1. 06 May, 2014 1 commit
  2. 05 May, 2014 1 commit
  3. 04 May, 2014 6 commits
    • Tejun Heo's avatar
      cgroup, memcg: implement css->id and convert css_from_id() to use it · 15a4c835
      Tejun Heo authored
      
      
      Until now, cgroup->id has been used to identify all the associated
      csses and css_from_id() takes cgroup ID and returns the matching css
      by looking up the cgroup and then dereferencing the css associated
      with it; however, now that the lifetimes of cgroup and css are
      separate, this is incorrect and breaks on the unified hierarchy when a
      controller is disabled and enabled back again before the previous
      instance is released.
      
      This patch adds css->id which is a subsystem-unique ID and converts
      css_from_id() to look up by the new css->id instead.  memcg is the
      only user of css_from_id() and also converted to use css->id instead.
      
      For traditional hierarchies, this shouldn't make any functional
      difference.
      
      Signed-off-by: default avatarTejun Heo <tj@kernel.org>
      Acked-by: default avatarMichal Hocko <mhocko@suse.cz>
      Cc: Johannes Weiner <hannes@cmpxchg.org>
      Cc: Jianyu Zhan <nasa4836@gmail.com>
      Acked-by: default avatarLi Zefan <lizefan@huawei.com>
      15a4c835
    • Tejun Heo's avatar
      cgroup: update init_css() into init_and_link_css() · ddfcadab
      Tejun Heo authored
      
      
      init_css() takes the cgroup the new css belongs to as an argument and
      initializes the new css's ->cgroup and ->parent pointers but doesn't
      acquire the matching reference counts.  After the previous patch,
      create_css() puts init_css() and reference acquisition right next to
      each other.  Let's move reference acquistion into init_css() and
      rename the function to init_and_link_css().  This makes sense and is
      easier to follow.  This makes the root csses to hold a reference on
      cgrp_dfl_root.cgrp, which is harmless.
      
      Signed-off-by: default avatarTejun Heo <tj@kernel.org>
      Acked-by: default avatarLi Zefan <lizefan@huawei.com>
      ddfcadab
    • Tejun Heo's avatar
      cgroup: use RCU free in create_css() failure path · a2bed820
      Tejun Heo authored
      
      
      Currently, when create_css() fails in the middle, the half-initialized
      css is freed by invoking cgroup_subsys->css_free() directly.  This
      patch updates the function so that it invokes RCU free path instead.
      As the RCU free path puts the parent css and owning cgroup, their
      references are now acquired right after a new css is successfully
      allocated.
      
      This doesn't make any visible difference now but is to enable
      implementing css->id and RCU protected lookup by such IDs.
      
      Signed-off-by: default avatarTejun Heo <tj@kernel.org>
      Acked-by: default avatarLi Zefan <lizefan@huawei.com>
      a2bed820
    • Tejun Heo's avatar
      cgroup: protect cgroup_root->cgroup_idr with a spinlock · 6fa4918d
      Tejun Heo authored
      
      
      Currently, cgroup_root->cgroup_idr is protected by cgroup_mutex, which
      ends up requiring cgroup_put() to be invoked under sleepable context.
      This is okay for now but is an unusual requirement and we'll soon add
      css->id which will have the same problem but won't be able to simply
      grab cgroup_mutex as removal will have to happen from css_release()
      which can't sleep.
      
      Introduce cgroup_idr_lock and idr_alloc/replace/remove() wrappers
      which protects the idr operations with the lock and use them for
      cgroup_root->cgroup_idr.  cgroup_put() no longer needs to grab
      cgroup_mutex and css_from_id() is updated to always require RCU read
      lock instead of either RCU read lock or cgroup_mutex, which doesn't
      affect the existing users.
      
      Signed-off-by: default avatarTejun Heo <tj@kernel.org>
      Acked-by: default avatarLi Zefan <lizefan@huawei.com>
      6fa4918d
    • Tejun Heo's avatar
      cgroup, memcg: allocate cgroup ID from 1 · 7d699ddb
      Tejun Heo authored
      
      
      Currently, cgroup->id is allocated from 0, which is always assigned to
      the root cgroup; unfortunately, memcg wants to use ID 0 to indicate
      invalid IDs and ends up incrementing all IDs by one.
      
      It's reasonable to reserve 0 for special purposes.  This patch updates
      cgroup core so that ID 0 is not used and the root cgroups get ID 1.
      The ID incrementing is removed form memcg.
      
      Signed-off-by: default avatarTejun Heo <tj@kernel.org>
      Acked-by: default avatarMichal Hocko <mhocko@suse.cz>
      Cc: Johannes Weiner <hannes@cmpxchg.org>
      Acked-by: default avatarLi Zefan <lizefan@huawei.com>
      7d699ddb
    • Tejun Heo's avatar
      cgroup: make flags and subsys_masks unsigned int · 69dfa00c
      Tejun Heo authored
      
      
      There's no reason to use atomic bitops for cgroup_subsys_state->flags,
      cgroup_root->flags and various subsys_masks.  This patch updates those
      to use bitwise and/or operations instead and converts them form
      unsigned long to unsigned int.
      
      This makes the fields occupy (marginally) smaller space and makes it
      clear that they don't require atomicity.
      
      This patch doesn't cause any behavior difference.
      
      Signed-off-by: default avatarTejun Heo <tj@kernel.org>
      Acked-by: default avatarLi Zefan <lizefan@huawei.com>
      69dfa00c
  4. 25 Apr, 2014 10 commits
    • Joe Perches's avatar
      cgroup: Use more current logging style · ed3d261b
      Joe Perches authored
      
      
      Use pr_fmt and remove embedded prefixes.
      Realign modified multi-line statements to open parenthesis.
      Convert embedded function name to "%s: ", __func__
      
      Signed-off-by: default avatarJoe Perches <joe@perches.com>
      Signed-off-by: default avatarTejun Heo <tj@kernel.org>
      ed3d261b
    • Jianyu Zhan's avatar
      cgroup: replace pr_warning with preferred pr_warn · a2a1f9ea
      Jianyu Zhan authored
      
      
      As suggested by scripts/checkpatch.pl, substitude all pr_warning()
      with pr_warn().
      
      No functional change.
      
      Signed-off-by: default avatarJianyu Zhan <nasa4836@gmail.com>
      Signed-off-by: default avatarTejun Heo <tj@kernel.org>
      a2a1f9ea
    • Jianyu Zhan's avatar
      cgroup: remove orphaned cgroup_pidlist_seq_operations · f8719ccf
      Jianyu Zhan authored
      6612f05b
      
       ("cgroup: unify pidlist and other file handling")
      has removed the only user of cgroup_pidlist_seq_operations :
      cgroup_pidlist_open().
      
      This patch removes it.
      
      Signed-off-by: default avatarJianyu Zhan <nasa4836@gmail.com>
      Signed-off-by: default avatarTejun Heo <tj@kernel.org>
      f8719ccf
    • Jianyu Zhan's avatar
      cgroup: clean up obsolete comment for parse_cgroupfs_options() · 2f0edc04
      Jianyu Zhan authored
      1d5be6b2
      
       ("cgroup: move module ref handling into
      rebind_subsystems()") makes parse_cgroupfs_options() no longer takes
      refcounts on subsystems.
      
      And unified hierachy makes parse_cgroupfs_options not need to call
      with cgroup_mutex held to protect the cgroup_subsys[].
      
      So this patch removes BUG_ON() and the comment.  As the comment
      doesn't contain useful information afterwards, the whole comment is
      removed.
      
      Signed-off-by: default avatarJianyu Zhan <nasa4836@gmail.com>
      Signed-off-by: default avatarTejun Heo <tj@kernel.org>
      2f0edc04
    • Tejun Heo's avatar
      cgroup: add documentation about unified hierarchy · 65731578
      Tejun Heo authored
      
      
      Unified hierarchy will be the new version of cgroup interface.  This
      patch adds Documentation/cgroups/unified-hierarchy.txt which describes
      the design and rationales of unified hierarchy.
      
      v2: Grammatical updates as per Randy Dunlap's review.
      
      Signed-off-by: default avatarTejun Heo <tj@kernel.org>
      Cc: Randy Dunlap <rdunlap@infradead.org>
      65731578
    • Tejun Heo's avatar
      cgroup: implement cgroup.populated for the default hierarchy · 842b597e
      Tejun Heo authored
      
      
      cgroup users often need a way to determine when a cgroup's
      subhierarchy becomes empty so that it can be cleaned up.  cgroup
      currently provides release_agent for it; unfortunately, this mechanism
      is riddled with issues.
      
      * It delivers events by forking and execing a userland binary
        specified as the release_agent.  This is a long deprecated method of
        notification delivery.  It's extremely heavy, slow and cumbersome to
        integrate with larger infrastructure.
      
      * There is single monitoring point at the root.  There's no way to
        delegate management of a subtree.
      
      * The event isn't recursive.  It triggers when a cgroup doesn't have
        any tasks or child cgroups.  Events for internal nodes trigger only
        after all children are removed.  This again makes it impossible to
        delegate management of a subtree.
      
      * Events are filtered from the kernel side.  "notify_on_release" file
        is used to subscribe to or suppress release event.  This is
        unnecessarily complicated and probably done this way because event
        delivery itself was expensive.
      
      This patch implements interface file "cgroup.populated" which can be
      used to monitor whether the cgroup's subhierarchy has tasks in it or
      not.  Its value is 0 if there is no task in the cgroup and its
      descendants; otherwise, 1, and kernfs_notify() notificaiton is
      triggers when the value changes, which can be monitored through poll
      and [di]notify.
      
      This is a lot ligther and simpler and trivially allows delegating
      management of subhierarchy - subhierarchy monitoring can block further
      propgation simply by putting itself or another process in the root of
      the subhierarchy and monitor events that it's interested in from there
      without interfering with monitoring higher in the tree.
      
      v2: Patch description updated as per Serge.
      
      v3: "cgroup.subtree_populated" renamed to "cgroup.populated".  The
          subtree_ prefix was a bit confusing because
          "cgroup.subtree_control" uses it to denote the tree rooted at the
          cgroup sans the cgroup itself while the populated state includes
          the cgroup itself.
      
      Signed-off-by: default avatarTejun Heo <tj@kernel.org>
      Acked-by: default avatarSerge Hallyn <serge.hallyn@ubuntu.com>
      Acked-by: default avatarLi Zefan <lizefan@huawei.com>
      Cc: Lennart Poettering <lennart@poettering.net>
      842b597e
    • Tejun Heo's avatar
      Merge branch 'driver-core-next' of... · 50bce01b
      Tejun Heo authored
      Merge branch 'driver-core-next' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-core
      
       into for-3.16
      
      Pull in driver-core-next to receive kernfs_notify() updates which will
      be used by the planned "cgroup.populated" implementation.
      
      Signed-off-by: default avatarTejun Heo <tj@kernel.org>
      50bce01b
    • Michael Marineau's avatar
      kobject: Make support for uevent_helper optional. · 86d56134
      Michael Marineau authored
      
      
      Support for uevent_helper, aka hotplug, is not required on many systems
      these days but it can still be enabled via sysfs or sysctl.
      
      Reported-by: default avatarDarren Shepherd <darren.s.shepherd@gmail.com>
      Signed-off-by: default avatarMichael Marineau <mike@marineau.org>
      Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
      86d56134
    • Tejun Heo's avatar
      kernfs: make kernfs_notify() trigger inotify events too · d911d987
      Tejun Heo authored
      
      
      kernfs_notify() is used to indicate either new data is available or
      the content of a file has changed.  It currently only triggers poll
      which may not be the most convenient to monitor especially when there
      are a lot to monitor.  Let's hook it up to fsnotify too so that the
      events can be monitored via inotify too.
      
      fsnotify_modify() requires file * but kernfs_notify() doesn't have any
      specific file associated; however, we can walk all super_blocks
      associated with a kernfs_root and as kernfs always associate one ino
      with inode and one dentry with an inode, it's trivial to look up the
      dentry associated with a given kernfs_node.  As any active monitor
      would pin dentry, just looking up existing dentry is enough.  This
      patch looks up the dentry associated with the specified kernfs_node
      and generates events equivalent to fsnotify_modify().
      
      Note that as fsnotify doesn't provide fsnotify_modify() equivalent
      which can be called with dentry, kernfs_notify() directly calls
      fsnotify_parent() and fsnotify().  It might be better to add a wrapper
      in fsnotify.h instead.
      
      Signed-off-by: default avatarTejun Heo <tj@kernel.org>
      Cc: John McCutchan <john@johnmccutchan.com>
      Cc: Robert Love <rlove@rlove.org>
      Cc: Eric Paris <eparis@parisplace.org>
      Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
      d911d987
    • Tejun Heo's avatar
      kernfs: implement kernfs_root->supers list · 7d568a83
      Tejun Heo authored
      
      
      Currently, there's no way to find out which super_blocks are
      associated with a given kernfs_root.  Let's implement it - the planned
      inotify extension to kernfs_notify() needs it.
      
      Make kernfs_super_info point back to the super_block and chain it at
      kernfs_root->supers.
      
      Signed-off-by: default avatarTejun Heo <tj@kernel.org>
      Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
      7d568a83
  5. 23 Apr, 2014 13 commits
    • Tejun Heo's avatar
      cgroup: implement dynamic subtree controller enable/disable on the default hierarchy · f8f22e53
      Tejun Heo authored
      
      
      cgroup is switching away from multiple hierarchies and will use one
      unified default hierarchy where controllers can be dynamically enabled
      and disabled per subtree.  The default hierarchy will serve as the
      unified hierarchy to which all controllers are attached and a css on
      the default hierarchy would need to also serve the tasks of descendant
      cgroups which don't have the controller enabled - ie. the tree may be
      collapsed from leaf towards root when viewed from specific
      controllers.  This has been implemented through effective css in the
      previous patches.
      
      This patch finally implements dynamic subtree controller
      enable/disable on the default hierarchy via a new knob -
      "cgroup.subtree_control" which controls which controllers are enabled
      on the child cgroups.  Let's assume a hierarchy like the following.
      
        root - A - B - C
                     \ D
      
      root's "cgroup.subtree_control" determines which controllers are
      enabled on A.  A's on B.  B's on C and D.  This coincides with the
      fact that controllers on the immediate sub-level are used to
      distribute the resources of the parent.  In fact, it's natural to
      assume that resource control knobs of a child belong to its parent.
      Enabling a controller in "cgroup.subtree_control" declares that
      distribution of the respective resources of the cgroup will be
      controlled.  Note that this means that controller enable states are
      shared among siblings.
      
      The default hierarchy has an extra restriction - only cgroups which
      don't contain any task may have controllers enabled in
      "cgroup.subtree_control".  Combined with the other properties of the
      default hierarchy, this guarantees that, from the view point of
      controllers, tasks are only on the leaf cgroups.  In other words, only
      leaf csses may contain tasks.  This rules out situations where child
      cgroups compete against internal tasks of the parent, which is a
      competition between two different types of entities without any clear
      way to determine resource distribution between the two.  Different
      controllers handle it differently and all the implemented behaviors
      are ambiguous, ad-hoc, cumbersome and/or just wrong.  Having this
      structural constraints imposed from cgroup core removes the burden
      from controller implementations and enables showing one consistent
      behavior across all controllers.
      
      When a controller is enabled or disabled, css associations for the
      controller in the subtrees of each child should be updated.  After
      enabling, the whole subtree of a child should point to the new css of
      the child.  After disabling, the whole subtree of a child should point
      to the cgroup's css.  This is implemented by first updating cgroup
      states such that cgroup_e_css() result points to the appropriate css
      and then invoking cgroup_update_dfl_csses() which migrates all tasks
      in the affected subtrees to the self cgroup on the default hierarchy.
      
      * When read, "cgroup.subtree_control" lists all the currently enabled
        controllers on the children of the cgroup.
      
      * White-space separated list of controller names prefixed with either
        '+' or '-' can be written to "cgroup.subtree_control".  The ones
        prefixed with '+' are enabled on the controller and '-' disabled.
      
      * A controller can be enabled iff the parent's
        "cgroup.subtree_control" enables it and disabled iff no child's
        "cgroup.subtree_control" has it enabled.
      
      * If a cgroup has tasks, no controller can be enabled via
        "cgroup.subtree_control".  Likewise, if "cgroup.subtree_control" has
        some controllers enabled, tasks can't be migrated into the cgroup.
      
      * All controllers which aren't bound on other hierarchies are
        automatically associated with the root cgroup of the default
        hierarchy.  All the controllers which are bound to the default
        hierarchy are listed in the read-only file "cgroup.controllers" in
        the root directory.
      
      * "cgroup.controllers" in all non-root cgroups is read-only file whose
        content is equal to that of "cgroup.subtree_control" of the parent.
        This indicates which controllers can be used in the cgroup's
        "cgroup.subtree_control".
      
      This is still experimental and there are some holes, one of which is
      that ->can_attach() failure during cgroup_update_dfl_csses() may leave
      the cgroups in an undefined state.  The issues will be addressed by
      future patches.
      
      v2: Non-root cgroups now also have "cgroup.controllers".
      
      Signed-off-by: default avatarTejun Heo <tj@kernel.org>
      Acked-by: default avatarLi Zefan <lizefan@huawei.com>
      f8f22e53
    • Tejun Heo's avatar
      cgroup: prepare migration path for unified hierarchy · f817de98
      Tejun Heo authored
      
      
      Unified hierarchy implementation would require re-migrating tasks onto
      the same cgroup on the default hierarchy to reflect updated effective
      csses.  Update cgroup_migrate_prepare_dst() so that it accepts NULL as
      the destination cgrp.  When NULL is specified, the destination is
      considered to be the cgroup on the default hierarchy associated with
      each css_set.
      
      After this change, the identity check in cgroup_migrate_add_src()
      isn't sufficient for noop detection as the associated csses may change
      without any cgroup association changing.  The only way to tell whether
      a migration is noop or not is testing whether the source and
      destination csets are identical.  The noop check in
      cgroup_migrate_add_src() is removed and cset identity test is added to
      cgroup_migreate_prepare_dst().  If it's detected that source and
      destination csets are identical, the cset is removed removed from
      @preloaded_csets and all the migration nodes are cleared which makes
      cgroup_migrate() ignore the cset.
      
      Also, make the function append the destination css_sets to
      @preloaded_list so that destination css_sets always come after source
      css_sets.
      
      Signed-off-by: default avatarTejun Heo <tj@kernel.org>
      Acked-by: default avatarLi Zefan <lizefan@huawei.com>
      f817de98
    • Tejun Heo's avatar
      cgroup: update subsystem rebind restrictions · 7fd8c565
      Tejun Heo authored
      
      
      Because the default root couldn't have any non-root csses attached to
      it, rebinding away from it was always allowed; however, the default
      hierarchy will soon host the unified hierarchy and have non-root csses
      so the rebind restrictions need to be updated accordingly.
      
      Instead of special casing rebinding from the default hierarchy and
      then checking whether the source hierarchy has children cgroups, which
      implies non-root csses for !dfl hierarchies, simply check whether the
      source hierarchy has non-root csses for the subsystem using
      css_next_child().
      
      Signed-off-by: default avatarTejun Heo <tj@kernel.org>
      Acked-by: default avatarLi Zefan <lizefan@huawei.com>
      7fd8c565
    • Tejun Heo's avatar
      cgroup: add css_set->dfl_cgrp · 6803c006
      Tejun Heo authored
      
      
      To implement the unified hierarchy behavior, we'll need to be able to
      determine the associated cgroup on the default hierarchy from css_set.
      Let's add css_set->dfl_cgrp so that it can be accessed conveniently
      and efficiently.
      
      Signed-off-by: default avatarTejun Heo <tj@kernel.org>
      Acked-by: default avatarLi Zefan <lizefan@huawei.com>
      6803c006
    • Tejun Heo's avatar
      cgroup: allow cgroup creation and suppress automatic css creation in the unified hierarchy · bd53d617
      Tejun Heo authored
      
      
      Now that effective css handling has been added and iterators updated
      accordingly, it's safe to allow cgroup creation in the default
      hierarchy.  Unblock cgroup creation in the default hierarchy.
      
      As the default hierarchy will implement explicit enabling and
      disabling of controllers on each cgroup, suppress automatic css
      enabling on cgroup creation.
      
      Signed-off-by: default avatarTejun Heo <tj@kernel.org>
      Acked-by: default avatarLi Zefan <lizefan@huawei.com>
      bd53d617
    • Tejun Heo's avatar
      cgroup: cgroup->subsys[] should be cleared after the css is offlined · e3297803
      Tejun Heo authored
      
      
      After a css finishes offlining, offline_css() mistakenly performs
      RCU_INIT_POINTER(css->cgroup->subsys[ss->id], css) which just sets the
      cgroup->subsys[] pointer to the current value.  The intention was to
      clear it after offline is complete, not reassign the same value.
      
      Update it to assign NULL instead of the current value.  This makes
      cgroup_css() to return NULL once offline is complete.  All the
      existing users of the function either can handle NULL return already
      or guarantee that the css doesn't get offlined.
      
      While this is a bugfix, as css lifetime is currently tied to the
      cgroup it belongs to, this bug doesn't cause any actual problems.
      
      Signed-off-by: default avatarTejun Heo <tj@kernel.org>
      Acked-by: default avatarLi Zefan <lizefan@huawei.com>
      e3297803
    • Tejun Heo's avatar
      cgroup: teach css_task_iter about effective csses · 3ebb2b6e
      Tejun Heo authored
      
      
      Currently, css_task_iter iterates tasks associated with a css by
      visiting each css_set associated with the owning cgroup and walking
      tasks of each of them.  This works fine for !unified hierarchies as
      each cgroup has its own css for each associated subsystem on the
      hierarchy; however, on the planned unified hierarchy, a cgroup may not
      have csses associated and its tasks would be considered associated
      with the matching css of the nearest ancestor which has the subsystem
      enabled.
      
      This means that on the default unified hierarchy, just walking all
      tasks associated with a cgroup isn't enough to walk all tasks which
      are associated with the specified css.  If any of its children doesn't
      have the matching css enabled, task iteration should also include all
      tasks from the subtree.  We already added cgroup->e_csets[] to list
      all css_sets effectively associated with a given css and walk css_sets
      on that list instead to achieve such iteration.
      
      This patch updates css_task_iter iteration such that it walks css_sets
      on cgroup->e_csets[] instead of cgroup->cset_links if iteration is
      requested on an non-dummy css.  Thanks to the previous iteration
      update, this change can be achieved with the addition of
      css_task_iter->ss and minimal updates to css_advance_task_iter() and
      css_task_iter_start().
      
      Signed-off-by: default avatarTejun Heo <tj@kernel.org>
      Acked-by: default avatarLi Zefan <lizefan@huawei.com>
      3ebb2b6e
    • Tejun Heo's avatar
      cgroup: reorganize css_task_iter · 0f0a2b4f
      Tejun Heo authored
      
      
      This patch reorganizes css_task_iter so that adding effective css
      support is easier.
      
      * s/->cset_link/->cset_pos/ and s/->task/->task_pos/ for consistency
      
      * ->origin_css is used to determine whether the iteration reached the
        last css_set.  Replace it with explicit ->cset_head so that
        css_advance_task_iter() doesn't have to know the termination
        condition directly.
      
      * css_task_iter_next() currently assumes that it's walking list of
        cgrp_cset_link and reaches into the current cset through the current
        link to determine the termination conditions for task walking.  As
        this won't always be true for effective css walking, add
        ->tasks_head and ->mg_tasks_head and use them to control task
        walking so that css_task_iter_next() doesn't have to know how
        css_sets are being walked.
      
      This patch doesn't make any behavior changes.  The iteration logic
      stays unchanged after the patch.
      
      Signed-off-by: default avatarTejun Heo <tj@kernel.org>
      Acked-by: default avatarLi Zefan <lizefan@huawei.com>
      0f0a2b4f
    • Tejun Heo's avatar
      cgroup: make css_next_child() skip missing csses · 3b281afb
      Tejun Heo authored
      
      
      css_next_child() walks the children of the specified css.  It does
      this by finding the next cgroup and then returning the requested css.
      On the default unified hierarchy, a cgroup may not have a css
      associated with it even if the hierarchy has the subsystem enabled.
      This patch updates css_next_child() so that it skips children without
      the requested css associated.
      
      Signed-off-by: default avatarTejun Heo <tj@kernel.org>
      Acked-by: default avatarLi Zefan <lizefan@huawei.com>
      3b281afb
    • Tejun Heo's avatar
      cgroup: implement cgroup->e_csets[] · 2d8f243a
      Tejun Heo authored
      
      
      On the default unified hierarchy, a cgroup may be associated with
      csses of its ancestors, which means that a css of a given cgroup may
      be associated with css_sets of descendant cgroups.  This means that we
      can't walk all tasks associated with a css by iterating the css_sets
      associated with the cgroup as there are css_sets which are pointing to
      the css but linked on the descendants.
      
      This patch adds per-subsystem list heads cgroup->e_csets[].  Any
      css_set which is pointing to a css is linked to
      css->cgroup->e_csets[$SUBSYS_ID] through
      css_set->e_cset_node[$SUBSYS_ID].  The lists are protected by
      css_set_rwsem and will allow us to walk all css_sets associated with a
      given css so that we can find out all associated tasks.
      
      Signed-off-by: default avatarTejun Heo <tj@kernel.org>
      Acked-by: default avatarLi Zefan <lizefan@huawei.com>
      2d8f243a
    • Tejun Heo's avatar
      cgroup: introduce effective cgroup_subsys_state · aec3dfcb
      Tejun Heo authored
      
      
      In the planned default unified hierarchy, controllers may get
      dynamically attached to and detached from a cgroup and a cgroup may
      not have csses for all the controllers associated with the hierarchy.
      
      When a cgroup doesn't have its own css for a given controller, the css
      of the nearest ancestor with the controller enabled will be used,
      which is called the effective css.  This patch introduces
      cgroup_e_css() and for_each_e_css() to access the effective csses and
      convert compare_css_sets(), find_existing_css_set() and
      cgroup_migrate() to use the effective csses so that they can handle
      cgroups with partial csses correctly.
      
      This means that for two css_sets to be considered identical, they
      should have both matching csses and cgroups.  compare_css_sets()
      already compares both, not for correctness but for optimization.  As
      this now becomes a matter of correctness, update the comments
      accordingly.
      
      For all !default hierarchies, cgroup_e_css() always equals
      cgroup_css(), so this patch doesn't change behavior.
      
      While at it, fix incorrect locking comment for for_each_css().
      
      Signed-off-by: default avatarTejun Heo <tj@kernel.org>
      Acked-by: default avatarLi Zefan <lizefan@huawei.com>
      aec3dfcb
    • Tejun Heo's avatar
      cgroup: update cgroup->subsys_mask to ->child_subsys_mask and restore cgroup_root->subsys_mask · f392e51c
      Tejun Heo authored
      94419627
      
       ("cgroup: move ->subsys_mask from cgroupfs_root to
      cgroup") moved ->subsys_mask from cgroup_root to cgroup to prepare for
      the unified hierarhcy; however, it turns out that carrying the
      subsys_mask of the children in the parent, instead of itself, is a lot
      more natural.  This patch restores cgroup_root->subsys_mask and morphs
      cgroup->subsys_mask into cgroup->child_subsys_mask.
      
      * Uses of root->cgrp.subsys_mask are restored to root->subsys_mask.
      
      * Remove automatic setting and clearing of cgrp->subsys_mask and
        instead just inherit ->child_subsys_mask from the parent during
        cgroup creation.  Note that this doesn't affect any current
        behaviors.
      
      * Undo __kill_css() separation.
      
      Signed-off-by: default avatarTejun Heo <tj@kernel.org>
      Acked-by: default avatarLi Zefan <lizefan@huawei.com>
      f392e51c
    • Tejun Heo's avatar
      cgroup: cgroup_apply_cftypes() shouldn't skip the default hierarhcy · ea8fd3b4
      Tejun Heo authored
      
      
      cgroup_apply_cftypes() skip creating or removing files if the
      subsystem is attached to the default hierarchy, which led to missing
      files in the root of the default hierarchy.
      
      Skipping made sense when the default hierarchy was dummy; however, now
      that the default hierarchy is full functional and planned to be used
      as the unified hierarchy, it shouldn't be skipped over.
      
      Reported-by: default avatarLi Zefan <lizefan@huawei.com>
      Signed-off-by: default avatarTejun Heo <tj@kernel.org>
      Acked-by: default avatarLi Zefan <lizefan@huawei.com>
      ea8fd3b4
  6. 20 Apr, 2014 5 commits
  7. 19 Apr, 2014 4 commits
    • Adrien BAK's avatar
      perf tools: Improve error reporting · ffa91880
      Adrien BAK authored
      In the current version, when using perf record, if something goes
      wrong in tools/perf/builtin-record.c:375
        session = perf_session__new(file, false, NULL);
      
      The error message:
      "Not enough memory for reading per file header"
      
      is issued. This error message seems to be outdated and is not very
      helpful. This patch proposes to replace this error message by
      "Perf session creation failed"
      
      I believe this issue has been brought to lkml:
      https://lkml.org/lkml/2014/2/24/458
      
      
      although this patch only tackles a (small) part of the issue.
      
      Additionnaly, this patch improves error reporting in
      tools/perf/util/data.c open_file_write.
      
      Currently, if the call to open fails, the user is unaware of it.
      This patch logs the error, before returning the error code to
      the caller.
      
      Reported-by: default avatarWill Deacon <will.deacon@arm.com>
      Signed-off-by: default avatarAdrien BAK <adrien.bak@metascale.org>
      Link: http://lkml.kernel.org/r/1397786443.3093.4.camel@beast
      
      
      [ Reorganize the changelog into paragraphs ]
      [ Added empty line after fd declaration in open_file_write ]
      Signed-off-by: default avatarJiri Olsa <jolsa@redhat.com>
      ffa91880
    • Vladimir Nikulichev's avatar
      perf tools: Adjust symbols in VDSO · 922d0e4d
      Vladimir Nikulichev authored
      
      
      pert-report doesn't resolve function names in VDSO:
      
      $ perf report --stdio -g flat,0.0,15,callee --sort pid
      ...
                  8.76%
                     0x7fff6b1fe861
                     __gettimeofday
                     ACE_OS::gettimeofday()
      ...
      
      In this case symbol values should be adjusted the same way as for executables,
      relocatable objects and prelinked libraries.
      
      After fix:
      
      $ perf report --stdio -g flat,0.0,15,callee --sort pid
      ...
                  8.76%
                     __vdso_gettimeofday
                     __gettimeofday
                     ACE_OS::gettimeofday()
      
      Signed-off-by: default avatarVladimir Nikulichev <nvs@tbricks.com>
      Tested-by: default avatarNamhyung Kim <namhyung@kernel.org>
      Reviewed-by: default avatarAdrian Hunter <adrian.hunter@intel.com>
      Link: http://lkml.kernel.org/r/969812.163009436-sendEmail@nvs
      
      
      Signed-off-by: default avatarJiri Olsa <jolsa@redhat.com>
      922d0e4d
    • Alexander Yarygin's avatar
      perf kvm: Fix 'Min time' counting in report command · acb61fc8
      Alexander Yarygin authored
      
      
      Every event in the perf-kvm has a 'stats' structure, which contains
      max/min/average/etc times of handling this event.
      The problem is that the 'perf-kvm stat report' command always shows
      that 'min time' is 0us for every event. Example:
      
       # perf kvm stat report
      
       Analyze events for all VCPUs:
      
          VM-EXIT    Samples  Samples%     Time%   Min Time   Max Time Avg time
        [..]
        0xB2 MSCH         12     0.07%     0.00%        0us        8us 7.31us ( +-   2.11% )
        0xB2 CHSC         12     0.07%     0.00%        0us       18us 9.39us ( +-   9.49% )
        0xB2 STPX          8     0.05%     0.00%        0us        2us 1.88us ( +-   7.18% )
        0xB2 STSI          7     0.04%     0.00%        0us       44us 16.49us ( +-  38.20% )
        [..]
      
      This happens because the 'stats' structure is not initialized and
      stats->min equals to 0. Lets initialize the structure for every
      event after its allocation using init_stats() function. This initializes
      stats->min to -1 and makes 'Min time' statistics counting work:
      
       # perf kvm stat report
      
       Analyze events for all VCPUs:
      
          VM-EXIT    Samples  Samples%     Time%   Min Time   Max Time Avg time
        [..]
        0xB2 MSCH         12     0.07%     0.00%        6us        8us 7.31us ( +-   2.11% )
        0xB2 CHSC         12     0.07%     0.00%        7us       18us 9.39us ( +-   9.49% )
        0xB2 STPX          8     0.05%     0.00%        1us        2us 1.88us ( +-   7.18% )
        0xB2 STSI          7     0.04%     0.00%        1us       44us 16.49us ( +-  38.20% )
        [..]
      
      Signed-off-by: default avatarAlexander Yarygin <yarygin@linux.vnet.ibm.com>
      Signed-off-by: default avatarChristian Borntraeger <borntraeger@de.ibm.com>
      Reviewed-by: default avatarDavid Ahern <dsahern@gmail.com>
      Link: http://lkml.kernel.org/r/1397053319-2130-3-git-send-email-borntraeger@de.ibm.com
      
      
      [ Fixing the perf examples changelog output ]
      Signed-off-by: default avatarJiri Olsa <jolsa@redhat.com>
      acb61fc8
    • Eric Dumazet's avatar
      coredump: fix va_list corruption · 404ca80e
      Eric Dumazet authored
      A va_list needs to be copied in case it needs to be used twice.
      
      Thanks to Hugh for debugging this issue, leading to various panics.
      
      Tested:
      
        lpq84:~# echo "|/foobar12345 %h %h %h %h %h %h %h %h %h %h %h %h %h %h %h %h %h %h %h %h" >/proc/sys/kernel/core_pattern
      
      'produce_core' is simply : main() { *(int *)0 = 1;}
      
        lpq84:~# ./produce_core
        Segmentation fault (core dumped)
        lpq84:~# dmesg | tail -1
        [  614.352947] Core dump to |/foobar12345 lpq84 lpq84 lpq84 lpq84 lpq84 lpq84 lpq84 lpq84 lpq84 lpq84 lpq84 lpq84 lpq84 lpq84 lpq84 lpq84 lpq84 lpq84 lpq84 (null) pipe failed
      
      Notice the last argument was replaced by a NULL (we were lucky enough to
      not crash, but do not try this on your production machine !)
      
      After fix :
      
        lpq83:~# echo "|/foobar12345 %h %h %h %h %h %h %h %h %h %h %h %h %h %h %h %h %h %h %h %h" >/proc/sys/kernel/core_pattern
        lpq83:~# ./produce_core
        Segmentation fault
        lpq83:~# dmesg | tail -1
        [  740.800441] Core dump to |/foobar12345 lpq83 lpq83 lpq83 lpq83 lpq83 lpq83 lpq83 lpq83 lpq83 lpq83 lpq83 lpq83 lpq83 lpq83 lpq83 lpq83 lpq83 lpq83 lpq83 lpq83 pipe failed
      
      Fixes: 5fe9d8ca
      
       ("coredump: cn_vprintf() has no reason to call vsnprintf() twice")
      Signed-off-by: default avatarEric Dumazet <edumazet@google.com>
      Diagnosed-by: default avatarHugh Dickins <hughd@google.com>
      Acked-by: default avatarOleg Nesterov <oleg@redhat.com>
      Cc: Neil Horman <nhorman@tuxdriver.com>
      Cc: Andrew Morton <akpm@linux-foundation.org>
      Cc: stable@vger.kernel.org # 3.11+
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      404ca80e