disassociation makes it difficult to track resources held by zombies or determine where the zombies came from. Currently, pids controller is completely broken as it uncharges on exit and zombies always escape the resource restriction. With cgroup association being reset on exit, fixing it is pretty painful. There's no reason to reset cgroup membership on exit. The zombie can be removed from its css_set so that it doesn't show up on "cgroup.procs" and thus can't be migrated or interfere with cgroup removal. It can still pin and point to the css_set so that its cgroup membership is maintained. This patch makes cgroup core keep zombies associated with their cgroups at the time of exit. * Previous patches decoupled populated_cnt tracking from css_set lifetime, so a dying task can be simply unlinked from its css_set while pinning and pointing to the css_set. This keeps css_set association from task side alive while hiding it from "cgroup.procs" and populated_cnt tracking. The css_set reference is dropped when the task_struct is freed. * ->exit() callback no longer needs the css arguments as the associated css never changes once PF_EXITING is set. Removed. * cpu and perf_events controllers no longer need ->exit() callbacks. There's no reason to explicitly switch away on exit. The final schedule out is enough. The callbacks are removed. * On traditional hierarchies, nothing changes. "/proc/PID/cgroup" still reports "/" for all zombies. On the default hierarchy, "/proc/PID/cgroup" keeps reporting the cgroup that the task belonged to at the time of exit. If the cgroup gets removed before the task is reaped, " (deleted)" is appended. v2: Build brekage due to missing dummy cgroup_free() when !CONFIG_CGROUP fixed. Signed-off-by: NTejun Heo <tj@kernel.org> Cc: Ingo Molnar <mingo@redhat.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Arnaldo Carvalho de Melo <acme@kernel.org>
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