linux-kernel - Re: [ckrm-tech] [PATCH 5/13] BC: user interface (syscalls)

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <44FECBCF.7080103@in.ibm.com>
Date:	Wed, 06 Sep 2006 18:53:27 +0530
From:	Balbir Singh <balbir@...ibm.com>
To:	Pavel Emelianov <xemul@...nvz.org>
Cc:	Rik van Riel <riel@...hat.com>, Andi Kleen <ak@...e.de>,
	CKRM-Tech <ckrm-tech@...ts.sourceforge.net>,
	Linux Kernel Mailing List <linux-kernel@...r.kernel.org>,
	Kirill Korotaev <dev@...ru>,
	Christoph Hellwig <hch@...radead.org>,
	Andrey Savochkin <saw@...ru>, devel@...nvz.org,
	Matt Helsley <matthltc@...ibm.com>,
	Hugh Dickins <hugh@...itas.com>,
	Alexey Dobriyan <adobriyan@...l.ru>,
	Oleg Nesterov <oleg@...sign.ru>,
	Alan Cox <alan@...rguk.ukuu.org.uk>
Subject: Re: [ckrm-tech] [PATCH 5/13] BC: user interface (syscalls)

Pavel Emelianov wrote:
> Balbir Singh wrote:
>> Pavel Emelianov wrote:
>>> Balbir Singh wrote:
>>>>> +
>>>>> +asmlinkage long sys_set_bcid(bcid_t id)
>>>>> +{
>>>>> +    int error;
>>>>> +    struct beancounter *bc;
>>>>> +    struct task_beancounter *task_bc;
>>>>> +
>>>>> +    task_bc = &current->task_bc;
>>>> I was playing around with the bc patches and found that to make
>>>> use of bc's, I had to actually call set_bcid() and then exec() a
>>>> task/shell so that the id would stick around. Would you consider
>>> That sounds very strange as sys_set_bcid() actually changes current's
>>> exec_bc.
>>> One note is about mm's bc - mm obtains new bc only after fork or exec -
>>> that's
>>> true. But kmemsize starts charging right after the sys_set_bcid.
>> I was playing around only with kmemsize. I think the reason for my
>> observation
>> is this
>>
>> bash --> (my utility) --> set_bcid()
>>
>> Since bash spawns my utility in a separate process, it creates and
>> assigns
>> a bean counter to it and then my utility exits. Unless it
>> spawns/exec()'s a
>> new shell, the beancounter is freed when the task exits (my utility).
> Well, beancounter is not "inherited" by parent task :)
> After setting bcid you need to spawn/exec a new shell.
> But seeting limits and getting stats is possible from the old shell
> as well as from the new one.

That's what I suspected. I suggest changing the system call to allow adding any
task to a particular id (not necessarily only the current one). It would help us
group tasks to a particular id. It would also solve my problem of spawning a
shell each time I decide to use a task with a beancounter and limits.

>>>> changing sys_set_bcid to sys_set_task_bcid() or adding a new
>>>> system call sys_set_task_bcid()? We could pass the pid that we
>>>> intend to associate with the new id. This also means we'll need
>>>> locking around to protect task->task_bc.
>>

-- 

	Balbir Singh,
	Linux Technology Center,
	IBM Software Labs
-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/