arm: mmu_gather rework

Fix up the arm mmu_gather code to conform to the new API.

Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: David Miller <davem@davemloft.net>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Russell King <rmk@arm.linux.org.uk>
Cc: Paul Mundt <lethal@linux-sh.org>
Cc: Jeff Dike <jdike@addtoit.com>
Cc: Richard Weinberger <richard@nod.at>
Cc: Tony Luck <tony.luck@intel.com>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Mel Gorman <mel@csn.ul.ie>
Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Cc: Nick Piggin <npiggin@kernel.dk>
Cc: Namhyung Kim <namhyung@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 37 insertions, 16 deletions

diff --git a/arch/arm/include/asm/tlb.h b/arch/arm/include/asm/tlb.h
index 82dfe5d0c41e..265f908c4a6e 100644
--- a/arch/arm/include/asm/tlb.h
+++ b/arch/arm/include/asm/tlb.h
@@ -41,12 +41,12 @@
  */
 #if defined(CONFIG_SMP) || defined(CONFIG_CPU_32v7)
 #define tlb_fast_mode(tlb)      0
-#define FREE_PTE_NR             500
 #else
 #define tlb_fast_mode(tlb)      1
-#define FREE_PTE_NR             0
 #endif
 
+#define MMU_GATHER_BUNDLE       8
+
 /*
  * TLB handling.  This allows us to remove pages from the page
  * tables, and efficiently handle the TLB issues.
@@ -58,7 +58,9 @@ struct mmu_gather {
         unsigned long           range_start;
         unsigned long           range_end;
         unsigned int            nr;
-        struct page             *pages[FREE_PTE_NR];
+        unsigned int            max;
+        struct page             **pages;
+        struct page             *local[MMU_GATHER_BUNDLE];
 };
 
 DECLARE_PER_CPU(struct mmu_gather, mmu_gathers);
@@ -97,26 +99,37 @@ static inline void tlb_add_flush(struct mmu_gather *tlb, unsigned long addr)
         }
 }
 
+static inline void __tlb_alloc_page(struct mmu_gather *tlb)
+{
+        unsigned long addr = __get_free_pages(GFP_NOWAIT | __GFP_NOWARN, 0);
+
+        if (addr) {
+                tlb->pages = (void *)addr;
+                tlb->max = PAGE_SIZE / sizeof(struct page *);
+        }
+}
+
 static inline void tlb_flush_mmu(struct mmu_gather *tlb)
 {
         tlb_flush(tlb);
         if (!tlb_fast_mode(tlb)) {
                 free_pages_and_swap_cache(tlb->pages, tlb->nr);
                 tlb->nr = 0;
+                if (tlb->pages == tlb->local)
+                        __tlb_alloc_page(tlb);
         }
 }
 
-static inline struct mmu_gather *
-tlb_gather_mmu(struct mm_struct *mm, unsigned int full_mm_flush)
+static inline void
+tlb_gather_mmu(struct mmu_gather *tlb, struct mm_struct *mm, unsigned int fullmm)
 {
-        struct mmu_gather *tlb = &get_cpu_var(mmu_gathers);
-
         tlb->mm = mm;
-        tlb->fullmm = full_mm_flush;
+        tlb->fullmm = fullmm;
         tlb->vma = NULL;
+        tlb->max = ARRAY_SIZE(tlb->local);
+        tlb->pages = tlb->local;
         tlb->nr = 0;
-
-        return tlb;
+        __tlb_alloc_page(tlb);
 }
 
 static inline void
@@ -127,7 +140,8 @@ tlb_finish_mmu(struct mmu_gather *tlb, unsigned long start, unsigned long end)
         /* keep the page table cache within bounds */
         check_pgt_cache();
 
-        put_cpu_var(mmu_gathers);
+        if (tlb->pages != tlb->local)
+                free_pages((unsigned long)tlb->pages, 0);
 }
 
 /*
@@ -162,15 +176,22 @@ tlb_end_vma(struct mmu_gather *tlb, struct vm_area_struct *vma)
                 tlb_flush(tlb);
 }
 
-static inline void tlb_remove_page(struct mmu_gather *tlb, struct page *page)
+static inline int __tlb_remove_page(struct mmu_gather *tlb, struct page *page)
 {
         if (tlb_fast_mode(tlb)) {
                 free_page_and_swap_cache(page);
-        } else {
-                tlb->pages[tlb->nr++] = page;
-                if (tlb->nr >= FREE_PTE_NR)
-                        tlb_flush_mmu(tlb);
+                return 1; /* avoid calling tlb_flush_mmu */
         }
+
+        tlb->pages[tlb->nr++] = page;
+        VM_BUG_ON(tlb->nr > tlb->max);
+        return tlb->max - tlb->nr;
+}
+
+static inline void tlb_remove_page(struct mmu_gather *tlb, struct page *page)
+{
+        if (!__tlb_remove_page(tlb, page))
+                tlb_flush_mmu(tlb);
 }
 
 static inline void __pte_free_tlb(struct mmu_gather *tlb, pgtable_t pte,