powerpc: mmu_gather rework

Fix up powerpc to the new mmu_gather stuff.

PPC has an extra batching queue to RCU free the actual pagetable
allocations, use the ARCH extentions for that for now.

For the ppc64_tlb_batch, which tracks the vaddrs to unhash from the
hardware hash-table, keep using per-cpu arrays but flush on context switch
and use a TLF bit to track the lazy_mmu state.

Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Acked-by: 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>

8 files changed, 46 insertions, 17 deletions

diff --git a/arch/powerpc/include/asm/pgalloc.h b/arch/powerpc/include/asm/pgalloc.h
index abe8532bd14e..df1b4cbb2e70 100644
--- a/arch/powerpc/include/asm/pgalloc.h
+++ b/arch/powerpc/include/asm/pgalloc.h
@@ -32,13 +32,13 @@ static inline void pte_free(struct mm_struct *mm, pgtable_t ptepage)
 
 #ifdef CONFIG_SMP
 extern void pgtable_free_tlb(struct mmu_gather *tlb, void *table, unsigned shift);
-extern void pte_free_finish(void);
+extern void pte_free_finish(struct mmu_gather *tlb);
 #else /* CONFIG_SMP */
 static inline void pgtable_free_tlb(struct mmu_gather *tlb, void *table, unsigned shift)
 {
         pgtable_free(table, shift);
 }
-static inline void pte_free_finish(void) { }
+static inline void pte_free_finish(struct mmu_gather *tlb) { }
 #endif /* !CONFIG_SMP */
 
 static inline void __pte_free_tlb(struct mmu_gather *tlb, struct page *ptepage,
diff --git a/arch/powerpc/include/asm/thread_info.h b/arch/powerpc/include/asm/thread_info.h
index d8529ef13b23..37c353e8af7c 100644
--- a/arch/powerpc/include/asm/thread_info.h
+++ b/arch/powerpc/include/asm/thread_info.h
@@ -139,10 +139,12 @@ static inline struct thread_info *current_thread_info(void)
 #define TLF_NAPPING             0       /* idle thread enabled NAP mode */
 #define TLF_SLEEPING            1       /* suspend code enabled SLEEP mode */
 #define TLF_RESTORE_SIGMASK     2       /* Restore signal mask in do_signal */
+#define TLF_LAZY_MMU            3       /* tlb_batch is active */
 
 #define _TLF_NAPPING            (1 << TLF_NAPPING)
 #define _TLF_SLEEPING           (1 << TLF_SLEEPING)
 #define _TLF_RESTORE_SIGMASK    (1 << TLF_RESTORE_SIGMASK)
+#define _TLF_LAZY_MMU           (1 << TLF_LAZY_MMU)
 
 #ifndef __ASSEMBLY__
 #define HAVE_SET_RESTORE_SIGMASK        1
diff --git a/arch/powerpc/include/asm/tlb.h b/arch/powerpc/include/asm/tlb.h
index e2b428b0f7ba..8f0ed7adcd12 100644
--- a/arch/powerpc/include/asm/tlb.h
+++ b/arch/powerpc/include/asm/tlb.h
@@ -28,6 +28,16 @@
 #define tlb_start_vma(tlb, vma) do { } while (0)
 #define tlb_end_vma(tlb, vma)   do { } while (0)
 
+#define HAVE_ARCH_MMU_GATHER 1
+
+struct pte_freelist_batch;
+
+struct arch_mmu_gather {
+        struct pte_freelist_batch *batch;
+};
+
+#define ARCH_MMU_GATHER_INIT (struct arch_mmu_gather){ .batch = NULL, }
+
 extern void tlb_flush(struct mmu_gather *tlb);
 
 /* Get the generic bits... */
diff --git a/arch/powerpc/kernel/process.c b/arch/powerpc/kernel/process.c
index 095043d79946..91e52df3d81d 100644
--- a/arch/powerpc/kernel/process.c
+++ b/arch/powerpc/kernel/process.c
@@ -395,6 +395,9 @@ struct task_struct *__switch_to(struct task_struct *prev,
         struct thread_struct *new_thread, *old_thread;
         unsigned long flags;
         struct task_struct *last;
+#ifdef CONFIG_PPC_BOOK3S_64
+        struct ppc64_tlb_batch *batch;
+#endif
 
 #ifdef CONFIG_SMP
         /* avoid complexity of lazy save/restore of fpu
@@ -513,7 +516,17 @@ struct task_struct *__switch_to(struct task_struct *prev,
                 old_thread->accum_tb += (current_tb - start_tb);
                 new_thread->start_tb = current_tb;
         }
-#endif
+#endif /* CONFIG_PPC64 */
+
+#ifdef CONFIG_PPC_BOOK3S_64
+        batch = &__get_cpu_var(ppc64_tlb_batch);
+        if (batch->active) {
+                current_thread_info()->local_flags |= _TLF_LAZY_MMU;
+                if (batch->index)
+                        __flush_tlb_pending(batch);
+                batch->active = 0;
+        }
+#endif /* CONFIG_PPC_BOOK3S_64 */
 
         local_irq_save(flags);
 
@@ -528,6 +541,14 @@ struct task_struct *__switch_to(struct task_struct *prev,
         hard_irq_disable();
         last = _switch(old_thread, new_thread);
 
+#ifdef CONFIG_PPC_BOOK3S_64
+        if (current_thread_info()->local_flags & _TLF_LAZY_MMU) {
+                current_thread_info()->local_flags &= ~_TLF_LAZY_MMU;
+                batch = &__get_cpu_var(ppc64_tlb_batch);
+                batch->active = 1;
+        }
+#endif /* CONFIG_PPC_BOOK3S_64 */
+
         local_irq_restore(flags);
 
         return last;
diff --git a/arch/powerpc/mm/pgtable.c b/arch/powerpc/mm/pgtable.c
index 6a3997f98dfb..6e72788598f8 100644
--- a/arch/powerpc/mm/pgtable.c
+++ b/arch/powerpc/mm/pgtable.c
@@ -33,8 +33,6 @@
 
 #include "mmu_decl.h"
 
-DEFINE_PER_CPU(struct mmu_gather, mmu_gathers);
-
 #ifdef CONFIG_SMP
 
 /*
@@ -43,7 +41,6 @@ DEFINE_PER_CPU(struct mmu_gather, mmu_gathers);
  * freeing a page table page that is being walked without locks
  */
 
-static DEFINE_PER_CPU(struct pte_freelist_batch *, pte_freelist_cur);
 static unsigned long pte_freelist_forced_free;
 
 struct pte_freelist_batch
@@ -97,12 +94,10 @@ static void pte_free_submit(struct pte_freelist_batch *batch)
 
 void pgtable_free_tlb(struct mmu_gather *tlb, void *table, unsigned shift)
 {
-        /* This is safe since tlb_gather_mmu has disabled preemption */
-        struct pte_freelist_batch **batchp = &__get_cpu_var(pte_freelist_cur);
+        struct pte_freelist_batch **batchp = &tlb->arch.batch;
         unsigned long pgf;
 
-        if (atomic_read(&tlb->mm->mm_users) < 2 ||
-            cpumask_equal(mm_cpumask(tlb->mm), cpumask_of(smp_processor_id()))){
+        if (atomic_read(&tlb->mm->mm_users) < 2) {
                 pgtable_free(table, shift);
                 return;
         }
@@ -124,10 +119,9 @@ void pgtable_free_tlb(struct mmu_gather *tlb, void *table, unsigned shift)
         }
 }
 
-void pte_free_finish(void)
+void pte_free_finish(struct mmu_gather *tlb)
 {
-        /* This is safe since tlb_gather_mmu has disabled preemption */
-        struct pte_freelist_batch **batchp = &__get_cpu_var(pte_freelist_cur);
+        struct pte_freelist_batch **batchp = &tlb->arch.batch;
 
         if (*batchp == NULL)
                 return;
diff --git a/arch/powerpc/mm/tlb_hash32.c b/arch/powerpc/mm/tlb_hash32.c
index 690566b66e8e..d555cdb06bc8 100644
--- a/arch/powerpc/mm/tlb_hash32.c
+++ b/arch/powerpc/mm/tlb_hash32.c
@@ -73,7 +73,7 @@ void tlb_flush(struct mmu_gather *tlb)
         }
 
         /* Push out batch of freed page tables */
-        pte_free_finish();
+        pte_free_finish(tlb);
 }
 
 /*
diff --git a/arch/powerpc/mm/tlb_hash64.c b/arch/powerpc/mm/tlb_hash64.c
index c14d09f614f3..5c94ca34cd79 100644
--- a/arch/powerpc/mm/tlb_hash64.c
+++ b/arch/powerpc/mm/tlb_hash64.c
@@ -155,7 +155,7 @@ void __flush_tlb_pending(struct ppc64_tlb_batch *batch)
 
 void tlb_flush(struct mmu_gather *tlb)
 {
-        struct ppc64_tlb_batch *tlbbatch = &__get_cpu_var(ppc64_tlb_batch);
+        struct ppc64_tlb_batch *tlbbatch = &get_cpu_var(ppc64_tlb_batch);
 
         /* If there's a TLB batch pending, then we must flush it because the
          * pages are going to be freed and we really don't want to have a CPU
@@ -164,8 +164,10 @@ void tlb_flush(struct mmu_gather *tlb)
         if (tlbbatch->index)
                 __flush_tlb_pending(tlbbatch);
 
+        put_cpu_var(ppc64_tlb_batch);
+
         /* Push out batch of freed page tables */
-        pte_free_finish();
+        pte_free_finish(tlb);
 }
 
 /**
diff --git a/arch/powerpc/mm/tlb_nohash.c b/arch/powerpc/mm/tlb_nohash.c
index 2a030d89bbc6..8eaf67d32043 100644
--- a/arch/powerpc/mm/tlb_nohash.c
+++ b/arch/powerpc/mm/tlb_nohash.c
@@ -301,7 +301,7 @@ void tlb_flush(struct mmu_gather *tlb)
         flush_tlb_mm(tlb->mm);
 
         /* Push out batch of freed page tables */
-        pte_free_finish();
+        pte_free_finish(tlb);
 }
 
 /*