Re: [PATCH 03/10] cgroups: Add previous cgroup incan_attach_task/attach_task callbacks

From: Kirill A. Shutemov
Date: Mon Oct 03 2011 - 20:22:58 EST


On Mon, Oct 03, 2011 at 09:07:05PM +0200, Frederic Weisbecker wrote:
> This is to prepare the integration of a new max number of proc
> cgroup subsystem. We'll need to release some resources from the
> previous cgroup.
>
> Signed-off-by: Frederic Weisbecker <fweisbec@xxxxxxxxx>
> Acked-by: Paul Menage <paul@xxxxxxxxxxxxxx>

Acked-by: Kirill A. Shutemov <kirill@xxxxxxxxxxxxx>

> Cc: Li Zefan <lizf@xxxxxxxxxxxxxx>
> Cc: Johannes Weiner <hannes@xxxxxxxxxxx>
> Cc: Aditya Kali <adityakali@xxxxxxxxxx>
> Cc: Oleg Nesterov <oleg@xxxxxxxxxx>
> Cc: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
> Cc: Kay Sievers <kay.sievers@xxxxxxxx>
> Cc: Tim Hockin <thockin@xxxxxxxxxx>
> Cc: Tejun Heo <tj@xxxxxxxxxx>
> Cc: Kirill A. Shutemov <kirill@xxxxxxxxxxxxx>
> Cc: Containers <containers@xxxxxxxxxxxxxxxxxxxxxxxxxx>
> ---
> Documentation/cgroups/cgroups.txt | 6 ++++--
> block/blk-cgroup.c | 12 ++++++++----
> include/linux/cgroup.h | 6 ++++--
> kernel/cgroup.c | 11 +++++++----
> kernel/cgroup_freezer.c | 3 ++-
> kernel/cpuset.c | 6 ++++--
> kernel/events/core.c | 5 +++--
> kernel/sched.c | 6 ++++--
> 8 files changed, 36 insertions(+), 19 deletions(-)
>
> diff --git a/Documentation/cgroups/cgroups.txt b/Documentation/cgroups/cgroups.txt
> index cd67e90..0621e93 100644
> --- a/Documentation/cgroups/cgroups.txt
> +++ b/Documentation/cgroups/cgroups.txt
> @@ -605,7 +605,8 @@ called on a fork. If this method returns 0 (success) then this should
> remain valid while the caller holds cgroup_mutex and it is ensured that either
> attach() or cancel_attach() will be called in future.
>
> -int can_attach_task(struct cgroup *cgrp, struct task_struct *tsk);
> +int can_attach_task(struct cgroup *cgrp, struct cgroup *old_cgrp,
> + struct task_struct *tsk);
> (cgroup_mutex held by caller)
>
> As can_attach, but for operations that must be run once per task to be
> @@ -635,7 +636,8 @@ void attach(struct cgroup_subsys *ss, struct cgroup *cgrp,
> Called after the task has been attached to the cgroup, to allow any
> post-attachment activity that requires memory allocations or blocking.
>
> -void attach_task(struct cgroup *cgrp, struct task_struct *tsk);
> +void attach_task(struct cgroup *cgrp, struct cgroup *old_cgrp,
> + struct task_struct *tsk);
> (cgroup_mutex held by caller)
>
> As attach, but for operations that must be run once per task to be attached,
> diff --git a/block/blk-cgroup.c b/block/blk-cgroup.c
> index bcaf16e..6eddc5f 100644
> --- a/block/blk-cgroup.c
> +++ b/block/blk-cgroup.c
> @@ -30,8 +30,10 @@ EXPORT_SYMBOL_GPL(blkio_root_cgroup);
>
> static struct cgroup_subsys_state *blkiocg_create(struct cgroup_subsys *,
> struct cgroup *);
> -static int blkiocg_can_attach_task(struct cgroup *, struct task_struct *);
> -static void blkiocg_attach_task(struct cgroup *, struct task_struct *);
> +static int blkiocg_can_attach_task(struct cgroup *, struct cgroup *,
> + struct task_struct *);
> +static void blkiocg_attach_task(struct cgroup *, struct cgroup *,
> + struct task_struct *);
> static void blkiocg_destroy(struct cgroup_subsys *, struct cgroup *);
> static int blkiocg_populate(struct cgroup_subsys *, struct cgroup *);
>
> @@ -1614,7 +1616,8 @@ done:
> * of the main cic data structures. For now we allow a task to change
> * its cgroup only if it's the only owner of its ioc.
> */
> -static int blkiocg_can_attach_task(struct cgroup *cgrp, struct task_struct *tsk)
> +static int blkiocg_can_attach_task(struct cgroup *cgrp, struct cgroup *old_cgrp,
> + struct task_struct *tsk)
> {
> struct io_context *ioc;
> int ret = 0;
> @@ -1629,7 +1632,8 @@ static int blkiocg_can_attach_task(struct cgroup *cgrp, struct task_struct *tsk)
> return ret;
> }
>
> -static void blkiocg_attach_task(struct cgroup *cgrp, struct task_struct *tsk)
> +static void blkiocg_attach_task(struct cgroup *cgrp, struct cgroup *old_cgrp,
> + struct task_struct *tsk)
> {
> struct io_context *ioc;
>
> diff --git a/include/linux/cgroup.h b/include/linux/cgroup.h
> index da7e4bc..ed34eb8 100644
> --- a/include/linux/cgroup.h
> +++ b/include/linux/cgroup.h
> @@ -468,11 +468,13 @@ struct cgroup_subsys {
> void (*destroy)(struct cgroup_subsys *ss, struct cgroup *cgrp);
> int (*can_attach)(struct cgroup_subsys *ss, struct cgroup *cgrp,
> struct task_struct *tsk);
> - int (*can_attach_task)(struct cgroup *cgrp, struct task_struct *tsk);
> + int (*can_attach_task)(struct cgroup *cgrp, struct cgroup *old_cgrp,
> + struct task_struct *tsk);
> void (*cancel_attach)(struct cgroup_subsys *ss, struct cgroup *cgrp,
> struct task_struct *tsk);
> void (*pre_attach)(struct cgroup *cgrp);
> - void (*attach_task)(struct cgroup *cgrp, struct task_struct *tsk);
> + void (*attach_task)(struct cgroup *cgrp, struct cgroup *old_cgrp,
> + struct task_struct *tsk);
> void (*attach)(struct cgroup_subsys *ss, struct cgroup *cgrp,
> struct cgroup *old_cgrp, struct task_struct *tsk);
> void (*fork)(struct cgroup_subsys *ss, struct task_struct *task);
> diff --git a/kernel/cgroup.c b/kernel/cgroup.c
> index 84bdace..fafebdb 100644
> --- a/kernel/cgroup.c
> +++ b/kernel/cgroup.c
> @@ -1844,7 +1844,7 @@ int cgroup_attach_task(struct cgroup *cgrp, struct task_struct *tsk)
> }
> }
> if (ss->can_attach_task) {
> - retval = ss->can_attach_task(cgrp, tsk);
> + retval = ss->can_attach_task(cgrp, oldcgrp, tsk);
> if (retval) {
> failed_ss = ss;
> goto out;
> @@ -1860,7 +1860,7 @@ int cgroup_attach_task(struct cgroup *cgrp, struct task_struct *tsk)
> if (ss->pre_attach)
> ss->pre_attach(cgrp);
> if (ss->attach_task)
> - ss->attach_task(cgrp, tsk);
> + ss->attach_task(cgrp, oldcgrp, tsk);
> if (ss->attach)
> ss->attach(ss, cgrp, oldcgrp, tsk);
> }
> @@ -2075,7 +2075,10 @@ int cgroup_attach_proc(struct cgroup *cgrp, struct task_struct *leader)
> /* run on each task in the threadgroup. */
> for (i = 0; i < group_size; i++) {
> tsk = flex_array_get_ptr(group, i);
> - retval = ss->can_attach_task(cgrp, tsk);
> + oldcgrp = task_cgroup_from_root(tsk, root);
> +
> + retval = ss->can_attach_task(cgrp,
> + oldcgrp, tsk);
> if (retval) {
> failed_ss = ss;
> cancel_failed_ss = true;
> @@ -2141,7 +2144,7 @@ int cgroup_attach_proc(struct cgroup *cgrp, struct task_struct *leader)
> /* attach each task to each subsystem */
> for_each_subsys(root, ss) {
> if (ss->attach_task)
> - ss->attach_task(cgrp, tsk);
> + ss->attach_task(cgrp, oldcgrp, tsk);
> }
> } else {
> BUG_ON(retval != -ESRCH);
> diff --git a/kernel/cgroup_freezer.c b/kernel/cgroup_freezer.c
> index e691818..c1421a1 100644
> --- a/kernel/cgroup_freezer.c
> +++ b/kernel/cgroup_freezer.c
> @@ -175,7 +175,8 @@ static int freezer_can_attach(struct cgroup_subsys *ss,
> return 0;
> }
>
> -static int freezer_can_attach_task(struct cgroup *cgrp, struct task_struct *tsk)
> +static int freezer_can_attach_task(struct cgroup *cgrp, struct cgroup *old_cgrp,
> + struct task_struct *tsk)
> {
> rcu_read_lock();
> if (__cgroup_freezing_or_frozen(tsk)) {
> diff --git a/kernel/cpuset.c b/kernel/cpuset.c
> index 10131fd..427be38 100644
> --- a/kernel/cpuset.c
> +++ b/kernel/cpuset.c
> @@ -1390,7 +1390,8 @@ static int cpuset_can_attach(struct cgroup_subsys *ss, struct cgroup *cont,
> return 0;
> }
>
> -static int cpuset_can_attach_task(struct cgroup *cgrp, struct task_struct *task)
> +static int cpuset_can_attach_task(struct cgroup *cgrp, struct cgroup *old_cgrp,
> + struct task_struct *task)
> {
> return security_task_setscheduler(task);
> }
> @@ -1418,7 +1419,8 @@ static void cpuset_pre_attach(struct cgroup *cont)
> }
>
> /* Per-thread attachment work. */
> -static void cpuset_attach_task(struct cgroup *cont, struct task_struct *tsk)
> +static void cpuset_attach_task(struct cgroup *cont, struct cgroup *old,
> + struct task_struct *tsk)
> {
> int err;
> struct cpuset *cs = cgroup_cs(cont);
> diff --git a/kernel/events/core.c b/kernel/events/core.c
> index b8785e2..509464e 100644
> --- a/kernel/events/core.c
> +++ b/kernel/events/core.c
> @@ -7001,7 +7001,8 @@ static int __perf_cgroup_move(void *info)
> }
>
> static void
> -perf_cgroup_attach_task(struct cgroup *cgrp, struct task_struct *task)
> +perf_cgroup_attach_task(struct cgroup *cgrp, struct cgroup *old_cgrp,
> + struct task_struct *task)
> {
> task_function_call(task, __perf_cgroup_move, task);
> }
> @@ -7017,7 +7018,7 @@ static void perf_cgroup_exit(struct cgroup_subsys *ss, struct cgroup *cgrp,
> if (!(task->flags & PF_EXITING))
> return;
>
> - perf_cgroup_attach_task(cgrp, task);
> + perf_cgroup_attach_task(cgrp, old_cgrp, task);
> }
>
> struct cgroup_subsys perf_subsys = {
> diff --git a/kernel/sched.c b/kernel/sched.c
> index ccacdbd..72ce1b1 100644
> --- a/kernel/sched.c
> +++ b/kernel/sched.c
> @@ -8967,7 +8967,8 @@ cpu_cgroup_destroy(struct cgroup_subsys *ss, struct cgroup *cgrp)
> }
>
> static int
> -cpu_cgroup_can_attach_task(struct cgroup *cgrp, struct task_struct *tsk)
> +cpu_cgroup_can_attach_task(struct cgroup *cgrp, struct cgroup *old_cgrp,
> + struct task_struct *tsk)
> {
> #ifdef CONFIG_RT_GROUP_SCHED
> if (!sched_rt_can_attach(cgroup_tg(cgrp), tsk))
> @@ -8981,7 +8982,8 @@ cpu_cgroup_can_attach_task(struct cgroup *cgrp, struct task_struct *tsk)
> }
>
> static void
> -cpu_cgroup_attach_task(struct cgroup *cgrp, struct task_struct *tsk)
> +cpu_cgroup_attach_task(struct cgroup *cgrp, struct cgroup *old_cgrp,
> + struct task_struct *tsk)
> {
> sched_move_task(tsk);
> }
> --
> 1.7.5.4
>

--
Kirill A. Shutemov
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