Pull cgroup updates from Tejun Heo:
"There are several notable changes here:
- Single thread migrating itself has been optimized so that it
doesn't need threadgroup rwsem anymore.
- Freezer optimization to avoid unnecessary frozen state changes.
- cgroup ID unification so that cgroup fs ino is the only unique ID
used for the cgroup and can be used to directly look up live
cgroups through filehandle interface on 64bit ino archs. On 32bit
archs, cgroup fs ino is still the only ID in use but it is only
unique when combined with gen.
- selftest and other changes"
* 'for-5.5' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup: (24 commits)
writeback: fix -Wformat compilation warnings
docs: cgroup: mm: Fix spelling of "list"
cgroup: fix incorrect WARN_ON_ONCE() in cgroup_setup_root()
cgroup: use cgrp->kn->id as the cgroup ID
kernfs: use 64bit inos if ino_t is 64bit
kernfs: implement custom exportfs ops and fid type
kernfs: combine ino/id lookup functions into kernfs_find_and_get_node_by_id()
kernfs: convert kernfs_node->id from union kernfs_node_id to u64
kernfs: kernfs_find_and_get_node_by_ino() should only look up activated nodes
kernfs: use dumber locking for kernfs_find_and_get_node_by_ino()
netprio: use css ID instead of cgroup ID
writeback: use ino_t for inodes in tracepoints
kernfs: fix ino wrap-around detection
kselftests: cgroup: Avoid the reuse of fd after it is deallocated
cgroup: freezer: don't change task and cgroups status unnecessarily
cgroup: use cgroup->last_bstat instead of cgroup->bstat_pending for consistency
cgroup: remove cgroup_enable_task_cg_lists() optimization
cgroup: pids: use atomic64_t for pids->limit
selftests: cgroup: Run test_core under interfering stress
selftests: cgroup: Add task migration tests
...
Pull misc vfs fixes from Al Viro:
"Assorted fixes all over the place; some of that is -stable fodder,
some regressions from the last window"
* 'fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs:
ecryptfs_lookup_interpose(): lower_dentry->d_parent is not stable either
ecryptfs_lookup_interpose(): lower_dentry->d_inode is not stable
ecryptfs: fix unlink and rmdir in face of underlying fs modifications
audit_get_nd(): don't unlock parent too early
exportfs_decode_fh(): negative pinned may become positive without the parent locked
cgroup: don't put ERR_PTR() into fc->root
autofs: fix a leak in autofs_expire_indirect()
aio: Fix io_pgetevents() struct __compat_aio_sigset layout
fs/namespace.c: fix use-after-free of mount in mnt_warn_timestamp_expiry()
743210386c ("cgroup: use cgrp->kn->id as the cgroup ID") added WARN
which triggers if cgroup_id(root_cgrp) is not 1. This is fine on
64bit ino archs but on 32bit archs cgroup ID is ((gen << 32) | ino)
and gen starts at 1, so the root id is 0x1_0000_0001 instead of 1
always triggering the WARN.
What we wanna make sure is that the ino part is 1. Fix it.
Reported-by: Naresh Kamboju <naresh.kamboju@linaro.org>
Fixes: 743210386c ("cgroup: use cgrp->kn->id as the cgroup ID")
Signed-off-by: Tejun Heo <tj@kernel.org>
cgroup ID is currently allocated using a dedicated per-hierarchy idr
and used internally and exposed through tracepoints and bpf. This is
confusing because there are tracepoints and other interfaces which use
the cgroupfs ino as IDs.
The preceding changes made kn->id exposed as ino as 64bit ino on
supported archs or ino+gen (low 32bits as ino, high gen). There's no
reason for cgroup to use different IDs. The kernfs IDs are unique and
userland can easily discover them and map them back to paths using
standard file operations.
This patch replaces cgroup IDs with kernfs IDs.
* cgroup_id() is added and all cgroup ID users are converted to use it.
* kernfs_node creation is moved to earlier during cgroup init so that
cgroup_id() is available during init.
* While at it, s/cgroup/cgrp/ in psi helpers for consistency.
* Fallback ID value is changed to 1 to be consistent with root cgroup
ID.
Signed-off-by: Tejun Heo <tj@kernel.org>
Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Namhyung Kim <namhyung@kernel.org>
kernfs_find_and_get_node_by_ino() looks the kernfs_node matching the
specified ino. On top of that, kernfs_get_node_by_id() and
kernfs_fh_get_inode() implement full ID matching by testing the rest
of ID.
On surface, confusingly, the two are slightly different in that the
latter uses 0 gen as wildcard while the former doesn't - does it mean
that the latter can't uniquely identify inodes w/ 0 gen? In practice,
this is a distinction without a difference because generation number
starts at 1. There are no actual IDs with 0 gen, so it can always
safely used as wildcard.
Let's simplify the code by renaming kernfs_find_and_get_node_by_ino()
to kernfs_find_and_get_node_by_id(), moving all lookup logics into it,
and removing now unnecessary kernfs_get_node_by_id().
Signed-off-by: Tejun Heo <tj@kernel.org>
Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
kernfs_node->id is currently a union kernfs_node_id which represents
either a 32bit (ino, gen) pair or u64 value. I can't see much value
in the usage of the union - all that's needed is a 64bit ID which the
current code is already limited to. Using a union makes the code
unnecessarily complicated and prevents using 64bit ino without adding
practical benefits.
This patch drops union kernfs_node_id and makes kernfs_node->id a u64.
ino is stored in the lower 32bits and gen upper. Accessors -
kernfs[_id]_ino() and kernfs[_id]_gen() - are added to retrieve the
ino and gen. This simplifies ID handling less cumbersome and will
allow using 64bit inos on supported archs.
This patch doesn't make any functional changes.
Signed-off-by: Tejun Heo <tj@kernel.org>
Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: Alexei Starovoitov <ast@kernel.org>
It's not necessary to adjust the task state and revisit the state
of source and destination cgroups if the cgroups are not in freeze
state and the task itself is not frozen.
And in this scenario, it wakes up the task who's not supposed to be
ready to run.
Don't do the unnecessary task state adjustment can help stop waking
up the task without a reason.
Signed-off-by: Honglei Wang <honglei.wang@oracle.com>
Acked-by: Roman Gushchin <guro@fb.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
cgroup->bstat_pending is used to determine the base stat delta to
propagate to the parent. While correct, this is different from how
percpu delta is determined for no good reason and the inconsistency
makes the code more difficult to understand.
This patch makes parent propagation delta calculation use the same
method as percpu to global propagation.
* cgroup_base_stat_accumulate() is renamed to cgroup_base_stat_add()
and cgroup_base_stat_sub() is added.
* percpu propagation calculation is updated to use the above helpers.
* cgroup->bstat_pending is replaced with cgroup->last_bstat and
updated to use the same calculation as percpu propagation.
Signed-off-by: Tejun Heo <tj@kernel.org>
cgroup_enable_task_cg_lists() is used to lazyily initialize task
cgroup associations on the first use to reduce fork / exit overheads
on systems which don't use cgroup. Unfortunately, locking around it
has never been actually correct and its value is dubious given how the
vast majority of systems use cgroup right away from boot.
This patch removes the optimization. For now, replace the cg_list
based branches with WARN_ON_ONCE()'s to be on the safe side. We can
simplify the logic further in the future.
Signed-off-by: Tejun Heo <tj@kernel.org>
Reported-by: Oleg Nesterov <oleg@redhat.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
Because pids->limit can be changed concurrently (but we don't want to
take a lock because it would be needlessly expensive), use atomic64_ts
instead.
Fixes: commit 49b786ea14 ("cgroup: implement the PIDs subsystem")
Cc: stable@vger.kernel.org # v4.3+
Signed-off-by: Aleksa Sarai <cyphar@cyphar.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
There are reports of users who use thread migrations between cgroups and
they report performance drop after d59cfc09c3 ("sched, cgroup: replace
signal_struct->group_rwsem with a global percpu_rwsem"). The effect is
pronounced on machines with more CPUs.
The migration is affected by forking noise happening in the background,
after the mentioned commit a migrating thread must wait for all
(forking) processes on the system, not only of its threadgroup.
There are several places that need to synchronize with migration:
a) do_exit,
b) de_thread,
c) copy_process,
d) cgroup_update_dfl_csses,
e) parallel migration (cgroup_{proc,thread}s_write).
In the case of self-migrating thread, we relax the synchronization on
cgroup_threadgroup_rwsem to avoid the cost of waiting. d) and e) are
excluded with cgroup_mutex, c) does not matter in case of single thread
migration and the executing thread cannot exec(2) or exit(2) while it is
writing into cgroup.threads. In case of do_exit because of signal
delivery, we either exit before the migration or finish the migration
(of not yet PF_EXITING thread) and die afterwards.
This patch handles only the case of self-migration by writing "0" into
cgroup.threads. For simplicity, we always take cgroup_threadgroup_rwsem
with numeric PIDs.
This change improves migration dependent workload performance similar
to per-signal_struct state.
Signed-off-by: Michal Koutný <mkoutny@suse.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
We no longer take cgroup_mutex in cgroup_exit and the exiting tasks are
not moved to init_css_set, reflect that in several comments to prevent
confusion.
Signed-off-by: Michal Koutný <mkoutny@suse.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
Like commit 13d82fb77a ("cgroup: short-circuit cset_cgroup_from_root() on
the default hierarchy"), short-circuit current_cgns_cgroup_from_root() on
the default hierarchy.
Signed-off-by: Miaohe Lin <linmiaohe@huawei.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
Pull cgroup updates from Tejun Heo:
"Three minor cleanup patches"
* 'for-5.4' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup:
Use kvmalloc in cgroups-v1
cgroup: minor tweak for logic to get cgroup css
cgroup: Replace a seq_printf() call by seq_puts() in cgroup_print_ss_mask()
Pull scheduler updates from Ingo Molnar:
- MAINTAINERS: Add Mark Rutland as perf submaintainer, Juri Lelli and
Vincent Guittot as scheduler submaintainers. Add Dietmar Eggemann,
Steven Rostedt, Ben Segall and Mel Gorman as scheduler reviewers.
As perf and the scheduler is getting bigger and more complex,
document the status quo of current responsibilities and interests,
and spread the review pain^H^H^H^H fun via an increase in the Cc:
linecount generated by scripts/get_maintainer.pl. :-)
- Add another series of patches that brings the -rt (PREEMPT_RT) tree
closer to mainline: split the monolithic CONFIG_PREEMPT dependencies
into a new CONFIG_PREEMPTION category that will allow the eventual
introduction of CONFIG_PREEMPT_RT. Still a few more hundred patches
to go though.
- Extend the CPU cgroup controller with uclamp.min and uclamp.max to
allow the finer shaping of CPU bandwidth usage.
- Micro-optimize energy-aware wake-ups from O(CPUS^2) to O(CPUS).
- Improve the behavior of high CPU count, high thread count
applications running under cpu.cfs_quota_us constraints.
- Improve balancing with SCHED_IDLE (SCHED_BATCH) tasks present.
- Improve CPU isolation housekeeping CPU allocation NUMA locality.
- Fix deadline scheduler bandwidth calculations and logic when cpusets
rebuilds the topology, or when it gets deadline-throttled while it's
being offlined.
- Convert the cpuset_mutex to percpu_rwsem, to allow it to be used from
setscheduler() system calls without creating global serialization.
Add new synchronization between cpuset topology-changing events and
the deadline acceptance tests in setscheduler(), which were broken
before.
- Rework the active_mm state machine to be less confusing and more
optimal.
- Rework (simplify) the pick_next_task() slowpath.
- Improve load-balancing on AMD EPYC systems.
- ... and misc cleanups, smaller fixes and improvements - please see
the Git log for more details.
* 'sched-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (53 commits)
sched/psi: Correct overly pessimistic size calculation
sched/fair: Speed-up energy-aware wake-ups
sched/uclamp: Always use 'enum uclamp_id' for clamp_id values
sched/uclamp: Update CPU's refcount on TG's clamp changes
sched/uclamp: Use TG's clamps to restrict TASK's clamps
sched/uclamp: Propagate system defaults to the root group
sched/uclamp: Propagate parent clamps
sched/uclamp: Extend CPU's cgroup controller
sched/topology: Improve load balancing on AMD EPYC systems
arch, ia64: Make NUMA select SMP
sched, perf: MAINTAINERS update, add submaintainers and reviewers
sched/fair: Use rq_lock/unlock in online_fair_sched_group
cpufreq: schedutil: fix equation in comment
sched: Rework pick_next_task() slow-path
sched: Allow put_prev_task() to drop rq->lock
sched/fair: Expose newidle_balance()
sched: Add task_struct pointer to sched_class::set_curr_task
sched: Rework CPU hotplug task selection
sched/{rt,deadline}: Fix set_next_task vs pick_next_task
sched: Fix kerneldoc comment for ia64_set_curr_task
...
If a new child cgroup is created in the frozen cgroup hierarchy
(one or more of ancestor cgroups is frozen), the CGRP_FREEZE cgroup
flag should be set. Otherwise if a process will be attached to the
child cgroup, it won't become frozen.
The problem can be reproduced with the test_cgfreezer_mkdir test.
This is the output before this patch:
~/test_freezer
ok 1 test_cgfreezer_simple
ok 2 test_cgfreezer_tree
ok 3 test_cgfreezer_forkbomb
Cgroup /sys/fs/cgroup/cg_test_mkdir_A/cg_test_mkdir_B isn't frozen
not ok 4 test_cgfreezer_mkdir
ok 5 test_cgfreezer_rmdir
ok 6 test_cgfreezer_migrate
ok 7 test_cgfreezer_ptrace
ok 8 test_cgfreezer_stopped
ok 9 test_cgfreezer_ptraced
ok 10 test_cgfreezer_vfork
And with this patch:
~/test_freezer
ok 1 test_cgfreezer_simple
ok 2 test_cgfreezer_tree
ok 3 test_cgfreezer_forkbomb
ok 4 test_cgfreezer_mkdir
ok 5 test_cgfreezer_rmdir
ok 6 test_cgfreezer_migrate
ok 7 test_cgfreezer_ptrace
ok 8 test_cgfreezer_stopped
ok 9 test_cgfreezer_ptraced
ok 10 test_cgfreezer_vfork
Reported-by: Mark Crossen <mcrossen@fb.com>
Signed-off-by: Roman Gushchin <guro@fb.com>
Fixes: 76f969e894 ("cgroup: cgroup v2 freezer")
Cc: Tejun Heo <tj@kernel.org>
Cc: stable@vger.kernel.org # v5.2+
Signed-off-by: Tejun Heo <tj@kernel.org>
Instead of using its own logic for k-/vmalloc rely on
kvmalloc which is actually doing quite the same.
Signed-off-by: Marc Koderer <marc@koderer.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
We could only handle the case that css exists
and css_try_get_online() fails.
Signed-off-by: Peng Wang <rocking@whu.edu.cn>
Signed-off-by: Tejun Heo <tj@kernel.org>
A string which did not contain a data format specification should be put
into a sequence. Thus use the corresponding function “seq_puts”.
This issue was detected by using the Coccinelle software.
Signed-off-by: Markus Elfring <elfring@users.sourceforge.net>
Signed-off-by: Tejun Heo <tj@kernel.org>
