From eb83ccb01d35cfe61a12dc895856ad7834972083 Mon Sep 17 00:00:00 2001 From: Dan Magenheimer Date: Mon, 29 Aug 2011 14:11:48 -0600 Subject: [PATCH] mm: frontswap: swap data structure changes This first patch of four in the frontswap series makes available core swap data structures (swap_lock, swap_list and swap_info) that are needed by frontswap.c but we don't need to expose them to the dozens of files that include swap.h so we create a new swapfile.h just to extern-ify these. Also add frontswap-related elements to swap_info_struct. Frontswap_map points to vzalloc'ed one-bit-per-swap-page metadata that indicates whether the swap page is in frontswap or in the device and frontswap_pages counts how many pages are in frontswap. [v8: rebase to 3.0-rc4] [v8: kamezawa.hiroyu@jp.fujitsu.com: frontswap_pages should be atomic_t] [v8: kamezawa.hiroyu@jp.fujitsu.com: comment to clarify informational counters] [v7: rebase to 3.0-rc3] [v7: JBeulich@novell.com: add new swap struct elements only if config'd] [v6: rebase to 3.0-rc1] [v5: no change from v4] [v4: rebase to 2.6.39] Signed-off-by: Dan Magenheimer Reviewed-by: Konrad Wilk Reviewed-by: Kamezawa Hiroyuki Acked-by: Jan Beulich Acked-by: Seth Jennings Cc: Jeremy Fitzhardinge Cc: Hugh Dickins Cc: Johannes Weiner Cc: Nitin Gupta Cc: Matthew Wilcox Cc: Chris Mason Cc: Rik Riel Cc: Andrew Morton --- include/linux/swap.h | 4 ++++ include/linux/swapfile.h | 13 +++++++++++++ 2 files changed, 17 insertions(+) create mode 100644 include/linux/swapfile.h diff --git a/include/linux/swap.h b/include/linux/swap.h index 14d62490922e..5d4edbf889d4 100644 --- a/include/linux/swap.h +++ b/include/linux/swap.h @@ -194,6 +194,10 @@ 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 */ +#ifdef CONFIG_FRONTSWAP + unsigned long *frontswap_map; /* frontswap in-use, one bit per page */ + atomic_t frontswap_pages; /* frontswap pages in-use counter */ +#endif }; struct swap_list_t { diff --git a/include/linux/swapfile.h b/include/linux/swapfile.h new file mode 100644 index 000000000000..e282624e8c10 --- /dev/null +++ b/include/linux/swapfile.h @@ -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 */ -- 2.39.5