diff options
Diffstat (limited to 'arch/x86/mm/init_64.c')
| -rw-r--r-- | arch/x86/mm/init_64.c | 21 |
1 files changed, 21 insertions, 0 deletions
diff --git a/arch/x86/mm/init_64.c b/arch/x86/mm/init_64.c index 5ecb23a57d2f..d99bc6ac4884 100644 --- a/arch/x86/mm/init_64.c +++ b/arch/x86/mm/init_64.c @@ -741,8 +741,22 @@ unsigned long __init_refok init_memory_mapping(unsigned long start, /* head if not big page alignment ? */ start_pfn = start >> PAGE_SHIFT; pos = start_pfn << PAGE_SHIFT; +#ifdef CONFIG_X86_32 + /* + * 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. + */ + if (pos == 0) + end_pfn = 1<<(PMD_SHIFT - PAGE_SHIFT); + else + end_pfn = ((pos + (PMD_SIZE - 1))>>PMD_SHIFT) + << (PMD_SHIFT - PAGE_SHIFT); +#else /* CONFIG_X86_64 */ end_pfn = ((pos + (PMD_SIZE - 1)) >> PMD_SHIFT) << (PMD_SHIFT - PAGE_SHIFT); +#endif if (end_pfn > (end >> PAGE_SHIFT)) end_pfn = end >> PAGE_SHIFT; if (start_pfn < end_pfn) { @@ -753,16 +767,22 @@ unsigned long __init_refok init_memory_mapping(unsigned long start, /* big page (2M) range */ start_pfn = ((pos + (PMD_SIZE - 1))>>PMD_SHIFT) << (PMD_SHIFT - PAGE_SHIFT); +#ifdef CONFIG_X86_32 + end_pfn = (end>>PMD_SHIFT) << (PMD_SHIFT - PAGE_SHIFT); +#else /* CONFIG_X86_64 */ end_pfn = ((pos + (PUD_SIZE - 1))>>PUD_SHIFT) << (PUD_SHIFT - PAGE_SHIFT); if (end_pfn > ((end>>PMD_SHIFT)<<(PMD_SHIFT - PAGE_SHIFT))) end_pfn = ((end>>PMD_SHIFT)<<(PMD_SHIFT - PAGE_SHIFT)); +#endif + if (start_pfn < end_pfn) { nr_range = save_mr(mr, nr_range, start_pfn, end_pfn, page_size_mask & (1<<PG_LEVEL_2M)); pos = end_pfn << PAGE_SHIFT; } +#ifdef CONFIG_X86_64 /* big page (1G) range */ start_pfn = ((pos + (PUD_SIZE - 1))>>PUD_SHIFT) << (PUD_SHIFT - PAGE_SHIFT); @@ -783,6 +803,7 @@ unsigned long __init_refok init_memory_mapping(unsigned long start, page_size_mask & (1<<PG_LEVEL_2M)); pos = end_pfn << PAGE_SHIFT; } +#endif /* tail is not big page (2M) alignment */ start_pfn = pos>>PAGE_SHIFT; |