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Merge branch 'for-4.21' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup

Browse Source 
Pull cgroup updates from Tejun Heo:

 - Waiman's cgroup2 cpuset support has been finally merged closing one
   of the last remaining feature gaps.

 - cgroup.procs could show non-leader threads when cgroup2 threaded mode
   was used in certain ways. I forgot to push the fix during the last
   cycle.

 - A patch to fix mount option parsing when all mount options have been
   consumed by someone else (LSM).

 - cgroup_no_v1 boot param can now block named cgroup1 hierarchies too.

* 'for-4.21' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup:
  cgroup: Add named hierarchy disabling to cgroup_no_v1 boot param
  cgroup: fix parsing empty mount option string
  cpuset: Remove set but not used variable 'cs'
  cgroup: fix CSS_TASK_ITER_PROCS
  cgroup: Add .__DEBUG__. prefix to debug file names
  cpuset: Minor cgroup2 interface updates
  cpuset: Expose cpuset.cpus.subpartitions with cgroup_debug
  cpuset: Add documentation about the new "cpuset.sched.partition" flag
  cpuset: Use descriptive text when reading/writing cpuset.sched.partition
  cpuset: Expose cpus.effective and mems.effective on cgroup v2 root
  cpuset: Make generate_sched_domains() work with partition
  cpuset: Make CPU hotplug work with partition
  cpuset: Track cpusets that use parent's effective_cpus
  cpuset: Add an error state to cpuset.sched.partition
  cpuset: Add new v2 cpuset.sched.partition flag
  cpuset: Simply allocation and freeing of cpumasks
  cpuset: Define data structures to support scheduling partition
  cpuset: Enable cpuset controller in default hierarchy
  cgroup: remove unnecessary unlikely()
This commit is contained in:
Linus Torvalds 2018-12-29 10:57:20 -08:00
commit 6f9d71c9c7
8 changed files with 1115 additions and 100 deletions
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182
Documentation/admin-guide/cgroup-v2.rst
View File

@ -56,11 +56,13 @@ v1 is available under Documentation/cgroup-v1/.
5-3-3-2. IO Latency Interface Files
5-4. PID
5-4-1. PID Interface Files
5-5. Device
5-6. RDMA
5-6-1. RDMA Interface Files
5-7. Misc
5-7-1. perf_event
5-5. Cpuset
5.5-1. Cpuset Interface Files
5-6. Device
5-7. RDMA
5-7-1. RDMA Interface Files
5-8. Misc
5-8-1. perf_event
5-N. Non-normative information
5-N-1. CPU controller root cgroup process behaviour
5-N-2. IO controller root cgroup process behaviour
@ -1610,6 +1612,176 @@ through fork() or clone(). These will return -EAGAIN if the creation
of a new process would cause a cgroup policy to be violated.
Cpuset
------
The "cpuset" controller provides a mechanism for constraining
the CPU and memory node placement of tasks to only the resources
specified in the cpuset interface files in a task's current cgroup.
This is especially valuable on large NUMA systems where placing jobs
on properly sized subsets of the systems with careful processor and
memory placement to reduce cross-node memory access and contention
can improve overall system performance.
The "cpuset" controller is hierarchical. That means the controller
cannot use CPUs or memory nodes not allowed in its parent.
Cpuset Interface Files
~~~~~~~~~~~~~~~~~~~~~~
cpuset.cpus
A read-write multiple values file which exists on non-root
cpuset-enabled cgroups.
It lists the requested CPUs to be used by tasks within this
cgroup. The actual list of CPUs to be granted, however, is
subjected to constraints imposed by its parent and can differ
from the requested CPUs.
The CPU numbers are comma-separated numbers or ranges.
For example:
# cat cpuset.cpus
0-4,6,8-10
An empty value indicates that the cgroup is using the same
setting as the nearest cgroup ancestor with a non-empty
"cpuset.cpus" or all the available CPUs if none is found.
The value of "cpuset.cpus" stays constant until the next update
and won't be affected by any CPU hotplug events.
cpuset.cpus.effective
A read-only multiple values file which exists on all
cpuset-enabled cgroups.
It lists the onlined CPUs that are actually granted to this
cgroup by its parent. These CPUs are allowed to be used by
tasks within the current cgroup.
If "cpuset.cpus" is empty, the "cpuset.cpus.effective" file shows
all the CPUs from the parent cgroup that can be available to
be used by this cgroup. Otherwise, it should be a subset of
"cpuset.cpus" unless none of the CPUs listed in "cpuset.cpus"
can be granted. In this case, it will be treated just like an
empty "cpuset.cpus".
Its value will be affected by CPU hotplug events.
cpuset.mems
A read-write multiple values file which exists on non-root
cpuset-enabled cgroups.
It lists the requested memory nodes to be used by tasks within
this cgroup. The actual list of memory nodes granted, however,
is subjected to constraints imposed by its parent and can differ
from the requested memory nodes.
The memory node numbers are comma-separated numbers or ranges.
For example:
# cat cpuset.mems
0-1,3
An empty value indicates that the cgroup is using the same
setting as the nearest cgroup ancestor with a non-empty
"cpuset.mems" or all the available memory nodes if none
is found.
The value of "cpuset.mems" stays constant until the next update
and won't be affected by any memory nodes hotplug events.
cpuset.mems.effective
A read-only multiple values file which exists on all
cpuset-enabled cgroups.
It lists the onlined memory nodes that are actually granted to
this cgroup by its parent. These memory nodes are allowed to
be used by tasks within the current cgroup.
If "cpuset.mems" is empty, it shows all the memory nodes from the
parent cgroup that will be available to be used by this cgroup.
Otherwise, it should be a subset of "cpuset.mems" unless none of
the memory nodes listed in "cpuset.mems" can be granted. In this
case, it will be treated just like an empty "cpuset.mems".
Its value will be affected by memory nodes hotplug events.
cpuset.cpus.partition
A read-write single value file which exists on non-root
cpuset-enabled cgroups. This flag is owned by the parent cgroup
and is not delegatable.
It accepts only the following input values when written to.
"root" - a paritition root
"member" - a non-root member of a partition
When set to be a partition root, the current cgroup is the
root of a new partition or scheduling domain that comprises
itself and all its descendants except those that are separate
partition roots themselves and their descendants. The root
cgroup is always a partition root.
There are constraints on where a partition root can be set.
It can only be set in a cgroup if all the following conditions
are true.
1) The "cpuset.cpus" is not empty and the list of CPUs are
exclusive, i.e. they are not shared by any of its siblings.
2) The parent cgroup is a partition root.
3) The "cpuset.cpus" is also a proper subset of the parent's
"cpuset.cpus.effective".
4) There is no child cgroups with cpuset enabled. This is for
eliminating corner cases that have to be handled if such a
condition is allowed.
Setting it to partition root will take the CPUs away from the
effective CPUs of the parent cgroup. Once it is set, this
file cannot be reverted back to "member" if there are any child
cgroups with cpuset enabled.
A parent partition cannot distribute all its CPUs to its
child partitions. There must be at least one cpu left in the
parent partition.
Once becoming a partition root, changes to "cpuset.cpus" is
generally allowed as long as the first condition above is true,
the change will not take away all the CPUs from the parent
partition and the new "cpuset.cpus" value is a superset of its
children's "cpuset.cpus" values.
Sometimes, external factors like changes to ancestors'
"cpuset.cpus" or cpu hotplug can cause the state of the partition
root to change. On read, the "cpuset.sched.partition" file
can show the following values.
"member" Non-root member of a partition
"root" Partition root
"root invalid" Invalid partition root
It is a partition root if the first 2 partition root conditions
above are true and at least one CPU from "cpuset.cpus" is
granted by the parent cgroup.
A partition root can become invalid if none of CPUs requested
in "cpuset.cpus" can be granted by the parent cgroup or the
parent cgroup is no longer a partition root itself. In this
case, it is not a real partition even though the restriction
of the first partition root condition above will still apply.
The cpu affinity of all the tasks in the cgroup will then be
associated with CPUs in the nearest ancestor partition.
An invalid partition root can be transitioned back to a
real partition root if at least one of the requested CPUs
can now be granted by its parent. In this case, the cpu
affinity of all the tasks in the formerly invalid partition
will be associated to the CPUs of the newly formed partition.
Changing the partition state of an invalid partition root to
"member" is always allowed even if child cpusets are present.
Device controller
-----------------

8
Documentation/admin-guide/kernel-parameters.txt
View File

@ -486,10 +486,14 @@
cut the overhead, others just disable the usage. So
only cgroup_disable=memory is actually worthy}
cgroup_no_v1= [KNL] Disable one, multiple, all cgroup controllers in v1
Format: { controller[,controller...] | "all" }
cgroup_no_v1= [KNL] Disable cgroup controllers and named hierarchies in v1
Format: { { controller | "all" | "named" }
[,{ controller | "all" | "named" }...] }
Like cgroup_disable, but only applies to cgroup v1;
the blacklisted controllers remain available in cgroup2.
"all" blacklists all controllers and "named" disables
named mounts. Specifying both "all" and "named" disables
all v1 hierarchies.
cgroup.memory= [KNL] Pass options to the cgroup memory controller.
Format: <string>

1
include/linux/cgroup-defs.h
View File

@ -92,6 +92,7 @@ enum {
CFTYPE_NO_PREFIX = (1 << 3), /* (DON'T USE FOR NEW FILES) no subsys prefix */
CFTYPE_WORLD_WRITABLE = (1 << 4), /* (DON'T USE FOR NEW FILES) S_IWUGO */
CFTYPE_DEBUG = (1 << 5), /* create when cgroup_debug */
/* internal flags, do not use outside cgroup core proper */
__CFTYPE_ONLY_ON_DFL = (1 << 16), /* only on default hierarchy */

2
kernel/cgroup/cgroup-internal.h
View File

@ -11,6 +11,8 @@
#define TRACE_CGROUP_PATH_LEN 1024
extern spinlock_t trace_cgroup_path_lock;
extern char trace_cgroup_path[TRACE_CGROUP_PATH_LEN];
extern bool cgroup_debug;
extern void __init enable_debug_cgroup(void);
/*
* cgroup_path() takes a spin lock. It is good practice not to take

14
kernel/cgroup/cgroup-v1.c
View File

@ -27,6 +27,9 @@
/* Controllers blocked by the commandline in v1 */
static u16 cgroup_no_v1_mask;
/* disable named v1 mounts */
static bool cgroup_no_v1_named;
/*
* pidlist destructions need to be flushed on cgroup destruction. Use a
* separate workqueue as flush domain.
@ -963,6 +966,10 @@ static int parse_cgroupfs_options(char *data, struct cgroup_sb_opts *opts)
}
if (!strncmp(token, "name=", 5)) {
const char *name = token + 5;
/* blocked by boot param? */
if (cgroup_no_v1_named)
return -ENOENT;
/* Can't specify an empty name */
if (!strlen(name))
return -EINVAL;
@ -1292,7 +1299,12 @@ static int __init cgroup_no_v1(char *str)
if (!strcmp(token, "all")) {
cgroup_no_v1_mask = U16_MAX;
break;
continue;
}
if (!strcmp(token, "named")) {
cgroup_no_v1_named = true;
continue;
}
for_each_subsys(ss, i) {

60
kernel/cgroup/cgroup.c
View File

@ -86,6 +86,7 @@ EXPORT_SYMBOL_GPL(css_set_lock);
DEFINE_SPINLOCK(trace_cgroup_path_lock);
char trace_cgroup_path[TRACE_CGROUP_PATH_LEN];
bool cgroup_debug __read_mostly;
/*
* Protects cgroup_idr and css_idr so that IDs can be released without
@ -1429,12 +1430,15 @@ static char *cgroup_file_name(struct cgroup *cgrp, const struct cftype *cft,
struct cgroup_subsys *ss = cft->ss;
if (cft->ss && !(cft->flags & CFTYPE_NO_PREFIX) &&
!(cgrp->root->flags & CGRP_ROOT_NOPREFIX))
snprintf(buf, CGROUP_FILE_NAME_MAX, "%s.%s",
cgroup_on_dfl(cgrp) ? ss->name : ss->legacy_name,
!(cgrp->root->flags & CGRP_ROOT_NOPREFIX)) {
const char *dbg = (cft->flags & CFTYPE_DEBUG) ? ".__DEBUG__." : "";
snprintf(buf, CGROUP_FILE_NAME_MAX, "%s%s.%s",
dbg, cgroup_on_dfl(cgrp) ? ss->name : ss->legacy_name,
cft->name);
else
} else {
strscpy(buf, cft->name, CGROUP_FILE_NAME_MAX);
}
return buf;
}
@ -1774,7 +1778,7 @@ static int parse_cgroup_root_flags(char *data, unsigned int *root_flags)
*root_flags = 0;
if (!data)
if (!data || *data == '\0')
return 0;
while ((token = strsep(&data, ",")) != NULL) {
@ -3669,7 +3673,8 @@ restart:
continue;
if ((cft->flags & CFTYPE_ONLY_ON_ROOT) && cgroup_parent(cgrp))
continue;
if ((cft->flags & CFTYPE_DEBUG) && !cgroup_debug)
continue;
if (is_add) {
ret = cgroup_add_file(css, cgrp, cft);
if (ret) {
@ -4232,20 +4237,25 @@ static void css_task_iter_advance(struct css_task_iter *it)
lockdep_assert_held(&css_set_lock);
repeat:
/*
* Advance iterator to find next entry. cset->tasks is consumed
* first and then ->mg_tasks. After ->mg_tasks, we move onto the
* next cset.
*/
next = it->task_pos->next;
if (it->task_pos) {
/*
* Advance iterator to find next entry. cset->tasks is
* consumed first and then ->mg_tasks. After ->mg_tasks,
* we move onto the next cset.
*/
next = it->task_pos->next;
if (next == it->tasks_head)
next = it->mg_tasks_head->next;
if (next == it->tasks_head)
next = it->mg_tasks_head->next;
if (next == it->mg_tasks_head)
if (next == it->mg_tasks_head)
css_task_iter_advance_css_set(it);
else
it->task_pos = next;
} else {
/* called from start, proceed to the first cset */
css_task_iter_advance_css_set(it);
else
it->task_pos = next;
}
/* if PROCS, skip over tasks which aren't group leaders */
if ((it->flags & CSS_TASK_ITER_PROCS) && it->task_pos &&
@ -4285,7 +4295,7 @@ void css_task_iter_start(struct cgroup_subsys_state *css, unsigned int flags,
it->cset_head = it->cset_pos;
css_task_iter_advance_css_set(it);
css_task_iter_advance(it);
spin_unlock_irq(&css_set_lock);
}
@ -5773,6 +5783,16 @@ static int __init cgroup_disable(char *str)
}
__setup("cgroup_disable=", cgroup_disable);
void __init __weak enable_debug_cgroup(void) { }
static int __init enable_cgroup_debug(char *str)
{
cgroup_debug = true;
enable_debug_cgroup();
return 1;
}
__setup("cgroup_debug", enable_cgroup_debug);
/**
* css_tryget_online_from_dir - get corresponding css from a cgroup dentry
* @dentry: directory dentry of interest
@ -6008,10 +6028,8 @@ static ssize_t show_delegatable_files(struct cftype *files, char *buf,
ret += snprintf(buf + ret, size - ret, "%s\n", cft->name);
if (unlikely(ret >= size)) {
WARN_ON(1);
if (WARN_ON(ret >= size))
break;
}
}
return ret;

944
kernel/cgroup/cpuset.c
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File diff suppressed because it is too large Load Diff

4
kernel/cgroup/debug.c
View File

@ -373,11 +373,9 @@ struct cgroup_subsys debug_cgrp_subsys = {
* On v2, debug is an implicit controller enabled by "cgroup_debug" boot
* parameter.
*/
static int __init enable_cgroup_debug(char *str)
void __init enable_debug_cgroup(void)
{
debug_cgrp_subsys.dfl_cftypes = debug_files;
debug_cgrp_subsys.implicit_on_dfl = true;
debug_cgrp_subsys.threaded = true;
return 1;
}
__setup("cgroup_debug", enable_cgroup_debug);