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From: Kamezawa Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
To: "Luck, Tony" <tony.luck@intel.com>,
	Taku Izumi <izumi.taku@jp.fujitsu.com>,
	"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
	"linux-mm@kvack.org" <linux-mm@kvack.org>
Cc: "qiuxishi@huawei.com" <qiuxishi@huawei.com>,
	"mel@csn.ul.ie" <mel@csn.ul.ie>,
	"akpm@linux-foundation.org" <akpm@linux-foundation.org>,
	"Hansen, Dave" <dave.hansen@intel.com>,
	"matt@codeblueprint.co.uk" <matt@codeblueprint.co.uk>
Subject: Re: [PATCH] mm: Introduce kernelcore=reliable option
Date: Thu, 22 Oct 2015 19:02:15 +0900	[thread overview]
Message-ID: <5628B427.3050403@jp.fujitsu.com> (raw)
In-Reply-To: <3908561D78D1C84285E8C5FCA982C28F32B5A060@ORSMSX114.amr.corp.intel.com>

On 2015/10/22 3:17, Luck, Tony wrote:
> +	if (reliable_kernelcore) {
> +		for_each_memblock(memory, r) {
> +			if (memblock_is_mirror(r))
> +				continue;
>
> Should we have a safety check here that there is some mirrored memory?  If you give
> the kernelcore=reliable option on a machine which doesn't have any mirror configured,
> then we'll mark all memory as removable.

You're right.

> What happens then?  Do kernel allocations fail?  Or do they fall back to using removable memory?

Maybe the kernel cannot boot because NORMAL zone is empty.

> Is there a /proc or /sys file that shows the current counts for the removable zone?  I just
> tried this patch with a high percentage of memory marked as mirror ... but I'd like to see
> how much is actually being used to tune things a bit.
>

I think /proc/zoneinfo can show detailed numbers per zone. Do we need some for meminfo ?

Thanks,
-Kame



  reply	other threads:[~2015-10-22 10:02 UTC|newest]

Thread overview: 13+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2015-10-15 13:32 [PATCH] mm: Introduce kernelcore=reliable option Taku Izumi
2015-10-19  2:25 ` Xishi Qiu
2015-10-20  0:34   ` Izumi, Taku
2015-10-20  1:42     ` Xishi Qiu
2015-10-21 18:17 ` Luck, Tony
2015-10-22 10:02   ` Kamezawa Hiroyuki [this message]
2015-10-22 23:26     ` Luck, Tony
2015-10-23  1:01       ` Izumi, Taku
2015-10-23  1:44         ` Luck, Tony
2015-10-30  6:19           ` Kamezawa Hiroyuki
2015-10-30 19:42             ` Luck, Tony
2015-11-04  6:56               ` Kamezawa Hiroyuki
2015-10-23  3:36 ` Xishi Qiu

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