Re: [PATCH] sched: make pushable_tasks CONFIG_SMP dependant.

From: Gregory Haskins
Date: Tue Nov 30 2010 - 16:01:51 EST


>>> On 11/30/2010 at 02:02 PM, in message
<1291143732.27486.36.camel@xxxxxxxxxxxxxxxxxxx>, Steven Rostedt
<rostedt@xxxxxxxxxxx> wrote:
> On Tue, 2010-11-30 at 19:51 +0100, Dario Faggioli wrote:
>> As noted by Peter Zijlstra here https://lkml.org/lkml/2010/11/10/391
>> (while reviewing other stuff, though), tracking pushable tasks
>> only makes sense on SMPs.
>
> Acked-by: Steven Rostedt <rostedt@xxxxxxxxxxx>

Acked-by: Gregory Haskins <ghaskins@xxxxxxxxxx>

>
> -- Steve
>
>>
>> Signed-off-by: Dario Faggioli <raistlin@xxxxxxxx>
>> ---
>> include/linux/init_task.h | 9 ++++++++-
>> include/linux/sched.h | 2 ++
>> kernel/sched.c | 2 ++
>> 3 files changed, 12 insertions(+), 1 deletions(-)
>>
>> diff --git a/include/linux/init_task.h b/include/linux/init_task.h
>> index 1f8c06c..6ed8812 100644
>> --- a/include/linux/init_task.h
>> +++ b/include/linux/init_task.h
>> @@ -12,6 +12,13 @@
>> #include <linux/securebits.h>
>> #include <net/net_namespace.h>
>>
>> +#ifdef CONFIG_SMP
>> +# define INIT_PUSHABLE_TASKS(tsk) \
>> + .pushable_tasks = PLIST_NODE_INIT(tsk.pushable_tasks, MAX_PRIO),
>> +#else
>> +# define INIT_PUSHABLE_TASKS(tsk)
>> +#endif
>> +
>> extern struct files_struct init_files;
>> extern struct fs_struct init_fs;
>>
>> @@ -137,7 +144,7 @@ extern struct cred init_cred;
>> .nr_cpus_allowed = NR_CPUS, \
>> }, \
>> .tasks = LIST_HEAD_INIT(tsk.tasks), \
>> - .pushable_tasks = PLIST_NODE_INIT(tsk.pushable_tasks, MAX_PRIO), \
>> + INIT_PUSHABLE_TASKS(tsk) \
>> .ptraced = LIST_HEAD_INIT(tsk.ptraced), \
>> .ptrace_entry = LIST_HEAD_INIT(tsk.ptrace_entry), \
>> .real_parent = &tsk, \
>> diff --git a/include/linux/sched.h b/include/linux/sched.h
>> index b0fc8ee..eae4131 100644
>> --- a/include/linux/sched.h
>> +++ b/include/linux/sched.h
>> @@ -1244,7 +1244,9 @@ struct task_struct {
>> #endif
>>
>> struct list_head tasks;
>> +#ifdef CONFIG_SMP
>> struct plist_node pushable_tasks;
>> +#endif
>>
>> struct mm_struct *mm, *active_mm;
>> #if defined(SPLIT_RSS_COUNTING)
>> diff --git a/kernel/sched.c b/kernel/sched.c
>> index 0debad9..166f9f8 100644
>> --- a/kernel/sched.c
>> +++ b/kernel/sched.c
>> @@ -2595,7 +2595,9 @@ void sched_fork(struct task_struct *p, int clone_flags)
>> /* Want to start with kernel preemption disabled. */
>> task_thread_info(p)->preempt_count = 1;
>> #endif
>> +#ifdef CONFIG_SMP
>> plist_node_init(&p->pushable_tasks, MAX_PRIO);
>> +#endif
>>
>> put_cpu();
>> }
>> --
>> 1.7.2.3
>>



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