linux-kernel - Re: [RFC][PATCH] remove rq->lock from cpuacct cgroup (Was Re: [PATCH] cpuacct: add a branch prediction

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]

Date:	Tue, 3 Mar 2009 19:42:24 +0900 (JST)
From:	"KAMEZAWA Hiroyuki" <kamezawa.hiroyu@...fujitsu.com>
To:	"Peter Zijlstra" <a.p.zijlstra@...llo.nl>
Cc:	"KAMEZAWA Hiroyuki" <kamezawa.hiroyu@...fujitsu.com>,
	paulmck@...ux.vnet.ibm.com,
	"Bharata B Rao" <bharata.rao@...il.com>,
	"Li Zefan" <lizf@...fujitsu.com>, "Ingo Molnar" <mingo@...e.hu>,
	"Paul Menage" <menage@...gle.com>,
	"Balbir Singh" <balbir@...ux.vnet.ibm.com>,
	"LKML" <linux-kernel@...r.kernel.org>
Subject: Re: [RFC][PATCH] remove rq->lock from cpuacct cgroup (Was Re:
 [PATCH] cpuacct: add a branch prediction

Peter Zijlstra  wrote:
> On Tue, 2009-03-03 at 18:04 +0900, KAMEZAWA Hiroyuki wrote:
>> Peter Zijlstra wrote:
>> > On Tue, 2009-03-03 at 08:42 +0900, KAMEZAWA Hiroyuki wrote:
>> >
>> >> > Furthermore, if you want something like schedule_work_on() for each
>> >> cpu,
>> >> > there's schedule_on_each_cpu().
>> >> >
>> >> It can't pass arguments...Maybe I should use rq->lock here to reset
>> >> other cpu's value.
>> >
>> > Why bother with serializing the reset code at all?
>> >
>>   I don't think reset v.s. read is problem but reset v.s. increment
>>   (read-modify-write) can't be ?
>
> Sure, can be, do we care?
>
If small/easy code allows us to declare "there are any racy case!
and you don't have to check whether you successfully reseted",
it's worth to do I think.

Thanks,
-Kame


--
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/