powerpc, thp: remove infrastructure for handling splitting PMDs

With new refcounting we don't need to mark PMDs splitting.  Let's drop
code to handle this.

pmdp_splitting_flush() is not needed too: on splitting PMD we will do
pmdp_clear_flush() + set_pte_at().  pmdp_clear_flush() will do IPI as
needed for fast_gup.

Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Tested-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Reviewed-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Cc: Sasha Levin <sasha.levin@oracle.com>
Cc: Jerome Marchand <jmarchan@redhat.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Dave Hansen <dave.hansen@intel.com>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Rik van Riel <riel@redhat.com>
Cc: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Cc: Steve Capper <steve.capper@linaro.org>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Michal Hocko <mhocko@suse.cz>
Cc: Christoph Lameter <cl@linux.com>
Cc: David Rientjes <rientjes@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

diff --git a/arch/powerpc/include/asm/book3s/64/hash-64k.h b/arch/powerpc/include/asm/book3s/64/hash-64k.h
index 9e55e3b..849bbec 100644 (file)
--- a/arch/powerpc/include/asm/book3s/64/hash-64k.h
+++ b/arch/powerpc/include/asm/book3s/64/hash-64k.h
@@ -256,13 +256,6 @@ static inline int pmd_trans_huge(pmd_t pmd)
                  (_PAGE_PTE | _PAGE_THP_HUGE));
 }
 
-static inline int pmd_trans_splitting(pmd_t pmd)
-{
-       if (pmd_trans_huge(pmd))
-               return pmd_val(pmd) & _PAGE_SPLITTING;
-       return 0;
-}
-
 static inline int pmd_large(pmd_t pmd)
 {
        return !!(pmd_val(pmd) & _PAGE_PTE);
@@ -273,11 +266,6 @@ static inline pmd_t pmd_mknotpresent(pmd_t pmd)
        return __pmd(pmd_val(pmd) & ~_PAGE_PRESENT);
 }
 
-static inline pmd_t pmd_mksplitting(pmd_t pmd)
-{
-       return __pmd(pmd_val(pmd) | _PAGE_SPLITTING);
-}
-
 #define __HAVE_ARCH_PMD_SAME
 static inline int pmd_same(pmd_t pmd_a, pmd_t pmd_b)
 {

diff --git a/arch/powerpc/include/asm/book3s/64/hash.h b/arch/powerpc/include/asm/book3s/64/hash.h
index 2ff8b3d..06f17e7 100644 (file)
--- a/arch/powerpc/include/asm/book3s/64/hash.h
+++ b/arch/powerpc/include/asm/book3s/64/hash.h
@@ -40,11 +40,6 @@
 #define _PAGE_SOFT_DIRTY       0x00000
 #endif
 
-/*
- * THP pages can't be special. So use the _PAGE_SPECIAL
- */
-#define _PAGE_SPLITTING _PAGE_SPECIAL
-
 /*
  * We need to differentiate between explicit huge page and THP huge
  * page, since THP huge page also need to track real subpage details
@@ -54,9 +49,8 @@
 /*
  * set of bits not changed in pmd_modify.
  */
-#define _HPAGE_CHG_MASK (PTE_RPN_MASK | _PAGE_HPTEFLAGS |              \
-                        _PAGE_DIRTY | _PAGE_ACCESSED | _PAGE_SPLITTING | \
-                        _PAGE_THP_HUGE | _PAGE_PTE | _PAGE_SOFT_DIRTY)
+#define _HPAGE_CHG_MASK (PTE_RPN_MASK | _PAGE_HPTEFLAGS | _PAGE_DIRTY | \
+                        _PAGE_ACCESSED | _PAGE_THP_HUGE)
 
 #ifdef CONFIG_PPC_64K_PAGES
 #include <asm/book3s/64/hash-64k.h>

diff --git a/arch/powerpc/include/asm/book3s/64/pgtable.h b/arch/powerpc/include/asm/book3s/64/pgtable.h
index b3a5bad..da11c4a 100644 (file)
--- a/arch/powerpc/include/asm/book3s/64/pgtable.h
+++ b/arch/powerpc/include/asm/book3s/64/pgtable.h
@@ -266,10 +266,6 @@ extern int pmdp_clear_flush_young(struct vm_area_struct *vma,
 extern pmd_t pmdp_huge_get_and_clear(struct mm_struct *mm,
                                     unsigned long addr, pmd_t *pmdp);
 
-#define __HAVE_ARCH_PMDP_SPLITTING_FLUSH
-extern void pmdp_splitting_flush(struct vm_area_struct *vma,
-                                unsigned long address, pmd_t *pmdp);
-
 extern pmd_t pmdp_collapse_flush(struct vm_area_struct *vma,
                                 unsigned long address, pmd_t *pmdp);
 #define pmdp_collapse_flush pmdp_collapse_flush

diff --git a/arch/powerpc/mm/hugepage-hash64.c b/arch/powerpc/mm/hugepage-hash64.c
index baf1301..49b152b 100644 (file)
--- a/arch/powerpc/mm/hugepage-hash64.c
+++ b/arch/powerpc/mm/hugepage-hash64.c
@@ -39,9 +39,6 @@ int __hash_page_thp(unsigned long ea, unsigned long access, unsigned long vsid,
                /* If PMD busy, retry the access */
                if (unlikely(old_pmd & _PAGE_BUSY))
                        return 0;
-               /* If PMD is trans splitting retry the access */
-               if (unlikely(old_pmd & _PAGE_SPLITTING))
-                       return 0;
                /* If PMD permissions don't match, take page fault */
                if (unlikely(access & ~old_pmd))
                        return 1;

diff --git a/arch/powerpc/mm/hugetlbpage.c b/arch/powerpc/mm/hugetlbpage.c
index 6bd3afa..744e24b 100644 (file)
--- a/arch/powerpc/mm/hugetlbpage.c
+++ b/arch/powerpc/mm/hugetlbpage.c
@@ -958,10 +958,6 @@ pte_t *__find_linux_pte_or_hugepte(pgd_t *pgdir, unsigned long ea,
                        /*
                         * A hugepage collapse is captured by pmd_none, because
                         * it mark the pmd none and do a hpte invalidate.
-                        *
-                        * We don't worry about pmd_trans_splitting here, The
-                        * caller if it needs to handle the splitting case
-                        * should check for that.
                         */
                        if (pmd_none(pmd))
                                return NULL;

diff --git a/arch/powerpc/mm/pgtable_64.c b/arch/powerpc/mm/pgtable_64.c
index ea6bc31..3124a20 100644 (file)
--- a/arch/powerpc/mm/pgtable_64.c
+++ b/arch/powerpc/mm/pgtable_64.c
@@ -603,55 +603,6 @@ int pmdp_clear_flush_young(struct vm_area_struct *vma,
        return __pmdp_test_and_clear_young(vma->vm_mm, address, pmdp);
 }
 
-/*
- * We mark the pmd splitting and invalidate all the hpte
- * entries for this hugepage.
- */
-void pmdp_splitting_flush(struct vm_area_struct *vma,
-                         unsigned long address, pmd_t *pmdp)
-{
-       unsigned long old, tmp;
-
-       VM_BUG_ON(address & ~HPAGE_PMD_MASK);
-
-#ifdef CONFIG_DEBUG_VM
-       WARN_ON(!pmd_trans_huge(*pmdp));
-       assert_spin_locked(&vma->vm_mm->page_table_lock);
-#endif
-
-#ifdef PTE_ATOMIC_UPDATES
-
-       __asm__ __volatile__(
-       "1:     ldarx   %0,0,%3\n\
-               andi.   %1,%0,%6\n\
-               bne-    1b \n\
-               oris    %1,%0,%4@h \n\
-               stdcx.  %1,0,%3 \n\
-               bne-    1b"
-       : "=&r" (old), "=&r" (tmp), "=m" (*pmdp)
-       : "r" (pmdp), "i" (_PAGE_SPLITTING), "m" (*pmdp), "i" (_PAGE_BUSY)
-       : "cc" );
-#else
-       old = pmd_val(*pmdp);
-       *pmdp = __pmd(old | _PAGE_SPLITTING);
-#endif
-       /*
-        * If we didn't had the splitting flag set, go and flush the
-        * HPTE entries.
-        */
-       trace_hugepage_splitting(address, old);
-       if (!(old & _PAGE_SPLITTING)) {
-               /* We need to flush the hpte */
-               if (old & _PAGE_HASHPTE)
-                       hpte_do_hugepage_flush(vma->vm_mm, address, pmdp, old);
-       }
-       /*
-        * This ensures that generic code that rely on IRQ disabling
-        * to prevent a parallel THP split work as expected.
-        */
-       kick_all_cpus_sync();
-}
-
 /*
  * We want to put the pgtable in pmd and use pgtable for tracking
  * the base page size hptes