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authorAnton Arapov <anton@redhat.com>2012-04-16 10:05:28 +0200
committerAnton Arapov <anton@redhat.com>2012-04-16 10:05:28 +0200
commitb4b6116a13633898cf868f2f103c96a90c4c20f8 (patch)
tree93d1b7e2cfcdf473d8d4ff3ad141fa864f8491f6 /arch/x86/mm/hugetlbpage.c
parentedd4be777c953e5faafc80d091d3084b4343f5d3 (diff)
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fedora kernel: d9aad82f3319f3cfd1aebc01234254ef0c37ad84v3.3.2-1
Signed-off-by: Anton Arapov <anton@redhat.com>
Diffstat (limited to 'arch/x86/mm/hugetlbpage.c')
-rw-r--r--arch/x86/mm/hugetlbpage.c449
1 files changed, 449 insertions, 0 deletions
diff --git a/arch/x86/mm/hugetlbpage.c b/arch/x86/mm/hugetlbpage.c
new file mode 100644
index 00000000000..8ecbb4bba4b
--- /dev/null
+++ b/arch/x86/mm/hugetlbpage.c
@@ -0,0 +1,449 @@
+/*
+ * IA-32 Huge TLB Page Support for Kernel.
+ *
+ * Copyright (C) 2002, Rohit Seth <rohit.seth@intel.com>
+ */
+
+#include <linux/init.h>
+#include <linux/fs.h>
+#include <linux/mm.h>
+#include <linux/hugetlb.h>
+#include <linux/pagemap.h>
+#include <linux/err.h>
+#include <linux/sysctl.h>
+#include <asm/mman.h>
+#include <asm/tlb.h>
+#include <asm/tlbflush.h>
+#include <asm/pgalloc.h>
+
+static unsigned long page_table_shareable(struct vm_area_struct *svma,
+ struct vm_area_struct *vma,
+ unsigned long addr, pgoff_t idx)
+{
+ unsigned long saddr = ((idx - svma->vm_pgoff) << PAGE_SHIFT) +
+ svma->vm_start;
+ unsigned long sbase = saddr & PUD_MASK;
+ unsigned long s_end = sbase + PUD_SIZE;
+
+ /* Allow segments to share if only one is marked locked */
+ unsigned long vm_flags = vma->vm_flags & ~VM_LOCKED;
+ unsigned long svm_flags = svma->vm_flags & ~VM_LOCKED;
+
+ /*
+ * match the virtual addresses, permission and the alignment of the
+ * page table page.
+ */
+ if (pmd_index(addr) != pmd_index(saddr) ||
+ vm_flags != svm_flags ||
+ sbase < svma->vm_start || svma->vm_end < s_end)
+ return 0;
+
+ return saddr;
+}
+
+static int vma_shareable(struct vm_area_struct *vma, unsigned long addr)
+{
+ unsigned long base = addr & PUD_MASK;
+ unsigned long end = base + PUD_SIZE;
+
+ /*
+ * check on proper vm_flags and page table alignment
+ */
+ if (vma->vm_flags & VM_MAYSHARE &&
+ vma->vm_start <= base && end <= vma->vm_end)
+ return 1;
+ return 0;
+}
+
+/*
+ * search for a shareable pmd page for hugetlb.
+ */
+static void huge_pmd_share(struct mm_struct *mm, unsigned long addr, pud_t *pud)
+{
+ struct vm_area_struct *vma = find_vma(mm, addr);
+ struct address_space *mapping = vma->vm_file->f_mapping;
+ pgoff_t idx = ((addr - vma->vm_start) >> PAGE_SHIFT) +
+ vma->vm_pgoff;
+ struct prio_tree_iter iter;
+ struct vm_area_struct *svma;
+ unsigned long saddr;
+ pte_t *spte = NULL;
+
+ if (!vma_shareable(vma, addr))
+ return;
+
+ mutex_lock(&mapping->i_mmap_mutex);
+ vma_prio_tree_foreach(svma, &iter, &mapping->i_mmap, idx, idx) {
+ if (svma == vma)
+ continue;
+
+ saddr = page_table_shareable(svma, vma, addr, idx);
+ if (saddr) {
+ spte = huge_pte_offset(svma->vm_mm, saddr);
+ if (spte) {
+ get_page(virt_to_page(spte));
+ break;
+ }
+ }
+ }
+
+ if (!spte)
+ goto out;
+
+ spin_lock(&mm->page_table_lock);
+ if (pud_none(*pud))
+ pud_populate(mm, pud, (pmd_t *)((unsigned long)spte & PAGE_MASK));
+ else
+ put_page(virt_to_page(spte));
+ spin_unlock(&mm->page_table_lock);
+out:
+ mutex_unlock(&mapping->i_mmap_mutex);
+}
+
+/*
+ * unmap huge page backed by shared pte.
+ *
+ * Hugetlb pte page is ref counted at the time of mapping. If pte is shared
+ * indicated by page_count > 1, unmap is achieved by clearing pud and
+ * decrementing the ref count. If count == 1, the pte page is not shared.
+ *
+ * called with vma->vm_mm->page_table_lock held.
+ *
+ * returns: 1 successfully unmapped a shared pte page
+ * 0 the underlying pte page is not shared, or it is the last user
+ */
+int huge_pmd_unshare(struct mm_struct *mm, unsigned long *addr, pte_t *ptep)
+{
+ pgd_t *pgd = pgd_offset(mm, *addr);
+ pud_t *pud = pud_offset(pgd, *addr);
+
+ BUG_ON(page_count(virt_to_page(ptep)) == 0);
+ if (page_count(virt_to_page(ptep)) == 1)
+ return 0;
+
+ pud_clear(pud);
+ put_page(virt_to_page(ptep));
+ *addr = ALIGN(*addr, HPAGE_SIZE * PTRS_PER_PTE) - HPAGE_SIZE;
+ return 1;
+}
+
+pte_t *huge_pte_alloc(struct mm_struct *mm,
+ unsigned long addr, unsigned long sz)
+{
+ pgd_t *pgd;
+ pud_t *pud;
+ pte_t *pte = NULL;
+
+ pgd = pgd_offset(mm, addr);
+ pud = pud_alloc(mm, pgd, addr);
+ if (pud) {
+ if (sz == PUD_SIZE) {
+ pte = (pte_t *)pud;
+ } else {
+ BUG_ON(sz != PMD_SIZE);
+ if (pud_none(*pud))
+ huge_pmd_share(mm, addr, pud);
+ pte = (pte_t *) pmd_alloc(mm, pud, addr);
+ }
+ }
+ BUG_ON(pte && !pte_none(*pte) && !pte_huge(*pte));
+
+ return pte;
+}
+
+pte_t *huge_pte_offset(struct mm_struct *mm, unsigned long addr)
+{
+ pgd_t *pgd;
+ pud_t *pud;
+ pmd_t *pmd = NULL;
+
+ pgd = pgd_offset(mm, addr);
+ if (pgd_present(*pgd)) {
+ pud = pud_offset(pgd, addr);
+ if (pud_present(*pud)) {
+ if (pud_large(*pud))
+ return (pte_t *)pud;
+ pmd = pmd_offset(pud, addr);
+ }
+ }
+ return (pte_t *) pmd;
+}
+
+#if 0 /* This is just for testing */
+struct page *
+follow_huge_addr(struct mm_struct *mm, unsigned long address, int write)
+{
+ unsigned long start = address;
+ int length = 1;
+ int nr;
+ struct page *page;
+ struct vm_area_struct *vma;
+
+ vma = find_vma(mm, addr);
+ if (!vma || !is_vm_hugetlb_page(vma))
+ return ERR_PTR(-EINVAL);
+
+ pte = huge_pte_offset(mm, address);
+
+ /* hugetlb should be locked, and hence, prefaulted */
+ WARN_ON(!pte || pte_none(*pte));
+
+ page = &pte_page(*pte)[vpfn % (HPAGE_SIZE/PAGE_SIZE)];
+
+ WARN_ON(!PageHead(page));
+
+ return page;
+}
+
+int pmd_huge(pmd_t pmd)
+{
+ return 0;
+}
+
+int pud_huge(pud_t pud)
+{
+ return 0;
+}
+
+struct page *
+follow_huge_pmd(struct mm_struct *mm, unsigned long address,
+ pmd_t *pmd, int write)
+{
+ return NULL;
+}
+
+#else
+
+struct page *
+follow_huge_addr(struct mm_struct *mm, unsigned long address, int write)
+{
+ return ERR_PTR(-EINVAL);
+}
+
+int pmd_huge(pmd_t pmd)
+{
+ return !!(pmd_val(pmd) & _PAGE_PSE);
+}
+
+int pud_huge(pud_t pud)
+{
+ return !!(pud_val(pud) & _PAGE_PSE);
+}
+
+struct page *
+follow_huge_pmd(struct mm_struct *mm, unsigned long address,
+ pmd_t *pmd, int write)
+{
+ struct page *page;
+
+ page = pte_page(*(pte_t *)pmd);
+ if (page)
+ page += ((address & ~PMD_MASK) >> PAGE_SHIFT);
+ return page;
+}
+
+struct page *
+follow_huge_pud(struct mm_struct *mm, unsigned long address,
+ pud_t *pud, int write)
+{
+ struct page *page;
+
+ page = pte_page(*(pte_t *)pud);
+ if (page)
+ page += ((address & ~PUD_MASK) >> PAGE_SHIFT);
+ return page;
+}
+
+#endif
+
+/* x86_64 also uses this file */
+
+#ifdef HAVE_ARCH_HUGETLB_UNMAPPED_AREA
+static unsigned long hugetlb_get_unmapped_area_bottomup(struct file *file,
+ unsigned long addr, unsigned long len,
+ unsigned long pgoff, unsigned long flags)
+{
+ struct hstate *h = hstate_file(file);
+ struct mm_struct *mm = current->mm;
+ struct vm_area_struct *vma;
+ unsigned long start_addr;
+
+ if (len > mm->cached_hole_size) {
+ start_addr = mm->free_area_cache;
+ } else {
+ start_addr = TASK_UNMAPPED_BASE;
+ mm->cached_hole_size = 0;
+ }
+
+full_search:
+ addr = ALIGN(start_addr, huge_page_size(h));
+
+ for (vma = find_vma(mm, addr); ; vma = vma->vm_next) {
+ /* At this point: (!vma || addr < vma->vm_end). */
+ if (TASK_SIZE - len < addr) {
+ /*
+ * Start a new search - just in case we missed
+ * some holes.
+ */
+ if (start_addr != TASK_UNMAPPED_BASE) {
+ start_addr = TASK_UNMAPPED_BASE;
+ mm->cached_hole_size = 0;
+ goto full_search;
+ }
+ return -ENOMEM;
+ }
+ if (!vma || addr + len <= vma->vm_start) {
+ mm->free_area_cache = addr + len;
+ return addr;
+ }
+ if (addr + mm->cached_hole_size < vma->vm_start)
+ mm->cached_hole_size = vma->vm_start - addr;
+ addr = ALIGN(vma->vm_end, huge_page_size(h));
+ }
+}
+
+static unsigned long hugetlb_get_unmapped_area_topdown(struct file *file,
+ unsigned long addr0, unsigned long len,
+ unsigned long pgoff, unsigned long flags)
+{
+ struct hstate *h = hstate_file(file);
+ struct mm_struct *mm = current->mm;
+ struct vm_area_struct *vma, *prev_vma;
+ unsigned long base = mm->mmap_base, addr = addr0;
+ unsigned long largest_hole = mm->cached_hole_size;
+ int first_time = 1;
+
+ /* don't allow allocations above current base */
+ if (mm->free_area_cache > base)
+ mm->free_area_cache = base;
+
+ if (len <= largest_hole) {
+ largest_hole = 0;
+ mm->free_area_cache = base;
+ }
+try_again:
+ /* make sure it can fit in the remaining address space */
+ if (mm->free_area_cache < len)
+ goto fail;
+
+ /* either no address requested or can't fit in requested address hole */
+ addr = (mm->free_area_cache - len) & huge_page_mask(h);
+ do {
+ /*
+ * Lookup failure means no vma is above this address,
+ * i.e. return with success:
+ */
+ vma = find_vma(mm, addr);
+ if (!vma)
+ return addr;
+
+ /*
+ * new region fits between prev_vma->vm_end and
+ * vma->vm_start, use it:
+ */
+ prev_vma = vma->vm_prev;
+ if (addr + len <= vma->vm_start &&
+ (!prev_vma || (addr >= prev_vma->vm_end))) {
+ /* remember the address as a hint for next time */
+ mm->cached_hole_size = largest_hole;
+ return (mm->free_area_cache = addr);
+ } else {
+ /* pull free_area_cache down to the first hole */
+ if (mm->free_area_cache == vma->vm_end) {
+ mm->free_area_cache = vma->vm_start;
+ mm->cached_hole_size = largest_hole;
+ }
+ }
+
+ /* remember the largest hole we saw so far */
+ if (addr + largest_hole < vma->vm_start)
+ largest_hole = vma->vm_start - addr;
+
+ /* try just below the current vma->vm_start */
+ addr = (vma->vm_start - len) & huge_page_mask(h);
+ } while (len <= vma->vm_start);
+
+fail:
+ /*
+ * if hint left us with no space for the requested
+ * mapping then try again:
+ */
+ if (first_time) {
+ mm->free_area_cache = base;
+ largest_hole = 0;
+ first_time = 0;
+ goto try_again;
+ }
+ /*
+ * A failed mmap() very likely causes application failure,
+ * so fall back to the bottom-up function here. This scenario
+ * can happen with large stack limits and large mmap()
+ * allocations.
+ */
+ mm->free_area_cache = TASK_UNMAPPED_BASE;
+ mm->cached_hole_size = ~0UL;
+ addr = hugetlb_get_unmapped_area_bottomup(file, addr0,
+ len, pgoff, flags);
+
+ /*
+ * Restore the topdown base:
+ */
+ mm->free_area_cache = base;
+ mm->cached_hole_size = ~0UL;
+
+ return addr;
+}
+
+unsigned long
+hugetlb_get_unmapped_area(struct file *file, unsigned long addr,
+ unsigned long len, unsigned long pgoff, unsigned long flags)
+{
+ struct hstate *h = hstate_file(file);
+ struct mm_struct *mm = current->mm;
+ struct vm_area_struct *vma;
+
+ if (len & ~huge_page_mask(h))
+ return -EINVAL;
+ if (len > TASK_SIZE)
+ return -ENOMEM;
+
+ if (flags & MAP_FIXED) {
+ if (prepare_hugepage_range(file, addr, len))
+ return -EINVAL;
+ return addr;
+ }
+
+ if (addr) {
+ addr = ALIGN(addr, huge_page_size(h));
+ vma = find_vma(mm, addr);
+ if (TASK_SIZE - len >= addr &&
+ (!vma || addr + len <= vma->vm_start))
+ return addr;
+ }
+ if (mm->get_unmapped_area == arch_get_unmapped_area)
+ return hugetlb_get_unmapped_area_bottomup(file, addr, len,
+ pgoff, flags);
+ else
+ return hugetlb_get_unmapped_area_topdown(file, addr, len,
+ pgoff, flags);
+}
+
+#endif /*HAVE_ARCH_HUGETLB_UNMAPPED_AREA*/
+
+#ifdef CONFIG_X86_64
+static __init int setup_hugepagesz(char *opt)
+{
+ unsigned long ps = memparse(opt, &opt);
+ if (ps == PMD_SIZE) {
+ hugetlb_add_hstate(PMD_SHIFT - PAGE_SHIFT);
+ } else if (ps == PUD_SIZE && cpu_has_gbpages) {
+ hugetlb_add_hstate(PUD_SHIFT - PAGE_SHIFT);
+ } else {
+ printk(KERN_ERR "hugepagesz: Unsupported page size %lu M\n",
+ ps >> 20);
+ return 0;
+ }
+ return 1;
+}
+__setup("hugepagesz=", setup_hugepagesz);
+#endif