[PATCH] Hugepage consolidation
A lot of the code in arch/*/mm/hugetlbpage.c is quite similar. This patch
attempts to consolidate a lot of the code across the arch's, putting the
combined version in mm/hugetlb.c. There are a couple of uglyish hacks in
order to covert all the hugepage archs, but the result is a very large
reduction in the total amount of code. It also means things like hugepage
lazy allocation could be implemented in one place, instead of six.
Tested, at least a little, on ppc64, i386 and x86_64.
Notes:
- this patch changes the meaning of set_huge_pte() to be more
analagous to set_pte()
- does SH4 need s special huge_ptep_get_and_clear()??
Acked-by: William Lee Irwin <wli@holomorphy.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
diff --git a/mm/hugetlb.c b/mm/hugetlb.c
index 4eb5ae3..fbd1111 100644
--- a/mm/hugetlb.c
+++ b/mm/hugetlb.c
@@ -7,10 +7,14 @@
#include <linux/init.h>
#include <linux/module.h>
#include <linux/mm.h>
-#include <linux/hugetlb.h>
#include <linux/sysctl.h>
#include <linux/highmem.h>
#include <linux/nodemask.h>
+#include <linux/pagemap.h>
+#include <asm/page.h>
+#include <asm/pgtable.h>
+
+#include <linux/hugetlb.h>
const unsigned long hugetlb_zero = 0, hugetlb_infinity = ~0UL;
static unsigned long nr_huge_pages, free_huge_pages;
@@ -249,6 +253,72 @@
.nopage = hugetlb_nopage,
};
+static pte_t make_huge_pte(struct vm_area_struct *vma, struct page *page)
+{
+ pte_t entry;
+
+ if (vma->vm_flags & VM_WRITE) {
+ 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);
+ entry = pte_mkhuge(entry);
+
+ return entry;
+}
+
+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);
+ BUG_ON(!src_pte || pte_none(*src_pte)); /* prefaulted */
+ entry = *src_pte;
+ ptepage = pte_page(entry);
+ get_page(ptepage);
+ add_mm_counter(dst, rss, HPAGE_SIZE / PAGE_SIZE);
+ set_huge_pte_at(dst, addr, dst_pte, entry);
+ addr += HPAGE_SIZE;
+ }
+ return 0;
+
+nomem:
+ return -ENOMEM;
+}
+
+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;
+
+ WARN_ON(!is_vm_hugetlb_page(vma));
+ BUG_ON(start & ~HPAGE_MASK);
+ BUG_ON(end & ~HPAGE_MASK);
+
+ for (address = start; address < end; address += HPAGE_SIZE) {
+ pte = huge_ptep_get_and_clear(mm, address, huge_pte_offset(mm, address));
+ if (pte_none(pte))
+ continue;
+ page = pte_page(pte);
+ put_page(page);
+ }
+ add_mm_counter(mm, rss, -((end - start) >> PAGE_SHIFT));
+ flush_tlb_range(vma, start, end);
+}
+
void zap_hugepage_range(struct vm_area_struct *vma,
unsigned long start, unsigned long length)
{
@@ -258,3 +328,108 @@
unmap_hugepage_range(vma, start, start + length);
spin_unlock(&mm->page_table_lock);
}
+
+int hugetlb_prefault(struct address_space *mapping, struct vm_area_struct *vma)
+{
+ struct mm_struct *mm = current->mm;
+ unsigned long addr;
+ int ret = 0;
+
+ WARN_ON(!is_vm_hugetlb_page(vma));
+ BUG_ON(vma->vm_start & ~HPAGE_MASK);
+ BUG_ON(vma->vm_end & ~HPAGE_MASK);
+
+ hugetlb_prefault_arch_hook(mm);
+
+ 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))
+ hugetlb_clean_stale_pgtable(pte);
+
+ 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;
+ }
+ }
+ add_mm_counter(mm, rss, HPAGE_SIZE / PAGE_SIZE);
+ set_huge_pte_at(mm, addr, pte, make_huge_pte(vma, page));
+ }
+out:
+ spin_unlock(&mm->page_table_lock);
+ return ret;
+}
+
+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)
+{
+ unsigned long vpfn, vaddr = *position;
+ int remainder = *length;
+
+ BUG_ON(!is_vm_hugetlb_page(vma));
+
+ vpfn = vaddr/PAGE_SIZE;
+ while (vaddr < vma->vm_end && remainder) {
+
+ if (pages) {
+ pte_t *pte;
+ struct page *page;
+
+ /* Some archs (sparc64, sh*) have multiple
+ * pte_ts to each hugepage. We have to make
+ * sure we get the first, for the page
+ * indexing below to work. */
+ pte = huge_pte_offset(mm, vaddr & HPAGE_MASK);
+
+ /* hugetlb should be locked, and hence, prefaulted */
+ WARN_ON(!pte || pte_none(*pte));
+
+ page = &pte_page(*pte)[vpfn % (HPAGE_SIZE/PAGE_SIZE)];
+
+ WARN_ON(!PageCompound(page));
+
+ get_page(page);
+ pages[i] = page;
+ }
+
+ if (vmas)
+ vmas[i] = vma;
+
+ vaddr += PAGE_SIZE;
+ ++vpfn;
+ --remainder;
+ ++i;
+ }
+
+ *length = remainder;
+ *position = vaddr;
+
+ return i;
+}