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Commit bb63be0a authored by Hugh Dickins's avatar Hugh Dickins Committed by Linus Torvalds
Browse files

tmpfs: move swap_state stats update 



Both unionfs and memcgroups pose challenges to tmpfs and shmem.  To help fix,
it's best to move the swap swizzling functions from swap_state.c to shmem.c.
As a preliminary to that, move swap stats updating down into
__add_to_swap_cache, which will remain internal to swap_state.c.

Well, actually, just move down the incrementation of add_total: remove
noent_race and exist_race completely, they are relics of my 2.4.11 testing.
Alt-SysRq-m users will be thrilled if 2.6.25 is at last free of "race M+N"s.

Signed-off-by: default avatarHugh Dickins <hugh@veritas.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 818db359

mm/swap_state.c

+6 −16
Original line number Diff line number Diff line
@@ -52,16 +52,13 @@ static struct { 
	unsigned long del_total;

	unsigned long find_success;

	unsigned long find_total;

	unsigned long noent_race;

	unsigned long exist_race;

} swap_cache_info;



void show_swap_cache_info(void)

{

	printk("Swap cache: add %lu, delete %lu, find %lu/%lu, race %lu+%lu\n",

	printk("Swap cache: add %lu, delete %lu, find %lu/%lu\n",

		swap_cache_info.add_total, swap_cache_info.del_total,

		swap_cache_info.find_success, swap_cache_info.find_total,

		swap_cache_info.noent_race, swap_cache_info.exist_race);

		swap_cache_info.find_success, swap_cache_info.find_total);

	printk("Free swap  = %lukB\n", nr_swap_pages << (PAGE_SHIFT - 10));

	printk("Total swap = %lukB\n", total_swap_pages << (PAGE_SHIFT - 10));

}
@@ -89,6 +86,7 @@ static int __add_to_swap_cache(struct page *page, swp_entry_t entry, 
			set_page_private(page, entry.val);

			total_swapcache_pages++;

			__inc_zone_page_state(page, NR_FILE_PAGES);

			INC_CACHE_INFO(add_total);

		}

		write_unlock_irq(&swapper_space.tree_lock);

		radix_tree_preload_end();
@@ -102,10 +100,9 @@ static int add_to_swap_cache(struct page *page, swp_entry_t entry, 
	int error;



	BUG_ON(PageLocked(page));

	if (!swap_duplicate(entry)) {

		INC_CACHE_INFO(noent_race);

	if (!swap_duplicate(entry))

		return -ENOENT;

	}



	SetPageLocked(page);

	error = __add_to_swap_cache(page, entry, gfp_mask & GFP_KERNEL);

	/*
@@ -114,11 +111,8 @@ static int add_to_swap_cache(struct page *page, swp_entry_t entry, 
	if (error) {

		ClearPageLocked(page);

		swap_free(entry);

		if (error == -EEXIST)

			INC_CACHE_INFO(exist_race);

		return error;

	}

	INC_CACHE_INFO(add_total);

	return 0;

}
@@ -178,11 +172,9 @@ int add_to_swap(struct page * page, gfp_t gfp_mask) 
		case 0:				/* Success */

			SetPageUptodate(page);

			SetPageDirty(page);

			INC_CACHE_INFO(add_total);

			return 1;

		case -EEXIST:

			/* Raced with "speculative" read_swap_cache_async */

			INC_CACHE_INFO(exist_race);

			swap_free(entry);

			continue;

		default:
@@ -225,9 +217,7 @@ int move_to_swap_cache(struct page *page, swp_entry_t entry) 
		if (!swap_duplicate(entry))

			BUG();

		SetPageDirty(page);

		INC_CACHE_INFO(add_total);

	} else if (err == -EEXIST)

		INC_CACHE_INFO(exist_race);

	}

	return err;

}