linux-kernel - Re: Early boot panic on machine with lots of memory

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Message-ID: <20120619212618.GK32733@google.com>
Date:	Tue, 19 Jun 2012 14:26:18 -0700
From:	Tejun Heo <tj@...nel.org>
To:	Gavin Shan <shangw@...ux.vnet.ibm.com>
Cc:	Sasha Levin <levinsasha928@...il.com>,
	Andrew Morton <akpm@...ux-foundation.org>,
	David Miller <davem@...emloft.net>, hpa@...ux.intel.com,
	linux-mm <linux-mm@...ck.org>,
	"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>
Subject: Re: Early boot panic on machine with lots of memory

On Tue, Jun 19, 2012 at 02:20:59PM -0700, Tejun Heo wrote:
> Something like the following should fix it.
> 
> diff --git a/mm/memblock.c b/mm/memblock.c
> index 32a0a5e..2770970 100644
> --- a/mm/memblock.c
> +++ b/mm/memblock.c
> @@ -148,11 +148,15 @@ phys_addr_t __init_memblock memblock_find_in_range(phys_addr_t start,
>   */
>  int __init_memblock memblock_free_reserved_regions(void)
>  {
> +#ifndef CONFIG_DEBUG_PAGEALLOC
>  	if (memblock.reserved.regions == memblock_reserved_init_regions)
>  		return 0;
>  
>  	return memblock_free(__pa(memblock.reserved.regions),
>  		 sizeof(struct memblock_region) * memblock.reserved.max);
> +#else
> +	return 0;
> +#endif

BTW, this is just ugly and I don't think we're saving any noticeable
amount by doing this "free - give it to page allocator - reserve
again" dancing.  We should just allocate regions aligned to page
boundaries and free them later when memblock is no longer in use.

Thanks.

-- 
tejun
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