From: Prarit Bhargava <prarit@redhat.com>
To: 7eggert@gmx.de
Cc: linux-kernel@vger.kernel.org,
Thomas Gleixner <tglx@linutronix.de>,
Ingo Molnar <mingo@redhat.com>, "H. Peter Anvin" <hpa@zytor.com>,
x86@kernel.org, Len Brown <lenb@kernel.org>,
"Rafael J. Wysocki" <rjw@rjwysocki.net>,
Linn Crosetto <linn@hp.com>, Pekka Enberg <penberg@kernel.org>,
Yinghai Lu <yinghai@kernel.org>,
Andrew Morton <akpm@linux-foundation.org>,
Toshi Kani <toshi.kani@hp.com>,
Tang Chen <tangchen@cn.fujitsu.com>,
Wen Congyang <wency@cn.fujitsu.com>,
Vivek Goyal <vgoyal@redhat.com>,
kosaki.motohiro@gmail.com, dyoung@redhat.com,
linux-acpi@vger.kernel.org, linux-mm@kvack.org
Subject: Re: [PATCH 2/2] x86, e820 disable ACPI Memory Hotplug if memory mapping is specified by user [v2]
Date: Sun, 12 Jan 2014 18:46:42 -0500 [thread overview]
Message-ID: <52D32962.5050908@redhat.com> (raw)
In-Reply-To: <alpine.DEB.2.02.1401111624170.20677@be1.lrz>
On 01/11/2014 11:35 AM, 7eggert@gmx.de wrote:
>
>
> On Fri, 10 Jan 2014, Prarit Bhargava wrote:
>
>> kdump uses memmap=exactmap and mem=X values to configure the memory
>> mapping for the kdump kernel. If memory is hotadded during the boot of
>> the kdump kernel it is possible that the page tables for the new memory
>> cause the kdump kernel to run out of memory.
>>
>> Since the user has specified a specific mapping ACPI Memory Hotplug should be
>> disabled in this case.
>
> I'll ask just in case: Is it possible to want memory hotplug in spite of
> using memmap=exactmap or mem=X?
Good question -- I can't think of a case. When a user specifies "memmap" or
"mem" IMO they are asking for a very specific memory configuration. Having
extra memory added above what the user has specified seems to defeat the purpose
of "memmap" and "mem".
P.
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WARNING: multiple messages have this Message-ID (diff)
From: Prarit Bhargava <prarit@redhat.com>
To: 7eggert@gmx.de
Cc: linux-kernel@vger.kernel.org,
Thomas Gleixner <tglx@linutronix.de>,
Ingo Molnar <mingo@redhat.com>, "H. Peter Anvin" <hpa@zytor.com>,
x86@kernel.org, Len Brown <lenb@kernel.org>,
"Rafael J. Wysocki" <rjw@rjwysocki.net>,
Linn Crosetto <linn@hp.com>, Pekka Enberg <penberg@kernel.org>,
Yinghai Lu <yinghai@kernel.org>,
Andrew Morton <akpm@linux-foundation.org>,
Toshi Kani <toshi.kani@hp.com>,
Tang Chen <tangchen@cn.fujitsu.com>,
Wen Congyang <wency@cn.fujitsu.com>,
Vivek Goyal <vgoyal@redhat.com>,
kosaki.motohiro@gmail.com, dyoung@redhat.com,
linux-acpi@vger.kernel.org, linux-mm@kvack.org
Subject: Re: [PATCH 2/2] x86, e820 disable ACPI Memory Hotplug if memory mapping is specified by user [v2]
Date: Sun, 12 Jan 2014 18:46:42 -0500 [thread overview]
Message-ID: <52D32962.5050908@redhat.com> (raw)
In-Reply-To: <alpine.DEB.2.02.1401111624170.20677@be1.lrz>
On 01/11/2014 11:35 AM, 7eggert@gmx.de wrote:
>
>
> On Fri, 10 Jan 2014, Prarit Bhargava wrote:
>
>> kdump uses memmap=exactmap and mem=X values to configure the memory
>> mapping for the kdump kernel. If memory is hotadded during the boot of
>> the kdump kernel it is possible that the page tables for the new memory
>> cause the kdump kernel to run out of memory.
>>
>> Since the user has specified a specific mapping ACPI Memory Hotplug should be
>> disabled in this case.
>
> I'll ask just in case: Is it possible to want memory hotplug in spite of
> using memmap=exactmap or mem=X?
Good question -- I can't think of a case. When a user specifies "memmap" or
"mem" IMO they are asking for a very specific memory configuration. Having
extra memory added above what the user has specified seems to defeat the purpose
of "memmap" and "mem".
P.
next prev parent reply other threads:[~2014-01-12 23:46 UTC|newest]
Thread overview: 37+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-01-10 19:04 [PATCH 0/2] Add option to disable ACPI Memory Hotplug [v2] Prarit Bhargava
2014-01-10 19:04 ` Prarit Bhargava
2014-01-10 19:04 ` [PATCH 0/2] Add option to disable ACPI Memory Hotplug Prarit Bhargava
2014-01-10 19:04 ` [PATCH 1/2] acpi memory hotplug, add parameter to disable memory hotplug [v2] Prarit Bhargava
2014-01-10 19:04 ` Prarit Bhargava
2014-01-10 21:34 ` Toshi Kani
2014-01-10 21:34 ` Toshi Kani
2014-01-10 19:04 ` [PATCH 2/2] x86, e820 disable ACPI Memory Hotplug if memory mapping is specified by user [v2] Prarit Bhargava
2014-01-10 19:04 ` Prarit Bhargava
2014-01-10 21:12 ` Vivek Goyal
2014-01-10 21:12 ` Vivek Goyal
2014-01-10 21:34 ` Toshi Kani
2014-01-10 21:34 ` Toshi Kani
2014-01-11 16:35 ` 7eggert
2014-01-11 16:35 ` 7eggert
2014-01-12 23:46 ` Prarit Bhargava [this message]
2014-01-12 23:46 ` Prarit Bhargava
2014-01-13 20:31 ` KOSAKI Motohiro
2014-01-13 20:31 ` KOSAKI Motohiro
2014-01-13 23:39 ` Prarit Bhargava
2014-01-13 23:39 ` Prarit Bhargava
2014-01-14 0:33 ` Toshi Kani
2014-01-14 0:33 ` Toshi Kani
2014-01-14 0:53 ` H. Peter Anvin
2014-01-14 0:53 ` H. Peter Anvin
2014-01-14 1:09 ` Toshi Kani
2014-01-14 1:09 ` Toshi Kani
2014-01-14 1:29 ` H. Peter Anvin
2014-01-14 1:29 ` H. Peter Anvin
2014-01-14 1:40 ` Toshi Kani
2014-01-14 1:40 ` Toshi Kani
2014-01-14 1:52 ` Dave Young
2014-01-14 1:52 ` Dave Young
2014-01-14 1:47 ` Toshi Kani
2014-01-14 1:47 ` Toshi Kani
2014-01-14 11:02 ` Prarit Bhargava
2014-01-14 11:02 ` Prarit Bhargava
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