* Copyright (C) 2002, Rohit Seth <rohit.seth@intel.com>
*/
-#include <linux/config.h>
#include <linux/init.h>
#include <linux/fs.h>
#include <linux/mm.h>
#include <asm/tlb.h>
#include <asm/tlbflush.h>
-static pte_t *huge_pte_alloc(struct mm_struct *mm, unsigned long addr)
+static unsigned long page_table_shareable(struct vm_area_struct *svma,
+ struct vm_area_struct *vma,
+ unsigned long addr, pgoff_t idx)
{
- pgd_t *pgd;
- pud_t *pud;
- pmd_t *pmd = NULL;
-
- pgd = pgd_offset(mm, addr);
- pud = pud_alloc(mm, pgd, addr);
- pmd = pmd_alloc(mm, pud, addr);
- return (pte_t *) pmd;
-}
+ 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;
-static pte_t *huge_pte_offset(struct mm_struct *mm, unsigned long addr)
-{
- pgd_t *pgd;
- pud_t *pud;
- pmd_t *pmd = NULL;
+ /*
+ * match the virtual addresses, permission and the alignment of the
+ * page table page.
+ */
+ if (pmd_index(addr) != pmd_index(saddr) ||
+ vma->vm_flags != svma->vm_flags ||
+ sbase < svma->vm_start || svma->vm_end < s_end)
+ return 0;
- pgd = pgd_offset(mm, addr);
- pud = pud_offset(pgd, addr);
- pmd = pmd_offset(pud, addr);
- return (pte_t *) pmd;
+ return saddr;
}
-static void set_huge_pte(struct mm_struct *mm, struct vm_area_struct *vma, struct page *page, pte_t * page_table, int write_access)
+static int vma_shareable(struct vm_area_struct *vma, unsigned long addr)
{
- pte_t entry;
-
- vx_rsspages_add(mm, HPAGE_SIZE / PAGE_SIZE);
- if (write_access) {
- entry =
- pte_mkwrite(pte_mkdirty(mk_pte(page, vma->vm_page_prot)));
- } else
- entry = pte_wrprotect(mk_pte(page, vma->vm_page_prot));
- entry = pte_mkyoung(entry);
- mk_pte_huge(entry);
- set_pte(page_table, entry);
+ 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;
}
/*
- * This function checks for proper alignment of input addr and len parameters.
+ * search for a shareable pmd page for hugetlb.
*/
-int is_aligned_hugepage_range(unsigned long addr, unsigned long len)
+static void huge_pmd_share(struct mm_struct *mm, unsigned long addr, pud_t *pud)
{
- if (len & ~HPAGE_MASK)
- return -EINVAL;
- if (addr & ~HPAGE_MASK)
- return -EINVAL;
- return 0;
-}
+ 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;
+
+ spin_lock(&mapping->i_mmap_lock);
+ vma_prio_tree_foreach(svma, &iter, &mapping->i_mmap, idx, idx) {
+ if (svma == vma)
+ continue;
-int copy_hugetlb_page_range(struct mm_struct *dst, struct mm_struct *src,
- struct vm_area_struct *vma)
-{
- pte_t *src_pte, *dst_pte, entry;
- struct page *ptepage;
- unsigned long addr = vma->vm_start;
- unsigned long end = vma->vm_end;
-
- while (addr < end) {
- dst_pte = huge_pte_alloc(dst, addr);
- if (!dst_pte)
- goto nomem;
- src_pte = huge_pte_offset(src, addr);
- entry = *src_pte;
- ptepage = pte_page(entry);
- get_page(ptepage);
- set_pte(dst_pte, entry);
- vx_rsspages_add(dst, HPAGE_SIZE / PAGE_SIZE);
- addr += HPAGE_SIZE;
+ 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;
+ }
+ }
}
- return 0;
-nomem:
- return -ENOMEM;
+ if (!spte)
+ goto out;
+
+ spin_lock(&mm->page_table_lock);
+ if (pud_none(*pud))
+ pud_populate(mm, pud, (unsigned long) spte & PAGE_MASK);
+ else
+ put_page(virt_to_page(spte));
+ spin_unlock(&mm->page_table_lock);
+out:
+ spin_unlock(&mapping->i_mmap_lock);
}
-int
-follow_hugetlb_page(struct mm_struct *mm, struct vm_area_struct *vma,
- struct page **pages, struct vm_area_struct **vmas,
- unsigned long *position, int *length, int i)
+/*
+ * 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)
{
- unsigned long vpfn, vaddr = *position;
- int remainder = *length;
-
- WARN_ON(!is_vm_hugetlb_page(vma));
+ pgd_t *pgd = pgd_offset(mm, *addr);
+ pud_t *pud = pud_offset(pgd, *addr);
- vpfn = vaddr/PAGE_SIZE;
- while (vaddr < vma->vm_end && remainder) {
+ BUG_ON(page_count(virt_to_page(ptep)) == 0);
+ if (page_count(virt_to_page(ptep)) == 1)
+ return 0;
- if (pages) {
- pte_t *pte;
- struct page *page;
-
- pte = huge_pte_offset(mm, vaddr);
-
- /* hugetlb should be locked, and hence, prefaulted */
- WARN_ON(!pte || pte_none(*pte));
+ pud_clear(pud);
+ put_page(virt_to_page(ptep));
+ *addr = ALIGN(*addr, HPAGE_SIZE * PTRS_PER_PTE) - HPAGE_SIZE;
+ return 1;
+}
- page = &pte_page(*pte)[vpfn % (HPAGE_SIZE/PAGE_SIZE)];
+pte_t *huge_pte_alloc(struct mm_struct *mm, unsigned long addr)
+{
+ pgd_t *pgd;
+ pud_t *pud;
+ pte_t *pte = NULL;
- WARN_ON(!PageCompound(page));
+ pgd = pgd_offset(mm, addr);
+ pud = pud_alloc(mm, pgd, addr);
+ if (pud) {
+ 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));
- get_page(page);
- pages[i] = page;
- }
+ return pte;
+}
- if (vmas)
- vmas[i] = vma;
+pte_t *huge_pte_offset(struct mm_struct *mm, unsigned long addr)
+{
+ pgd_t *pgd;
+ pud_t *pud;
+ pmd_t *pmd = NULL;
- vaddr += PAGE_SIZE;
- ++vpfn;
- --remainder;
- ++i;
+ pgd = pgd_offset(mm, addr);
+ if (pgd_present(*pgd)) {
+ pud = pud_offset(pgd, addr);
+ if (pud_present(*pud))
+ pmd = pmd_offset(pud, addr);
}
-
- *length = remainder;
- *position = vaddr;
-
- return i;
+ return (pte_t *) pmd;
}
#if 0 /* This is just for testing */
}
#endif
-void unmap_hugepage_range(struct vm_area_struct *vma,
- unsigned long start, unsigned long end)
-{
- struct mm_struct *mm = vma->vm_mm;
- unsigned long address;
- pte_t pte;
- struct page *page;
-
- BUG_ON(start & (HPAGE_SIZE - 1));
- BUG_ON(end & (HPAGE_SIZE - 1));
-
- for (address = start; address < end; address += HPAGE_SIZE) {
- pte = ptep_get_and_clear(huge_pte_offset(mm, address));
- if (pte_none(pte))
- continue;
- page = pte_page(pte);
- put_page(page);
- }
- vx_rsspages_sub(mm, (end - start) >> PAGE_SHIFT);
- flush_tlb_range(vma, start, end);
-}
-
-int hugetlb_prefault(struct address_space *mapping, struct vm_area_struct *vma)
-{
- struct mm_struct *mm = current->mm;
- unsigned long addr;
- int ret = 0;
-
- BUG_ON(vma->vm_start & ~HPAGE_MASK);
- BUG_ON(vma->vm_end & ~HPAGE_MASK);
-
- spin_lock(&mm->page_table_lock);
- for (addr = vma->vm_start; addr < vma->vm_end; addr += HPAGE_SIZE) {
- unsigned long idx;
- pte_t *pte = huge_pte_alloc(mm, addr);
- struct page *page;
-
- if (!pte) {
- ret = -ENOMEM;
- goto out;
- }
-
- if (!pte_none(*pte)) {
- pmd_t *pmd = (pmd_t *) pte;
-
- page = pmd_page(*pmd);
- pmd_clear(pmd);
- mm->nr_ptes--;
- dec_page_state(nr_page_table_pages);
- page_cache_release(page);
- }
-
- idx = ((addr - vma->vm_start) >> HPAGE_SHIFT)
- + (vma->vm_pgoff >> (HPAGE_SHIFT - PAGE_SHIFT));
- page = find_get_page(mapping, idx);
- if (!page) {
- /* charge the fs quota first */
- if (hugetlb_get_quota(mapping)) {
- ret = -ENOMEM;
- goto out;
- }
- page = alloc_huge_page();
- if (!page) {
- hugetlb_put_quota(mapping);
- ret = -ENOMEM;
- goto out;
- }
- ret = add_to_page_cache(page, mapping, idx, GFP_ATOMIC);
- if (! ret) {
- unlock_page(page);
- } else {
- hugetlb_put_quota(mapping);
- free_huge_page(page);
- goto out;
- }
- }
- set_huge_pte(mm, vma, page, pte, vma->vm_flags & VM_WRITE);
- }
-out:
- spin_unlock(&mm->page_table_lock);
- return ret;
-}
-
/* x86_64 also uses this file */
#ifdef HAVE_ARCH_HUGETLB_UNMAPPED_AREA
struct vm_area_struct *vma;
unsigned long start_addr;
- start_addr = mm->free_area_cache;
+ 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, HPAGE_SIZE);
*/
if (start_addr != TASK_UNMAPPED_BASE) {
start_addr = TASK_UNMAPPED_BASE;
+ mm->cached_hole_size = 0;
goto full_search;
}
return -ENOMEM;
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, HPAGE_SIZE);
}
}
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)
* vma->vm_start, use it:
*/
if (addr + len <= vma->vm_start &&
- (!prev_vma || (addr >= prev_vma->vm_end)))
+ (!prev_vma || (addr >= prev_vma->vm_end))) {
/* remember the address as a hint for next time */
- return (mm->free_area_cache = addr);
- else
+ 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)
+ 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) & HPAGE_MASK;
*/
if (first_time) {
mm->free_area_cache = base;
+ largest_hole = 0;
first_time = 0;
goto try_again;
}
* 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;
}
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