Before we start allowing different page orders we better get checkpoints in
at various places in the VM. Checkpoints will help debugging whenever a
wrong order page shows up in a mapping. This will be helpful for converting
new filesystems to utilize larger pages.
Signed-off-by: Christoph Lameter <[EMAIL PROTECTED]>
---
fs/buffer.c | 1 +
mm/filemap.c | 18 +++++++++++++++---
2 files changed, 16 insertions(+), 3 deletions(-)
Index: linux-2.6.22-rc4-mm2/mm/filemap.c
===================================================================
--- linux-2.6.22-rc4-mm2.orig/mm/filemap.c 2007-06-18 23:09:36.000000000
-0700
+++ linux-2.6.22-rc4-mm2/mm/filemap.c 2007-06-19 19:20:29.000000000 -0700
@@ -128,6 +128,7 @@ void remove_from_page_cache(struct page
struct address_space *mapping = page->mapping;
BUG_ON(!PageLocked(page));
+ VM_BUG_ON(mapping_order(mapping) != compound_order(page));
write_lock_irq(&mapping->tree_lock);
__remove_from_page_cache(page);
@@ -269,6 +270,7 @@ int wait_on_page_writeback_range(struct
if (page->index > end)
continue;
+ VM_BUG_ON(mapping_order(mapping) !=
compound_order(page));
wait_on_page_writeback(page);
if (PageError(page))
ret = -EIO;
@@ -441,6 +443,7 @@ int add_to_page_cache(struct page *page,
{
int error = radix_tree_preload(gfp_mask & ~__GFP_HIGHMEM);
+ VM_BUG_ON(mapping_order(mapping) != compound_order(page));
if (error == 0) {
write_lock_irq(&mapping->tree_lock);
error = radix_tree_insert(&mapping->page_tree, offset, page);
@@ -600,8 +603,10 @@ struct page * find_get_page(struct addre
read_lock_irq(&mapping->tree_lock);
page = radix_tree_lookup(&mapping->page_tree, offset);
- if (page)
+ if (page) {
+ VM_BUG_ON(mapping_order(mapping) != compound_order(page));
page_cache_get(page);
+ }
read_unlock_irq(&mapping->tree_lock);
return page;
}
@@ -626,6 +631,7 @@ struct page *find_lock_page(struct addre
repeat:
page = radix_tree_lookup(&mapping->page_tree, offset);
if (page) {
+ VM_BUG_ON(mapping_order(mapping) != compound_order(page));
page_cache_get(page);
if (TestSetPageLocked(page)) {
read_unlock_irq(&mapping->tree_lock);
@@ -711,8 +717,10 @@ unsigned find_get_pages(struct address_s
read_lock_irq(&mapping->tree_lock);
ret = radix_tree_gang_lookup(&mapping->page_tree,
(void **)pages, start, nr_pages);
- for (i = 0; i < ret; i++)
+ for (i = 0; i < ret; i++) {
+ VM_BUG_ON(mapping_order(mapping) != compound_order(pages[i]));
page_cache_get(pages[i]);
+ }
read_unlock_irq(&mapping->tree_lock);
return ret;
}
@@ -743,6 +751,7 @@ unsigned find_get_pages_contig(struct ad
if (pages[i]->mapping == NULL || pages[i]->index != index)
break;
+ VM_BUG_ON(mapping_order(mapping) != compound_order(pages[i]));
page_cache_get(pages[i]);
index++;
}
@@ -771,8 +780,10 @@ unsigned find_get_pages_tag(struct addre
read_lock_irq(&mapping->tree_lock);
ret = radix_tree_gang_lookup_tag(&mapping->page_tree,
(void **)pages, *index, nr_pages, tag);
- for (i = 0; i < ret; i++)
+ for (i = 0; i < ret; i++) {
+ VM_BUG_ON(mapping_order(mapping) != compound_order(pages[i]));
page_cache_get(pages[i]);
+ }
if (ret)
*index = pages[ret - 1]->index + 1;
read_unlock_irq(&mapping->tree_lock);
@@ -2610,6 +2621,7 @@ int try_to_release_page(struct page *pag
struct address_space * const mapping = page->mapping;
BUG_ON(!PageLocked(page));
+ VM_BUG_ON(mapping_order(mapping) != compound_order(page));
if (PageWriteback(page))
return 0;
Index: linux-2.6.22-rc4-mm2/fs/buffer.c
===================================================================
--- linux-2.6.22-rc4-mm2.orig/fs/buffer.c 2007-06-19 19:20:29.000000000
-0700
+++ linux-2.6.22-rc4-mm2/fs/buffer.c 2007-06-19 19:24:12.000000000 -0700
@@ -901,6 +901,7 @@ struct buffer_head *alloc_page_buffers(s
long offset;
unsigned page_size = page_cache_size(page->mapping);
+ BUG_ON(size > page_size);
try_again:
head = NULL;
offset = page_size;
--
-
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