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    SubjectRe: [PATCH v8 29/46] x86, mm: only call early_ioremap_page_table_range_init() once
    On Fri, Nov 16, 2012 at 07:39:06PM -0800, Yinghai Lu wrote:
    > On 32bit, before patcheset that only set page table for ram, we only
    > call that one time.

    Um.. Which patchset? x86, mm: Only direct map addresses that are marked as E820_RAM?

    >
    > Now, we are calling that during every init_memory_mapping if we have holes
    > under max_low_pfn.
    >
    > We should only call it one time after all ranges under max_low_page get
    > mapped just like we did before.
    >
    > Also that could avoid the risk to run out of pgt_buf in BRK.
    ^^- 'of running out of pgt_buf in BRK.'

    >
    > Need to update page_table_range_init() to count the pages for kmap page table
    > at first, and use new added alloc_low_pages() to get pages in sequence.
    > That will conform to the requirement that pages need to be in low to high order.
    >
    > Signed-off-by: Yinghai Lu <yinghai@kernel.org>
    > ---
    > arch/x86/mm/init.c | 13 +++++--------
    > arch/x86/mm/init_32.c | 47 +++++++++++++++++++++++++++++++++++++++++------
    > 2 files changed, 46 insertions(+), 14 deletions(-)
    >
    > diff --git a/arch/x86/mm/init.c b/arch/x86/mm/init.c
    > index cb4f8ba..bed4888 100644
    > --- a/arch/x86/mm/init.c
    > +++ b/arch/x86/mm/init.c
    > @@ -343,14 +343,6 @@ unsigned long __init_refok init_memory_mapping(unsigned long start,
    > ret = kernel_physical_mapping_init(mr[i].start, mr[i].end,
    > mr[i].page_size_mask);
    >
    > -#ifdef CONFIG_X86_32
    > - early_ioremap_page_table_range_init();
    > -
    > - load_cr3(swapper_pg_dir);
    > -#endif
    > -
    > - __flush_tlb_all();
    > -
    > add_pfn_range_mapped(start >> PAGE_SHIFT, ret >> PAGE_SHIFT);
    >
    > return ret >> PAGE_SHIFT;
    > @@ -447,7 +439,12 @@ void __init init_mem_mapping(void)
    > /* can we preseve max_low_pfn ?*/
    > max_low_pfn = max_pfn;
    > }
    > +#else
    > + early_ioremap_page_table_range_init();
    > + load_cr3(swapper_pg_dir);
    > + __flush_tlb_all();
    > #endif
    > +
    > early_memtest(0, max_pfn_mapped << PAGE_SHIFT);
    > }
    >
    > diff --git a/arch/x86/mm/init_32.c b/arch/x86/mm/init_32.c
    > index a7f2df1..0ae1ba8 100644
    > --- a/arch/x86/mm/init_32.c
    > +++ b/arch/x86/mm/init_32.c
    > @@ -135,8 +135,39 @@ pte_t * __init populate_extra_pte(unsigned long vaddr)
    > return one_page_table_init(pmd) + pte_idx;
    > }
    >
    > +static unsigned long __init
    > +page_table_range_init_count(unsigned long start, unsigned long end)
    > +{
    > + unsigned long count = 0;
    > +#ifdef CONFIG_HIGHMEM
    > + int pmd_idx_kmap_begin = fix_to_virt(FIX_KMAP_END) >> PMD_SHIFT;
    > + int pmd_idx_kmap_end = fix_to_virt(FIX_KMAP_BEGIN) >> PMD_SHIFT;
    > + int pgd_idx, pmd_idx;
    > + unsigned long vaddr;
    > +
    > + if (pmd_idx_kmap_begin == pmd_idx_kmap_end)
    > + return 0;
    > +
    > + vaddr = start;
    > + pgd_idx = pgd_index(vaddr);
    > +
    > + for ( ; (pgd_idx < PTRS_PER_PGD) && (vaddr != end); pgd_idx++) {
    > + for (; (pmd_idx < PTRS_PER_PMD) && (vaddr != end);
    > + pmd_idx++) {
    > + if ((vaddr >> PMD_SHIFT) >= pmd_idx_kmap_begin &&
    > + (vaddr >> PMD_SHIFT) <= pmd_idx_kmap_end)
    > + count++;
    > + vaddr += PMD_SIZE;
    > + }
    > + pmd_idx = 0;
    > + }
    > +#endif
    > + return count;
    > +}
    > +
    > static pte_t *__init page_table_kmap_check(pte_t *pte, pmd_t *pmd,
    > - unsigned long vaddr, pte_t *lastpte)
    > + unsigned long vaddr, pte_t *lastpte,
    > + void **adr)
    > {
    > #ifdef CONFIG_HIGHMEM
    > /*
    > @@ -150,16 +181,15 @@ static pte_t *__init page_table_kmap_check(pte_t *pte, pmd_t *pmd,
    >
    > if (pmd_idx_kmap_begin != pmd_idx_kmap_end
    > && (vaddr >> PMD_SHIFT) >= pmd_idx_kmap_begin
    > - && (vaddr >> PMD_SHIFT) <= pmd_idx_kmap_end
    > - && ((__pa(pte) >> PAGE_SHIFT) < pgt_buf_start
    > - || (__pa(pte) >> PAGE_SHIFT) >= pgt_buf_end)) {
    > + && (vaddr >> PMD_SHIFT) <= pmd_idx_kmap_end) {
    > pte_t *newpte;
    > int i;
    >
    > BUG_ON(after_bootmem);
    > - newpte = alloc_low_page();
    > + newpte = *adr;
    > for (i = 0; i < PTRS_PER_PTE; i++)
    > set_pte(newpte + i, pte[i]);
    > + *adr = (void *)(((unsigned long)(*adr)) + PAGE_SIZE);
    >
    > paravirt_alloc_pte(&init_mm, __pa(newpte) >> PAGE_SHIFT);
    > set_pmd(pmd, __pmd(__pa(newpte)|_PAGE_TABLE));
    > @@ -193,6 +223,11 @@ page_table_range_init(unsigned long start, unsigned long end, pgd_t *pgd_base)
    > pgd_t *pgd;
    > pmd_t *pmd;
    > pte_t *pte = NULL;
    > + unsigned long count = page_table_range_init_count(start, end);
    > + void *adr = NULL;
    > +
    > + if (count)
    > + adr = alloc_low_pages(count);
    >
    > vaddr = start;
    > pgd_idx = pgd_index(vaddr);
    > @@ -205,7 +240,7 @@ page_table_range_init(unsigned long start, unsigned long end, pgd_t *pgd_base)
    > for (; (pmd_idx < PTRS_PER_PMD) && (vaddr != end);
    > pmd++, pmd_idx++) {
    > pte = page_table_kmap_check(one_page_table_init(pmd),
    > - pmd, vaddr, pte);
    > + pmd, vaddr, pte, &adr);
    >
    > vaddr += PMD_SIZE;
    > }
    > --
    > 1.7.7


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