mm: change the interface for __tlb_remove_page()

This updates the generic and arch specific implementation to return true
if we need to do a tlb flush.  That means if a __tlb_remove_page
indicate a flush is needed, the page we try to remove need to be tracked
and added again after the flush.  We need to track it because we have
already update the pte to none and we can't just loop back.

This change is done to enable us to do a tlb_flush when we try to flush
a range that consists of different page sizes.  For architectures like
ppc64, we can do a range based tlb flush and we need to track page size
for that.  When we try to remove a huge page, we will force a tlb flush
and starts a new mmu gather.

[aneesh.kumar@linux.vnet.ibm.com: mm-change-the-interface-for-__tlb_remove_page-v3]
  Link: http://lkml.kernel.org/r/1465049193-22197-2-git-send-email-aneesh.kumar@linux.vnet.ibm.com
Link: http://lkml.kernel.org/r/1464860389-29019-2-git-send-email-aneesh.kumar@linux.vnet.ibm.com
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Hugh Dickins <hughd@google.com>
Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: Mel Gorman <mgorman@suse.de>
Cc: David Rientjes <rientjes@google.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Minchan Kim <minchan.kim@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 33 insertions, 11 deletions

diff --git a/include/asm-generic/tlb.h b/include/asm-generic/tlb.h
index 9dbb739cafa0..7b899a46a4cb 100644
--- a/include/asm-generic/tlb.h
+++ b/include/asm-generic/tlb.h
@@ -107,6 +107,11 @@ struct mmu_gather {
         struct mmu_gather_batch local;
         struct page             *__pages[MMU_GATHER_BUNDLE];
         unsigned int            batch_count;
+        /*
+         * __tlb_adjust_range  will track the new addr here,
+         * that that we can adjust the range after the flush
+         */
+        unsigned long addr;
 };
 
 #define HAVE_GENERIC_MMU_GATHER
@@ -115,23 +120,19 @@ void tlb_gather_mmu(struct mmu_gather *tlb, struct mm_struct *mm, unsigned long
 void tlb_flush_mmu(struct mmu_gather *tlb);
 void tlb_finish_mmu(struct mmu_gather *tlb, unsigned long start,
                                                         unsigned long end);
-int __tlb_remove_page(struct mmu_gather *tlb, struct page *page);
-
-/* tlb_remove_page
- *      Similar to __tlb_remove_page but will call tlb_flush_mmu() itself when
- *      required.
- */
-static inline void tlb_remove_page(struct mmu_gather *tlb, struct page *page)
-{
-        if (!__tlb_remove_page(tlb, page))
-                tlb_flush_mmu(tlb);
-}
+bool __tlb_remove_page(struct mmu_gather *tlb, struct page *page);
 
 static inline void __tlb_adjust_range(struct mmu_gather *tlb,
                                       unsigned long address)
 {
         tlb->start = min(tlb->start, address);
         tlb->end = max(tlb->end, address + PAGE_SIZE);
+        /*
+         * Track the last address with which we adjusted the range. This
+         * will be used later to adjust again after a mmu_flush due to
+         * failed __tlb_remove_page
+         */
+        tlb->addr = address;
 }
 
 static inline void __tlb_reset_range(struct mmu_gather *tlb)
@@ -144,6 +145,27 @@ static inline void __tlb_reset_range(struct mmu_gather *tlb)
         }
 }
 
+/* tlb_remove_page
+ *      Similar to __tlb_remove_page but will call tlb_flush_mmu() itself when
+ *      required.
+ */
+static inline void tlb_remove_page(struct mmu_gather *tlb, struct page *page)
+{
+        if (__tlb_remove_page(tlb, page)) {
+                tlb_flush_mmu(tlb);
+                __tlb_adjust_range(tlb, tlb->addr);
+                __tlb_remove_page(tlb, page);
+        }
+}
+
+static inline bool __tlb_remove_pte_page(struct mmu_gather *tlb, struct page *page)
+{
+        /* active->nr should be zero when we call this */
+        VM_BUG_ON_PAGE(tlb->active->nr, page);
+        __tlb_adjust_range(tlb, tlb->addr);
+        return __tlb_remove_page(tlb, page);
+}
+
 /*
  * In the case of tlb vma handling, we can optimise these away in the
  * case where we're doing a full MM flush.  When we're doing a munmap,