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Date: Wed, 26 Oct 2011 12:31:26 -0400
From: Konrad Rzeszutek Wilk <konrad.wilk@...cle.com>
To: Ingo Molnar <mingo@...e.hu>, hpa@...or.com
Cc: Linus Torvalds <torvalds@...ux-foundation.org>,
linux-kernel@...r.kernel.org, "H. Peter Anvin" <hpa@...or.com>,
Thomas Gleixner <tglx@...utronix.de>,
Andrew Morton <akpm@...ux-foundation.org>
Subject: Re: [GIT PULL] x86/mm changes for v3.2
On Wed, Oct 26, 2011 at 05:36:00PM +0200, Ingo Molnar wrote:
> Linus,
>
> Please pull the latest x86-mm-for-linus git tree from:
>
> git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip.git x86-mm-for-linus
>
Hey Ingo,
When I spoke to hpa (LinuxCon in Canada) he mentioned that you guys decided
against this patchset and just stick with the
"x86,xen: introduce x86_init.mapping.pagetable_reserve"?
Maybe I am misremembering the conversation - there was a fair amount of beer
involved.
> Thanks,
>
> Ingo
>
> ------------------>
> Stefano Stabellini (5):
> x86, mm: Calculate precisely the memory needed by init_memory_mapping
> Revert "x86,xen: introduce x86_init.mapping.pagetable_reserve"
> x86, init : Move memblock_x86_reserve_range PGTABLE to find_early_table_space
> x86-64, mm: Do not assume head_64.S used 4KB pages when !use_pse
> x86_32: Calculate additional memory needed by the fixmap
>
>
> arch/x86/include/asm/pgtable_types.h | 1 -
> arch/x86/include/asm/x86_init.h | 12 ---
> arch/x86/kernel/x86_init.c | 4 -
> arch/x86/mm/init.c | 147 +++++++++++++++++++++++++---------
> arch/x86/xen/mmu.c | 15 ----
> 5 files changed, 109 insertions(+), 70 deletions(-)
>
> diff --git a/arch/x86/include/asm/pgtable_types.h b/arch/x86/include/asm/pgtable_types.h
> index d56187c..7db7723 100644
> --- a/arch/x86/include/asm/pgtable_types.h
> +++ b/arch/x86/include/asm/pgtable_types.h
> @@ -299,7 +299,6 @@ int phys_mem_access_prot_allowed(struct file *file, unsigned long pfn,
> /* Install a pte for a particular vaddr in kernel space. */
> void set_pte_vaddr(unsigned long vaddr, pte_t pte);
>
> -extern void native_pagetable_reserve(u64 start, u64 end);
> #ifdef CONFIG_X86_32
> extern void native_pagetable_setup_start(pgd_t *base);
> extern void native_pagetable_setup_done(pgd_t *base);
> diff --git a/arch/x86/include/asm/x86_init.h b/arch/x86/include/asm/x86_init.h
> index d3d8590..643ebf2 100644
> --- a/arch/x86/include/asm/x86_init.h
> +++ b/arch/x86/include/asm/x86_init.h
> @@ -68,17 +68,6 @@ struct x86_init_oem {
> };
>
> /**
> - * struct x86_init_mapping - platform specific initial kernel pagetable setup
> - * @pagetable_reserve: reserve a range of addresses for kernel pagetable usage
> - *
> - * For more details on the purpose of this hook, look in
> - * init_memory_mapping and the commit that added it.
> - */
> -struct x86_init_mapping {
> - void (*pagetable_reserve)(u64 start, u64 end);
> -};
> -
> -/**
> * struct x86_init_paging - platform specific paging functions
> * @pagetable_setup_start: platform specific pre paging_init() call
> * @pagetable_setup_done: platform specific post paging_init() call
> @@ -134,7 +123,6 @@ struct x86_init_ops {
> struct x86_init_mpparse mpparse;
> struct x86_init_irqs irqs;
> struct x86_init_oem oem;
> - struct x86_init_mapping mapping;
> struct x86_init_paging paging;
> struct x86_init_timers timers;
> struct x86_init_iommu iommu;
> diff --git a/arch/x86/kernel/x86_init.c b/arch/x86/kernel/x86_init.c
> index 6f164bd..6eee082 100644
> --- a/arch/x86/kernel/x86_init.c
> +++ b/arch/x86/kernel/x86_init.c
> @@ -61,10 +61,6 @@ struct x86_init_ops x86_init __initdata = {
> .banner = default_banner,
> },
>
> - .mapping = {
> - .pagetable_reserve = native_pagetable_reserve,
> - },
> -
> .paging = {
> .pagetable_setup_start = native_pagetable_setup_start,
> .pagetable_setup_done = native_pagetable_setup_done,
> diff --git a/arch/x86/mm/init.c b/arch/x86/mm/init.c
> index 3032644..a90ccc4 100644
> --- a/arch/x86/mm/init.c
> +++ b/arch/x86/mm/init.c
> @@ -28,22 +28,110 @@ int direct_gbpages
> #endif
> ;
>
> -static void __init find_early_table_space(unsigned long end, int use_pse,
> - int use_gbpages)
> +static unsigned long __init find_early_fixmap_space(void)
> {
> - unsigned long puds, pmds, ptes, tables, start = 0, good_end = end;
> + unsigned long size = 0;
> +#ifdef CONFIG_X86_32
> + int kmap_begin_pmd_idx, kmap_end_pmd_idx;
> + int fixmap_begin_pmd_idx, fixmap_end_pmd_idx;
> + int btmap_begin_pmd_idx;
> +
> + fixmap_begin_pmd_idx =
> + __fix_to_virt(__end_of_fixed_addresses - 1) >> PMD_SHIFT;
> + /*
> + * fixmap_end_pmd_idx is the end of the fixmap minus the PMD that
> + * has been defined in the data section by head_32.S (see
> + * initial_pg_fixmap).
> + * Note: This is similar to what early_ioremap_page_table_range_init
> + * does except that the "end" has PMD_SIZE expunged as per previous
> + * comment.
> + */
> + fixmap_end_pmd_idx = (FIXADDR_TOP - 1) >> PMD_SHIFT;
> + btmap_begin_pmd_idx = __fix_to_virt(FIX_BTMAP_BEGIN) >> PMD_SHIFT;
> + kmap_begin_pmd_idx = __fix_to_virt(FIX_KMAP_END) >> PMD_SHIFT;
> + kmap_end_pmd_idx = __fix_to_virt(FIX_KMAP_BEGIN) >> PMD_SHIFT;
> +
> + size = fixmap_end_pmd_idx - fixmap_begin_pmd_idx;
> + /*
> + * early_ioremap_init has already allocated a PMD at
> + * btmap_begin_pmd_idx
> + */
> + if (btmap_begin_pmd_idx < fixmap_end_pmd_idx)
> + size--;
> +
> +#ifdef CONFIG_HIGHMEM
> + /*
> + * see page_table_kmap_check: if the kmap spans multiple PMDs, make
> + * sure the pte pages are allocated contiguously. It might need up
> + * to two additional pte pages to replace the page declared by
> + * head_32.S and the one allocated by early_ioremap_init, if they
> + * are even partially used for the kmap.
> + */
> + if (kmap_begin_pmd_idx != kmap_end_pmd_idx) {
> + if (kmap_end_pmd_idx == fixmap_end_pmd_idx)
> + size++;
> + if (btmap_begin_pmd_idx >= kmap_begin_pmd_idx &&
> + btmap_begin_pmd_idx <= kmap_end_pmd_idx)
> + size++;
> + }
> +#endif
> +#endif
> + return (size * PMD_SIZE + PAGE_SIZE - 1) >> PAGE_SHIFT;
> +}
> +
> +static void __init find_early_table_space(unsigned long start,
> + unsigned long end, int use_pse, int use_gbpages)
> +{
> + unsigned long pmds = 0, ptes = 0, tables = 0, good_end = end,
> + pud_mapped = 0, pmd_mapped = 0, size = end - start;
> phys_addr_t base;
>
> - puds = (end + PUD_SIZE - 1) >> PUD_SHIFT;
> - tables = roundup(puds * sizeof(pud_t), PAGE_SIZE);
> + pud_mapped = DIV_ROUND_UP(PFN_PHYS(max_pfn_mapped),
> + (PUD_SIZE * PTRS_PER_PUD));
> + pud_mapped *= (PUD_SIZE * PTRS_PER_PUD);
> + pmd_mapped = DIV_ROUND_UP(PFN_PHYS(max_pfn_mapped),
> + (PMD_SIZE * PTRS_PER_PMD));
> + pmd_mapped *= (PMD_SIZE * PTRS_PER_PMD);
> +
> + /*
> + * On x86_64 do not limit the size we need to cover with 4KB pages
> + * depending on the initial allocation because head_64.S always uses
> + * 2MB pages.
> + */
> +#ifdef CONFIG_X86_32
> + if (start < PFN_PHYS(max_pfn_mapped)) {
> + if (PFN_PHYS(max_pfn_mapped) < end)
> + size -= PFN_PHYS(max_pfn_mapped) - start;
> + else
> + size = 0;
> + }
> +#endif
> +
> +#ifndef __PAGETABLE_PUD_FOLDED
> + if (end > pud_mapped) {
> + unsigned long puds;
> + if (start < pud_mapped)
> + puds = (end - pud_mapped + PUD_SIZE - 1) >> PUD_SHIFT;
> + else
> + puds = (end - start + PUD_SIZE - 1) >> PUD_SHIFT;
> + tables += roundup(puds * sizeof(pud_t), PAGE_SIZE);
> + }
> +#endif
>
> if (use_gbpages) {
> unsigned long extra;
>
> extra = end - ((end>>PUD_SHIFT) << PUD_SHIFT);
> pmds = (extra + PMD_SIZE - 1) >> PMD_SHIFT;
> - } else
> - pmds = (end + PMD_SIZE - 1) >> PMD_SHIFT;
> + }
> +#ifndef __PAGETABLE_PMD_FOLDED
> + else if (end > pmd_mapped) {
> + if (start < pmd_mapped)
> + pmds = (end - pmd_mapped + PMD_SIZE - 1) >> PMD_SHIFT;
> + else
> + pmds = (end - start + PMD_SIZE - 1) >> PMD_SHIFT;
> + }
> +#endif
>
> tables += roundup(pmds * sizeof(pmd_t), PAGE_SIZE);
>
> @@ -51,23 +139,22 @@ static void __init find_early_table_space(unsigned long end, int use_pse,
> unsigned long extra;
>
> extra = end - ((end>>PMD_SHIFT) << PMD_SHIFT);
> -#ifdef CONFIG_X86_32
> - extra += PMD_SIZE;
> -#endif
> ptes = (extra + PAGE_SIZE - 1) >> PAGE_SHIFT;
> } else
> - ptes = (end + PAGE_SIZE - 1) >> PAGE_SHIFT;
> + ptes = (size + PAGE_SIZE - 1) >> PAGE_SHIFT;
> +
> + ptes += find_early_fixmap_space();
>
> tables += roundup(ptes * sizeof(pte_t), PAGE_SIZE);
>
> -#ifdef CONFIG_X86_32
> - /* for fixmap */
> - tables += roundup(__end_of_fixed_addresses * sizeof(pte_t), PAGE_SIZE);
> + if (!tables)
> + return;
>
> +#ifdef CONFIG_X86_32
> good_end = max_pfn_mapped << PAGE_SHIFT;
> #endif
>
> - base = memblock_find_in_range(start, good_end, tables, PAGE_SIZE);
> + base = memblock_find_in_range(0x00, good_end, tables, PAGE_SIZE);
> if (base == MEMBLOCK_ERROR)
> panic("Cannot find space for the kernel page tables");
>
> @@ -77,11 +164,10 @@ static void __init find_early_table_space(unsigned long end, int use_pse,
>
> printk(KERN_DEBUG "kernel direct mapping tables up to %lx @ %lx-%lx\n",
> end, pgt_buf_start << PAGE_SHIFT, pgt_buf_top << PAGE_SHIFT);
> -}
>
> -void __init native_pagetable_reserve(u64 start, u64 end)
> -{
> - memblock_x86_reserve_range(start, end, "PGTABLE");
> + if (pgt_buf_top > pgt_buf_start)
> + memblock_x86_reserve_range(pgt_buf_start << PAGE_SHIFT,
> + pgt_buf_top << PAGE_SHIFT, "PGTABLE");
> }
>
> struct map_range {
> @@ -261,7 +347,7 @@ unsigned long __init_refok init_memory_mapping(unsigned long start,
> * nodes are discovered.
> */
> if (!after_bootmem)
> - find_early_table_space(end, use_pse, use_gbpages);
> + find_early_table_space(start, end, use_pse, use_gbpages);
>
> for (i = 0; i < nr_range; i++)
> ret = kernel_physical_mapping_init(mr[i].start, mr[i].end,
> @@ -275,24 +361,9 @@ unsigned long __init_refok init_memory_mapping(unsigned long start,
>
> __flush_tlb_all();
>
> - /*
> - * Reserve the kernel pagetable pages we used (pgt_buf_start -
> - * pgt_buf_end) and free the other ones (pgt_buf_end - pgt_buf_top)
> - * so that they can be reused for other purposes.
> - *
> - * On native it just means calling memblock_x86_reserve_range, on Xen it
> - * also means marking RW the pagetable pages that we allocated before
> - * but that haven't been used.
> - *
> - * In fact on xen we mark RO the whole range pgt_buf_start -
> - * pgt_buf_top, because we have to make sure that when
> - * init_memory_mapping reaches the pagetable pages area, it maps
> - * RO all the pagetable pages, including the ones that are beyond
> - * pgt_buf_end at that time.
> - */
> - if (!after_bootmem && pgt_buf_end > pgt_buf_start)
> - x86_init.mapping.pagetable_reserve(PFN_PHYS(pgt_buf_start),
> - PFN_PHYS(pgt_buf_end));
> + if (pgt_buf_end != pgt_buf_top)
> + printk(KERN_DEBUG "initial kernel pagetable allocation wasted %lx"
> + " pages\n", pgt_buf_top - pgt_buf_end);
>
> if (!after_bootmem)
> early_memtest(start, end);
> diff --git a/arch/x86/xen/mmu.c b/arch/x86/xen/mmu.c
> index dc708dc..2004f1e 100644
> --- a/arch/x86/xen/mmu.c
> +++ b/arch/x86/xen/mmu.c
> @@ -1153,20 +1153,6 @@ static void __init xen_pagetable_setup_start(pgd_t *base)
> {
> }
>
> -static __init void xen_mapping_pagetable_reserve(u64 start, u64 end)
> -{
> - /* reserve the range used */
> - native_pagetable_reserve(start, end);
> -
> - /* set as RW the rest */
> - printk(KERN_DEBUG "xen: setting RW the range %llx - %llx\n", end,
> - PFN_PHYS(pgt_buf_top));
> - while (end < PFN_PHYS(pgt_buf_top)) {
> - make_lowmem_page_readwrite(__va(end));
> - end += PAGE_SIZE;
> - }
> -}
> -
> static void xen_post_allocator_init(void);
>
> static void __init xen_pagetable_setup_done(pgd_t *base)
> @@ -1997,7 +1983,6 @@ static const struct pv_mmu_ops xen_mmu_ops __initconst = {
>
> void __init xen_init_mmu_ops(void)
> {
> - x86_init.mapping.pagetable_reserve = xen_mapping_pagetable_reserve;
> x86_init.paging.pagetable_setup_start = xen_pagetable_setup_start;
> x86_init.paging.pagetable_setup_done = xen_pagetable_setup_done;
> pv_mmu_ops = xen_mmu_ops;
> --
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