- 21 7月, 2017 3 次提交
-
-
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>
-
由 Tejun Heo 提交于
css_task_iter currently always walks all tasks. With the scheduled cgroup v2 thread support, the iterator would need to handle multiple types of iteration. As a preparation, add @flags to css_task_iter_start() and implement CSS_TASK_ITER_PROCS. If the flag is not specified, it walks all tasks as before. When asserted, the iterator only walks the group leaders. For now, the only user of the flag is cgroup v2 "cgroup.procs" file which no longer needs to skip non-leader tasks in cgroup_procs_next(). Note that cgroup v1 "cgroup.procs" can't use the group leader walk as v1 "cgroup.procs" doesn't mean "list all thread group leaders in the cgroup" but "list all thread group id's with any threads in the cgroup". While at it, update cgroup_procs_show() to use task_pid_vnr() instead of task_tgid_vnr(). As the iteration guarantees that the function only sees group leaders, this doesn't change the output and will allow sharing the function for thread iteration. Signed-off-by: NTejun Heo <tj@kernel.org>
-
由 Tejun Heo 提交于
Currently, writes "cgroup.procs" and "cgroup.tasks" files are all handled by __cgroup_procs_write() on both v1 and v2. This patch reoragnizes the write path so that there are common helper functions that different write paths use. While this somewhat increases LOC, the different paths are no longer intertwined and each path has more flexibility to implement different behaviors which will be necessary for the planned v2 thread support. v3: - Restructured so that cgroup_procs_write_permission() takes @src_cgrp and @dst_cgrp. v2: - Rolled in Waiman's task reference count fix. - Updated on top of nsdelegate changes. Signed-off-by: NTejun Heo <tj@kernel.org> Cc: Waiman Long <longman@redhat.com>
-
- 15 6月, 2017 2 次提交
-
-
由 Waiman Long 提交于
The debug cgroup currently resides within cgroup-v1.c and is enabled only for v1 cgroup. To enable the debug cgroup also for v2, it makes sense to put the code into its own file as it will no longer be v1 specific. There is no change to the debug cgroup specific code. Signed-off-by: NWaiman Long <longman@redhat.com> Signed-off-by: NTejun Heo <tj@kernel.org>
-
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>
-
- 29 4月, 2017 1 次提交
-
-
由 Zefan Li 提交于
Commit bfb0b80d ("cgroup: avoid attaching a cgroup root to two different superblocks") is broken. Now we try to fix the race by delaying the initialization of cgroup root refcnt until a superblock has been allocated. Reported-by: NDmitry Vyukov <dvyukov@google.com> Reported-by: NAndrei Vagin <avagin@virtuozzo.com> Tested-by: NAndrei Vagin <avagin@virtuozzo.com> Signed-off-by: NZefan Li <lizefan@huawei.com> Signed-off-by: NTejun Heo <tj@kernel.org>
-
- 16 4月, 2017 1 次提交
-
-
由 Tejun Heo 提交于
This reverts commit bfb0b80d. Andrei reports CRIU test hangs with the patch applied. The bug fixed by the patch isn't too likely to trigger in actual uses. Revert the patch for now. Signed-off-by: NTejun Heo <tj@kernel.org> Reported-by: NAndrei Vagin <avagin@virtuozzo.com> Link: http://lkml.kernel.org/r/20170414232737.GC20350@outlook.office365.com
-
- 11 4月, 2017 1 次提交
-
-
由 Zefan Li 提交于
Run this: touch file0 for ((; ;)) { mount -t cpuset xxx file0 } And this concurrently: touch file1 for ((; ;)) { mount -t cpuset xxx file1 } We'll trigger a warning like this: ------------[ cut here ]------------ WARNING: CPU: 1 PID: 4675 at lib/percpu-refcount.c:317 percpu_ref_kill_and_confirm+0x92/0xb0 percpu_ref_kill_and_confirm called more than once on css_release! CPU: 1 PID: 4675 Comm: mount Not tainted 4.11.0-rc5+ #5 Hardware name: Bochs Bochs, BIOS Bochs 01/01/2007 Call Trace: dump_stack+0x63/0x84 __warn+0xd1/0xf0 warn_slowpath_fmt+0x5f/0x80 percpu_ref_kill_and_confirm+0x92/0xb0 cgroup_kill_sb+0x95/0xb0 deactivate_locked_super+0x43/0x70 deactivate_super+0x46/0x60 ... ---[ end trace a79f61c2a2633700 ]--- Here's a race: Thread A Thread B cgroup1_mount() # alloc a new cgroup root cgroup_setup_root() cgroup1_mount() # no sb yet, returns NULL kernfs_pin_sb() # but succeeds in getting the refcnt, # so re-use cgroup root percpu_ref_tryget_live() # alloc sb with cgroup root cgroup_do_mount() cgroup_kill_sb() # alloc another sb with same root cgroup_do_mount() cgroup_kill_sb() We end up using the same cgroup root for two different superblocks, so percpu_ref_kill() will be called twice on the same root when the two superblocks are destroyed. We should fix to make sure the superblock pinning is really successful. Cc: stable@vger.kernel.org # 3.16+ Reported-by: NDmitry Vyukov <dvyukov@google.com> Signed-off-by: NZefan Li <lizefan@huawei.com> Signed-off-by: NTejun Heo <tj@kernel.org>
-
- 09 3月, 2017 1 次提交
-
-
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>
-
- 07 3月, 2017 1 次提交
-
-
由 Kees Cook 提交于
As found in grsecurity, this avoids exposing a kernel pointer through the cgroup debug entries. Signed-off-by: NKees Cook <keescook@chromium.org> Signed-off-by: NTejun Heo <tj@kernel.org>
-
- 03 3月, 2017 3 次提交
-
-
由 Ingo Molnar 提交于
It's not used by any of the scheduler methods, but <linux/sched/task_stack.h> needs it to pick up STACK_END_MAGIC. 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> Signed-off-by: NIngo Molnar <mingo@kernel.org>
-
由 Ingo Molnar 提交于
The task_lock()/task_unlock() APIs are not realated to core scheduling, they are task lifetime APIs, i.e. they belong into <linux/sched/task.h>. Move them. 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>
-
由 Ingo Molnar 提交于
sched/headers: Move task_struct::signal and task_struct::sighand types and accessors into <linux/sched/signal.h> task_struct::signal and task_struct::sighand are pointers, which would normally make it straightforward to not define those types in sched.h. That is not so, because the types are accompanied by a myriad of APIs (macros and inline functions) that dereference them. Split the types and the APIs out of sched.h and move them into a new header, <linux/sched/signal.h>. With this change sched.h does not know about 'struct signal' and 'struct sighand' anymore, trying to put accessors into sched.h as a test fails the following way: ./include/linux/sched.h: In function ‘test_signal_types’: ./include/linux/sched.h:2461:18: error: dereferencing pointer to incomplete type ‘struct signal_struct’ ^ This reduces the size and complexity of sched.h significantly. Update all headers and .c code that relied on getting the signal handling functionality from <linux/sched.h> to include <linux/sched/signal.h>. The list of affected files in the preparatory patch was partly generated by grepping for the APIs, and partly by doing coverage build testing, both all[yes|mod|def|no]config builds on 64-bit and 32-bit x86, and an array of cross-architecture builds. Nevertheless some (trivial) build breakage is still expected related to rare Kconfig combinations and in-flight patches to various kernel code, but most of it should be handled by this patch. 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>
-
- 16 1月, 2017 2 次提交
-
-
由 Tejun Heo 提交于
Currently, subsys->*attach() callbacks are called for all subsystems which are attached to the hierarchy on which the migration is taking place. With cgroup_migrate_prepare_dst() filtering out identity migrations, v1 hierarchies can avoid spurious ->*attach() callback invocations where the source and destination csses are identical; however, this isn't enough on v2 as only a subset of the attached controllers can be affected on controller enable/disable. While spurious ->*attach() invocations aren't critically broken, they're unnecessary overhead and can lead to temporary overcharges on certain controllers. Fix it by tracking which subsystems are affected by a migration and invoking ->*attach() callbacks only on those subsystems. Signed-off-by: NTejun Heo <tj@kernel.org> Acked-by: NZefan Li <lizefan@huawei.com>
-
由 Tejun Heo 提交于
cgroup migration is performed in four steps - css_set preloading, addition of target tasks, actual migration, and clean up. A list named preloaded_csets is used to track the preloading. This is a bit too restricted and the code is already depending on the subtlety that all source css_sets appear before destination ones. Let's create struct cgroup_mgctx which keeps track of everything during migration. Currently, it has separate preload lists for source and destination csets and also embeds cgroup_taskset which is used during the actual migration. This moves struct cgroup_taskset definition to cgroup-internal.h. This patch doesn't cause any functional changes. Signed-off-by: NTejun Heo <tj@kernel.org> Acked-by: NZefan Li <lizefan@huawei.com>
-
- 28 12月, 2016 5 次提交
-
-
由 Tejun Heo 提交于
kn->priv which is a void * is used as a RCU pointer by cgroup. When dereferencing it, it was passing kn->priv to rcu_derefreence() without casting it into a RCU pointer triggering address space mismatch warning from sparse. Fix them. Signed-off-by: NTejun Heo <tj@kernel.org> Reported-by: NFengguang Wu <fengguang.wu@intel.com> Acked-by: NAcked-by: Zefan Li <lizefan@huawei.com>
-
由 Tejun Heo 提交于
Now that v1 functions are separated out, rename some functions for consistency. cgroup_dfl_base_files -> cgroup_base_files cgroup_legacy_base_files -> cgroup1_base_files cgroup_ssid_no_v1() -> cgroup1_ssid_disabled() cgroup_pidlist_destroy_all -> cgroup1_pidlist_destroy_all() cgroup_release_agent() -> cgroup1_release_agent() check_for_release() -> cgroup1_check_for_release() Signed-off-by: NTejun Heo <tj@kernel.org> Acked-by: NAcked-by: Zefan Li <lizefan@huawei.com>
-
由 Tejun Heo 提交于
Now that the v1 mount code is split into separate functions, move them to kernel/cgroup/cgroup-v1.c along with the mount option handling code. As this puts all v1-only kernfs_syscall_ops in cgroup-v1.c, move cgroup1_kf_syscall_ops to cgroup-v1.c too. Signed-off-by: NTejun Heo <tj@kernel.org> Acked-by: NAcked-by: Zefan Li <lizefan@huawei.com>
-
由 Tejun Heo 提交于
Currently, cgroup_kf_syscall_ops is shared by v1 and v2 and the specific methods test the version and take different actions. Split out v1 functions and put them in cgroup1_kf_syscall_ops and remove the now unnecessary explicit branches in specific methods. Signed-off-by: NTejun Heo <tj@kernel.org> Acked-by: NAcked-by: Zefan Li <lizefan@huawei.com>
-
由 Tejun Heo 提交于
cgroup.c is getting too unwieldy. Let's move out cgroup v1 specific code along with the debug controller into kernel/cgroup/cgroup-v1.c. v2: cgroup_mutex and css_set_lock made available in cgroup-internal.h regardless of CONFIG_PROVE_RCU. Signed-off-by: NTejun Heo <tj@kernel.org> Acked-by: NAcked-by: Zefan Li <lizefan@huawei.com>
-