Tejun Heo
53fa526174
cgroup: add cgroup->serial_nr and implement cgroup_next_sibling() ...
Currently, there's no easy way to find out the next sibling cgroup
unless it's known that the current cgroup is accessed from the
parent's children list in a single RCU critical section. This in turn
forces all iterators to require whole iteration to be enclosed in a
single RCU critical section, which sometimes is too restrictive. This
patch implements cgroup_next_sibling() which can reliably determine
the next sibling regardless of the state of the current cgroup as long
as it's accessible.
It currently is impossible to determine the next sibling after
dropping RCU read lock because the cgroup being iterated could be
removed anytime and if RCU read lock is dropped, nothing guarantess
its ->sibling.next pointer is accessible. A removed cgroup would
continue to point to its next sibling for RCU accesses but stop
receiving updates from the sibling. IOW, the next sibling could be
removed and then complete its grace period while RCU read lock is
dropped, making it unsafe to dereference ->sibling.next after dropping
and re-acquiring RCU read lock.
This can be solved by adding a way to traverse to the next sibling
without dereferencing ->sibling.next. This patch adds a monotonically
increasing cgroup serial number, cgroup->serial_nr, which guarantees
that all cgroup->children lists are kept in increasing serial_nr
order. A new function, cgroup_next_sibling(), is implemented, which,
if CGRP_REMOVED is not set on the current cgroup, follows
->sibling.next; otherwise, traverses the parent's ->children list
until it sees a sibling with higher ->serial_nr.
This allows the function to always return the next sibling regardless
of the state of the current cgroup without adding overhead in the fast
path.
Further patches will update the iterators to use cgroup_next_sibling()
so that they allow dropping RCU read lock and blocking while iteration
is in progress which in turn will be used to simplify controllers.
v2: Typo fix as per Serge.
Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: Serge E. Hallyn <serge.hallyn@ubuntu.com>
2013-05-24 10:55:38 +09:00
Merge branch 'timers-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
2013-04-30 08:15:40 -07:00
kgdb/sysrq: fix inconstistent help message of sysrq key
2013-04-30 17:04:10 -07:00
Merge branch 'timers-nohz-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
2013-05-05 13:23:27 -07:00
kernel/gcov: remove depends on CONFIG_EXPERIMENTAL
2013-01-11 11:39:33 -08:00
irqdomain: Allow quiet failure mode
2013-05-06 11:37:43 +10:00
Merge branch 'drm-next' of git://people.freedesktop.org/~airlied/linux
2013-05-02 19:40:34 -07:00
Merge branch 'timers-nohz-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
2013-05-05 13:23:27 -07:00
Merge branch 'timers-nohz-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
2013-05-05 13:23:27 -07:00
The majority of these changes are from Masami Hiramatsu bringing
2013-05-11 17:04:59 -07:00
kernel/hz.bc: ignore.
2013-04-22 07:09:06 -07:00
fs: Fix hang with BSD accounting on frozen filesystem
2013-05-04 14:57:58 -04:00
async: rename and redefine async_func_ptr
2013-03-12 13:59:14 -07:00
Merge git://git.infradead.org/users/eparis/audit
2013-05-11 14:29:11 -07:00
Merge git://git.infradead.org/users/eparis/audit
2013-05-11 14:29:11 -07:00
kernel/audit_tree.c: tree will leak memory when failure occurs in audit_trim_trees()
2013-04-29 15:54:26 -07:00
audit: catch possible NULL audit buffers
2013-01-11 14:54:55 -08:00
Merge git://git.infradead.org/users/eparis/audit
2013-05-11 14:29:11 -07:00
audit: Make testing for a valid loginuid explicit.
2013-05-07 22:27:15 -04:00
Add file_ns_capable() helper function for open-time capability checking
2013-04-14 10:06:31 -07:00
cgroup: add cgroup->serial_nr and implement cgroup_next_sibling()
2013-05-24 10:55:38 +09:00
cgroup: rename ->create/post_create/pre_destroy/destroy() to ->css_alloc/online/offline/free()
2012-11-19 08:13:38 -08:00
Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/signal
2013-05-01 07:21:43 -07:00
proc: Supply PDE attribute setting accessor functions
2013-05-01 17:29:18 -04:00
Merge branch 'sched-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
2013-02-19 18:19:48 -08:00
Merge branch 'smp-hotplug-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
2013-02-19 19:04:55 -08:00
Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs
2013-05-01 17:51:54 -07:00
Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/user-namespace
2012-12-18 10:55:28 -08:00
cputime: Use accessors to read task cputime stats
2013-01-27 19:23:31 +01:00
Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs
2013-05-01 17:51:54 -07:00
extable: Flip the sorting message
2013-04-15 13:25:16 +02:00
Merge branch 'for-3.10/drivers' of git://git.kernel.dk/linux-block
2013-05-08 11:51:05 -07:00
freezer: change ptrace_stop/do_signal_stop to use freezable_schedule()
2012-10-26 14:27:49 -07:00
futex: fix kernel-doc notation and spello
2013-03-12 20:42:10 -07:00
Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/signal
2013-02-23 18:50:11 -08:00
Merge branch 'timers-nohz-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
2013-05-05 13:23:27 -07:00
Merge branch 'nohz/printk-v8' into irq/core
2013-02-05 00:48:46 +01:00
kernel: kallsyms: memory override issue, need check destination buffer length
2013-04-15 15:17:26 +09:30
kcmp: include linux/ptrace.h
2012-12-20 17:40:19 -08:00
locking: Adjust spin lock inlining Kconfig options
2012-09-13 17:56:13 +02:00
kexec: Use min() and min_t() to simplify logic
2013-04-30 17:04:07 -07:00
kmod: remove call_usermodehelper_fns()
2013-04-30 17:04:06 -07:00
kprobes: Fix a double lock bug of kprobe_mutex
2013-04-18 08:58:38 -07:00
Merge branch 'core-rcu-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
2012-12-11 18:10:49 -08:00
kthread: implement probe_kthread_data()
2013-04-30 17:04:02 -07:00
Merge branch 'for-3.10/drivers' of git://git.kernel.dk/linux-block
2013-05-08 11:51:05 -07:00
lockdep: Use KSYM_NAME_LEN'ed buffer for __get_key_name()
2012-10-24 12:39:09 +02:00
We get rid of the general module prefix confusion with a binary config option,
2013-05-05 10:58:06 -07:00
CONFIG_SYMBOL_PREFIX: cleanup.
2013-03-15 15:09:43 +10:30
keys: use keyring_alloc() to create module signing keyring
2012-12-20 17:40:21 -08:00
MODSIGN: Move the magic string to the end of a module and eliminate the search
2012-10-19 17:30:40 -07:00
module: don't unlink the module until we've removed all exposure.
2013-04-17 13:23:02 +09:30
MODSIGN: Don't use enum-type bitfields in module signature info block
2012-12-05 11:27:24 +10:30
mutex: Back out architecture specific check for negative mutex count
2013-04-19 09:33:36 +02:00
proc: Split the namespace stuff out into linux/proc_ns.h
2013-05-01 17:29:39 -04:00
padata: use __this_cpu_read per-cpu helper
2012-12-06 17:16:23 +08:00
dump_stack: implement arch-specific hardware description in task dumps
2013-04-30 17:04:02 -07:00
params: Fix potential memory leak in add_sysfs_param()
2013-03-18 11:40:21 +00:00
Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs
2013-05-01 17:51:54 -07:00
Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs
2013-05-01 17:51:54 -07:00
posix_timers: Fix pre-condition to stop the tick on full dynticks
2013-04-22 19:59:25 +02:00
posix-timers: Remove unused variable
2013-04-18 12:51:19 +02:00
aio: don't include aio.h in sched.h
2013-05-07 20:16:25 -07:00
proc: Supply PDE attribute setting accessor functions
2013-05-01 17:29:18 -04:00
aio: don't include aio.h in sched.h
2013-05-07 20:16:25 -07:00
kernel/range.c: subtract_range: fix the broken phrase issued by printk
2013-04-30 17:04:01 -07:00
rcu: Provide RCU CPU stall warnings for tiny RCU
2013-01-28 22:06:21 -08:00
Merge branches 'doctorture.2013.01.29a', 'fixes.2013.01.26a', 'tagcb.2013.01.24a' and 'tiny.2013.01.29b' into HEAD
2013-01-28 22:25:21 -08:00
Merge branches 'doctorture.2013.01.29a', 'fixes.2013.01.26a', 'tagcb.2013.01.24a' and 'tiny.2013.01.29b' into HEAD
2013-01-28 22:25:21 -08:00
rcu: Provide RCU CPU stall warnings for tiny RCU
2013-01-28 22:06:21 -08:00
rcu: Allow rcutorture to be built at low optimization levels
2013-02-04 12:18:20 -08:00
Merge commit ' 8700c95adb' into timers/nohz
2013-05-02 17:54:19 +02:00
Merge commit ' 8700c95adb' into timers/nohz
2013-05-02 17:54:19 +02:00
Merge branch 'timers-nohz-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
2013-05-05 13:23:27 -07:00
rcutrace: single_open() leaks
2013-05-05 00:16:35 -04:00
Merge branch 'for-3.10/core' of git://git.kernel.dk/linux-block
2013-05-08 10:13:35 -07:00
res_counter: return amount of charges after res_counter_uncharge()
2012-12-18 15:02:12 -08:00
mem hotunplug: fix kfree() of bootmem memory
2013-04-29 15:54:40 -07:00
sched/rt: Move rt specific bits into new header file
2013-02-07 20:51:08 +01:00
locking/rtmutex/tester: Set correct permissions on sysfs files
2013-04-10 14:48:37 +02:00
sched/rt: Move rt specific bits into new header file
2013-02-07 20:51:08 +01:00
Revert "rw_semaphore: remove up/down_read_non_owner"
2013-03-23 15:53:52 -07:00
seccomp: allow BPF_XOR based ALU instructions.
2013-03-26 11:07:19 +11:00
semaphore: use `bool' type for semaphore_waiter's up
2013-04-30 17:04:08 -07:00
Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net-next
2013-05-01 14:08:52 -07:00
kernel/smp.c: cleanups
2013-04-30 17:04:03 -07:00
kthread: Prevent unpark race which puts threads on the wrong cpu
2013-04-12 14:18:43 +02:00
Merge branch 'timers-nohz-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
2013-05-05 13:23:27 -07:00
srcu: use ACCESS_ONCE() to access sp->completed in srcu_read_lock()
2013-02-07 15:19:36 -08:00
stop_machine: Mark per cpu stopper enabled early
2013-02-26 22:25:17 +01:00
Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/signal
2013-05-01 07:21:43 -07:00
unify compat fanotify_mark(2), switch to COMPAT_SYSCALL_DEFINE
2013-05-09 13:46:38 -04:00
mm: replace hardcoded 3% with admin_reserve_pages knob
2013-04-29 15:54:36 -07:00
switch compat_sys_sysctl to COMPAT_SYSCALL_DEFINE
2013-05-09 14:53:20 -04:00
task_work: task_work_add() should not succeed after exit_task_work()
2012-09-13 16:47:34 +02:00
taskstats: cgroupstats_user_cmd() may leak on error
2012-10-06 03:05:31 +09:00
kernel/: rename random32() to prandom_u32()
2013-04-29 18:28:42 -07:00
timekeeping: Use inject_offset in warp_clock
2013-03-15 16:50:20 -07:00
kernel: Replace timeconst.pl with a bc script
2013-02-16 23:17:25 +01:00
Merge branch 'timers-nohz-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
2013-05-05 13:23:27 -07:00
Tracing updates for Linux 3.10
2013-04-29 13:55:38 -07:00
cputime: Use accessors to read task cputime stats
2013-01-27 19:23:31 +01:00
make SYSCALL_DEFINE<n>-generated wrappers do asmlinkage_protect
2013-03-03 22:58:33 -05:00
hlist: drop the node parameter from iterators
2013-02-27 19:10:24 -08:00
Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs
2013-05-01 17:51:54 -07:00
Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs
2013-05-01 17:51:54 -07:00
proc: Split the namespace stuff out into linux/proc_ns.h
2013-05-01 17:29:39 -04:00
kernel/utsname_sysctl.c: put get/get_uts() into CONFIG_PROC_SYSCTL code block
2013-02-27 19:10:22 -08:00
propagate name change to comments in kernel source
2012-12-06 10:39:54 +01:00
watchdog: Add comments to explain the watchdog_disabled variable
2013-03-14 08:24:05 +01:00
workqueue: include workqueue info when printing debug dump of a worker task
2013-04-30 17:04:02 -07:00
workqueue: include workqueue info when printing debug dump of a worker task
2013-04-30 17:04:02 -07:00
53fa526174