From: Chandru <chandru@in.ibm.com>
To: Dave Hansen <dave@linux.vnet.ibm.com>
Cc: linuxppc-dev@ozlabs.org,
Andrew Morton <akpm@linux-foundation.org>,
Paul Mackerras <paulus@samba.org>,
linux-kernel@vger.kernel.org
Subject: Re: 2.6.28-rc9 panics with crashkernel=256M while booting
Date: Wed, 7 Jan 2009 18:28:13 +0530 [thread overview]
Message-ID: <200901071828.13719.chandru@in.ibm.com> (raw)
In-Reply-To: <1231173033.19452.190.camel@nimitz>
On Monday 05 January 2009 22:00:33 Dave Hansen wrote:
> OK, I had to think about this for a good, long time. That's bad. :)
>
> There are two things that we're dealing with here: "active regions" and
> the NODE_DATA's. The if() you've pasted above resizes the reservation
> so that it fits into the current active region. However, as you noted,
> we haven't resized it so that it fits into the NODE_DATA() that we're
> looking at. We call into the bootmem code, and BUG_ON().
>
> The thing I don't like about this is that it might hide bugs in other
> callers. This really is a ppc-specific thing and, although what you
> wrote will fix the bug on ppc, it will probably cause someone in the
> future to call reserve_bootmem_node() with too large a reservation and
> get a silent failure (not reserving the requested size) back.
>
> We really do need to go take a hard look at the whole interaction
> between lmb's, node active regions, and the NUMA code some day. It has
> kinda grown to be a bit ungainly.
>
> How about we just consult the NODE_DATA() in
> mark_reserved_regions_for_nid() instead of reserve_bootmem_node()?
I don't know how you wanted NODE_DATA() to be consulted here. i.e before
calling reserve_bootmem_node() should we have a condition
if (PFN_UP(physbase+reserve_size) > node_end_pfn)
then
resize reserve_size again so that PFN_UP() will equate to node_end_pfn ??
end
Also I was wondering if in reserve_bootmem_node()
end = PFN_DOWN() ; will do..
With the recent changes from you that went into 2.6.28 stable
(commit:a4c74ddd5ea3db53fc73d29c222b22656a7d05be), it worked on the system
with PFN_DOWN().
Thanks,
Chandru
next prev parent reply other threads:[~2009-01-07 12:58 UTC|newest]
Thread overview: 19+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <200812241325.49404.chandru@in.ibm.com>
2008-12-25 7:35 ` 2.6.28-rc9 panics with crashkernel=256M while booting Andrew Morton
2008-12-25 8:07 ` Andrew Morton
2008-12-26 0:59 ` Paul Mackerras
2008-12-29 21:36 ` Dave Hansen
2009-01-05 13:49 ` Chandru
2009-01-05 16:30 ` Dave Hansen
2009-01-07 12:58 ` Chandru [this message]
2009-01-07 17:25 ` Dave Hansen
2009-01-08 10:29 ` Chandru
2009-01-08 20:03 ` Dave Hansen
2009-01-09 11:07 ` Chandru
2009-01-15 8:05 ` Chandru
2009-01-16 12:16 ` Chandru
2009-01-16 17:52 ` Dave Hansen
2009-01-19 8:11 ` Chandru
2009-01-19 11:30 ` Chandru
2009-01-20 8:13 ` Chandru
2009-01-22 0:29 ` Dave Hansen
2009-01-22 8:20 ` Chandru
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