From: "Andi Kleen" <andi@firstfloor.org>
To: Wu Fengguang <fengguang.wu@intel.com>
Cc: Andi Kleen <andi@firstfloor.org>,
KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>,
Kenneth <liguozhu@huawei.com>,
greg@kroah.com, linux-kernel@vger.kernel.org,
Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>,
linux-mm <linux-mm@kvack.org>
Subject: Re: Problem with debugfs
Date: Tue, 21 Sep 2010 10:12:23 +0200 [thread overview]
Message-ID: <562d0c45d5a10d80c3583c2fe1c318c7.squirrel@www.firstfloor.org> (raw)
In-Reply-To: <20100921080459.GA29540@localhost>
>
> Thanks for the report. Did this show up as a real bug? What's your
> use case? Or is it a theoretic concern raised when doing code review?
I assume it was code review, right?
> Yeah the hwpoison_filter_flags_* values are not referenced strictly
> safe to concurrent updates. I didn't care it because the typical usage
> is for hwpoison test tools to _first_ echo hwpoison_filter_flags_*
> values into the debugfs and _then_ start injecting hwpoison errors.
> Otherwise you cannot get reliable test results. The updated value is
> guaranteed to be visible because there are file mutex UNLOCK and page
> LOCK operations in between.
Sorry that's not true -- all the x86 memory ordering constraints only
apply to a single CPU or same address.
But I agree it doesn't really matter for a debugging feature
like this.
So unless there's a very simple fix I would be inclined to leave
it alone, perhaps with a comment added. Comments?
-Andi
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prev parent reply other threads:[~2010-09-21 8:12 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <20100921022112.GA10336@localhost>
[not found] ` <20100921061310.GA11526@localhost>
2010-09-21 7:23 ` Problem with debugfs KOSAKI Motohiro
2010-09-21 7:31 ` Andi Kleen
2010-09-21 8:04 ` Wu Fengguang
2010-09-21 8:12 ` Andi Kleen [this message]
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