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From: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
To: Andi Kleen <ak@linux.intel.com>
Cc: "H. Peter Anvin" <hpa@kernel.org>,
	"Zheng, Shaohui" <shaohui.zheng@intel.com>,
	"linux-mm@kvack.org" <linux-mm@kvack.org>,
	"akpm@linux-foundation.org" <akpm@linux-foundation.org>,
	"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
	"y-goto@jp.fujitsu.com" <y-goto@jp.fujitsu.com>,
	Dave Hansen <haveblue@us.ibm.com>,
	"Wu, Fengguang" <fengguang.wu@intel.com>,
	"x86@kernel.org" <x86@kernel.org>
Subject: Re: [PATCH - resend] Memory-Hotplug: Fix the bug on interface /dev/mem for 64-bit kernel(v1)
Date: Tue, 12 Jan 2010 09:58:48 +0900	[thread overview]
Message-ID: <20100112095848.b2cee1f3.kamezawa.hiroyu@jp.fujitsu.com> (raw)
In-Reply-To: <4B478BEA.1010504@linux.intel.com>

On Fri, 08 Jan 2010 20:47:54 +0100
Andi Kleen <ak@linux.intel.com> wrote:

> H. Peter Anvin wrote:
> > On 01/07/2010 07:32 PM, Zheng, Shaohui wrote:
> >> Resend the patch to the mailing-list, the original patch URL is 
> >> http://patchwork.kernel.org/patch/69075/, it is not accepted without comments,
> >> sent it again to review.
> >>
> >> Memory-Hotplug: Fix the bug on interface /dev/mem for 64-bit kernel
> >>
> >> The new added memory can not be access by interface /dev/mem, because we do not
> >>  update the variable high_memory. This patch add a new e820 entry in e820 table,
> >>  and update max_pfn, max_low_pfn and high_memory.
> >>
> >> We add a function update_pfn in file arch/x86/mm/init.c to udpate these
> >>  varibles. Memory hotplug does not make sense on 32-bit kernel, so we did not
> >>  concern it in this function.
> >>
> > 
> > Memory hotplug makes sense on 32-bit kernels, at least in virtual
> > environments.
> 
> No VM currently supports it to my knowledge. They all use traditional
> balooning.
> 
> If someone adds that they can still fix it, but right now fixing it on 64bit
> is the important part.
> 
I wonder...with some modification, memory hotplug (or Mel's page coalescing)
can be used for balloning in MAX_ORDER page size.
I'm sorry if VM' baloon drivers has no fragmentaion problem.

Thanks,
-Kame


WARNING: multiple messages have this Message-ID (diff)
From: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
To: Andi Kleen <ak@linux.intel.com>
Cc: "H. Peter Anvin" <hpa@kernel.org>,
	"Zheng, Shaohui" <shaohui.zheng@intel.com>,
	"linux-mm@kvack.org" <linux-mm@kvack.org>,
	"akpm@linux-foundation.org" <akpm@linux-foundation.org>,
	"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
	"y-goto@jp.fujitsu.com" <y-goto@jp.fujitsu.com>,
	Dave Hansen <haveblue@us.ibm.com>,
	"Wu, Fengguang" <fengguang.wu@intel.com>,
	"x86@kernel.org" <x86@kernel.org>
Subject: Re: [PATCH - resend] Memory-Hotplug: Fix the bug on interface /dev/mem for 64-bit kernel(v1)
Date: Tue, 12 Jan 2010 09:58:48 +0900	[thread overview]
Message-ID: <20100112095848.b2cee1f3.kamezawa.hiroyu@jp.fujitsu.com> (raw)
In-Reply-To: <4B478BEA.1010504@linux.intel.com>

On Fri, 08 Jan 2010 20:47:54 +0100
Andi Kleen <ak@linux.intel.com> wrote:

> H. Peter Anvin wrote:
> > On 01/07/2010 07:32 PM, Zheng, Shaohui wrote:
> >> Resend the patch to the mailing-list, the original patch URL is 
> >> http://patchwork.kernel.org/patch/69075/, it is not accepted without comments,
> >> sent it again to review.
> >>
> >> Memory-Hotplug: Fix the bug on interface /dev/mem for 64-bit kernel
> >>
> >> The new added memory can not be access by interface /dev/mem, because we do not
> >>  update the variable high_memory. This patch add a new e820 entry in e820 table,
> >>  and update max_pfn, max_low_pfn and high_memory.
> >>
> >> We add a function update_pfn in file arch/x86/mm/init.c to udpate these
> >>  varibles. Memory hotplug does not make sense on 32-bit kernel, so we did not
> >>  concern it in this function.
> >>
> > 
> > Memory hotplug makes sense on 32-bit kernels, at least in virtual
> > environments.
> 
> No VM currently supports it to my knowledge. They all use traditional
> balooning.
> 
> If someone adds that they can still fix it, but right now fixing it on 64bit
> is the important part.
> 
I wonder...with some modification, memory hotplug (or Mel's page coalescing)
can be used for balloning in MAX_ORDER page size.
I'm sorry if VM' baloon drivers has no fragmentaion problem.

Thanks,
-Kame

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  reply	other threads:[~2010-01-12  1:02 UTC|newest]

Thread overview: 39+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2010-01-08  3:32 [PATCH - resend] Memory-Hotplug: Fix the bug on interface /dev/mem for 64-bit kernel(v1) Zheng, Shaohui
2010-01-08  5:02 ` H. Peter Anvin
2010-01-08  5:02   ` H. Peter Anvin
2010-01-08  5:18   ` Zheng, Shaohui
2010-01-08  5:18     ` Zheng, Shaohui
2010-01-08 19:47   ` Andi Kleen
2010-01-08 19:47     ` Andi Kleen
2010-01-12  0:58     ` KAMEZAWA Hiroyuki [this message]
2010-01-12  0:58       ` KAMEZAWA Hiroyuki
2010-01-08 12:48 ` Wu Fengguang
2010-01-08 12:48   ` Wu Fengguang
2010-01-11  2:20   ` Zheng, Shaohui
2010-01-11  2:20     ` Zheng, Shaohui
2010-01-11 12:43     ` Wu Fengguang
2010-01-11 12:43       ` Wu Fengguang
2010-01-12  0:30       ` KAMEZAWA Hiroyuki
2010-01-12  0:30         ` KAMEZAWA Hiroyuki
2010-01-12  1:38         ` Andi Kleen
2010-01-12  1:38           ` Andi Kleen
2010-01-12  1:39           ` KAMEZAWA Hiroyuki
2010-01-12  1:39             ` KAMEZAWA Hiroyuki
2010-01-12  1:50             ` KAMEZAWA Hiroyuki
2010-01-12  1:50               ` KAMEZAWA Hiroyuki
2010-01-12  2:45               ` Wu Fengguang
2010-01-12  2:45                 ` Wu Fengguang
2010-01-12  2:33         ` Wu Fengguang
2010-01-12  2:33           ` Wu Fengguang
2010-01-12  2:39           ` KAMEZAWA Hiroyuki
2010-01-12  2:39             ` KAMEZAWA Hiroyuki
2010-01-12 13:35             ` Wu Fengguang
2010-01-12 13:35               ` Wu Fengguang
2010-01-12 23:01               ` Yinghai Lu
2010-01-12 23:01                 ` Yinghai Lu
2010-01-13  2:29                 ` Wu Fengguang
2010-01-13  2:29                   ` Wu Fengguang
2010-01-12  5:45         ` Zheng, Shaohui
2010-01-12  5:45           ` Zheng, Shaohui
2010-01-12  5:51       ` Zheng, Shaohui
2010-01-12  5:51         ` Zheng, Shaohui

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