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From: "Jan Beulich" <>
To: "Matthew Helsley" <>
Cc: "Paul Jackson" <>, <>
Subject: Re: [PATCH 1/4] add task handling notifier: base definitions
Date: Wed, 09 Jan 2008 09:46:25 +0000	[thread overview]
Message-ID: <> (raw)
In-Reply-To: <1199852889.17010.243.camel@localhost.localdomain>

>> +BLOCKING_NOTIFIER_HEAD(task_notifier_list);
>> +EXPORT_SYMBOL_GPL(task_notifier_list);
>> +ATOMIC_NOTIFIER_HEAD(atomic_task_notifier_list);
>> +EXPORT_SYMBOL_GPL(atomic_task_notifier_list);
>> +
>When these global notifier lists were proposed years ago folks at SGI
>loudly objected with concerns over anticipated cache line bouncing on
>512+ cpu machines. Is that no longer a concern?

I can't see an alternative, since the serialization is unavoidable.

>> @@ -121,6 +127,9 @@ void __put_task_struct(struct task_struc
>>  	WARN_ON(atomic_read(&tsk->usage));
>>  	WARN_ON(tsk == current);
>> +	atomic_notifier_call_chain(&atomic_task_notifier_list,
>> +				   TASK_DELETE, tsk);
>> +
>>  	security_task_free(tsk);
>>  	free_uid(tsk->user);
>>  	put_group_info(tsk->group_info);
>Would the atomic notifier call chain be necessary if you hooked into an
>earlier section of do_exit() instead?

I'm afraid it is, as I was told that sleeping in the do_exit() path is not
generally possible.


  reply	other threads:[~2008-01-09  9:46 UTC|newest]

Thread overview: 5+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2007-12-20 13:12 [PATCH 1/4] add task handling notifier: base definitions Jan Beulich
2007-12-21 23:32 ` Andi Kleen
2008-01-09  4:28 ` Matthew Helsley
2008-01-09  9:46   ` Jan Beulich [this message]
2008-01-23 19:11     ` Matt Helsley

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