[PATCH] swap: show span of swap extents

The "Adding %dk swap" message shows the number of swap extents, as a guide to
how fragmented the swapfile may be.  But a useful further guide is what total
extent they span across (sometimes scarily large).

And there's no need to keep nr_extents in swap_info: it's unused after the
initial message, so save a little space by keeping it on stack.

Signed-off-by: Hugh Dickins <hugh@veritas.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

include/linux/swap.h

@@ -123,7 +123,6 @@ struct swap_info_struct {
 	struct file *swap_file;
 	struct block_device *bdev;
 	struct list_head extent_list;
-	int nr_extents;
 	struct swap_extent *curr_swap_extent;
 	unsigned old_block_size;
 	unsigned short * swap_map;