From: Dave Hansen <dave@linux.vnet.ibm.com>
To: Yasunori Goto <y-goto@jp.fujitsu.com>
Cc: Gary Hade <garyhade@us.ibm.com>,
linux-mm@kvack.org, Andrew Morton <akpm@linux-foundation.org>,
Badari Pulavarty <pbadari@us.ibm.com>, Mel Gorman <mel@csn.ul.ie>,
Chris McDermott <lcm@us.ibm.com>,
linux-kernel@vger.kernel.org, Ingo Molnar <mingo@elte.hu>,
Greg KH <greg@kroah.com>,
Nish Aravamudan <nish.aravamudan@gmail.com>
Subject: Re: [PATCH] mm: show node to memory section relationship with symlinks in sysfs
Date: Tue, 30 Sep 2008 08:50:37 -0700 [thread overview]
Message-ID: <1222789837.17630.41.camel@nimitz> (raw)
In-Reply-To: <20080930163324.44A7.E1E9C6FF@jp.fujitsu.com>
On Tue, 2008-09-30 at 17:06 +0900, Yasunori Goto wrote:
> > +#define section_nr_to_nid(section_nr) pfn_to_nid(section_nr_to_pfn(section_nr))
> > #endif /* CONFIG_MEMORY_HOTPLUG_SPARSE */
>
> If the first page of the section is not valid, then this section_nr_to_nid()
> doesn't return correct value.
>
> I tested this patch. In my box, the start_pfn of node 1 is 1200400, but
> section_nr_to_pfn(mem_blk->phys_index) returns 1200000. As a result,
> the section is linked to node 0.
Crap, I was worried about that.
Gary, this means that we have a N:1 relationship between NUMA nodes and
sections. This normally isn't a problem because sections don't really
care about nodes and they layer underneath them.
We'll probably need multiple symlinks in each section directory.
-- Dave
WARNING: multiple messages have this Message-ID (diff)
From: Dave Hansen <dave@linux.vnet.ibm.com>
To: Yasunori Goto <y-goto@jp.fujitsu.com>
Cc: Gary Hade <garyhade@us.ibm.com>,
linux-mm@kvack.org, Andrew Morton <akpm@linux-foundation.org>,
Badari Pulavarty <pbadari@us.ibm.com>, Mel Gorman <mel@csn.ul.ie>,
Chris McDermott <lcm@us.ibm.com>,
linux-kernel@vger.kernel.org, Ingo Molnar <mingo@elte.hu>,
Greg KH <greg@kroah.com>,
Nish Aravamudan <nish.aravamudan@gmail.com>
Subject: Re: [PATCH] mm: show node to memory section relationship with symlinks in sysfs
Date: Tue, 30 Sep 2008 08:50:37 -0700 [thread overview]
Message-ID: <1222789837.17630.41.camel@nimitz> (raw)
In-Reply-To: <20080930163324.44A7.E1E9C6FF@jp.fujitsu.com>
On Tue, 2008-09-30 at 17:06 +0900, Yasunori Goto wrote:
> > +#define section_nr_to_nid(section_nr) pfn_to_nid(section_nr_to_pfn(section_nr))
> > #endif /* CONFIG_MEMORY_HOTPLUG_SPARSE */
>
> If the first page of the section is not valid, then this section_nr_to_nid()
> doesn't return correct value.
>
> I tested this patch. In my box, the start_pfn of node 1 is 1200400, but
> section_nr_to_pfn(mem_blk->phys_index) returns 1200000. As a result,
> the section is linked to node 0.
Crap, I was worried about that.
Gary, this means that we have a N:1 relationship between NUMA nodes and
sections. This normally isn't a problem because sections don't really
care about nodes and they layer underneath them.
We'll probably need multiple symlinks in each section directory.
-- Dave
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next prev parent reply other threads:[~2008-09-30 15:51 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2008-09-29 20:05 [PATCH] mm: show node to memory section relationship with symlinks in sysfs Gary Hade
2008-09-29 20:05 ` Gary Hade
2008-09-30 8:06 ` Yasunori Goto
2008-09-30 8:06 ` Yasunori Goto
2008-09-30 15:50 ` Dave Hansen [this message]
2008-09-30 15:50 ` Dave Hansen
2008-09-30 19:41 ` Gary Hade
2008-09-30 19:41 ` Gary Hade
2008-10-01 2:48 ` Yasunori Goto
2008-10-01 2:48 ` Yasunori Goto
2008-10-01 16:51 ` Gary Hade
2008-10-01 16:51 ` Gary Hade
2008-09-30 23:29 ` Gary Hade
2008-09-30 23:29 ` Gary Hade
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