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authorKirill A. Shutemov <kirill.shutemov@linux.intel.com>2016-07-26 15:25:29 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2016-07-26 16:19:19 -0700
commit1010245964415bb7403463115bab2cd26244b445 (patch)
tree0bb07c499e1816334dd405ea9f82381223c7479a
parentdd78fedde4b99b322f2dc849d467d365a82e23ca (diff)
downloadlinux-1010245964415bb7403463115bab2cd26244b445.tar.bz2
mm: introduce do_set_pmd()
With postponed page table allocation we have chance to setup huge pages. do_set_pte() calls do_set_pmd() if following criteria met: - page is compound; - pmd entry in pmd_none(); - vma has suitable size and alignment; Link: http://lkml.kernel.org/r/1466021202-61880-12-git-send-email-kirill.shutemov@linux.intel.com Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
-rw-r--r--include/linux/huge_mm.h2
-rw-r--r--mm/huge_memory.c5
-rw-r--r--mm/memory.c72
-rw-r--r--mm/migrate.c3
4 files changed, 74 insertions, 8 deletions
diff --git a/include/linux/huge_mm.h b/include/linux/huge_mm.h
index 9bed9249156f..254aac4c3963 100644
--- a/include/linux/huge_mm.h
+++ b/include/linux/huge_mm.h
@@ -143,6 +143,8 @@ static inline bool is_huge_zero_pmd(pmd_t pmd)
struct page *get_huge_zero_page(void);
void put_huge_zero_page(void);
+#define mk_huge_pmd(page, prot) pmd_mkhuge(mk_pmd(page, prot))
+
#else /* CONFIG_TRANSPARENT_HUGEPAGE */
#define HPAGE_PMD_SHIFT ({ BUILD_BUG(); 0; })
#define HPAGE_PMD_MASK ({ BUILD_BUG(); 0; })
diff --git a/mm/huge_memory.c b/mm/huge_memory.c
index 90f5dd22b1c8..5bc058ad12c2 100644
--- a/mm/huge_memory.c
+++ b/mm/huge_memory.c
@@ -796,11 +796,6 @@ pmd_t maybe_pmd_mkwrite(pmd_t pmd, struct vm_area_struct *vma)
return pmd;
}
-static inline pmd_t mk_huge_pmd(struct page *page, pgprot_t prot)
-{
- return pmd_mkhuge(mk_pmd(page, prot));
-}
-
static inline struct list_head *page_deferred_list(struct page *page)
{
/*
diff --git a/mm/memory.c b/mm/memory.c
index 30cda24ff205..650622a3a0a1 100644
--- a/mm/memory.c
+++ b/mm/memory.c
@@ -2920,6 +2920,66 @@ map_pte:
return 0;
}
+#ifdef CONFIG_TRANSPARENT_HUGEPAGE
+
+#define HPAGE_CACHE_INDEX_MASK (HPAGE_PMD_NR - 1)
+static inline bool transhuge_vma_suitable(struct vm_area_struct *vma,
+ unsigned long haddr)
+{
+ if (((vma->vm_start >> PAGE_SHIFT) & HPAGE_CACHE_INDEX_MASK) !=
+ (vma->vm_pgoff & HPAGE_CACHE_INDEX_MASK))
+ return false;
+ if (haddr < vma->vm_start || haddr + HPAGE_PMD_SIZE > vma->vm_end)
+ return false;
+ return true;
+}
+
+static int do_set_pmd(struct fault_env *fe, struct page *page)
+{
+ struct vm_area_struct *vma = fe->vma;
+ bool write = fe->flags & FAULT_FLAG_WRITE;
+ unsigned long haddr = fe->address & HPAGE_PMD_MASK;
+ pmd_t entry;
+ int i, ret;
+
+ if (!transhuge_vma_suitable(vma, haddr))
+ return VM_FAULT_FALLBACK;
+
+ ret = VM_FAULT_FALLBACK;
+ page = compound_head(page);
+
+ fe->ptl = pmd_lock(vma->vm_mm, fe->pmd);
+ if (unlikely(!pmd_none(*fe->pmd)))
+ goto out;
+
+ for (i = 0; i < HPAGE_PMD_NR; i++)
+ flush_icache_page(vma, page + i);
+
+ entry = mk_huge_pmd(page, vma->vm_page_prot);
+ if (write)
+ entry = maybe_pmd_mkwrite(pmd_mkdirty(entry), vma);
+
+ add_mm_counter(vma->vm_mm, MM_FILEPAGES, HPAGE_PMD_NR);
+ page_add_file_rmap(page, true);
+
+ set_pmd_at(vma->vm_mm, haddr, fe->pmd, entry);
+
+ update_mmu_cache_pmd(vma, haddr, fe->pmd);
+
+ /* fault is handled */
+ ret = 0;
+out:
+ spin_unlock(fe->ptl);
+ return ret;
+}
+#else
+static int do_set_pmd(struct fault_env *fe, struct page *page)
+{
+ BUILD_BUG();
+ return 0;
+}
+#endif
+
/**
* alloc_set_pte - setup new PTE entry for given page and add reverse page
* mapping. If needed, the fucntion allocates page table or use pre-allocated.
@@ -2939,9 +2999,19 @@ int alloc_set_pte(struct fault_env *fe, struct mem_cgroup *memcg,
struct vm_area_struct *vma = fe->vma;
bool write = fe->flags & FAULT_FLAG_WRITE;
pte_t entry;
+ int ret;
+
+ if (pmd_none(*fe->pmd) && PageTransCompound(page)) {
+ /* THP on COW? */
+ VM_BUG_ON_PAGE(memcg, page);
+
+ ret = do_set_pmd(fe, page);
+ if (ret != VM_FAULT_FALLBACK)
+ return ret;
+ }
if (!fe->pte) {
- int ret = pte_alloc_one_map(fe);
+ ret = pte_alloc_one_map(fe);
if (ret)
return ret;
}
diff --git a/mm/migrate.c b/mm/migrate.c
index e85a72c0d6f0..2232f6923cc7 100644
--- a/mm/migrate.c
+++ b/mm/migrate.c
@@ -1986,8 +1986,7 @@ fail_putback:
}
orig_entry = *pmd;
- entry = mk_pmd(new_page, vma->vm_page_prot);
- entry = pmd_mkhuge(entry);
+ entry = mk_huge_pmd(new_page, vma->vm_page_prot);
entry = maybe_pmd_mkwrite(pmd_mkdirty(entry), vma);
/*