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Date: Wed, 28 Nov 2012 14:02:49 -0500
From: Konrad Rzeszutek Wilk <konrad.wilk@...cle.com>
To: Yinghai Lu <yinghai@...nel.org>
Cc: Thomas Gleixner <tglx@...utronix.de>, Ingo Molnar <mingo@...e.hu>,
"H. Peter Anvin" <hpa@...or.com>, Jacob Shin <jacob.shin@....com>,
Andrew Morton <akpm@...ux-foundation.org>,
Stefano Stabellini <stefano.stabellini@...citrix.com>,
linux-kernel@...r.kernel.org
Subject: Re: [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@...nel.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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