From 51726b1222863852c46ca21ed0115b85d1edfd89 Mon Sep 17 00:00:00 2001 From: Hugh Dickins Date: Tue, 6 Jan 2009 14:39:25 -0800 Subject: [PATCH] mm: replace some BUG_ONs by VM_BUG_ONs The swap code is over-provisioned with BUG_ONs on assorted page flags, mostly dating back to 2.3. They're good documentation, and guard against developer error, but a waste of space on most systems: change them to VM_BUG_ONs, conditional on CONFIG_DEBUG_VM. Just delete the PagePrivate ones: they're later, from 2.5.69, but even less interesting now. Signed-off-by: Hugh Dickins Reviewed-by: Christoph Lameter Cc: Nick Piggin Cc: Mel Gorman Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- mm/page_io.c | 4 ++-- mm/swap_state.c | 19 +++++++++---------- mm/swapfile.c | 8 +++----- 3 files changed, 14 insertions(+), 17 deletions(-) diff --git a/mm/page_io.c b/mm/page_io.c index 065c4480eaf..d277a80efa7 100644 --- a/mm/page_io.c +++ b/mm/page_io.c @@ -125,8 +125,8 @@ int swap_readpage(struct file *file, struct page *page) struct bio *bio; int ret = 0; - BUG_ON(!PageLocked(page)); - BUG_ON(PageUptodate(page)); + VM_BUG_ON(!PageLocked(page)); + VM_BUG_ON(PageUptodate(page)); bio = get_swap_bio(GFP_KERNEL, page_private(page), page, end_swap_bio_read); if (bio == NULL) { diff --git a/mm/swap_state.c b/mm/swap_state.c index 3353c9029ce..e793fdea275 100644 --- a/mm/swap_state.c +++ b/mm/swap_state.c @@ -72,10 +72,10 @@ int add_to_swap_cache(struct page *page, swp_entry_t entry, gfp_t gfp_mask) { int error; - BUG_ON(!PageLocked(page)); - BUG_ON(PageSwapCache(page)); - BUG_ON(PagePrivate(page)); - BUG_ON(!PageSwapBacked(page)); + VM_BUG_ON(!PageLocked(page)); + VM_BUG_ON(PageSwapCache(page)); + VM_BUG_ON(!PageSwapBacked(page)); + error = radix_tree_preload(gfp_mask); if (!error) { page_cache_get(page); @@ -108,10 +108,9 @@ int add_to_swap_cache(struct page *page, swp_entry_t entry, gfp_t gfp_mask) */ void __delete_from_swap_cache(struct page *page) { - BUG_ON(!PageLocked(page)); - BUG_ON(!PageSwapCache(page)); - BUG_ON(PageWriteback(page)); - BUG_ON(PagePrivate(page)); + VM_BUG_ON(!PageLocked(page)); + VM_BUG_ON(!PageSwapCache(page)); + VM_BUG_ON(PageWriteback(page)); radix_tree_delete(&swapper_space.page_tree, page_private(page)); set_page_private(page, 0); @@ -134,8 +133,8 @@ int add_to_swap(struct page * page, gfp_t gfp_mask) swp_entry_t entry; int err; - BUG_ON(!PageLocked(page)); - BUG_ON(!PageUptodate(page)); + VM_BUG_ON(!PageLocked(page)); + VM_BUG_ON(!PageUptodate(page)); for (;;) { entry = get_swap_page(); diff --git a/mm/swapfile.c b/mm/swapfile.c index 54a9f87e516..214e90b9494 100644 --- a/mm/swapfile.c +++ b/mm/swapfile.c @@ -333,7 +333,7 @@ int can_share_swap_page(struct page *page) { int count; - BUG_ON(!PageLocked(page)); + VM_BUG_ON(!PageLocked(page)); count = page_mapcount(page); if (count <= 1 && PageSwapCache(page)) count += page_swapcount(page); @@ -350,8 +350,7 @@ static int remove_exclusive_swap_page_count(struct page *page, int count) struct swap_info_struct * p; swp_entry_t entry; - BUG_ON(PagePrivate(page)); - BUG_ON(!PageLocked(page)); + VM_BUG_ON(!PageLocked(page)); if (!PageSwapCache(page)) return 0; @@ -432,7 +431,6 @@ void free_swap_and_cache(swp_entry_t entry) if (page) { int one_user; - BUG_ON(PagePrivate(page)); one_user = (page_count(page) == 2); /* Only cache user (+us), or swap space full? Free it! */ /* Also recheck PageSwapCache after page is locked (above) */ @@ -1209,7 +1207,7 @@ int page_queue_congested(struct page *page) { struct backing_dev_info *bdi; - BUG_ON(!PageLocked(page)); /* It pins the swap_info_struct */ + VM_BUG_ON(!PageLocked(page)); /* It pins the swap_info_struct */ if (PageSwapCache(page)) { swp_entry_t entry = { .val = page_private(page) }; -- 2.41.1