Previously if a get_page is called we must invalidate cache of the page in
cleancache backend, because at next put_page we don't know if the page's
content is changed. If we know whether the page content is changed, we don't
need always invalidate cache in get_page of cleancache backend, which could
save a lot of IO if we do put_page/get_page later. The detection can be done at
page dirty, where the page content is changed. If we dirty a page, we
invalidate the page's cache in cleancache backend, get_page doesn't need do
invalidation any more. Of course, it's ok if get_page insists doing
invalidation.
Signed-off-by: Shaohua Li <shli@xxxxxxxxxx>
---
fs/buffer.c | 2 ++
mm/page-writeback.c | 3 +++
2 files changed, 5 insertions(+)
Index: linux/fs/buffer.c
===================================================================
--- linux.orig/fs/buffer.c 2013-09-26 21:25:03.671450043 +0800
+++ linux/fs/buffer.c 2013-09-26 21:25:03.663449708 +0800
@@ -40,6 +40,7 @@
#include <linux/cpu.h>
#include <linux/bitops.h>
#include <linux/mpage.h>
+#include <linux/cleancache.h>
#include <linux/bit_spinlock.h>
#include <trace/events/block.h>
@@ -661,6 +662,7 @@ static void __set_page_dirty(struct page
radix_tree_tag_set(&mapping->page_tree,
page_index(page), PAGECACHE_TAG_DIRTY);
}
+ cleancache_invalidate_page(mapping, page);
spin_unlock_irq(&mapping->tree_lock);
__mark_inode_dirty(mapping->host, I_DIRTY_PAGES);
}
Index: linux/mm/page-writeback.c
===================================================================
--- linux.orig/mm/page-writeback.c 2013-09-26 21:25:03.671450043 +0800
+++ linux/mm/page-writeback.c 2013-09-26 21:25:03.667449885 +0800
@@ -37,6 +37,7 @@
#include <linux/timer.h>
#include <linux/sched/rt.h>
#include <linux/mm_inline.h>
+#include <linux/cleancache.h>
#include <trace/events/writeback.h>
#include "internal.h"
@@ -2191,6 +2192,8 @@ int __set_page_dirty_nobuffers(struct pa
radix_tree_tag_set(&mapping->page_tree,
page_index(page), PAGECACHE_TAG_DIRTY);
}
+ if (mapping->host)
+ cleancache_invalidate_page(mapping, page);
spin_unlock_irq(&mapping->tree_lock);
if (mapping->host) {
/* !PageAnon && !swapper_space */
--
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