On Tue, Aug 23, 2011 at 3:19 PM, Tejun Heo <tj@xxxxxxxxxx> wrote:
> ->pre_attach() is supposed to be called before migration, which is
> observed during process migration but task migration does it the other
> way around. The only ->pre_attach() user is cpuset which can do the
> same operaitons in ->can_attach(). Collapse cpuset_pre_attach() into
> cpuset_can_attach().
>
> Signed-off-by: Tejun Heo <tj@xxxxxxxxxx>
Acked-by: Paul Menage <paul@xxxxxxxxxxxxxx>
Code looks good, but I think that the some of the Documentation
changes slipped in here by mistake.
Paul
> Cc: Paul Menage <paul@xxxxxxxxxxxxxx>
> Cc: Li Zefan <lizf@xxxxxxxxxxxxxx>
> ---
> Documentation/cgroups/cgroups.txt | 20 --------------------
> kernel/cpuset.c | 29 ++++++++++++-----------------
> 2 files changed, 12 insertions(+), 37 deletions(-)
>
> diff --git a/Documentation/cgroups/cgroups.txt b/Documentation/cgroups/cgroups.txt
> index 2eee7cf..afb7cde 100644
> --- a/Documentation/cgroups/cgroups.txt
> +++ b/Documentation/cgroups/cgroups.txt
> @@ -610,13 +610,6 @@ 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);
> -(cgroup_mutex held by caller)
> -
> -As can_attach, but for operations that must be run once per task to be
> -attached (possibly many when using cgroup_attach_proc). Called after
> -can_attach.
> -
> void cancel_attach(struct cgroup_subsys *ss, struct cgroup *cgrp,
> struct cgroup_taskset *tset)
> (cgroup_mutex held by caller)
> @@ -627,12 +620,6 @@ function, so that the subsystem can implement a rollback. If not, not necessary.
> This will be called only about subsystems whose can_attach() operation have
> succeeded. The parameters are identical to can_attach().
>
> -void pre_attach(struct cgroup *cgrp);
> -(cgroup_mutex held by caller)
> -
> -For any non-per-thread attachment work that needs to happen before
> -attach_task. Needed by cpuset.
> -
> void attach(struct cgroup_subsys *ss, struct cgroup *cgrp,
> struct cgroup_taskset *tset)
> (cgroup_mutex held by caller)
> @@ -641,13 +628,6 @@ Called after the task has been attached to the cgroup, to allow any
> post-attachment activity that requires memory allocations or blocking.
> The parameters are identical to can_attach().
>
> -void attach_task(struct cgroup *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,
> -like can_attach_task. Called before attach. Currently does not support any
> -subsystem that might need the old_cgrp for every thread in the group.
> -
> void fork(struct cgroup_subsy *ss, struct task_struct *task)
>
> Called when a task is forked into a cgroup.
> diff --git a/kernel/cpuset.c b/kernel/cpuset.c
> index 472ddd6..f0b8df3 100644
> --- a/kernel/cpuset.c
> +++ b/kernel/cpuset.c
> @@ -1367,6 +1367,15 @@ static int fmeter_getrate(struct fmeter *fmp)
> return val;
> }
>
> +/*
> + * Protected by cgroup_lock. The nodemasks must be stored globally because
> + * dynamically allocating them is not allowed in can_attach, and they must
> + * persist until attach.
> + */
> +static cpumask_var_t cpus_attach;
> +static nodemask_t cpuset_attach_nodemask_from;
> +static nodemask_t cpuset_attach_nodemask_to;
> +
> /* Called by cgroups to determine if a cpuset is usable; cgroup_mutex held */
> static int cpuset_can_attach(struct cgroup_subsys *ss, struct cgroup *cgrp,
> struct cgroup_taskset *tset)
> @@ -1393,29 +1402,16 @@ static int cpuset_can_attach(struct cgroup_subsys *ss, struct cgroup *cgrp,
> if ((ret = security_task_setscheduler(task)))
> return ret;
> }
> - return 0;
> -}
> -
> -/*
> - * Protected by cgroup_lock. The nodemasks must be stored globally because
> - * dynamically allocating them is not allowed in pre_attach, and they must
> - * persist among pre_attach, and attach.
> - */
> -static cpumask_var_t cpus_attach;
> -static nodemask_t cpuset_attach_nodemask_from;
> -static nodemask_t cpuset_attach_nodemask_to;
> -
> -/* Set-up work for before attaching each task. */
> -static void cpuset_pre_attach(struct cgroup *cont)
> -{
> - struct cpuset *cs = cgroup_cs(cont);
>
> + /* prepare for attach */
> if (cs == &top_cpuset)
> cpumask_copy(cpus_attach, cpu_possible_mask);
> else
> guarantee_online_cpus(cs, cpus_attach);
>
> guarantee_online_mems(cs, &cpuset_attach_nodemask_to);
> +
> + return 0;
> }
>
> static void cpuset_attach(struct cgroup_subsys *ss, struct cgroup *cgrp,
> @@ -1901,7 +1897,6 @@ struct cgroup_subsys cpuset_subsys = {
> .create = cpuset_create,
> .destroy = cpuset_destroy,
> .can_attach = cpuset_can_attach,
> - .pre_attach = cpuset_pre_attach,
> .attach = cpuset_attach,
> .populate = cpuset_populate,
> .post_clone = cpuset_post_clone,
> --
> 1.7.6
>
>
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