[linux-mm-cc] [PATCH 01/12] clean up initialization

[IKEDA Munehiro]

This is code clean up patch for initialization part.
This tries to make fs_backed and anon ccache procedures
as symmetric as possible for readabiliby and maintenanceability.


Signed-off-by: IKEDA, Munehiro <m-ikeda at ds.jp.nec.com>
---
 include/linux/ccache.h |    3 +--
 mm/ccache.c            |   44 +++++++++++++++++++++++++++++++++-----------
 mm/swapfile.c          |    6 ++----
 3 files changed, 36 insertions(+), 17 deletions(-)

diff --git a/include/linux/ccache.h b/include/linux/ccache.h
index 8aee787..31e3b49 100644
--- a/include/linux/ccache.h
+++ b/include/linux/ccache.h
@@ -138,9 +138,8 @@ static inline void wait_on_chunk_head(unsigned long *flags)
 #endif
 }
 
-extern int init_ccache(void);
 extern int is_page_in_virt_swap(struct page *page);
-extern int set_anon_cc_size(unsigned long size);
+extern int init_virt_swap(unsigned long size);
 extern int should_add_to_ccache(struct page *page);
 extern int cc_writepage(struct page *page);
 extern struct page* handle_ccache_fault(struct chunk_head *ch,
diff --git a/mm/ccache.c b/mm/ccache.c
index 2d20b2c..12ebbd5 100644
--- a/mm/ccache.c
+++ b/mm/ccache.c
@@ -408,7 +408,7 @@ out:
 	return len;
 }
 
-int init_ccache(void)
+static int init_ccache(void)
 {
 	if (anon_cc_started || fs_backed_cc_started) return 0;
 
@@ -442,6 +442,24 @@ int init_ccache(void)
 	return 0;
 }
 
+static int init_anon_ccache(unsigned long num)
+{
+	if (anon_cc_started)
+		return 0;
+
+	init_ccache();
+	return init_virt_swap(num);
+}
+
+static int init_fs_backed_ccache(unsigned long num)
+{
+	if (fs_backed_cc_started)
+		return 0;
+
+	init_ccache();
+	return 0;
+}
+
 int sysctl_max_anon_cc_size(ctl_table *table, int write,
 	struct file *file, void __user *buffer, size_t *length, loff_t *ppos)
 {
@@ -461,9 +479,13 @@ int sysctl_max_anon_cc_size(ctl_table *table, int write,
 	proc_doulongvec_minmax(table, write, file, buffer, length, ppos);
 	if (!write)
 		goto out;
-	ret = set_anon_cc_size(max_anon_cc_size);
-	if (ret)
+
+	ret = init_anon_ccache(max_anon_cc_size);
+	if (ret) {
+		CC_INFO("Error Initializing anon ccache");
 		goto out;
+	}
+
 	CC_INFO("Max anon ccache size: %lu pages", max_anon_cc_size);
 	anon_cc_started=1;
 out:
@@ -490,15 +512,14 @@ int sysctl_max_fs_backed_cc_size(ctl_table *table, int write,
 	if (!write)
 		goto out;
 
-	ret = init_ccache();
+	ret = init_fs_backed_ccache(max_fs_backed_cc_size);
 	if (ret) {
-		CC_INFO("Error Initializing ccache");
+		CC_INFO("Error Initializing fs_backed ccache");
 		goto out;
 	}
 	
 	CC_INFO("Max filesystem backed ccache size: %lu pages\n",
 			max_fs_backed_cc_size);
-	atomic_set(&fs_backed_cc_size, 0);
 	fs_backed_cc_started = 1;
 out:
 	return ret;
@@ -672,7 +693,9 @@ int cc_writepage(struct page *page)
 	if (page_count(page) != 2) {
 		CC_DEBUG2("(start) Page count not 2 (%d)"
 			"flags=0x%08lx", page_count(page), page->flags);
-		if (!PageSwapCache(page))
+		if (PageSwapCache(page))
+			atomic_dec(&anon_cc_size);
+		else
 			atomic_dec(&fs_backed_cc_size);
 		return -EBUSY;
 	}
@@ -764,9 +787,6 @@ int cc_writepage(struct page *page)
 	radix_tree_replace_slot((void **)slot, (void *)ch);
 	CC_DEBUG2("after set slot");
 
-	if (PageSwapCache(page))
-		atomic_inc(&anon_cc_size);
-	
 	/* or else it will be bad_page() when freed */
 	page->mapping = NULL;
 	ClearPageDirty(page);
@@ -793,7 +813,9 @@ out_locked:
 	write_unlock_irq(&mapping->tree_lock);
 	CC_DEBUG2("in out_locked: after WUQ");
 out:
-	if (!PageSwapCache(page))
+	if (PageSwapCache(page))
+		atomic_dec(&anon_cc_size);
+	else
 		atomic_dec(&fs_backed_cc_size);
 	if (ch)
 		free_chunk_head(ch);
diff --git a/mm/swapfile.c b/mm/swapfile.c
index f2df6b2..c94a56f 100644
--- a/mm/swapfile.c
+++ b/mm/swapfile.c
@@ -1451,7 +1451,7 @@ int is_page_in_virt_swap(struct page *page)
 	return 0;
 }
 
-int set_anon_cc_size(unsigned long num_pages)
+int init_virt_swap(unsigned long num_pages)
 {
 	int i, error, prev;
 	unsigned int type;
@@ -1459,8 +1459,6 @@ int set_anon_cc_size(unsigned long num_pages)
 	struct swap_info_struct *p;
 	struct swap_extent *new_se;
 
-	init_ccache();
-
 	error=0;
 	spin_lock(&swap_lock);
 	p = swap_info;
@@ -1542,7 +1540,7 @@ out:
 	return error;
 }
 
-EXPORT_SYMBOL(set_anon_cc_size);
+EXPORT_SYMBOL(init_virt_swap);
 
 /*
  * Written 01/25/92 by Simmule Turner, heavily changed by Linus.
-- 
1.4.4.4