[PATCH 2/6] mm: balance dirty pages

Peter Zijlstra
2006-06-19T17:53:04Z

From: Peter Zijlstra <a.p.zijlstra@chello.nl>

Now that we can detect writers of shared mappings, throttle them.
Avoids OOM by surprise.

Changes -v2:

- small helper function (Andrew Morton)

Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>

include/linux/writeback.h | 1 +
mm/memory.c | 5 +++--
mm/page-writeback.c | 10 ++++++++++
3 files changed, 14 insertions(+), 2 deletions(-)

Index: 2.6-mm/mm/memory.c
===================================================================
--- 2.6-mm.orig/mm/memory.c 2006-06-19 16:21:15.000000000 +0200
+++ 2.6-mm/mm/memory.c 2006-06-19 16:21:16.000000000 +0200
@@ -49,6 +49,7 @@
#include <linux/module.h>
#include <linux/delayacct.h>
#include <linux/init.h>
+#include <linux/writeback.h>

#include <asm/pgalloc.h>
#include <asm/uaccess.h>
@@ -1572,7 +1573,7 @@ gotten:
unlock:
pte_unmap_unlock(page_table, ptl);
if (dirty_page) {
- set_page_dirty(dirty_page);
+ set_page_dirty_balance(dirty_page);
put_page(dirty_page);
}
return ret;
@@ -2219,7 +2220,7 @@ retry:
unlock:
pte_unmap_unlock(page_table, ptl);
if (dirty_page) {
- set_page_dirty(dirty_page);
+ set_page_dirty_balance(dirty_page);
put_page(dirty_page);
}
return ret;
Index: 2.6-mm/include/linux/writeback.h
===================================================================
--- 2.6-mm.orig/include/linux/writeback.h 2006-06-19 16:21:13.000000000 +0200
+++ 2.6-mm/include/linux/writeback.h 2006-06-19 16:21:16.000000000 +0200
@@ -121,6 +121,7 @@ int sync_page_range(struct inode *inode,
loff_t pos, loff_t count);
int sync_page_range_nolock(struct inode *inode, struct address_space *mapping,
loff_t pos, loff_t count);
+void set_page_dirty_balance(struct page *page);

/* pdflush.c */
extern int nr_pdflush_threads; /* Global so it can be exported to sysctl
Index: 2.6-mm/mm/page-writeback.c
===================================================================
--- 2.6-mm.orig/mm/page-writeback.c 2006-06-19 16:21:15.000000000 +0200
+++ 2.6-mm/mm/page-writeback.c 2006-06-19 16:21:16.000000000 +0200
@@ -237,6 +237,16 @@ static void balance_dirty_pages(struct a
pdflush_operation(background_writeout, 0);
}

+void set_page_dirty_balance(struct page *page)
+{
+ if (set_page_dirty(page)) {
+ struct address_space *mapping = page_mapping(page);
+
+ if (mapping)
+ balance_dirty_pages_ratelimited(mapping);
+ }
+}
+
/**
* balance_dirty_pages_ratelimited_nr - balance dirty memory state
* @mapping: address_space which was dirtied