[PATCH] atomic_long_t & include/asm-generic/atomic.h V2

Several counters already have the need to use 64 atomic variables on 64 bit
platforms (see mm_counter_t in sched.h).  We have to do ugly ifdefs to fall
back to 32 bit atomic on 32 bit platforms.

The VM statistics patch that I am working on will also make more extensive
use of atomic64.

This patch introduces a new type atomic_long_t by providing definitions in
asm-generic/atomic.h that works similar to the c "long" type.  Its 32 bits
on 32 bit platforms and 64 bits on 64 bit platforms.

Also cleans up the determination of the mm_counter_t in sched.h.

Signed-off-by: Christoph Lameter <clameter@sgi.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

1 files changed, 6 insertions, 19 deletions

diff --git a/include/linux/sched.h b/include/linux/sched.h
index b0ad6f30679e..7da33619d5d0 100644
--- a/include/linux/sched.h
+++ b/include/linux/sched.h
@@ -254,25 +254,12 @@ extern void arch_unmap_area_topdown(struct mm_struct *, unsigned long);
  * The mm counters are not protected by its page_table_lock,
  * so must be incremented atomically.
  */
-#ifdef ATOMIC64_INIT
-#define set_mm_counter(mm, member, value) atomic64_set(&(mm)->_##member, value)
-#define get_mm_counter(mm, member) ((unsigned long)atomic64_read(&(mm)->_##member))
-#define add_mm_counter(mm, member, value) atomic64_add(value, &(mm)->_##member)
-#define inc_mm_counter(mm, member) atomic64_inc(&(mm)->_##member)
-#define dec_mm_counter(mm, member) atomic64_dec(&(mm)->_##member)
-typedef atomic64_t mm_counter_t;
-#else /* !ATOMIC64_INIT */
-/*
- * The counters wrap back to 0 at 2^32 * PAGE_SIZE,
- * that is, at 16TB if using 4kB page size.
- */
-#define set_mm_counter(mm, member, value) atomic_set(&(mm)->_##member, value)
-#define get_mm_counter(mm, member) ((unsigned long)atomic_read(&(mm)->_##member))
-#define add_mm_counter(mm, member, value) atomic_add(value, &(mm)->_##member)
-#define inc_mm_counter(mm, member) atomic_inc(&(mm)->_##member)
-#define dec_mm_counter(mm, member) atomic_dec(&(mm)->_##member)
-typedef atomic_t mm_counter_t;
-#endif /* !ATOMIC64_INIT */
+#define set_mm_counter(mm, member, value) atomic_long_set(&(mm)->_##member, value)
+#define get_mm_counter(mm, member) ((unsigned long)atomic_long_read(&(mm)->_##member))
+#define add_mm_counter(mm, member, value) atomic_long_add(value, &(mm)->_##member)
+#define inc_mm_counter(mm, member) atomic_long_inc(&(mm)->_##member)
+#define dec_mm_counter(mm, member) atomic_long_dec(&(mm)->_##member)
+typedef atomic_long_t mm_counter_t;
 
 #else  /* NR_CPUS < CONFIG_SPLIT_PTLOCK_CPUS */
 /*