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Date: Thu, 05 Mar 2009 11:11:36 -0800
From: Yinghai Lu <yinghai@...nel.org>
To: Pekka Enberg <penberg@...helsinki.fi>
CC: mingo@...e.hu, x86@...nel.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH 01/17] x86: init_memory_mapping() trivial cleanups
Pekka Enberg wrote:
> Impact: cleanup
>
> To reduce the diff between the 32-bit and 64-bit versions of
> init_memory_mapping(), fix up all trivial issues.
>
> Cc: Yinghai Lu <yinghai@...nel.org>
> Signed-off-by: Pekka Enberg <penberg@...helsinki.fi>
> ---
> arch/x86/mm/init_32.c | 42 +++++++++++++++++++++++++-----------------
> arch/x86/mm/init_64.c | 26 +++++++++++++++-----------
> 2 files changed, 40 insertions(+), 28 deletions(-)
>
> diff --git a/arch/x86/mm/init_32.c b/arch/x86/mm/init_32.c
> index c351456..ad4e03c 100644
> --- a/arch/x86/mm/init_32.c
> +++ b/arch/x86/mm/init_32.c
> @@ -868,11 +868,10 @@ static void __init find_early_table_space(unsigned long end, int use_pse)
>
> table_start >>= PAGE_SHIFT;
> table_end = table_start;
> - table_top = table_start + (tables>>PAGE_SHIFT);
> + table_top = table_start + (tables >> PAGE_SHIFT);
>
> printk(KERN_DEBUG "kernel direct mapping tables up to %lx @ %lx-%lx\n",
> - end, table_start << PAGE_SHIFT,
> - (table_start << PAGE_SHIFT) + tables);
> + end, table_start << PAGE_SHIFT, table_top << PAGE_SHIFT);
> }
>
> struct map_range {
> @@ -899,8 +898,13 @@ static int save_mr(struct map_range *mr, int nr_range,
> return nr_range;
> }
>
> +/*
> + * Setup the direct mapping of the physical memory at PAGE_OFFSET.
> + * This runs before bootmem is initialized and gets pages directly from
> + * the physical memory. To access them they are temporarily mapped.
> + */
> unsigned long __init_refok init_memory_mapping(unsigned long start,
> - unsigned long end)
> + unsigned long end)
> {
> pgd_t *pgd_base = swapper_pg_dir;
> unsigned long page_size_mask = 0;
> @@ -911,7 +915,7 @@ unsigned long __init_refok init_memory_mapping(unsigned long start,
> int nr_range, i;
> int use_pse;
>
> - printk(KERN_INFO "init_memory_mapping: %08lx-%08lx\n", start, end);
> + printk(KERN_INFO "init_memory_mapping: %016lx-%016lx\n", start, end);
>
> #ifdef CONFIG_DEBUG_PAGEALLOC
> /*
> @@ -940,19 +944,19 @@ unsigned long __init_refok init_memory_mapping(unsigned long start,
> __supported_pte_mask |= _PAGE_GLOBAL;
> }
>
> - memset(mr, 0, sizeof(mr));
> - nr_range = 0;
> -
> if (use_pse)
> page_size_mask |= 1 << PG_LEVEL_2M;
>
> + memset(mr, 0, sizeof(mr));
> + nr_range = 0;
> +
> /*
> * Don't use a large page for the first 2/4MB of memory
> * because there are often fixed size MTRRs in there
> * and overlapping MTRRs into large pages can cause
> * slowdowns.
> */
> - /* head could not be big page alignment ? */
> + /* head if not big page alignment ? */
> start_pfn = start >> PAGE_SHIFT;
> pos = start_pfn << PAGE_SHIFT;
> if (pos == 0)
> @@ -960,14 +964,14 @@ unsigned long __init_refok init_memory_mapping(unsigned long start,
> else
> end_pfn = ((pos + (PMD_SIZE - 1))>>PMD_SHIFT)
> << (PMD_SHIFT - PAGE_SHIFT);
> - if (end_pfn > (end>>PAGE_SHIFT))
> - end_pfn = end>>PAGE_SHIFT;
> + if (end_pfn > (end >> PAGE_SHIFT))
> + end_pfn = end >> PAGE_SHIFT;
> if (start_pfn < end_pfn) {
> nr_range = save_mr(mr, nr_range, start_pfn, end_pfn, 0);
> pos = end_pfn << PAGE_SHIFT;
> }
>
> - /* big page range */
> + /* big page (2M) range */
> start_pfn = ((pos + (PMD_SIZE - 1))>>PMD_SHIFT)
> << (PMD_SHIFT - PAGE_SHIFT);
> end_pfn = (end>>PMD_SHIFT) << (PMD_SHIFT - PAGE_SHIFT);
> @@ -977,7 +981,7 @@ unsigned long __init_refok init_memory_mapping(unsigned long start,
> pos = end_pfn << PAGE_SHIFT;
> }
>
> - /* tail is not big page alignment ? */
> + /* tail is not big page (2M) alignment */
> start_pfn = pos>>PAGE_SHIFT;
> end_pfn = end>>PAGE_SHIFT;
> if (start_pfn < end_pfn)
> @@ -998,13 +1002,17 @@ unsigned long __init_refok init_memory_mapping(unsigned long start,
> }
>
> for (i = 0; i < nr_range; i++)
> - printk(KERN_DEBUG " %08lx - %08lx page %s\n",
> - mr[i].start, mr[i].end,
> - (mr[i].page_size_mask & (1<<PG_LEVEL_2M)) ?
> - "big page" : "4k");
> + printk(KERN_DEBUG " %010lx - %010lx page %s\n",
> + mr[i].start, mr[i].end,
> + (mr[i].page_size_mask & (1<<PG_LEVEL_1G))?"1G":(
> + (mr[i].page_size_mask & (1<<PG_LEVEL_2M))?"2M":"4k"));
sometime big page on 32bit could be 4M?
YH
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