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Merge tag 'kernel-6.19-rc1.cred' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs
Pull cred guard updates from Christian Brauner:
"This contains substantial credential infrastructure improvements
adding guard-based credential management that simplifies code and
eliminates manual reference counting in many subsystems.
Features:
- Kernel Credential Guards
Add with_kernel_creds() and scoped_with_kernel_creds() guards that
allow using the kernel credentials without allocating and copying
them. This was requested by Linus after seeing repeated
prepare_kernel_creds() calls that duplicate the kernel credentials
only to drop them again later.
The new guards completely avoid the allocation and never expose the
temporary variable to hold the kernel credentials anywhere in
callers.
- Generic Credential Guards
Add scoped_with_creds() guards for the common override_creds() and
revert_creds() pattern. This builds on earlier work that made
override_creds()/revert_creds() completely reference count free.
- Prepare Credential Guards
Add prepare credential guards for the more complex pattern of
preparing a new set of credentials and overriding the current
credentials with them:
- prepare_creds()
- modify new creds
- override_creds()
- revert_creds()
- put_cred()
Cleanups:
- Make init_cred static since it should not be directly accessed
- Add kernel_cred() helper to properly access the kernel credentials
- Fix scoped_class() macro that was introduced two cycles ago
- coredump: split out do_coredump() from vfs_coredump() for cleaner
credential handling
- coredump: move revert_cred() before coredump_cleanup()
- coredump: mark struct mm_struct as const
- coredump: pass struct linux_binfmt as const
- sev-dev: use guard for path"
* tag 'kernel-6.19-rc1.cred' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs: (36 commits)
trace: use override credential guard
trace: use prepare credential guard
coredump: use override credential guard
coredump: use prepare credential guard
coredump: split out do_coredump() from vfs_coredump()
coredump: mark struct mm_struct as const
coredump: pass struct linux_binfmt as const
coredump: move revert_cred() before coredump_cleanup()
sev-dev: use override credential guards
sev-dev: use prepare credential guard
sev-dev: use guard for path
cred: add prepare credential guard
net/dns_resolver: use credential guards in dns_query()
cgroup: use credential guards in cgroup_attach_permissions()
act: use credential guards in acct_write_process()
smb: use credential guards in cifs_get_spnego_key()
nfs: use credential guards in nfs_idmap_get_key()
nfs: use credential guards in nfs_local_call_write()
nfs: use credential guards in nfs_local_call_read()
erofs: use credential guards
...
Bring in the shared branch with the kbuild tree to enable
'-fms-extensions' for 6.19. Further namespace cleanup work
requires this extension.
Signed-off-by: Christian Brauner <brauner@kernel.org>
The current naming is very misleading as this really isn't exiting all
of the task's namespaces. It is only exiting the namespaces that hang of
off nsproxy. Reflect that in the name.
Link: https://patch.msgid.link/20251029-work-namespace-nstree-listns-v4-10-2e6f823ebdc0@kernel.org
Reviewed-by: Jeff Layton <jlayton@kernel.org>
Signed-off-by: Christian Brauner <brauner@kernel.org>
The commit afa3701c0e ("cgroup: cgroup.stat.local time accounting")
introduced a seqcount to track freeze timing but initialized it as a
plain seqcount_t using seqcount_init().
However, the write-side critical section in cgroup_do_freeze() holds
the css_set_lock spinlock while calling write_seqcount_begin(). On
PREEMPT_RT kernels, spinlocks do not disable preemption, causing the
lockdep assertion for a plain seqcount_t, which checks for preemption
being disabled, to fail.
This triggers the following warning:
WARNING: CPU: 0 PID: 9692 at include/linux/seqlock.h:221
Fix this by changing the type to seqcount_spinlock_t and initializing
it with seqcount_spinlock_init() to associate css_set_lock with the
seqcount. This allows lockdep to correctly validate that the spinlock
is held during write operations, resolving the assertion failure on all
kernel configurations.
Reported-by: syzbot+27a2519eb4dad86d0156@syzkaller.appspotmail.com
Closes: https://syzkaller.appspot.com/bug?extid=27a2519eb4dad86d0156
Fixes: afa3701c0e ("cgroup: cgroup.stat.local time accounting")
Signed-off-by: Nirbhay Sharma <nirbhay.lkd@gmail.com>
Link: https://lore.kernel.org/r/20251002165510.KtY3IT--@linutronix.de/
Acked-by: Michal Koutný <mkoutny@suse.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
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Merge tag 'bpf-next-6.18' of git://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf-next
Pull bpf updates from Alexei Starovoitov:
- Support pulling non-linear xdp data with bpf_xdp_pull_data() kfunc
(Amery Hung)
Applied as a stable branch in bpf-next and net-next trees.
- Support reading skb metadata via bpf_dynptr (Jakub Sitnicki)
Also a stable branch in bpf-next and net-next trees.
- Enforce expected_attach_type for tailcall compatibility (Daniel
Borkmann)
- Replace path-sensitive with path-insensitive live stack analysis in
the verifier (Eduard Zingerman)
This is a significant change in the verification logic. More details,
motivation, long term plans are in the cover letter/merge commit.
- Support signed BPF programs (KP Singh)
This is another major feature that took years to materialize.
Algorithm details are in the cover letter/marge commit
- Add support for may_goto instruction to s390 JIT (Ilya Leoshkevich)
- Add support for may_goto instruction to arm64 JIT (Puranjay Mohan)
- Fix USDT SIB argument handling in libbpf (Jiawei Zhao)
- Allow uprobe-bpf program to change context registers (Jiri Olsa)
- Support signed loads from BPF arena (Kumar Kartikeya Dwivedi and
Puranjay Mohan)
- Allow access to union arguments in tracing programs (Leon Hwang)
- Optimize rcu_read_lock() + migrate_disable() combination where it's
used in BPF subsystem (Menglong Dong)
- Introduce bpf_task_work_schedule*() kfuncs to schedule deferred
execution of BPF callback in the context of a specific task using the
kernel’s task_work infrastructure (Mykyta Yatsenko)
- Enforce RCU protection for KF_RCU_PROTECTED kfuncs (Kumar Kartikeya
Dwivedi)
- Add stress test for rqspinlock in NMI (Kumar Kartikeya Dwivedi)
- Improve the precision of tnum multiplier verifier operation
(Nandakumar Edamana)
- Use tnums to improve is_branch_taken() logic (Paul Chaignon)
- Add support for atomic operations in arena in riscv JIT (Pu Lehui)
- Report arena faults to BPF error stream (Puranjay Mohan)
- Search for tracefs at /sys/kernel/tracing first in bpftool (Quentin
Monnet)
- Add bpf_strcasecmp() kfunc (Rong Tao)
- Support lookup_and_delete_elem command in BPF_MAP_STACK_TRACE (Tao
Chen)
* tag 'bpf-next-6.18' of git://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf-next: (197 commits)
libbpf: Replace AF_ALG with open coded SHA-256
selftests/bpf: Add stress test for rqspinlock in NMI
selftests/bpf: Add test case for different expected_attach_type
bpf: Enforce expected_attach_type for tailcall compatibility
bpftool: Remove duplicate string.h header
bpf: Remove duplicate crypto/sha2.h header
libbpf: Fix error when st-prefix_ops and ops from differ btf
selftests/bpf: Test changing packet data from kfunc
selftests/bpf: Add stacktrace map lookup_and_delete_elem test case
selftests/bpf: Refactor stacktrace_map case with skeleton
bpf: Add lookup_and_delete_elem for BPF_MAP_STACK_TRACE
selftests/bpf: Fix flaky bpf_cookie selftest
selftests/bpf: Test changing packet data from global functions with a kfunc
bpf: Emit struct bpf_xdp_sock type in vmlinux BTF
selftests/bpf: Task_work selftest cleanup fixes
MAINTAINERS: Delete inactive maintainers from AF_XDP
bpf: Mark kfuncs as __noclone
selftests/bpf: Add kprobe multi write ctx attach test
selftests/bpf: Add kprobe write ctx attach test
selftests/bpf: Add uprobe context ip register change test
...
- Extensive cpuset code cleanup and refactoring work with no functional
changes: CPU mask computation logic refactoring, introducing new helpers,
removing redundant code paths, and improving error handling for better
maintainability.
- A few bug fixes to cpuset including fixes for partition creation failures
when isolcpus is in use, missing error returns, and null pointer access
prevention in free_tmpmasks().
- Core cgroup changes include replacing the global percpu_rwsem with
per-threadgroup rwsem when writing to cgroup.procs for better scalability,
workqueue conversions to use WQ_PERCPU and system_percpu_wq to prepare for
workqueue default switching from percpu to unbound, and removal of unused
code including the post_attach callback.
- New cgroup.stat.local time accounting feature that tracks frozen time
duration.
- Misc changes including selftests updates (new freezer time tests and
backward compatibility fixes), documentation sync, string function safety
improvements, and 64-bit division fixes.
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Merge tag 'cgroup-for-6.18' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup
Pull cgroup updates from Tejun Heo:
- Extensive cpuset code cleanup and refactoring work with no functional
changes: CPU mask computation logic refactoring, introducing new
helpers, removing redundant code paths, and improving error handling
for better maintainability.
- A few bug fixes to cpuset including fixes for partition creation
failures when isolcpus is in use, missing error returns, and null
pointer access prevention in free_tmpmasks().
- Core cgroup changes include replacing the global percpu_rwsem with
per-threadgroup rwsem when writing to cgroup.procs for better
scalability, workqueue conversions to use WQ_PERCPU and
system_percpu_wq to prepare for workqueue default switching from
percpu to unbound, and removal of unused code including the
post_attach callback.
- New cgroup.stat.local time accounting feature that tracks frozen time
duration.
- Misc changes including selftests updates (new freezer time tests and
backward compatibility fixes), documentation sync, string function
safety improvements, and 64-bit division fixes.
* tag 'cgroup-for-6.18' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup: (39 commits)
cpuset: remove is_prs_invalid helper
cpuset: remove impossible warning in update_parent_effective_cpumask
cpuset: remove redundant special case for null input in node mask update
cpuset: fix missing error return in update_cpumask
cpuset: Use new excpus for nocpu error check when enabling root partition
cpuset: fix failure to enable isolated partition when containing isolcpus
Documentation: cgroup-v2: Sync manual toctree
cpuset: use partition_cpus_change for setting exclusive cpus
cpuset: use parse_cpulist for setting cpus.exclusive
cpuset: introduce partition_cpus_change
cpuset: refactor cpus_allowed_validate_change
cpuset: refactor out validate_partition
cpuset: introduce cpus_excl_conflict and mems_excl_conflict helpers
cpuset: refactor CPU mask buffer parsing logic
cpuset: Refactor exclusive CPU mask computation logic
cpuset: change return type of is_partition_[in]valid to bool
cpuset: remove unused assignment to trialcs->partition_root_state
cpuset: move the root cpuset write check earlier
cgroup/cpuset: Remove redundant rcu_read_lock/unlock() in spin_lock
cgroup: Remove redundant rcu_read_lock/unlock() in spin_lock
...
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Merge tag 'namespace-6.18-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs
Pull namespace updates from Christian Brauner:
"This contains a larger set of changes around the generic namespace
infrastructure of the kernel.
Each specific namespace type (net, cgroup, mnt, ...) embedds a struct
ns_common which carries the reference count of the namespace and so
on.
We open-coded and cargo-culted so many quirks for each namespace type
that it just wasn't scalable anymore. So given there's a bunch of new
changes coming in that area I've started cleaning all of this up.
The core change is to make it possible to correctly initialize every
namespace uniformly and derive the correct initialization settings
from the type of the namespace such as namespace operations, namespace
type and so on. This leaves the new ns_common_init() function with a
single parameter which is the specific namespace type which derives
the correct parameters statically. This also means the compiler will
yell as soon as someone does something remotely fishy.
The ns_common_init() addition also allows us to remove ns_alloc_inum()
and drops any special-casing of the initial network namespace in the
network namespace initialization code that Linus complained about.
Another part is reworking the reference counting. The reference
counting was open-coded and copy-pasted for each namespace type even
though they all followed the same rules. This also removes all open
accesses to the reference count and makes it private and only uses a
very small set of dedicated helpers to manipulate them just like we do
for e.g., files.
In addition this generalizes the mount namespace iteration
infrastructure introduced a few cycles ago. As reminder, the vfs makes
it possible to iterate sequentially and bidirectionally through all
mount namespaces on the system or all mount namespaces that the caller
holds privilege over. This allow userspace to iterate over all mounts
in all mount namespaces using the listmount() and statmount() system
call.
Each mount namespace has a unique identifier for the lifetime of the
systems that is exposed to userspace. The network namespace also has a
unique identifier working exactly the same way. This extends the
concept to all other namespace types.
The new nstree type makes it possible to lookup namespaces purely by
their identifier and to walk the namespace list sequentially and
bidirectionally for all namespace types, allowing userspace to iterate
through all namespaces. Looking up namespaces in the namespace tree
works completely locklessly.
This also means we can move the mount namespace onto the generic
infrastructure and remove a bunch of code and members from struct
mnt_namespace itself.
There's a bunch of stuff coming on top of this in the future but for
now this uses the generic namespace tree to extend a concept
introduced first for pidfs a few cycles ago. For a while now we have
supported pidfs file handles for pidfds. This has proven to be very
useful.
This extends the concept to cover namespaces as well. It is possible
to encode and decode namespace file handles using the common
name_to_handle_at() and open_by_handle_at() apis.
As with pidfs file handles, namespace file handles are exhaustive,
meaning it is not required to actually hold a reference to nsfs in
able to decode aka open_by_handle_at() a namespace file handle.
Instead the FD_NSFS_ROOT constant can be passed which will let the
kernel grab a reference to the root of nsfs internally and thus decode
the file handle.
Namespaces file descriptors can already be derived from pidfds which
means they aren't subject to overmount protection bugs. IOW, it's
irrelevant if the caller would not have access to an appropriate
/proc/<pid>/ns/ directory as they could always just derive the
namespace based on a pidfd already.
It has the same advantage as pidfds. It's possible to reliably and for
the lifetime of the system refer to a namespace without pinning any
resources and to compare them trivially.
Permission checking is kept simple. If the caller is located in the
namespace the file handle refers to they are able to open it otherwise
they must hold privilege over the owning namespace of the relevant
namespace.
The namespace file handle layout is exposed as uapi and has a stable
and extensible format. For now it simply contains the namespace
identifier, the namespace type, and the inode number. The stable
format means that userspace may construct its own namespace file
handles without going through name_to_handle_at() as they are already
allowed for pidfs and cgroup file handles"
* tag 'namespace-6.18-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs: (65 commits)
ns: drop assert
ns: move ns type into struct ns_common
nstree: make struct ns_tree private
ns: add ns_debug()
ns: simplify ns_common_init() further
cgroup: add missing ns_common include
ns: use inode initializer for initial namespaces
selftests/namespaces: verify initial namespace inode numbers
ns: rename to __ns_ref
nsfs: port to ns_ref_*() helpers
net: port to ns_ref_*() helpers
uts: port to ns_ref_*() helpers
ipv4: use check_net()
net: use check_net()
net-sysfs: use check_net()
user: port to ns_ref_*() helpers
time: port to ns_ref_*() helpers
pid: port to ns_ref_*() helpers
ipc: port to ns_ref_*() helpers
cgroup: port to ns_ref_*() helpers
...
It's misplaced in struct proc_ns_operations and ns->ops might be NULL if
the namespace is compiled out but we still want to know the type of the
namespace for the initial namespace struct.
Reviewed-by: Jan Kara <jack@suse.cz>
Signed-off-by: Christian Brauner <brauner@kernel.org>
Support the generic ns lookup infrastructure to support file handles for
namespaces.
Acked-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Christian Brauner <brauner@kernel.org>
Since commit a8bb74acd8 ("rcu: Consolidate RCU-sched update-side function definitions")
there is no difference between rcu_read_lock(), rcu_read_lock_bh() and
rcu_read_lock_sched() in terms of RCU read section and the relevant grace
period. That means that spin_lock(), which implies rcu_read_lock_sched(),
also implies rcu_read_lock().
There is no need no explicitly start a RCU read section if one has already
been started implicitly by spin_lock().
Simplify the code and remove the inner rcu_read_lock() invocation.
Cc: Tejun Heo <tj@kernel.org>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Waiman Long <longman@redhat.com>
Signed-off-by: pengdonglin <pengdonglin@xiaomi.com>
Signed-off-by: pengdonglin <dolinux.peng@gmail.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
The bpf_cgroup_from_id kfunc relies on cgroup_get_from_id to obtain the
cgroup corresponding to a given cgroup ID. This helper can be called in
a lot of contexts where the current thread can be random. A recent
example was its use in sched_ext's ops.tick(), to obtain the root cgroup
pointer. Since the current task can be whatever random user space task
preempted by the timer tick, this makes the behavior of the helper
unreliable.
Refactor out __cgroup_get_from_id as the non-namespace aware version of
cgroup_get_from_id, and change bpf_cgroup_from_id to make use of it.
There is no compatibility breakage here, since changing the namespace
against which the lookup is being done to the root cgroup namespace only
permits a wider set of lookups to succeed now. The cgroup IDs across
namespaces are globally unique, and thus don't need to be retranslated.
Reported-by: Dan Schatzberg <dschatzberg@meta.com>
Signed-off-by: Kumar Kartikeya Dwivedi <memxor@gmail.com>
Acked-by: Tejun Heo <tj@kernel.org>
Link: https://lore.kernel.org/r/20250915032618.1551762-2-memxor@gmail.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
The static usage pattern of creating a cgroup, enabling controllers,
and then seeding it with CLONE_INTO_CGROUP doesn't require write
locking cgroup_threadgroup_rwsem and thus doesn't benefit from this
patch.
To avoid affecting other users, the per threadgroup rwsem is only used
when the favordynmods is enabled.
As computer hardware advances, modern systems are typically equipped
with many CPU cores and large amounts of memory, enabling the deployment
of numerous applications. On such systems, container creation and
deletion become frequent operations, making cgroup process migration no
longer a cold path. This leads to noticeable contention with common
process operations such as fork, exec, and exit.
To alleviate the contention between cgroup process migration and
operations like process fork, this patch modifies lock to take the write
lock on signal_struct->group_rwsem when writing pid to
cgroup.procs/threads instead of holding a global write lock.
Cgroup process migration has historically relied on
signal_struct->group_rwsem to protect thread group integrity. In commit
<1ed1328792ff> ("sched, cgroup: replace signal_struct->group_rwsem with
a global percpu_rwsem"), this was changed to a global
cgroup_threadgroup_rwsem. The advantage of using a global lock was
simplified handling of process group migrations. This patch retains the
use of the global lock for protecting process group migration, while
reducing contention by using per thread group lock during
cgroup.procs/threads writes.
The locking behavior is as follows:
write cgroup.procs/threads | process fork,exec,exit | process group migration
------------------------------------------------------------------------------
cgroup_lock() | down_read(&g_rwsem) | cgroup_lock()
down_write(&p_rwsem) | down_read(&p_rwsem) | down_write(&g_rwsem)
critical section | critical section | critical section
up_write(&p_rwsem) | up_read(&p_rwsem) | up_write(&g_rwsem)
cgroup_unlock() | up_read(&g_rwsem) | cgroup_unlock()
g_rwsem denotes cgroup_threadgroup_rwsem, p_rwsem denotes
signal_struct->group_rwsem.
This patch eliminates contention between cgroup migration and fork
operations for threads that belong to different thread groups, thereby
reducing the long-tail latency of cgroup migrations and lowering system
load.
With this patch, under heavy fork and exec interference, the long-tail
latency of cgroup migration has been reduced from milliseconds to
microseconds. Under heavy cgroup migration interference, the multi-CPU
score of the spawn test case in UnixBench increased by 9%.
tj: Update comment in cgroup_favor_dynmods() and switch WARN_ONCE() to
pr_warn_once().
Signed-off-by: Yi Tao <escape@linux.alibaba.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
Later patches will introduce a new parameter `task` to
cgroup_attach_lock, thus adjusting the position of cgroup_attach_lock
within cgroup_procs_write_start.
Between obtaining the threadgroup leader via PID and acquiring the
cgroup attach lock, the threadgroup leader may change, which could lead
to incorrect cgroup migration. Therefore, after acquiring the cgroup
attach lock, we check whether the threadgroup leader has changed, and if
so, retry the operation.
tj: Minor comment adjustments.
Signed-off-by: Yi Tao <escape@linux.alibaba.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
Dynamic cgroup migration involving threadgroup locks can be in one of
two states: no lock held, or holding the global lock. Explicitly
declaring the different lock modes to make the code easier to
understand and facilitates future extensions of the lock modes.
Signed-off-by: Yi Tao <escape@linux.alibaba.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
Pull for-6.17-fixes to receive 79f919a89c ("cgroup: split
cgroup_destroy_wq into 3 workqueues") to resolve its conflict with
7fa33aa3b0 ("cgroup: WQ_PERCPU added to alloc_workqueue users"). The
latter adds WQ_PERCPU when creating cgroup_destroy_wq and the former splits
the workqueue into three. Resolve by applying WQ_PERCPU to the three split
workqueues.
Signed-off-by: Tejun Heo <tj@kernel.org>
Currently if a user enqueue a work item using schedule_delayed_work() the
used wq is "system_wq" (per-cpu wq) while queue_delayed_work() use
WORK_CPU_UNBOUND (used when a cpu is not specified). The same applies to
schedule_work() that is using system_wq and queue_work(), that makes use
again of WORK_CPU_UNBOUND.
This lack of consistentcy cannot be addressed without refactoring the API.
alloc_workqueue() treats all queues as per-CPU by default, while unbound
workqueues must opt-in via WQ_UNBOUND.
This default is suboptimal: most workloads benefit from unbound queues,
allowing the scheduler to place worker threads where they’re needed and
reducing noise when CPUs are isolated.
This patch adds a new WQ_PERCPU flag to explicitly request the use of
the per-CPU behavior. Both flags coexist for one release cycle to allow
callers to transition their calls.
Once migration is complete, WQ_UNBOUND can be removed and unbound will
become the implicit default.
With the introduction of the WQ_PERCPU flag (equivalent to !WQ_UNBOUND),
any alloc_workqueue() caller that doesn’t explicitly specify WQ_UNBOUND
must now use WQ_PERCPU.
All existing users have been updated accordingly.
Suggested-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Marco Crivellari <marco.crivellari@suse.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
Currently if a user enqueue a work item using schedule_delayed_work() the
used wq is "system_wq" (per-cpu wq) while queue_delayed_work() use
WORK_CPU_UNBOUND (used when a cpu is not specified). The same applies to
schedule_work() that is using system_wq and queue_work(), that makes use
again of WORK_CPU_UNBOUND.
This lack of consistentcy cannot be addressed without refactoring the API.
system_wq is a per-CPU worqueue, yet nothing in its name tells about that
CPU affinity constraint, which is very often not required by users. Make
it clear by adding a system_percpu_wq.
queue_work() / queue_delayed_work() mod_delayed_work() will now use the
new per-cpu wq: whether the user still stick on the old name a warn will
be printed along a wq redirect to the new one.
This patch add the new system_percpu_wq except for mm, fs and net
subsystem, whom are handled in separated patches.
The old wq will be kept for a few release cylces.
Suggested-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Marco Crivellari <marco.crivellari@suse.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
d8b269e009 ("cgroup: Remove unused cgroup_subsys::post_attach") made $ss
and $ssid unused but didn't drop them leading to compilation warnings. Drop
them.
Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: Chuyi Zhou <zhouchuyi@bytedance.com>
cgroup_subsys::post_attach callback was introduced in commit 5cf1cacb49
("cgroup, cpuset: replace cpuset_post_attach_flush() with
cgroup_subsys->post_attach callback") and only cpuset would use this
callback to wait for the mm migration to complete at the end of
__cgroup_procs_write(). Since the previous patch defer the flush operation
until returning to userspace, no one use this callback now. Remove this
callback from cgroup_subsys.
Signed-off-by: Chuyi Zhou <zhouchuyi@bytedance.com>
Acked-by: Waiman Long <longman@redhat.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
There isn't yet a clear way to identify a set of "lost" time that
everyone (or at least a wider group of users) cares about. However,
users can perform some delay accounting by iterating over components of
interest. This patch allows cgroup v2 freezing time to be one of those
components.
Track the cumulative time that each v2 cgroup spends freezing and expose
it to userland via a new local stat file in cgroupfs. Thank you to
Michal, who provided the ASCII art in the updated documentation.
To access this value:
$ mkdir /sys/fs/cgroup/test
$ cat /sys/fs/cgroup/test/cgroup.stat.local
freeze_time_total 0
Ensure consistent freeze time reads with freeze_seq, a per-cgroup
sequence counter. Writes are serialized using the css_set_lock.
Signed-off-by: Tiffany Yang <ynaffit@google.com>
Cc: Tejun Heo <tj@kernel.org>
Cc: Michal Koutný <mkoutny@suse.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
A hung task can occur during [1] LTP cgroup testing when repeatedly
mounting/unmounting perf_event and net_prio controllers with
systemd.unified_cgroup_hierarchy=1. The hang manifests in
cgroup_lock_and_drain_offline() during root destruction.
Related case:
cgroup_fj_function_perf_event cgroup_fj_function.sh perf_event
cgroup_fj_function_net_prio cgroup_fj_function.sh net_prio
Call Trace:
cgroup_lock_and_drain_offline+0x14c/0x1e8
cgroup_destroy_root+0x3c/0x2c0
css_free_rwork_fn+0x248/0x338
process_one_work+0x16c/0x3b8
worker_thread+0x22c/0x3b0
kthread+0xec/0x100
ret_from_fork+0x10/0x20
Root Cause:
CPU0 CPU1
mount perf_event umount net_prio
cgroup1_get_tree cgroup_kill_sb
rebind_subsystems // root destruction enqueues
// cgroup_destroy_wq
// kill all perf_event css
// one perf_event css A is dying
// css A offline enqueues cgroup_destroy_wq
// root destruction will be executed first
css_free_rwork_fn
cgroup_destroy_root
cgroup_lock_and_drain_offline
// some perf descendants are dying
// cgroup_destroy_wq max_active = 1
// waiting for css A to die
Problem scenario:
1. CPU0 mounts perf_event (rebind_subsystems)
2. CPU1 unmounts net_prio (cgroup_kill_sb), queuing root destruction work
3. A dying perf_event CSS gets queued for offline after root destruction
4. Root destruction waits for offline completion, but offline work is
blocked behind root destruction in cgroup_destroy_wq (max_active=1)
Solution:
Split cgroup_destroy_wq into three dedicated workqueues:
cgroup_offline_wq – Handles CSS offline operations
cgroup_release_wq – Manages resource release
cgroup_free_wq – Performs final memory deallocation
This separation eliminates blocking in the CSS free path while waiting for
offline operations to complete.
[1] https://github.com/linux-test-project/ltp/blob/master/runtest/controllers
Fixes: 334c3679ec ("cgroup: reimplement rebind_subsystems() using cgroup_apply_control() and friends")
Reported-by: Gao Yingjie <gaoyingjie@uniontech.com>
Signed-off-by: Chen Ridong <chenridong@huawei.com>
Suggested-by: Teju Heo <tj@kernel.org>
Signed-off-by: Tejun Heo <tj@kernel.org>
One of key items in mprog API is revision for prog list. The revision
number will be increased if the prog list changed, e.g., attach, detach
or replace.
Add 'revisions' field to struct cgroup_bpf, representing revisions for
all cgroup related attachment types. The initial revision value is
set to 1, the same as kernel mprog implementations.
Signed-off-by: Yonghong Song <yonghong.song@linux.dev>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Acked-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20250606163136.2428732-1-yonghong.song@linux.dev
- cgroup rstat shared the tracking tree across all controlers with the
rationale being that a cgroup which is using one resource is likely to be
using other resources at the same time (ie. if something is allocating
memory, it's probably consuming CPU cycles). However, this turned out to
not scale very well especially with memcg using rstat for internal
operations which made memcg stat read and flush patterns substantially
different from other controllers. JP Kobryn split the rstat tree per
controller.
- cgroup BPF support was hooking into cgroup init/exit paths directly.
Convert them to use a notifier chain instead so that other usages can be
added easily. The two of the patches which implement this are mislabeled
as belonging to sched_ext instead of cgroup. Sorry.
- Relatively minor cpuset updates.
- Documentation updates.
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Merge tag 'cgroup-for-6.16' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup
Pull cgroup updates from Tejun Heo:
- cgroup rstat shared the tracking tree across all controllers with the
rationale being that a cgroup which is using one resource is likely
to be using other resources at the same time (ie. if something is
allocating memory, it's probably consuming CPU cycles).
However, this turned out to not scale very well especially with memcg
using rstat for internal operations which made memcg stat read and
flush patterns substantially different from other controllers. JP
Kobryn split the rstat tree per controller.
- cgroup BPF support was hooking into cgroup init/exit paths directly.
Convert them to use a notifier chain instead so that other usages can
be added easily. The two of the patches which implement this are
mislabeled as belonging to sched_ext instead of cgroup. Sorry.
- Relatively minor cpuset updates
- Documentation updates
* tag 'cgroup-for-6.16' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup: (23 commits)
sched_ext: Convert cgroup BPF support to use cgroup_lifetime_notifier
sched_ext: Introduce cgroup_lifetime_notifier
cgroup: Minor reorganization of cgroup_create()
cgroup, docs: cpu controller's interaction with various scheduling policies
cgroup, docs: convert space indentation to tab indentation
cgroup: avoid per-cpu allocation of size zero rstat cpu locks
cgroup, docs: be specific about bandwidth control of rt processes
cgroup: document the rstat per-cpu initialization
cgroup: helper for checking rstat participation of css
cgroup: use subsystem-specific rstat locks to avoid contention
cgroup: use separate rstat trees for each subsystem
cgroup: compare css to cgroup::self in helper for distingushing css
cgroup: warn on rstat usage by early init subsystems
cgroup/cpuset: drop useless cpumask_empty() in compute_effective_exclusive_cpumask()
cgroup/rstat: Improve cgroup_rstat_push_children() documentation
cgroup: fix goto ordering in cgroup_init()
cgroup: fix pointer check in css_rstat_init()
cgroup/cpuset: Add warnings to catch inconsistency in exclusive CPUs
cgroup/cpuset: Fix obsolete comment in cpuset_css_offline()
cgroup/cpuset: Always use cpu_active_mask
...
Other subsystems may make use of the cgroup hierarchy with the cgroup_bpf
support being one such example. For such a feature, it's useful to be able
to hook into cgroup creation and destruction paths to perform
feature-specific initializations and cleanups.
Add cgroup_lifetime_notifier which generates CGROUP_LIFETIME_ONLINE and
CGROUP_LIFETIME_OFFLINE events whenever cgroups are created and destroyed,
respectively.
The next patch will convert cgroup_bpf to use the new notifier and other
uses are planned.
Signed-off-by: Tejun Heo <tj@kernel.org>
cgroup_bpf init and exit handling will be moved to a notifier chain. In
prepartion, reorganize cgroup_create() a bit so that the new cgroup is fully
initialized before any outside changes are made.
- cgrp->ancestors[] initialization and the hierarchical nr_descendants and
nr_frozen_descendants updates were in the same loop. Separate them out and
do the former earlier and do the latter later.
- Relocate cgroup_bpf_inherit() call so that it's after all cgroup
initializations are complete.
No visible behavior changes expected.
Signed-off-by: Tejun Heo <tj@kernel.org>
It is possible to eliminate contention between subsystems when
updating/flushing stats by using subsystem-specific locks. Let the existing
rstat locks be dedicated to the cgroup base stats and rename them to
reflect that. Add similar locks to the cgroup_subsys struct for use with
individual subsystems.
Lock initialization is done in the new function ss_rstat_init(ss) which
replaces cgroup_rstat_boot(void). If NULL is passed to this function, the
global base stat locks will be initialized. Otherwise, the subsystem locks
will be initialized.
Change the existing lock helper functions to accept a reference to a css.
Then within these functions, conditionally select the appropriate locks
based on the subsystem affiliation of the given css. Add helper functions
for this selection routine to avoid repeated code.
Signed-off-by: JP Kobryn <inwardvessel@gmail.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
Different subsystems may call cgroup_rstat_updated() within the same
cgroup, resulting in a tree of pending updates from multiple subsystems.
When one of these subsystems is flushed via cgroup_rstat_flushed(), all
other subsystems with pending updates on the tree will also be flushed.
Change the paradigm of having a single rstat tree for all subsystems to
having separate trees for each subsystem. This separation allows for
subsystems to perform flushes without the side effects of other subsystems.
As an example, flushing the cpu stats will no longer cause the memory stats
to be flushed and vice versa.
In order to achieve subsystem-specific trees, change the tree node type
from cgroup to cgroup_subsys_state pointer. Then remove those pointers from
the cgroup and instead place them on the css. Finally, change update/flush
functions to make use of the different node type (css). These changes allow
a specific subsystem to be associated with an update or flush. Separate
rstat trees will now exist for each unique subsystem.
Since updating/flushing will now be done at the subsystem level, there is
no longer a need to keep track of updated css nodes at the cgroup level.
The list management of these nodes done within the cgroup (rstat_css_list
and related) has been removed accordingly.
Conditional guards for checking validity of a given css were placed within
css_rstat_updated/flush() to prevent undefined behavior occuring from kfunc
usage in bpf programs. Guards were also placed within css_rstat_init/exit()
in order to help consolidate calls to them. At call sites for all four
functions, the existing guards were removed.
Signed-off-by: JP Kobryn <inwardvessel@gmail.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
Adjust the implementation of css_is_cgroup() so that it compares the given
css to cgroup::self. Rename the function to css_is_self() in order to
reflect that. Change the existing css->ss NULL check to a warning in the
true branch. Finally, adjust call sites to use the new function name.
Signed-off-by: JP Kobryn <inwardvessel@gmail.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
An early init subsystem that attempts to make use of rstat can lead to
failures during early boot. The reason for this is the timing in which the
css's of the root cgroup have css_online() invoked on them. At the point of
this call, there is a stated assumption that a cgroup has "successfully
completed all allocations" [0]. An example of a subsystem that relies on
the previously mentioned assumption [0] is the memory subsystem. Within its
implementation of css_online(), work is queued to asynchronously begin
flushing via rstat. In the early init path for a given subsystem, having
rstat enabled leads to this sequence:
cgroup_init_early()
for_each_subsys(ss, ssid)
if (ss->early_init)
cgroup_init_subsys(ss, true)
cgroup_init_subsys(ss, early_init)
css = ss->css_alloc(...)
init_and_link_css(css, ss, ...)
...
online_css(css)
online_css(css)
ss = css->ss
ss->css_online(css)
Continuing to use the memory subsystem as an example, the issue with this
sequence is that css_rstat_init() has not been called yet. This means there
is now a race between the pending async work to flush rstat and the call to
css_rstat_init(). So a flush can occur within the given cgroup while the
rstat fields are not initialized.
Since we are in the early init phase, the rstat fields cannot be
initialized because they require per-cpu allocations. So it's not possible
to have css_rstat_init() called early enough (before online_css()). This
patch treats the combination of early init and rstat the same as as other
invalid conditions.
[0] Documentation/admin-guide/cgroup-v1/cgroups.rst (section: css_online)
Signed-off-by: JP Kobryn <inwardvessel@gmail.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
Go to the appropriate section labels when css_rstat_init() or
psi_cgroup_alloc() fails.
Signed-off-by: JP Kobryn <inwardvessel@gmail.com>
Fixes: a97915559f ("cgroup: change rstat function signatures from cgroup-based to css-based")
Signed-off-by: Tejun Heo <tj@kernel.org>
Android has mounted the v1 cpuset controller using filesystem type
"cpuset" (not "cgroup") since 2015 [1], and depends on the resulting
behavior where the controller name is not added as a prefix for cgroupfs
files. [2]
Later, a problem was discovered where cpu hotplug onlining did not
affect the cpuset/cpus files, which Android carried an out-of-tree patch
to address for a while. An attempt was made to upstream this patch, but
the recommendation was to use the "cpuset_v2_mode" mount option
instead. [3]
An effort was made to do so, but this fails with "cgroup: Unknown
parameter 'cpuset_v2_mode'" because commit e1cba4b85d ("cgroup: Add
mount flag to enable cpuset to use v2 behavior in v1 cgroup") did not
update the special cased cpuset_mount(), and only the cgroup (v1)
filesystem type was updated.
Add parameter parsing to the cpuset filesystem type so that
cpuset_v2_mode works like the cgroup filesystem type:
$ mkdir /dev/cpuset
$ mount -t cpuset -ocpuset_v2_mode none /dev/cpuset
$ mount|grep cpuset
none on /dev/cpuset type cgroup (rw,relatime,cpuset,noprefix,cpuset_v2_mode,release_agent=/sbin/cpuset_release_agent)
[1] b769c8d24f
[2] https://cs.android.com/android/platform/superproject/main/+/main:system/core/libprocessgroup/setup/cgroup_map_write.cpp;drc=2dac5d89a0f024a2d0cc46a80ba4ee13472f1681;l=192
[3] https://lore.kernel.org/lkml/f795f8be-a184-408a-0b5a-553d26061385@redhat.com/T/
Fixes: e1cba4b85d ("cgroup: Add mount flag to enable cpuset to use v2 behavior in v1 cgroup")
Signed-off-by: T.J. Mercier <tjmercier@google.com>
Acked-by: Waiman Long <longman@redhat.com>
Reviewed-by: Kamalesh Babulal <kamalesh.babulal@oracle.com>
Acked-by: Michal Koutný <mkoutny@suse.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
When adding folio_memcg function call in the zram module for
Android16-6.12, the following error occurs during compilation:
ERROR: modpost: "cgroup_mutex" [../soc-repo/zram.ko] undefined!
This error is caused by the indirect call to lockdep_is_held(&cgroup_mutex)
within folio_memcg. The export setting for cgroup_mutex is controlled by
the CONFIG_PROVE_RCU macro. If CONFIG_LOCKDEP is enabled while
CONFIG_PROVE_RCU is not, this compilation error will occur.
To resolve this issue, add a parallel macro CONFIG_LOCKDEP control to
ensure cgroup_mutex is properly exported when needed.
Signed-off-by: gao xu <gaoxu2@honor.com>
Acked-by: Michal Koutný <mkoutny@suse.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
- A number of cpuset remote partition related fixes and cleanups along with
selftest updates.
- A change from this merge window made cgroup_rstat_updated_list() called
outside cgroup_rstat_lock leading to list corruptions. Fix it by
relocating the call inside the lock.
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Merge tag 'cgroup-for-6.15-rc1-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup
Pull cgroup fixes from Tejun Heo:
- A number of cpuset remote partition related fixes and cleanups along
with selftest updates.
- A change from this merge window made cgroup_rstat_updated_list()
called outside cgroup_rstat_lock leading to list corruptions. Fix it
by relocating the call inside the lock.
* tag 'cgroup-for-6.15-rc1-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup:
cgroup/cpuset: Fix race between newly created partition and dying one
cgroup: rstat: call cgroup_rstat_updated_list with cgroup_rstat_lock
selftest/cgroup: Add a remote partition transition test to test_cpuset_prs.sh
selftest/cgroup: Clean up and restructure test_cpuset_prs.sh
selftest/cgroup: Update test_cpuset_prs.sh to use | as effective CPUs and state separator
cgroup/cpuset: Remove unneeded goto in sched_partition_write() and rename it
cgroup/cpuset: Code cleanup and comment update
cgroup/cpuset: Don't allow creation of local partition over a remote one
cgroup/cpuset: Remove remote_partition_check() & make update_cpumasks_hier() handle remote partition
cgroup/cpuset: Fix error handling in remote_partition_disable()
cgroup/cpuset: Fix incorrect isolated_cpus update in update_parent_effective_cpumask()
timer_delete[_sync]() replaces del_timer[_sync](). Convert the whole tree
over and remove the historical wrapper inlines.
Conversion was done with coccinelle plus manual fixups where necessary.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
This non-functional change serves as preparation for moving to
subsystem-based rstat trees. To simplify future commits, change the
signatures of existing cgroup-based rstat functions to become css-based and
rename them to reflect that.
Though the signatures have changed, the implementations have not. Within
these functions use the css->cgroup pointer to obtain the associated cgroup
and allow code to function the same just as it did before this patch. At
applicable call sites, pass the subsystem-specific css pointer as an
argument or pass a pointer to cgroup::self if not in subsystem context.
Note that cgroup_rstat_updated_list() and cgroup_rstat_push_children()
are not altered yet since there would be a larger amount of css to
cgroup conversions which may overcomplicate the code at this
intermediate phase.
Signed-off-by: JP Kobryn <inwardvessel@gmail.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
The cgroup struct has a css field called "self". The main difference
between this css and the others found in the cgroup::subsys array is that
cgroup::self has a NULL subsystem pointer. There are several places where
checks are performed to determine whether the css in question is
cgroup::self or not. Instead of accessing css->ss directly, introduce a
helper function that shows the intent and use where applicable.
Signed-off-by: JP Kobryn <inwardvessel@gmail.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
This non-functional change serves as preparation for moving to
subsystem-based rstat trees. The base stats are not an actual subsystem,
but in future commits they will have exclusive rstat trees just as other
subsystems will.
Moving the base stat objects into a new struct allows the cgroup_rstat_cpu
struct to become more compact since it now only contains the minimum amount
of pointers needed for rstat participation. Subsystems will (in future
commits) make use of the compact cgroup_rstat_cpu struct while avoiding the
memory overhead of the base stat objects which they will not use.
An instance of the new struct cgroup_rstat_base_cpu was placed on the
cgroup struct so it can retain ownership of these base stats common to all
cgroups. A helper function was added for looking up the cpu-specific base
stats of a given cgroup. Finally, initialization and variable names were
adjusted where applicable.
Signed-off-by: JP Kobryn <inwardvessel@gmail.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
There is a possible race between removing a cgroup diectory that is
a partition root and the creation of a new partition. The partition
to be removed can be dying but still online, it doesn't not currently
participate in checking for exclusive CPUs conflict, but the exclusive
CPUs are still there in subpartitions_cpus and isolated_cpus. These
two cpumasks are global states that affect the operation of cpuset
partitions. The exclusive CPUs in dying cpusets will only be removed
when cpuset_css_offline() function is called after an RCU delay.
As a result, it is possible that a new partition can be created with
exclusive CPUs that overlap with those of a dying one. When that dying
partition is finally offlined, it removes those overlapping exclusive
CPUs from subpartitions_cpus and maybe isolated_cpus resulting in an
incorrect CPU configuration.
This bug was found when a warning was triggered in
remote_partition_disable() during testing because the subpartitions_cpus
mask was empty.
One possible way to fix this is to iterate the dying cpusets as well and
avoid using the exclusive CPUs in those dying cpusets. However, this
can still cause random partition creation failures or other anomalies
due to racing. A better way to fix this race is to reset the partition
state at the moment when a cpuset is being killed.
Introduce a new css_killed() CSS function pointer and call it, if
defined, before setting CSS_DYING flag in kill_css(). Also update the
css_is_dying() helper to use the CSS_DYING flag introduced by commit
33c35aa481 ("cgroup: Prevent kill_css() from being called more than
once") for proper synchronization.
Add a new cpuset_css_killed() function to reset the partition state of
a valid partition root if it is being killed.
Fixes: ee8dde0cd2 ("cpuset: Add new v2 cpuset.sched.partition flag")
Signed-off-by: Waiman Long <longman@redhat.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
Here is the big set of driver core updates for 6.15-rc1. Lots of stuff
happened this development cycle, including:
- kernfs scaling changes to make it even faster thanks to rcu
- bin_attribute constify work in many subsystems
- faux bus minor tweaks for the rust bindings
- rust binding updates for driver core, pci, and platform busses,
making more functionaliy available to rust drivers. These are all
due to people actually trying to use the bindings that were in 6.14.
- make Rafael and Danilo full co-maintainers of the driver core
codebase
- other minor fixes and updates.
This has been in linux-next for a while now, with the only reported
issue being some merge conflicts with the rust tree. Depending on which
tree you pull first, you will have conflicts in one of them. The merge
resolution has been in linux-next as an example of what to do, or can be
found here:
https://lore.kernel.org/r/CANiq72n3Xe8JcnEjirDhCwQgvWoE65dddWecXnfdnbrmuah-RQ@mail.gmail.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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Merge tag 'driver-core-6.15-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-core
Pull driver core updatesk from Greg KH:
"Here is the big set of driver core updates for 6.15-rc1. Lots of stuff
happened this development cycle, including:
- kernfs scaling changes to make it even faster thanks to rcu
- bin_attribute constify work in many subsystems
- faux bus minor tweaks for the rust bindings
- rust binding updates for driver core, pci, and platform busses,
making more functionaliy available to rust drivers. These are all
due to people actually trying to use the bindings that were in
6.14.
- make Rafael and Danilo full co-maintainers of the driver core
codebase
- other minor fixes and updates"
* tag 'driver-core-6.15-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-core: (52 commits)
rust: platform: require Send for Driver trait implementers
rust: pci: require Send for Driver trait implementers
rust: platform: impl Send + Sync for platform::Device
rust: pci: impl Send + Sync for pci::Device
rust: platform: fix unrestricted &mut platform::Device
rust: pci: fix unrestricted &mut pci::Device
rust: device: implement device context marker
rust: pci: use to_result() in enable_device_mem()
MAINTAINERS: driver core: mark Rafael and Danilo as co-maintainers
rust/kernel/faux: mark Registration methods inline
driver core: faux: only create the device if probe() succeeds
rust/faux: Add missing parent argument to Registration::new()
rust/faux: Drop #[repr(transparent)] from faux::Registration
rust: io: fix devres test with new io accessor functions
rust: io: rename `io::Io` accessors
kernfs: Move dput() outside of the RCU section.
efi: rci2: mark bin_attribute as __ro_after_init
rapidio: constify 'struct bin_attribute'
firmware: qemu_fw_cfg: constify 'struct bin_attribute'
powerpc/perf/hv-24x7: Constify 'struct bin_attribute'
...
- Add deprecation info messages to cgroup1-only features.
- rstat updates including a bug fix and breaking up a critical section to
reduce interrupt latency impact.
- Other misc and doc updates.
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Merge tag 'cgroup-for-6.15' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup
Pull cgroup updates from Tejun Heo:
- Add deprecation info messages to cgroup1-only features
- rstat updates including a bug fix and breaking up a critical section
to reduce interrupt latency impact
- Other misc and doc updates
* tag 'cgroup-for-6.15' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup:
cgroup: rstat: Cleanup flushing functions and locking
cgroup/rstat: avoid disabling irqs for O(num_cpu)
mm: Fix a build breakage in memcontrol-v1.c
blk-cgroup: Simplify policy files registration
cgroup: Update file naming comment
cgroup: Add deprecation message to legacy freezer controller
mm: Add transformation message for per-memcg swappiness
RFC cgroup/cpuset-v1: Add deprecation messages to sched_relax_domain_level
cgroup/cpuset-v1: Add deprecation messages to memory_migrate
cgroup/cpuset-v1: Add deprecation messages to mem_exclusive and mem_hardwall
cgroup: Print message when /proc/cgroups is read on v2-only system
cgroup/blkio: Add deprecation messages to reset_stats
cgroup/cpuset-v1: Add deprecation messages to memory_spread_page and memory_spread_slab
cgroup/cpuset-v1: Add deprecation messages to sched_load_balance and memory_pressure_enabled
cgroup, docs: Be explicit about independence of RT_GROUP_SCHED and non-cpu controllers
cgroup/rstat: Fix forceidle time in cpu.stat
cgroup/misc: Remove unused misc_cg_res_total_usage
cgroup/cpuset: Move procfs cpuset attribute under cgroup-v1.c
cgroup: update comment about dropping cgroup kn refs
Use one set of files when there is no difference between default and
legacy files, similar to regular subsys files registration. No
functional change.
Signed-off-by: Michal Koutný <mkoutny@suse.com>
Acked-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Tejun Heo <tj@kernel.org>
As a followup to commits 6c2920926b ("cgroup: replace
unified-hierarchy.txt with a proper cgroup v2 documentation") and
ab03125268 ("cgroup: Show # of subsystem CSSes in cgroup.stat"),
add a runtime message to users who read status of controllers in
/proc/cgroups on v2-only system. The detection is based on a)
no controllers are attached to v1, b) default hierarchy is mounted (the
latter is for setups that never mount v2 but read /proc/cgroups upon
boot when controllers default to v2, so that this code may be backported
to older kernels).
Signed-off-by: Michal Koutný <mkoutny@suse.com>
Acked-by: Waiman Long <longman@redhat.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
Linus Torvalds
Christian Brauner
Nirbhay Sharma
pengdonglin
Kumar Kartikeya Dwivedi
Yi Tao
Tejun Heo
Marco Crivellari
Chuyi Zhou
Tiffany Yang
Chen Ridong
Yonghong Song
JP Kobryn
T.J. Mercier
gaoxu
Thomas Gleixner
Waiman Long
Michal Koutný