[PATCH V4 1/4] mm: frontswap: swap data structure changes
Core swap data structures are needed by frontswap.c but we don't
need to expose them to the dozens of files that include swap.h
so create a new swapfile.h just to extern-ify these.
Add frontswap-related elements to swap_info_struct. Don't tie
these to CONFIG_FRONTSWAP to avoid unnecessary clutter around
various frontswap hooks.
Signed-off-by: Dan Magenheimer <dan.magenheimer@xxxxxxxxxx>
Diffstat:
swap.h | 2 ++
swapfile.h | 13 +++++++++++++
2 files changed, 15 insertions(+)
--- linux-2.6.39/include/linux/swapfile.h 1969-12-31 17:00:00.000000000 -0700
+++ linux-2.6.39-frontswap/include/linux/swapfile.h 2011-05-26 15:37:25.200224614 -0600
@@ -0,0 +1,13 @@
+#ifndef _LINUX_SWAPFILE_H
+#define _LINUX_SWAPFILE_H
+
+/*
+ * these were static in swapfile.c but frontswap.c needs them and we don't
+ * want to expose them to the dozens of source files that include swap.h
+ */
+extern spinlock_t swap_lock;
+extern struct swap_list_t swap_list;
+extern struct swap_info_struct *swap_info[];
+extern int try_to_unuse(unsigned int, bool, unsigned long);
+
+#endif /* _LINUX_SWAPFILE_H */
--- linux-2.6.39/include/linux/swap.h 2011-05-18 22:06:34.000000000 -0600
+++ linux-2.6.39-frontswap/include/linux/swap.h 2011-05-26 15:37:25.222179479 -0600
@@ -194,6 +194,8 @@ struct swap_info_struct {
struct block_device *bdev; /* swap device or bdev of swap file */
struct file *swap_file; /* seldom referenced */
unsigned int old_block_size; /* seldom referenced */
+ unsigned long *frontswap_map; /* frontswap in-use, one bit per page */
+ unsigned int frontswap_pages; /* frontswap pages in-use counter */
};
struct swap_list_t {
--
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