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Message-ID: <2f86c2480908031735m7dbee753wf63724959ee135eb@mail.gmail.com>
Date: Mon, 3 Aug 2009 17:35:16 -0700
From: Benjamin Blum <bblum@...gle.com>
To: Li Zefan <lizf@...fujitsu.com>
Cc: linux-kernel@...r.kernel.org,
containers@...ts.linux-foundation.org, akpm@...ux-foundation.org,
serue@...ibm.com, menage@...gle.com
Subject: Re: [PATCH 5/6] Lets ss->can_attach and ss->attach do whole
threadgroups at a time
On Sun, Aug 2, 2009 at 7:22 PM, Li Zefan<lizf@...fujitsu.com> wrote:
> 09:51, Ben Blum wrote:
>> Lets ss->can_attach and ss->attach do whole threadgroups at a time
>>
>> This patch alters the ss->can_attach and ss->attach functions to be able to
>> deal with a whole threadgroup at a time, for use in cgroup_attach_proc. (This
>> is a pre-patch to cgroup-procs-writable.patch.)
>>
>> Currently, new mode of the attach function can only tell the subsystem about
>> the old cgroup of the threadgroup leader. No subsystem currently needs that
>> information for each thread that's being moved, but if one were to be added
>> (for example, one that counts tasks within a group) this bit would need to be
>> reworked a bit to tell the subsystem the right information.
>>
>> Signed-off-by: Ben Blum <bblum@...gle.com>
>>
>> ---
>>
>> include/linux/cgroup.h | 7 +++--
>> kernel/cgroup.c | 4 +--
>> kernel/cgroup_freezer.c | 15 +++++++++--
>> kernel/cpuset.c | 65 ++++++++++++++++++++++++++++++++++++----------
>> kernel/ns_cgroup.c | 16 ++++++++++-
>> kernel/sched.c | 37 ++++++++++++++++++++++++--
>> mm/memcontrol.c | 3 +-
>> security/device_cgroup.c | 3 +-
>> 8 files changed, 122 insertions(+), 28 deletions(-)
>>
>> diff --git a/include/linux/cgroup.h b/include/linux/cgroup.h
>> index 24e3f1a..8286758 100644
>> --- a/include/linux/cgroup.h
>> +++ b/include/linux/cgroup.h
>> @@ -408,10 +408,11 @@ struct cgroup_subsys {
>> struct cgroup *cgrp);
>> int (*pre_destroy)(struct cgroup_subsys *ss, struct cgroup *cgrp);
>> 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)(struct cgroup_subsys *ss, struct cgroup *cgrp,
>> + struct task_struct *tsk, bool threadgroup);
>> void (*attach)(struct cgroup_subsys *ss, struct cgroup *cgrp,
>> - struct cgroup *old_cgrp, struct task_struct *tsk);
>> + struct cgroup *old_cgrp, struct task_struct *tsk,
>> + bool threadgroup);
>
> Could you also update Documentation/cgroups/cgroups.txt?
>
>> void (*fork)(struct cgroup_subsys *ss, struct task_struct *task);
>> void (*exit)(struct cgroup_subsys *ss, struct task_struct *task);
>> int (*populate)(struct cgroup_subsys *ss,
>> diff --git a/kernel/cgroup.c b/kernel/cgroup.c
>> index a12bc8e..ea05d6b 100644
>> --- a/kernel/cgroup.c
>> +++ b/kernel/cgroup.c
>> @@ -1324,7 +1324,7 @@ int cgroup_attach_task(struct cgroup *cgrp, struct task_struct *tsk)
>>
>> for_each_subsys(root, ss) {
>> if (ss->can_attach) {
>> - retval = ss->can_attach(ss, cgrp, tsk);
>> + retval = ss->can_attach(ss, cgrp, tsk, false);
>> if (retval)
>> return retval;
>> }
>> @@ -1362,7 +1362,7 @@ int cgroup_attach_task(struct cgroup *cgrp, struct task_struct *tsk)
>>
>> for_each_subsys(root, ss) {
>> if (ss->attach)
>> - ss->attach(ss, cgrp, oldcgrp, tsk);
>> + ss->attach(ss, cgrp, oldcgrp, tsk, false);
>> }
>> set_bit(CGRP_RELEASABLE, &oldcgrp->flags);
>> synchronize_rcu();
>> diff --git a/kernel/cgroup_freezer.c b/kernel/cgroup_freezer.c
>> index fb249e2..4e352ab 100644
>> --- a/kernel/cgroup_freezer.c
>> +++ b/kernel/cgroup_freezer.c
>> @@ -159,10 +159,9 @@ static bool is_task_frozen_enough(struct task_struct *task)
>> */
>> static int freezer_can_attach(struct cgroup_subsys *ss,
>> struct cgroup *new_cgroup,
>> - struct task_struct *task)
>> + struct task_struct *task, bool threadgroup)
>> {
>> struct freezer *freezer;
>> -
>
> Please reserve this blank line.
>
>> /*
>> * Anything frozen can't move or be moved to/from.
>> *
>> @@ -177,6 +176,18 @@ static int freezer_can_attach(struct cgroup_subsys *ss,
>> if (freezer->state == CGROUP_FROZEN)
>> return -EBUSY;
>>
>> + if (threadgroup) {
>> + struct task_struct *c;
>
> And better have a blank line here. ;)
>
>> + rcu_read_lock();
>> + list_for_each_entry_rcu(c, &task->thread_group, thread_group) {
>> + if (is_task_frozen_enough(c)) {
>> + rcu_read_unlock();
>> + return -EBUSY;
>> + }
>> + }
>> + rcu_read_unlock();
>> + }
>> +
>> return 0;
>> }
>>
>> diff --git a/kernel/cpuset.c b/kernel/cpuset.c
>> index 7e75a41..86397f4 100644
>> --- a/kernel/cpuset.c
>> +++ b/kernel/cpuset.c
>> @@ -1324,9 +1324,10 @@ static int fmeter_getrate(struct fmeter *fmp)
>> static cpumask_var_t cpus_attach;
>>
>> /* Called by cgroups to determine if a cpuset is usable; cgroup_mutex held */
>> -static int cpuset_can_attach(struct cgroup_subsys *ss,
>> - struct cgroup *cont, struct task_struct *tsk)
>> +static int cpuset_can_attach(struct cgroup_subsys *ss, struct cgroup *cont,
>> + struct task_struct *tsk, bool threadgroup)
>> {
>> + int ret;
>> struct cpuset *cs = cgroup_cs(cont);
>>
>> if (cpumask_empty(cs->cpus_allowed) || nodes_empty(cs->mems_allowed))
>> @@ -1343,18 +1344,50 @@ static int cpuset_can_attach(struct cgroup_subsys *ss,
>> if (tsk->flags & PF_THREAD_BOUND)
>> return -EINVAL;
>>
>> - return security_task_setscheduler(tsk, 0, NULL);
>> + ret = security_task_setscheduler(tsk, 0, NULL);
>> + if (ret)
>> + return ret;
>> + if (threadgroup) {
>> + struct task_struct *c;
>
> ditto
>
>> + rcu_read_lock();
>> + list_for_each_entry_rcu(c, &tsk->thread_group, thread_group) {
>> + ret = security_task_setscheduler(c, 0, NULL);
>> + if (ret) {
>> + rcu_read_unlock();
>> + return ret;
>> + }
>> + }
>> + rcu_read_unlock();
>> + }
>> + return 0;
>> +}
>
>
All taken care of. Thanks.
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