When pageout a dirty page, try to piggy back more consecutive dirty
pages (up to 512KB) to improve IO efficiency.
Only ext3/reiserfs which don't have its own aops->writepages are
supported in this initial version.
CC: Dave Chinner <david@xxxxxxxxxxxxx>
Signed-off-by: Wu Fengguang <fengguang.wu@xxxxxxxxx>
---
mm/page-writeback.c | 12 ++++++++++++
mm/vmscan.c | 11 +++++++++++
2 files changed, 23 insertions(+)
--- linux.orig/mm/vmscan.c 2009-10-06 23:37:39.000000000 +0800
+++ linux/mm/vmscan.c 2009-10-06 23:39:30.000000000 +0800
@@ -344,6 +344,8 @@ typedef enum {
PAGE_CLEAN,
} pageout_t;
+#define LUMPY_PAGEOUT_PAGES (512 * 1024 / PAGE_CACHE_SIZE)
+
/*
* pageout is called by shrink_page_list() for each dirty page.
* Calls ->writepage().
@@ -409,6 +411,15 @@ static pageout_t pageout(struct page *pa
}
/*
+ * only write_cache_pages() supports for_reclaim for now
+ */
+ if (!mapping->a_ops->writepages) {
+ wbc.range_start = (page->index + 1) << PAGE_CACHE_SHIFT;
+ wbc.nr_to_write = LUMPY_PAGEOUT_PAGES - 1;
+ generic_writepages(mapping, &wbc);
+ }
+
+ /*
* Wait on writeback if requested to. This happens when
* direct reclaiming a large contiguous area and the
* first attempt to free a range of pages fails.
--- linux.orig/mm/page-writeback.c 2009-10-06 23:39:29.000000000 +0800
+++ linux/mm/page-writeback.c 2009-10-06 23:39:30.000000000 +0800
@@ -805,6 +805,11 @@ int write_cache_pages(struct address_spa
break;
}
+ if (wbc->for_reclaim && done_index != page->index) {
+ done = 1;
+ break;
+ }
+
if (nr_to_write != wbc->nr_to_write &&
done_index + WB_SEGMENT_DIST < page->index &&
--wbc->nr_segments <= 0) {
@@ -846,6 +851,13 @@ continue_unlock:
if (!clear_page_dirty_for_io(page))
goto continue_unlock;
+ /*
+ * active and unevictable pages will be checked at
+ * rotate time
+ */
+ if (wbc->for_reclaim)
+ SetPageReclaim(page);
+
ret = (*writepage)(page, wbc, data);
if (unlikely(ret)) {
if (ret == AOP_WRITEPAGE_ACTIVATE) {
--
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