cgroup is in the process of converting to css (cgroup_subsys_state)
from cgroup as the principal subsystem interface handle. This is
mostly to prepare for the unified hierarchy support where css's will
be created and destroyed dynamically but also helps cleaning up
subsystem implementations as css is usually what they are interested
in anyway.
cftype->[un]register_event() is among the remaining couple interfaces
which still use struct cgroup. Convert it to cgroup_subsys_state.
The conversion is mostly mechanical and removes the last users of
mem_cgroup_from_cont() and cg_to_vmpressure(), which are removed.
v2: indentation update as suggested by Li Zefan.
Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: Li Zefan <lizefan@huawei.com>
Acked-by: Michal Hocko <mhocko@suse.cz>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Balbir Singh <bsingharora@gmail.com>
cgroup is in the process of converting to css (cgroup_subsys_state)
from cgroup as the principal subsystem interface handle. This is
mostly to prepare for the unified hierarchy support where css's will
be created and destroyed dynamically but also helps cleaning up
subsystem implementations as css is usually what they are interested
in anyway.
This patch converts task iterators to deal with css instead of cgroup.
Note that under unified hierarchy, different sets of tasks will be
considered belonging to a given cgroup depending on the subsystem in
question and making the iterators deal with css instead cgroup
provides them with enough information about the iteration.
While at it, fix several function comment formats in cpuset.c.
This patch doesn't introduce any behavior differences.
Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: Li Zefan <lizefan@huawei.com>
Acked-by: Michal Hocko <mhocko@suse.cz>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Balbir Singh <bsingharora@gmail.com>
Cc: Matt Helsley <matthltc@us.ibm.com>
cgroup_scan_tasks() takes a pointer to struct cgroup_scanner as its
sole argument and the only function of that struct is packing the
arguments of the function call which are consisted of five fields.
It's not too unusual to pack parameters into a struct when the number
of arguments gets excessive or the whole set needs to be passed around
a lot, but neither holds here making it just weird.
Drop struct cgroup_scanner and pass the params directly to
cgroup_scan_tasks(). Note that struct cpuset_change_nodemask_arg was
added to cpuset.c to pass both ->cs and ->newmems pointer to
cpuset_change_nodemask() using single data pointer.
This doesn't make any functional differences.
Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: Li Zefan <lizefan@huawei.com>
Currently all cgroup_task_iter functions require @cgrp to be passed
in, which is superflous and increases chance of usage error. Make
cgroup_task_iter remember the cgroup being iterated and drop @cgrp
argument from next and end functions.
This patch doesn't introduce any behavior differences.
Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: Li Zefan <lizefan@huawei.com>
Acked-by: Michal Hocko <mhocko@suse.cz>
Cc: Matt Helsley <matthltc@us.ibm.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Balbir Singh <bsingharora@gmail.com>
cgroup now has multiple iterators and it's quite confusing to have
something which walks over tasks of a single cgroup named cgroup_iter.
Let's rename it to cgroup_task_iter.
While at it, reformat / update comments and replace the overview
comment above the interface function decls with proper function
comments. Such overview can be useful but function comments should be
more than enough here.
This is pure rename and doesn't introduce any functional changes.
Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: Li Zefan <lizefan@huawei.com>
Acked-by: Michal Hocko <mhocko@suse.cz>
Cc: Matt Helsley <matthltc@us.ibm.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Balbir Singh <bsingharora@gmail.com>
For some reason, cgroup_advance_iter() is standing lonely all away
from its iter comrades. Relocate it.
This is cosmetic.
Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: Li Zefan <lizefan@huawei.com>
cgroup is currently in the process of transitioning to using css
(cgroup_subsys_state) as the primary handle instead of cgroup in
subsystem API. For hierarchy iterators, this is beneficial because
* In most cases, css is the only thing subsystems care about anyway.
* On the planned unified hierarchy, iterations for different
subsystems will need to skip over different subtrees of the
hierarchy depending on which subsystems are enabled on each cgroup.
Passing around css makes it unnecessary to explicitly specify the
subsystem in question as css is intersection between cgroup and
subsystem
* For the planned unified hierarchy, css's would need to be created
and destroyed dynamically independent from cgroup hierarchy. Having
cgroup core manage css iteration makes enforcing deref rules a lot
easier.
Most subsystem conversions are straight-forward. Noteworthy changes
are
* blkio: cgroup_to_blkcg() is no longer used. Removed.
* freezer: cgroup_freezer() is no longer used. Removed.
* devices: cgroup_to_devcgroup() is no longer used. Removed.
Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: Li Zefan <lizefan@huawei.com>
Acked-by: Michal Hocko <mhocko@suse.cz>
Acked-by: Vivek Goyal <vgoyal@redhat.com>
Acked-by: Aristeu Rozanski <aris@redhat.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Balbir Singh <bsingharora@gmail.com>
Cc: Matt Helsley <matthltc@us.ibm.com>
Cc: Jens Axboe <axboe@kernel.dk>
There are several places where the children list is accessed directly.
This patch converts those places to use cgroup_next_child(). This
will help updating the hierarchy iterators to use @css instead of
@cgrp.
While cgroup_next_child() can be heavy in pathological cases - e.g. a
lot of dead children, this shouldn't cause any noticeable behavior
differences.
Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: Li Zefan <lizefan@huawei.com>
cgroup is transitioning to using css (cgroup_subsys_state) as the main
subsys interface handle instead of cgroup and the iterators will be
updated to use css too. The iterators need to walk the cgroup
hierarchy and return the css's matching the origin css, which is a bit
cumbersome to open code.
This patch converts cgroup_next_sibling() to cgroup_next_child() so
that it can handle all steps of direct child iteration. This will be
used to update iterators to take @css instead of @cgrp. In addition
to the new iteration init handling, cgroup_next_child() is
restructured so that the different branches share the end of iteration
condition check.
This patch doesn't change any behavior.
Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: Li Zefan <lizefan@huawei.com>
cgroup is currently in the process of transitioning to using struct
cgroup_subsys_state * as the primary handle instead of struct cgroup.
Please see the previous commit which converts the subsystem methods
for rationale.
This patch converts all cftype file operations to take @css instead of
@cgroup. cftypes for the cgroup core files don't have their subsytem
pointer set. These will automatically use the dummy_css added by the
previous patch and can be converted the same way.
Most subsystem conversions are straight forwards but there are some
interesting ones.
* freezer: update_if_frozen() is also converted to take @css instead
of @cgroup for consistency. This will make the code look simpler
too once iterators are converted to use css.
* memory/vmpressure: mem_cgroup_from_css() needs to be exported to
vmpressure while mem_cgroup_from_cont() can be made static.
Updated accordingly.
* cpu: cgroup_tg() doesn't have any user left. Removed.
* cpuacct: cgroup_ca() doesn't have any user left. Removed.
* hugetlb: hugetlb_cgroup_form_cgroup() doesn't have any user left.
Removed.
* net_cls: cgrp_cls_state() doesn't have any user left. Removed.
Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: Li Zefan <lizefan@huawei.com>
Acked-by: Michal Hocko <mhocko@suse.cz>
Acked-by: Vivek Goyal <vgoyal@redhat.com>
Acked-by: Aristeu Rozanski <aris@redhat.com>
Acked-by: Daniel Wagner <daniel.wagner@bmw-carit.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Balbir Singh <bsingharora@gmail.com>
Cc: Matt Helsley <matthltc@us.ibm.com>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: Steven Rostedt <rostedt@goodmis.org>
cgroup subsystem API is being converted to use css
(cgroup_subsys_state) as the main handle, which makes things a bit
awkward for subsystem agnostic core features - the "cgroup.*"
interface files and various iterations - a bit awkward as they don't
have a css to use.
This patch adds cgroup->dummy_css which has NULL ->ss and whose only
role is pointing back to the cgroup. This will be used to support
subsystem agnostic features on the coming css based API.
css_parent() is updated to handle dummy_css's. Note that css will
soon grow its own ->parent field and css_parent() will be made
trivial.
Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: Li Zefan <lizefan@huawei.com>
Previously, each file read/write operation relied on the inode
reference count pinning the cgroup and simply checked whether the
cgroup was marked dead before proceeding to invoke the per-subsystem
callback. This was rather silly as it didn't have any synchronization
or css pinning around the check and the cgroup may be removed and all
css refs drained between the DEAD check and actual method invocation.
This patch pins the css between open() and release() so that it is
guaranteed to be alive for all file operations and remove the silly
DEAD checks from cgroup_file_read/write().
Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: Li Zefan <lizefan@huawei.com>
cgroup is transitioning to using css (cgroup_subsys_state) instead of
cgroup as the primary subsystem handle. The cgroupfs file interface
will be converted to use css's which requires finding out the
subsystem from cftype so that the matching css can be determined from
the cgroup.
This patch adds cftype->ss which points to the subsystem the file
belongs to. The field is initialized while a cftype is being
registered. This makes it unnecessary to explicitly specify the
subsystem for other cftype handling functions. @ss argument dropped
from various cftype handling functions.
This patch shouldn't introduce any behavior differences.
Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: Li Zefan <lizefan@huawei.com>
Acked-by: Vivek Goyal <vgoyal@redhat.com>
Cc: Jens Axboe <axboe@kernel.dk>
cgroup is currently in the process of transitioning to using struct
cgroup_subsys_state * as the primary handle instead of struct cgroup *
in subsystem implementations for the following reasons.
* With unified hierarchy, subsystems will be dynamically bound and
unbound from cgroups and thus css's (cgroup_subsys_state) may be
created and destroyed dynamically over the lifetime of a cgroup,
which is different from the current state where all css's are
allocated and destroyed together with the associated cgroup. This
in turn means that cgroup_css() should be synchronized and may
return NULL, making it more cumbersome to use.
* Differing levels of per-subsystem granularity in the unified
hierarchy means that the task and descendant iterators should behave
differently depending on the specific subsystem the iteration is
being performed for.
* In majority of the cases, subsystems only care about its part in the
cgroup hierarchy - ie. the hierarchy of css's. Subsystem methods
often obtain the matching css pointer from the cgroup and don't
bother with the cgroup pointer itself. Passing around css fits
much better.
This patch converts all cgroup_subsys methods to take @css instead of
@cgroup. The conversions are mostly straight-forward. A few
noteworthy changes are
* ->css_alloc() now takes css of the parent cgroup rather than the
pointer to the new cgroup as the css for the new cgroup doesn't
exist yet. Knowing the parent css is enough for all the existing
subsystems.
* In kernel/cgroup.c::offline_css(), unnecessary open coded css
dereference is replaced with local variable access.
This patch shouldn't cause any behavior differences.
v2: Unnecessary explicit cgrp->subsys[] deref in css_online() replaced
with local variable @css as suggested by Li Zefan.
Rebased on top of new for-3.12 which includes for-3.11-fixes so
that ->css_free() invocation added by da0a12caff ("cgroup: fix a
leak when percpu_ref_init() fails") is converted too. Suggested
by Li Zefan.
Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: Li Zefan <lizefan@huawei.com>
Acked-by: Michal Hocko <mhocko@suse.cz>
Acked-by: Vivek Goyal <vgoyal@redhat.com>
Acked-by: Aristeu Rozanski <aris@redhat.com>
Acked-by: Daniel Wagner <daniel.wagner@bmw-carit.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Balbir Singh <bsingharora@gmail.com>
Cc: Matt Helsley <matthltc@us.ibm.com>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: Steven Rostedt <rostedt@goodmis.org>
Currently, controllers have to explicitly follow the cgroup hierarchy
to find the parent of a given css. cgroup is moving towards using
cgroup_subsys_state as the main controller interface construct, so
let's provide a way to climb the hierarchy using just csses.
This patch implements css_parent() which, given a css, returns its
parent. The function is guarnateed to valid non-NULL parent css as
long as the target css is not at the top of the hierarchy.
freezer, cpuset, cpu, cpuacct, hugetlb, memory, net_cls and devices
are converted to use css_parent() instead of accessing cgroup->parent
directly.
* __parent_ca() is dropped from cpuacct and its usage is replaced with
parent_ca(). The only difference between the two was NULL test on
cgroup->parent which is now embedded in css_parent() making the
distinction moot. Note that eventually a css->parent field will be
added to css and the NULL check in css_parent() will go away.
This patch shouldn't cause any behavior differences.
Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: Li Zefan <lizefan@huawei.com>
css (cgroup_subsys_state) is usually embedded in a subsys specific
data structure. Subsystems either use container_of() directly to cast
from css to such data structure or has an accessor function wrapping
such cast. As cgroup as whole is moving towards using css as the main
interface handle, add and update such accessors to ease dealing with
css's.
All accessors explicitly handle NULL input and return NULL in those
cases. While this looks like an extra branch in the code, as all
controllers specific data structures have css as the first field, the
casting doesn't involve any offsetting and the compiler can trivially
optimize out the branch.
* blkio, freezer, cpuset, cpu, cpuacct and net_cls didn't have such
accessor. Added.
* memory, hugetlb and devices already had one but didn't explicitly
handle NULL input. Updated.
Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: Li Zefan <lizefan@huawei.com>
Currently, given a cgroup_subsys_state, there's no way to find out
which subsystem the css is for, which we'll need to convert the cgroup
controller API to primarily use @css instead of @cgroup. This patch
adds cgroup_subsys_state->ss which points to the subsystem the @css
belongs to.
While at it, remove the comment about accessing @css->cgroup to
determine the hierarchy. cgroup core will provide API to traverse
hierarchy of css'es and we don't want subsystems to directly walk
cgroup hierarchies anymore.
Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: Li Zefan <lizefan@huawei.com>
cgroup controller API will be converted to primarily use struct
cgroup_subsys_state instead of struct cgroup. In preparation, make
hugetlb_cgroup functions pass around struct hugetlb_cgroup instead of
struct cgroup.
This patch shouldn't cause any behavior differences.
Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: Li Zefan <lizefan@huawei.com>
Reviewed-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Reviewed-by: Michal Hocko <mhocko@suse.cz>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
cgroup controller API will be converted to primarily use struct
cgroup_subsys_state instead of struct cgroup. In preparation, make
the internal functions of netprio_cgroup pass around @css instead of
@cgrp.
While at it, kill struct cgroup_netprio_state which only contained
struct cgroup_subsys_state without serving any purpose. All functions
are converted to deal with @css directly.
This patch shouldn't cause any behavior differences.
Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: Li Zefan <lizefan@huawei.com>
Acked-by: Neil Horman <nhorman@tuxdriver.com>
Acked-by: David S. Miller <davem@davemloft.net>
cpuset uses "const" qualifiers on struct cpuset in some functions;
however, it doesn't work well when a value derived from returned const
pointer has to be passed to an accessor. It's C after all.
Drop the "const" qualifiers except for the trivially leaf ones. This
patch doesn't make any functional changes.
Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: Li Zefan <lizefan@huawei.com>
The names of the two struct cgroup_subsys_state accessors -
cgroup_subsys_state() and task_subsys_state() - are somewhat awkward.
The former clashes with the type name and the latter doesn't even
indicate it's somehow related to cgroup.
We're about to revamp large portion of cgroup API, so, let's rename
them so that they're less awkward. Most per-controller usages of the
accessors are localized in accessor wrappers and given the amount of
scheduled changes, this isn't gonna add any noticeable headache.
Rename cgroup_subsys_state() to cgroup_css() and task_subsys_state()
to task_css(). This patch is pure rename.
Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: Li Zefan <lizefan@huawei.com>
for-3.12 branch is about to receive invasive updates which are
dependent on da0a12caff ("cgroup: fix a leak when percpu_ref_init()
fails"). Given the amount of scheduled changes, I think it'd less
painful to pull in for-3.11-fixes as preparation. Pull in
for-3.11-fixes into for-3.12.
Signed-off-by: Tejun Heo <tj@kernel.org>
It uses a single label and checks the validity of each pointer. This
is err-prone, and actually we had a bug because one of the check was
insufficient.
Use multi lables as we do in other places.
v2:
- drop initializations of local variables.
Signed-off-by: Li Zefan <lizefan@huawei.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
This will be used as a replacement for css_lookup().
There's a difference with cgroup id and css id. cgroup id starts with 0,
while css id starts with 1.
v4:
- also check if cggroup_mutex is held.
- make it an inline function.
Signed-off-by: Li Zefan <lizefan@huawei.com>
Reviewed-by: Michal Hocko <mhocko@suse.cz>
Signed-off-by: Tejun Heo <tj@kernel.org>
As cgroup id has been used in netprio cgroup and will be used in memcg,
it's important to make it clear how a cgroup id is allocated.
For example, in netprio cgroup, the id is used as index of anarray.
Signed-off-by: Li Zefan <lizefan@huwei.com>
Reviewed-by: Michal Hocko <mhocko@suse.cz>
Signed-off-by: Tejun Heo <tj@kernel.org>
This enables us to lookup a cgroup by its id.
v4:
- add a comment for idr_remove() in cgroup_offline_fn().
v3:
- on success, idr_alloc() returns the id but not 0, so fix the BUG_ON()
in cgroup_init().
- pass the right value to idr_alloc() so that the id for dummy cgroup is 0.
Signed-off-by: Li Zefan <lizefan@huawei.com>
Reviewed-by: Michal Hocko <mhocko@suse.cz>
Signed-off-by: Tejun Heo <tj@kernel.org>
Constantly use @cset for css_set variables and use @cgrp as cgroup
variables.
Signed-off-by: Li Zefan <lizefan@huawei.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
We can use struct cfent instead.
v2:
- remove cgroup_seqfile_release().
Signed-off-by: Li Zefan <lizefan@huawei.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
This should have been removed in commit d7eeac1913
("cgroup: hold cgroup_mutex before calling css_offline").
While at it, update the comments.
Signed-off-by: Li Zefan <lizefan@huawei.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
Comment for cpuset_css_offline() was on top of cpuset_css_free().
Move it.
Signed-off-by: Zhao Hongjiang <zhaohongjiang@huawei.com>
Acked-by: Li Zefan <lizefan@huawei.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
get rid of the useless forward declaration of the struct cpuset cause the
below define it.
Signed-off-by: Zhao Hongjiang <zhaohongjiang@huawei.com>
Acked-by: Li Zefan <lizefan@huawei.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
rebind_subsystems() performs santiy checks even on subsystems which
aren't specified to be added or removed and the checks aren't all that
useful given that these are in a very cold path while the violations
they check would trip up in much hotter paths.
Let's remove these from rebind_subsystems().
Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: Li Zefan <lizefan@huawei.com>
Module ref handling in cgroup is rather weird.
parse_cgroupfs_options() grabs all the modules for the specified
subsystems. A module ref is kept if the specified subsystem is newly
bound to the hierarchy. If not, or the operation fails, the refs are
dropped. This scatters module ref handling across multiple functions
making it difficult to track. It also make the function nasty to use
for dynamic subsystem binding which is necessary for the planned
unified hierarchy.
There's nothing which requires the subsystem modules to be pinned
between parse_cgroupfs_options() and rebind_subsystems() in both mount
and remount paths. parse_cgroupfs_options() can just parse and
rebind_subsystems() can handle pinning the subsystems that it wants to
bind, which is a natural part of its task - binding - anyway.
Move module ref handling into rebind_subsystems() which makes the code
a lot simpler - modules are gotten iff it's gonna be bound and put iff
unbound or binding fails.
v2: Li pointed out that if a controller module is unloaded between
parsing and binding, rebind_subsystems() won't notice the missing
controller as it only iterates through existing controllers. Fix
it by updating rebind_subsystems() to compare @added_mask to
@pinned and fail with -ENOENT if they don't match.
Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: Li Zefan <lizefan@huawei.com>
task_cgroup_path_from_hierarchy() was added for the planned new users
and none of the currently planned users wants to know about multiple
hierarchies. This patch drops the multiple hierarchy part and makes
it always return the path in the first non-dummy hierarchy.
As unified hierarchy will always have id 1, this is guaranteed to
return the path for the unified hierarchy if mounted; otherwise, it
will return the path from the hierarchy which happens to occupy the
lowest hierarchy id, which will usually be the first hierarchy mounted
after boot.
Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: Li Zefan <lizefan@huawei.com>
Cc: Lennart Poettering <lennart@poettering.net>
Cc: Kay Sievers <kay.sievers@vrfy.org>
Cc: Jan Kaluža <jkaluza@redhat.com>
rebind_subsystems() currently fails if the hierarchy has any !root
cgroups; however, on the planned unified hierarchy,
rebind_subsystems() will be used while populated. Move the test to
cgroup_remount(), which is the only place the test is necessary
anyway.
As it's impossible for the other two callers of rebind_subsystems() to
have populated hierarchy, this doesn't make any behavior changes.
Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: Li Zefan <lizefan@huawei.com>
Currently, creating and removing cgroup files in the root directory
are handled separately from the actual subsystem binding and unbinding
which happens in rebind_subsystems(). Also, rebind_subsystems() users
aren't handling file creation errors properly. Let's integrate
top_cgroup file handling into rebind_subsystems() so that it's simpler
to use and everyone handles file creation errors correctly.
* On a successful return, rebind_subsystems() is guaranteed to have
created all files of the new subsystems and deleted the ones
belonging to the removed subsystems. After a failure, no file is
created or removed.
* cgroup_remount() no longer needs to make explicit populate/clear
calls as it's all handled by rebind_subsystems(), and it gets proper
error handling automatically.
* cgroup_mount() has been updated such that the root dentry and cgroup
are linked before rebind_subsystems(). Also, the init_cred dancing
and base file handling are moved right above rebind_subsystems()
call and proper error handling for the base files is added. While
at it, add a comment explaining what's going on with the cred thing.
* cgroup_kill_sb() calls rebind_subsystems() to unbind all subsystems
which now implies removing all subsystem files which requires the
directory's i_mutex. Grab it. This means that files on the root
cgroup are removed earlier - they used to be deleted from generic
super_block cleanup from vfs. This doesn't lead to any functional
difference and it's cleaner to do the clean up explicitly for all
files.
Combined with the previous changes, this makes all cgroup file
creation errors handled correctly.
v2: Added comment on init_cred.
v3: Li spotted that cgroup_mount() wasn't freeing tmp_links after base
file addition failure. Fix it by adding free_tmp_links error
handling label.
v4: v3 introduced build bugs which got noticed by Fengguang's awesome
kbuild test robot. Fixed, and shame on me.
Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: Li Zefan <lizefan@huawei.com>
Cc: Fengguang Wu <fengguang.wu@intel.com>
rebind_subsystems() will be updated to handle file creations and
removals with proper error handling and to do that will need to
perform file operations before actually adding the subsystem to the
hierarchy.
To enable such usage, update cgroup_populate/clear_dir() to use
for_each_subsys() instead of for_each_root_subsys() so that they
operate on all subsystems specified by @subsys_mask whether that
subsystem is currently bound to the hierarchy or not.
Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: Li Zefan <lizefan@huawei.com>
cgroup_populate_dir() didn't use to check whether the actual file
creations were successful and could return success with only subset of
the requested files created, which is nasty.
This patch udpates cgroup_populate_dir() so that it either succeeds
with all files or fails with no file.
v2: The original patch also converted for_each_root_subsys() usages to
for_each_subsys() without explaining why. That part has been
moved to a separate patch.
Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: Li Zefan <lizefan@huawei.com>
cgroup_populate/clear_dir() currently take @base_files and adds and
removes, respectively, cgroup_base_files[] to the directory. File
additions and removals are being reorganized for proper error handling
and more dynamic handling for the unified hierarchy, and mixing base
and subsys file handling into the same functions gets a bit confusing.
This patch moves base file handling out of cgroup_populate/clear_dir()
into their users - cgroup_mount(), cgroup_create() and
cgroup_destroy_locked().
Note that this changes the behavior of base file removal. If
@base_files is %true, cgroup_clear_dir() used to delete files
regardless of cftype until there's no files left. Now, only files
with matching cfts are removed. As files can only be created by the
base or registered cftypes, this shouldn't result in any behavior
difference.
Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: Li Zefan <lizefan@huawei.com>
cgroup_add_cftypes() uses cgroup_cfts_commit() to actually create the
files; however, both functions ignore actual file creation errors and
just assume success. This can lead to, for example, blkio hierarchy
with some of the cgroups with only subset of interface files populated
after cfq-iosched is loaded under heavy memory pressure, which is
nasty.
This patch updates cgroup_cfts_commit() and cgroup_add_cftypes() to
guarantee that all files are created on success and no file is created
on failure.
Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: Li Zefan <lizefan@huawei.com>
cgroup_addrm_files() mishandled error return value from
cgroup_add_file() and returns error iff the last file fails to create.
As we're in the process of cleaning up file add/rm error handling and
will reliably propagate file creation failures, there's no point in
keeping adding files after a failure.
Replace the broken error collection logic with immediate error return.
While at it, add lockdep assertions and function comment.
Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: Li Zefan <lizefan@huawei.com>
* Rename it to cgroup_clear_dir() and make it take the pointer to the
target cgroup instead of the the dentry. This makes the function
consistent with its counterpart - cgroup_populate_dir().
* Move cgroup_clear_directory() invocation from cgroup_d_remove_dir()
to cgroup_remount() so that the function doesn't have to determine
the cgroup pointer back from the dentry. cgroup_d_remove_dir() now
only deals with vfs, which is slightly cleaner.
This patch doesn't introduce any functional differences.
Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: Li Zefan <lizefan@huawei.com>
framework for storage arrays that dynamically reconfigure their
preferred paths for different device regions.
Fix a bug in the verity target that prevented its use with some
specific sizes of devices.
Improve some locking mechanisms in the device-mapper core and bufio.
Add Mike Snitzer as a device-mapper maintainer.
A few more clean-ups and fixes.
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Merge tag 'dm-3.11-changes' of git://git.kernel.org/pub/scm/linux/kernel/git/agk/linux-dm
Pull device-mapper changes from Alasdair G Kergon:
"Add a device-mapper target called dm-switch to provide a multipath
framework for storage arrays that dynamically reconfigure their
preferred paths for different device regions.
Fix a bug in the verity target that prevented its use with some
specific sizes of devices.
Improve some locking mechanisms in the device-mapper core and bufio.
Add Mike Snitzer as a device-mapper maintainer.
A few more clean-ups and fixes"
* tag 'dm-3.11-changes' of git://git.kernel.org/pub/scm/linux/kernel/git/agk/linux-dm:
dm: add switch target
dm: update maintainers
dm: optimize reorder structure
dm: optimize use SRCU and RCU
dm bufio: submit writes outside lock
dm cache: fix arm link errors with inline
dm verity: use __ffs and __fls
dm flakey: correct ctr alloc failure mesg
dm verity: remove pointless comparison
dm: use __GFP_HIGHMEM in __vmalloc
dm verity: fix inability to use a few specific devices sizes
dm ioctl: set noio flag to avoid __vmalloc deadlock
dm mpath: fix ioctl deadlock when no paths
Pull core block IO updates from Jens Axboe:
"Here are the core IO block bits for 3.11. It contains:
- A tweak to the reserved tag logic from Jan, for weirdo devices with
just 3 free tags. But for those it improves things substantially
for random writes.
- Periodic writeback fix from Jan. Marked for stable as well.
- Fix for a race condition in IO scheduler switching from Jianpeng.
- The hierarchical blk-cgroup support from Tejun. This is the grunt
of the series.
- blk-throttle fix from Vivek.
Just a note that I'm in the middle of a relocation, whole family is
flying out tomorrow. Hence I will be awal the remainder of this week,
but back at work again on Monday the 15th. CC'ing Tejun, since any
potential "surprises" will most likely be from the blk-cgroup work.
But it's been brewing for a while and sitting in my tree and
linux-next for a long time, so should be solid."
* 'for-3.11/core' of git://git.kernel.dk/linux-block: (36 commits)
elevator: Fix a race in elevator switching
block: Reserve only one queue tag for sync IO if only 3 tags are available
writeback: Fix periodic writeback after fs mount
blk-throttle: implement proper hierarchy support
blk-throttle: implement throtl_grp->has_rules[]
blk-throttle: Account for child group's start time in parent while bio climbs up
blk-throttle: add throtl_qnode for dispatch fairness
blk-throttle: make throtl_pending_timer_fn() ready for hierarchy
blk-throttle: make tg_dispatch_one_bio() ready for hierarchy
blk-throttle: make blk_throtl_bio() ready for hierarchy
blk-throttle: make blk_throtl_drain() ready for hierarchy
blk-throttle: dispatch from throtl_pending_timer_fn()
blk-throttle: implement dispatch looping
blk-throttle: separate out throtl_service_queue->pending_timer from throtl_data->dispatch_work
blk-throttle: set REQ_THROTTLED from throtl_charge_bio() and gate stats update with it
blk-throttle: implement sq_to_tg(), sq_to_td() and throtl_log()
blk-throttle: add throtl_service_queue->parent_sq
blk-throttle: generalize update_disptime optimization in blk_throtl_bio()
blk-throttle: dispatch to throtl_data->service_queue.bio_lists[]
blk-throttle: move bio_lists[] and friends to throtl_service_queue
...
Pull SCSI target updates from Nicholas Bellinger:
"Lots of activity this round on performance improvements in target-core
while benchmarking the prototype scsi-mq initiator code with
vhost-scsi fabric ports, along with a number of iscsi/iser-target
improvements and hardening fixes for exception path cases post v3.10
merge.
The highlights include:
- Make persistent reservations APTPL buffer allocated on-demand, and
drop per t10_reservation buffer. (grover)
- Make virtual LUN=0 a NULLIO device, and skip allocation of NULLIO
device pages (grover)
- Add transport_cmd_check_stop write_pending bit to avoid extra
access of ->t_state_lock is WRITE I/O submission fast-path. (nab)
- Drop unnecessary CMD_T_DEV_ACTIVE check from
transport_lun_remove_cmd to avoid extra access of ->t_state_lock in
release fast-path. (nab)
- Avoid extra t_state_lock access in __target_execute_cmd fast-path
(nab)
- Drop unnecessary vhost-scsi wait_for_tasks=true usage +
->t_state_lock access in release fast-path. (nab)
- Convert vhost-scsi to use modern se_cmd->cmd_kref
TARGET_SCF_ACK_KREF usage (nab)
- Add tracepoints for SCSI commands being processed (roland)
- Refactoring of iscsi-target handling of ISCSI_OP_NOOP +
ISCSI_OP_TEXT to be transport independent (nab)
- Add iscsi-target SendTargets=$IQN support for in-band discovery
(nab)
- Add iser-target support for in-band discovery (nab + Or)
- Add iscsi-target demo-mode TPG authentication context support (nab)
- Fix isert_put_reject payload buffer post (nab)
- Fix iscsit_add_reject* usage for iser (nab)
- Fix iscsit_sequence_cmd reject handling for iser (nab)
- Fix ISCSI_OP_SCSI_TMFUNC handling for iser (nab)
- Fix session reset bug with RDMA_CM_EVENT_DISCONNECTED (nab)
The last five iscsi/iser-target items are CC'ed to stable, as they do
address issues present in v3.10 code. They are certainly larger than
I'd like for stable patch set, but are important to ensure proper
REJECT exception handling in iser-target for 3.10.y"
* 'for-next' of git://git.kernel.org/pub/scm/linux/kernel/git/nab/target-pending: (51 commits)
iser-target: Ignore non TEXT + LOGOUT opcodes for discovery
target: make queue_tm_rsp() return void
target: remove unused codes from enum tcm_tmrsp_table
iscsi-target: kstrtou* configfs attribute parameter cleanups
iscsi-target: Fix tfc_tpg_auth_cit configfs length overflow
iscsi-target: Fix tfc_tpg_nacl_auth_cit configfs length overflow
iser-target: Add support for ISCSI_OP_TEXT opcode + payload handling
iser-target: Rename sense_buf_[dma,len] to pdu_[dma,len]
iser-target: Add vendor_err debug output
target: Add (obsolete) checking for PMI/LBA fields in READ CAPACITY(10)
target: Return correct sense data for IO past the end of a device
target: Add tracepoints for SCSI commands being processed
iser-target: Fix session reset bug with RDMA_CM_EVENT_DISCONNECTED
iscsi-target: Fix ISCSI_OP_SCSI_TMFUNC handling for iser
iscsi-target: Fix iscsit_sequence_cmd reject handling for iser
iscsi-target: Fix iscsit_add_reject* usage for iser
iser-target: Fix isert_put_reject payload buffer post
iscsi-target: missing kfree() on error path
iscsi-target: Drop left-over iscsi_conn->bad_hdr
target: Make core_scsi3_update_and_write_aptpl return sense_reason_t
...
Tejun Heo
Li Zefan
Zhao Hongjiang
Linus Torvalds