[RFC][PATCH 3/6] mm: count writeback pages per BDI

Peter Zijlstra
2007-03-19T15:57:40Z

[-- Attachment #1: bdi_stat_writeback.patch --]
[-- Type: text/plain, Size: 1854 bytes --]

Count per BDI writeback pages.

Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
---
include/linux/backing-dev.h | 1 +
mm/page-writeback.c | 8 ++++++--
2 files changed, 7 insertions(+), 2 deletions(-)

Index: linux-2.6/mm/page-writeback.c
===================================================================
--- linux-2.6.orig/mm/page-writeback.c
+++ linux-2.6/mm/page-writeback.c
@@ -912,10 +912,12 @@ int test_clear_page_writeback(struct pag

write_lock_irqsave(&mapping->tree_lock, flags);
ret = TestClearPageWriteback(page);
- if (ret)
+ if (ret) {
radix_tree_tag_clear(&mapping->page_tree,
page_index(page),
PAGECACHE_TAG_WRITEBACK);
+ __dec_bdi_stat(mapping->backing_dev_info, BDI_WRITEBACK);
+ }
write_unlock_irqrestore(&mapping->tree_lock, flags);
} else {
ret = TestClearPageWriteback(page);
@@ -933,10 +935,12 @@ int test_set_page_writeback(struct page

write_lock_irqsave(&mapping->tree_lock, flags);
ret = TestSetPageWriteback(page);
- if (!ret)
+ if (!ret) {
radix_tree_tag_set(&mapping->page_tree,
page_index(page),
PAGECACHE_TAG_WRITEBACK);
+ __inc_bdi_stat(mapping->backing_dev_info, BDI_WRITEBACK);
+ }
if (!PageDirty(page))
radix_tree_tag_clear(&mapping->page_tree,
page_index(page),
Index: linux-2.6/include/linux/backing-dev.h
===================================================================
--- linux-2.6.orig/include/linux/backing-dev.h
+++ linux-2.6/include/linux/backing-dev.h
@@ -24,6 +24,7 @@ enum bdi_state {

enum bdi_stat_item {
BDI_DIRTY,
+ BDI_WRITEBACK,
NR_BDI_STAT_ITEMS
};