lkml.org 
[lkml]   [2011]   [Aug]   [25]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
From
Date
SubjectRe: [PATCH 6/6] cgroup: kill subsys->can_attach_task(), pre_attach() and attach_task()
On Tue, Aug 23, 2011 at 3:20 PM, Tejun Heo <tj@kernel.org> wrote:
> These three methods are no longer used.  Kill them.
>
> Signed-off-by: Tejun Heo <tj@kernel.org>

Acked-by: Paul Menage <paul@paulmenage.org>

Overall, I think this patch set is a great improvement in code
simplicity and clarity.

Thanks,
Paul

> Cc: Paul Menage <paul@paulmenage.org>
> Cc: Li Zefan <lizf@cn.fujitsu.com>
> ---
>  include/linux/cgroup.h |    3 --
>  kernel/cgroup.c        |   53 ++++-------------------------------------------
>  2 files changed, 5 insertions(+), 51 deletions(-)
>
> diff --git a/include/linux/cgroup.h b/include/linux/cgroup.h
> index 2470c8e..5659d37 100644
> --- a/include/linux/cgroup.h
> +++ b/include/linux/cgroup.h
> @@ -490,11 +490,8 @@ struct cgroup_subsys {
>        void (*destroy)(struct cgroup_subsys *ss, struct cgroup *cgrp);
>        int (*can_attach)(struct cgroup_subsys *ss, struct cgroup *cgrp,
>                          struct cgroup_taskset *tset);
> -       int (*can_attach_task)(struct cgroup *cgrp, struct task_struct *tsk);
>        void (*cancel_attach)(struct cgroup_subsys *ss, struct cgroup *cgrp,
>                              struct cgroup_taskset *tset);
> -       void (*pre_attach)(struct cgroup *cgrp);
> -       void (*attach_task)(struct cgroup *cgrp, struct task_struct *tsk);
>        void (*attach)(struct cgroup_subsys *ss, struct cgroup *cgrp,
>                       struct cgroup_taskset *tset);
>        void (*fork)(struct cgroup_subsys *ss, struct task_struct *task);
> diff --git a/kernel/cgroup.c b/kernel/cgroup.c
> index 474674b..374a4cb 100644
> --- a/kernel/cgroup.c
> +++ b/kernel/cgroup.c
> @@ -1926,13 +1926,6 @@ int cgroup_attach_task(struct cgroup *cgrp, struct task_struct *tsk)
>                                goto out;
>                        }
>                }
> -               if (ss->can_attach_task) {
> -                       retval = ss->can_attach_task(cgrp, tsk);
> -                       if (retval) {
> -                               failed_ss = ss;
> -                               goto out;
> -                       }
> -               }
>        }
>
>        retval = cgroup_task_migrate(cgrp, oldcgrp, tsk, false);
> @@ -1940,10 +1933,6 @@ int cgroup_attach_task(struct cgroup *cgrp, struct task_struct *tsk)
>                goto out;
>
>        for_each_subsys(root, ss) {
> -               if (ss->pre_attach)
> -                       ss->pre_attach(cgrp);
> -               if (ss->attach_task)
> -                       ss->attach_task(cgrp, tsk);
>                if (ss->attach)
>                        ss->attach(ss, cgrp, &tset);
>        }
> @@ -2075,7 +2064,6 @@ int cgroup_attach_proc(struct cgroup *cgrp, struct task_struct *leader)
>  {
>        int retval, i, group_size, nr_todo;
>        struct cgroup_subsys *ss, *failed_ss = NULL;
> -       bool cancel_failed_ss = false;
>        /* guaranteed to be initialized later, but the compiler needs this */
>        struct css_set *oldcg;
>        struct cgroupfs_root *root = cgrp->root;
> @@ -2166,21 +2154,6 @@ int cgroup_attach_proc(struct cgroup *cgrp, struct task_struct *leader)
>                                goto out_cancel_attach;
>                        }
>                }
> -               /* a callback to be run on every thread in the threadgroup. */
> -               if (ss->can_attach_task) {
> -                       /* run on each task in the threadgroup. */
> -                       for (i = 0; i < group_size; i++) {
> -                               tc = flex_array_get(group, i);
> -                               if (tc->cgrp == cgrp)
> -                                       continue;
> -                               retval = ss->can_attach_task(cgrp, tc->task);
> -                               if (retval) {
> -                                       failed_ss = ss;
> -                                       cancel_failed_ss = true;
> -                                       goto out_cancel_attach;
> -                               }
> -                       }
> -               }
>        }
>
>        /*
> @@ -2217,15 +2190,10 @@ int cgroup_attach_proc(struct cgroup *cgrp, struct task_struct *leader)
>        }
>
>        /*
> -        * step 3: now that we're guaranteed success wrt the css_sets, proceed
> -        * to move all tasks to the new cgroup, calling ss->attach_task for each
> -        * one along the way. there are no failure cases after here, so this is
> -        * the commit point.
> +        * step 3: now that we're guaranteed success wrt the css_sets,
> +        * proceed to move all tasks to the new cgroup.  There are no
> +        * failure cases after here, so this is the commit point.
>         */
> -       for_each_subsys(root, ss) {
> -               if (ss->pre_attach)
> -                       ss->pre_attach(cgrp);
> -       }
>        for (i = 0; i < group_size; i++) {
>                tc = flex_array_get(group, i);
>                /* leave current thread as it is if it's already there */
> @@ -2235,19 +2203,11 @@ int cgroup_attach_proc(struct cgroup *cgrp, struct task_struct *leader)
>                /* if the thread is PF_EXITING, it can just get skipped. */
>                retval = cgroup_task_migrate(cgrp, tc->cgrp, tc->task, true);
>                BUG_ON(retval != 0 && retval != -ESRCH);
> -
> -               /* attach each task to each subsystem */
> -               for_each_subsys(root, ss) {
> -                       if (ss->attach_task)
> -                               ss->attach_task(cgrp, tc->task);
> -               }
>        }
>        /* nothing is sensitive to fork() after this point. */
>
>        /*
> -        * step 4: do expensive, non-thread-specific subsystem callbacks.
> -        * TODO: if ever a subsystem needs to know the oldcgrp for each task
> -        * being moved, this call will need to be reworked to communicate that.
> +        * step 4: do subsystem attach callbacks.
>         */
>        for_each_subsys(root, ss) {
>                if (ss->attach)
> @@ -2271,11 +2231,8 @@ out_cancel_attach:
>        /* same deal as in cgroup_attach_task */
>        if (retval) {
>                for_each_subsys(root, ss) {
> -                       if (ss == failed_ss) {
> -                               if (cancel_failed_ss && ss->cancel_attach)
> -                                       ss->cancel_attach(ss, cgrp, &tset);
> +                       if (ss == failed_ss)
>                                break;
> -                       }
>                        if (ss->cancel_attach)
>                                ss->cancel_attach(ss, cgrp, &tset);
>                }
> --
> 1.7.6
>
>
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/

\
 
 \ /
  Last update: 2011-08-25 11:47    [from the cache]
©2003-2014 Jasper Spaans. Advertise on this site