From: "H. Peter Anvin" <hpa@zytor.com>
To: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Yinghai Lu <yinghai@kernel.org>, Ingo Molnar <mingo@elte.hu>,
Thomas Gleixner <tglx@linutronix.de>,
Andrew Morton <akpm@linux-foundation.org>,
David Miller <davem@davemloft.net>,
Linus Torvalds <torvalds@linux-foundation.org>,
Johannes Weiner <hannes@cmpxchg.org>,
linux-kernel@vger.kernel.org, linux-arch@vger.kernel.org
Subject: Re: [PATCH 28/31] memblock: Export MEMBLOCK_ERROR again
Date: Tue, 27 Jul 2010 22:53:21 -0700 [thread overview]
Message-ID: <4C4FC5D1.3070708@zytor.com> (raw)
In-Reply-To: <1280294376.1970.239.camel@pasglop>
On 07/27/2010 10:19 PM, Benjamin Herrenschmidt wrote:
>
> Screw it, I don't like it but I'll just split your patch in two for now
> and keep 0. It's a bit fishy but memblock does mostly top-down
> allocations and so shouldn't hit 0, and in practice the region at 0 is,
> I beleive, reserved, but we need to be extra careful and might need to
> revisit that a bit.
>
> That's an area where I don't completely agree with Linus, ie, 0 is a
> perfectly valid physical address for memblock to return :-)
>
On x86, physical address 0 contains the real-mode IVT and will thus be
reserved, at least for the forseeable future. Other architectures may
very well have non-special RAM there.
-hpa
--
H. Peter Anvin, Intel Open Source Technology Center
I work for Intel. I don't speak on their behalf.
next prev parent reply other threads:[~2010-07-28 5:54 UTC|newest]
Thread overview: 92+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-07-22 18:20 [PATCH -v26 00/31] generic changes for memblock Yinghai Lu
2010-07-22 18:20 ` Yinghai Lu
2010-07-22 18:20 ` [PATCH 01/31] memblock: Rename memblock_region to memblock_type and memblock_property to memblock_region Yinghai Lu
2010-07-22 18:20 ` Yinghai Lu
2010-07-22 18:20 ` [PATCH 02/31] memblock: No reason to include asm/memblock.h late Yinghai Lu
2010-07-22 18:20 ` Yinghai Lu
2010-07-22 18:20 ` [PATCH 03/31] memblock: Introduce for_each_memblock() and new accessors, and use it Yinghai Lu
2010-07-22 18:20 ` Yinghai Lu
2010-07-22 18:20 ` [PATCH 04/31] memblock: Remove nid_range argument, arch provides memblock_nid_range() instead Yinghai Lu
2010-07-22 18:20 ` Yinghai Lu
2010-07-22 18:20 ` [PATCH 05/31] memblock: Factor the lowest level alloc function Yinghai Lu
2010-07-22 18:20 ` Yinghai Lu
2010-07-22 18:20 ` [PATCH 06/31] memblock: Expose MEMBLOCK_ALLOC_ANYWHERE Yinghai Lu
2010-07-22 18:20 ` Yinghai Lu
2010-07-22 18:20 ` [PATCH 07/31] memblock: Introduce default allocation limit and use it to replace explicit ones Yinghai Lu
2010-07-22 18:20 ` Yinghai Lu
2010-07-22 18:20 ` [PATCH 08/31] memblock: Remove rmo_size, burry it in arch/powerpc where it belongs Yinghai Lu
2010-07-22 18:20 ` Yinghai Lu
2010-07-22 18:20 ` [PATCH 09/31] memblock: Change u64 to phys_addr_t Yinghai Lu
2010-07-22 18:20 ` Yinghai Lu
2010-07-22 18:20 ` [PATCH 10/31] memblock: Remove unused memblock.debug struct member Yinghai Lu
2010-07-22 18:20 ` Yinghai Lu
2010-07-22 18:20 ` [PATCH 11/31] memblock: Remove memblock_type.size and add memblock.memory_size instead Yinghai Lu
2010-07-22 18:20 ` Yinghai Lu
2010-07-22 18:20 ` [PATCH 12/31] memblock: Move memblock arrays to static storage in memblock.c and make their size a variable Yinghai Lu
2010-07-22 18:20 ` Yinghai Lu
2010-07-22 18:20 ` [PATCH 13/31] memblock: Add debug markers at the end of the array Yinghai Lu
2010-07-22 18:20 ` Yinghai Lu
2010-07-22 18:20 ` [PATCH 14/31] memblock: Make memblock_find_region() out of memblock_alloc_region() Yinghai Lu
2010-07-22 18:20 ` Yinghai Lu
2010-07-22 18:20 ` [PATCH 15/31] memblock: Define MEMBLOCK_ERROR internally instead of using ~(phys_addr_t)0 Yinghai Lu
2010-07-22 18:20 ` Yinghai Lu
2010-07-22 18:20 ` [PATCH 16/31] memblock: Move memblock_init() to the bottom of the file Yinghai Lu
2010-07-22 18:20 ` Yinghai Lu
2010-07-22 18:20 ` [PATCH 17/31] memblock: split memblock_find_base() out of __memblock_alloc_base() Yinghai Lu
2010-07-22 18:20 ` Yinghai Lu
2010-07-22 18:20 ` [PATCH 18/31] memblock: Move functions around into a more sensible order Yinghai Lu
2010-07-22 18:20 ` Yinghai Lu
2010-07-22 18:20 ` [PATCH 19/31] memblock: Add array resizing support Yinghai Lu
2010-07-22 18:20 ` Yinghai Lu
2010-07-22 18:20 ` [PATCH 20/31] memblock: Add arch function to control coalescing of memblock memory regions Yinghai Lu
2010-07-22 18:20 ` Yinghai Lu
2010-07-22 18:20 ` [PATCH 21/31] memblock: Add "start" argument to memblock_find_base() Yinghai Lu
2010-07-22 18:20 ` Yinghai Lu
2010-07-22 18:20 ` [PATCH 22/31] memblock: NUMA allocate can now use early_pfn_map Yinghai Lu
2010-07-22 18:20 ` Yinghai Lu
2010-07-22 18:20 ` [PATCH 23/31] memblock: Separate memblock_alloc_nid() and memblock_alloc_try_nid() Yinghai Lu
2010-07-22 18:20 ` Yinghai Lu
2010-07-22 18:20 ` [PATCH 24/31] memblock: Make memblock_alloc_try_nid() fallback to MEMBLOCK_ALLOC_ANYWHERE Yinghai Lu
2010-07-22 18:20 ` Yinghai Lu
2010-07-22 18:20 ` [PATCH 25/31] memblock: Add debugfs files to dump the arrays content Yinghai Lu
2010-07-22 18:20 ` Yinghai Lu
2010-07-22 18:20 ` [PATCH 26/31] memblock: Prepare x86 to use memblock to replace early_res Yinghai Lu
2010-07-22 18:20 ` Yinghai Lu
2010-07-22 18:21 ` [PATCH 27/31] memblock: Print new doubled array location info Yinghai Lu
2010-07-22 18:21 ` Yinghai Lu
2010-07-22 18:21 ` [PATCH 28/31] memblock: Export MEMBLOCK_ERROR again Yinghai Lu
2010-07-22 18:21 ` Yinghai Lu
2010-07-28 5:15 ` Benjamin Herrenschmidt
2010-07-28 5:19 ` Benjamin Herrenschmidt
2010-07-28 5:53 ` H. Peter Anvin [this message]
2010-07-28 6:01 ` David Miller
2010-07-28 6:13 ` Yinghai Lu
2010-07-28 9:29 ` Benjamin Herrenschmidt
2010-07-28 9:25 ` Benjamin Herrenschmidt
2010-07-28 6:29 ` Benjamin Herrenschmidt
2010-07-28 5:24 ` Benjamin Herrenschmidt
2010-07-22 18:21 ` [PATCH 29/31] memblock: Prepare to include linux/memblock.h in core file Yinghai Lu
2010-07-22 18:21 ` Yinghai Lu
2010-07-28 5:27 ` Benjamin Herrenschmidt
2010-07-22 18:21 ` [PATCH 30/31] memblock: Add ARCH_DISCARD_MEMBLOCK to put memblock code to .init Yinghai Lu
2010-07-22 18:21 ` Yinghai Lu
2010-07-28 5:45 ` Benjamin Herrenschmidt
2010-07-22 18:21 ` [PATCH 31/31] memblock: Add memblock_find_in_range() Yinghai Lu
2010-07-22 18:21 ` Yinghai Lu
2010-07-28 5:36 ` Benjamin Herrenschmidt
2010-07-28 6:08 ` Yinghai Lu
2010-07-28 6:38 ` H. Peter Anvin
2010-07-28 7:12 ` Yinghai Lu
2010-07-28 16:06 ` H. Peter Anvin
2010-07-28 17:02 ` James Bottomley
2010-07-28 17:53 ` H. Peter Anvin
2010-07-28 18:10 ` James Bottomley
2010-07-28 18:30 ` H. Peter Anvin
2010-07-28 19:27 ` Yinghai Lu
2010-07-28 19:58 ` H. Peter Anvin
2010-07-28 22:58 ` Ralph Campbell
2010-07-28 23:41 ` H. Peter Anvin
2010-07-28 9:27 ` Benjamin Herrenschmidt
2010-07-28 6:22 ` H. Peter Anvin
2010-07-22 21:35 ` [PATCH -v26 00/31] generic changes for memblock Benjamin Herrenschmidt
2010-07-22 22:00 ` Yinghai Lu
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