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    Subject[PATCH -v2 01/13] x86, mm: Add global page_size_mask
    Date
    detect if need to use 1G or 2M and store them in page_size_mask.

    Only probe them one time.

    Suggested-by: Ingo Molnar <mingo@elte.hu>
    Signed-off-by: Yinghai Lu <yinghai@kernel.org>
    ---
    arch/x86/include/asm/pgtable.h | 1 +
    arch/x86/kernel/setup.c | 1 +
    arch/x86/mm/init.c | 66 +++++++++++++++++++---------------------
    3 files changed, 33 insertions(+), 35 deletions(-)

    diff --git a/arch/x86/include/asm/pgtable.h b/arch/x86/include/asm/pgtable.h
    index 49afb3f..e47e4db 100644
    --- a/arch/x86/include/asm/pgtable.h
    +++ b/arch/x86/include/asm/pgtable.h
    @@ -597,6 +597,7 @@ static inline int pgd_none(pgd_t pgd)
    #ifndef __ASSEMBLY__

    extern int direct_gbpages;
    +void probe_page_size_mask(void);

    /* local pte updates need not use xchg for locking */
    static inline pte_t native_local_ptep_get_and_clear(pte_t *ptep)
    diff --git a/arch/x86/kernel/setup.c b/arch/x86/kernel/setup.c
    index f4b9b80..d6e8c03 100644
    --- a/arch/x86/kernel/setup.c
    +++ b/arch/x86/kernel/setup.c
    @@ -912,6 +912,7 @@ void __init setup_arch(char **cmdline_p)
    setup_real_mode();

    init_gbpages();
    + probe_page_size_mask();

    /* max_pfn_mapped is updated here */
    max_low_pfn_mapped = init_memory_mapping(0, max_low_pfn<<PAGE_SHIFT);
    diff --git a/arch/x86/mm/init.c b/arch/x86/mm/init.c
    index e0e6990..838e9bc 100644
    --- a/arch/x86/mm/init.c
    +++ b/arch/x86/mm/init.c
    @@ -35,8 +35,10 @@ struct map_range {
    unsigned page_size_mask;
    };

    -static void __init find_early_table_space(struct map_range *mr, unsigned long end,
    - int use_pse, int use_gbpages)
    +static int page_size_mask;
    +
    +static void __init find_early_table_space(struct map_range *mr,
    + unsigned long end)
    {
    unsigned long puds, pmds, ptes, tables, start = 0, good_end = end;
    phys_addr_t base;
    @@ -44,7 +46,7 @@ static void __init find_early_table_space(struct map_range *mr, unsigned long en
    puds = (end + PUD_SIZE - 1) >> PUD_SHIFT;
    tables = roundup(puds * sizeof(pud_t), PAGE_SIZE);

    - if (use_gbpages) {
    + if (page_size_mask & (1 << PG_LEVEL_1G)) {
    unsigned long extra;

    extra = end - ((end>>PUD_SHIFT) << PUD_SHIFT);
    @@ -54,7 +56,7 @@ static void __init find_early_table_space(struct map_range *mr, unsigned long en

    tables += roundup(pmds * sizeof(pmd_t), PAGE_SIZE);

    - if (use_pse) {
    + if (page_size_mask & (1 << PG_LEVEL_2M)) {
    unsigned long extra;

    extra = end - ((end>>PMD_SHIFT) << PMD_SHIFT);
    @@ -90,6 +92,30 @@ static void __init find_early_table_space(struct map_range *mr, unsigned long en
    (pgt_buf_top << PAGE_SHIFT) - 1);
    }

    +void probe_page_size_mask(void)
    +{
    +#if !defined(CONFIG_DEBUG_PAGEALLOC) && !defined(CONFIG_KMEMCHECK)
    + /*
    + * For CONFIG_DEBUG_PAGEALLOC, identity mapping will use small pages.
    + * This will simplify cpa(), which otherwise needs to support splitting
    + * large pages into small in interrupt context, etc.
    + */
    + if (direct_gbpages)
    + page_size_mask |= 1 << PG_LEVEL_1G;
    + if (cpu_has_pse)
    + page_size_mask |= 1 << PG_LEVEL_2M;
    +#endif
    +
    + /* Enable PSE if available */
    + if (cpu_has_pse)
    + set_in_cr4(X86_CR4_PSE);
    +
    + /* Enable PGE if available */
    + if (cpu_has_pge) {
    + set_in_cr4(X86_CR4_PGE);
    + __supported_pte_mask |= _PAGE_GLOBAL;
    + }
    +}
    void __init native_pagetable_reserve(u64 start, u64 end)
    {
    memblock_reserve(start, end - start);
    @@ -125,45 +151,15 @@ static int __meminit save_mr(struct map_range *mr, int nr_range,
    unsigned long __init_refok init_memory_mapping(unsigned long start,
    unsigned long end)
    {
    - unsigned long page_size_mask = 0;
    unsigned long start_pfn, end_pfn;
    unsigned long ret = 0;
    unsigned long pos;
    -
    struct map_range mr[NR_RANGE_MR];
    int nr_range, i;
    - int use_pse, use_gbpages;

    printk(KERN_INFO "init_memory_mapping: [mem %#010lx-%#010lx]\n",
    start, end - 1);

    -#if defined(CONFIG_DEBUG_PAGEALLOC) || defined(CONFIG_KMEMCHECK)
    - /*
    - * For CONFIG_DEBUG_PAGEALLOC, identity mapping will use small pages.
    - * This will simplify cpa(), which otherwise needs to support splitting
    - * large pages into small in interrupt context, etc.
    - */
    - use_pse = use_gbpages = 0;
    -#else
    - use_pse = cpu_has_pse;
    - use_gbpages = direct_gbpages;
    -#endif
    -
    - /* Enable PSE if available */
    - if (cpu_has_pse)
    - set_in_cr4(X86_CR4_PSE);
    -
    - /* Enable PGE if available */
    - if (cpu_has_pge) {
    - set_in_cr4(X86_CR4_PGE);
    - __supported_pte_mask |= _PAGE_GLOBAL;
    - }
    -
    - if (use_gbpages)
    - page_size_mask |= 1 << PG_LEVEL_1G;
    - if (use_pse)
    - page_size_mask |= 1 << PG_LEVEL_2M;
    -
    memset(mr, 0, sizeof(mr));
    nr_range = 0;

    @@ -267,7 +263,7 @@ unsigned long __init_refok init_memory_mapping(unsigned long start,
    * nodes are discovered.
    */
    if (!after_bootmem)
    - find_early_table_space(&mr[0], end, use_pse, use_gbpages);
    + find_early_table_space(&mr[0], end);

    for (i = 0; i < nr_range; i++)
    ret = kernel_physical_mapping_init(mr[i].start, mr[i].end,
    --
    1.7.7


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