[RFC zsmalloc 4/4] zsmalloc: move struct zs_meta from mapping to somewhere

From: Minchan Kim
Date: Mon Aug 10 2015 - 03:13:12 EST


For supporting runtime compaction with VM, we need to have proper
address_space on every page so zsmalloc shouldn't use page->mapping.

This patch moves zsmalloc metadata from mapping to freelist.

Signed-off-by: Minchan Kim <minchan@xxxxxxxxxx>
---
mm/zsmalloc.c | 18 +++++++++---------
1 file changed, 9 insertions(+), 9 deletions(-)

diff --git a/mm/zsmalloc.c b/mm/zsmalloc.c
index 55dc066..1b18144 100644
--- a/mm/zsmalloc.c
+++ b/mm/zsmalloc.c
@@ -30,7 +30,7 @@
* Look at size_class->huge.
* page->lru: links together first pages of various zspages.
* Basically forming list of zspages in a fullness group.
- * page->mapping: override by struct zs_meta
+ * page->freelist: override by struct zs_meta
*
* Usage of struct page flags:
* PG_private: identifies the first component page
@@ -261,7 +261,7 @@ struct zs_pool {

/*
* In this implementation, a free_idx, zspage's class index, fullness group,
- * inuse object count are encoded in its (first)page->mapping
+ * inuse object count are encoded in its (first)page->freelist
* sizeof(struct zs_meta) should be equal to sizeof(unsigned long).
*/
struct zs_meta {
@@ -414,7 +414,7 @@ static int get_inuse_obj(struct page *page)

BUG_ON(!is_first_page(page));

- m = (struct zs_meta *)&page->mapping;
+ m = (struct zs_meta *)&page->freelist;

return m->inuse;
}
@@ -425,19 +425,19 @@ static void set_inuse_obj(struct page *page, int inc)

BUG_ON(!is_first_page(page));

- m = (struct zs_meta *)&page->mapping;
+ m = (struct zs_meta *)&page->freelist;
m->inuse += inc;
}

static void set_free_obj_idx(struct page *first_page, int idx)
{
- struct zs_meta *m = (struct zs_meta *)&first_page->mapping;
+ struct zs_meta *m = (struct zs_meta *)&first_page->freelist;
m->free_idx = idx;
}

static unsigned long get_free_obj_idx(struct page *first_page)
{
- struct zs_meta *m = (struct zs_meta *)&first_page->mapping;
+ struct zs_meta *m = (struct zs_meta *)&first_page->freelist;
return m->free_idx;
}

@@ -447,7 +447,7 @@ static void get_zspage_mapping(struct page *page, unsigned int *class_idx,
struct zs_meta *m;
BUG_ON(!is_first_page(page));

- m = (struct zs_meta *)&page->mapping;
+ m = (struct zs_meta *)&page->freelist;
*fullness = m->fullness;
*class_idx = m->class_idx;
}
@@ -462,7 +462,7 @@ static void set_zspage_mapping(struct page *page, unsigned int class_idx,
BUG_ON(class_idx >= (1 << CLASS_IDX_BITS));
BUG_ON(fullness >= (1 << FULLNESS_BITS));

- m = (struct zs_meta *)&page->mapping;
+ m = (struct zs_meta *)&page->freelist;
m->fullness = fullness;
m->class_idx = class_idx;
}
@@ -908,7 +908,7 @@ static void reset_page(struct page *page)
clear_bit(PG_private, &page->flags);
clear_bit(PG_private_2, &page->flags);
set_page_private(page, 0);
- page->mapping = NULL;
+ page->freelist = NULL;
page_mapcount_reset(page);
}

--
1.9.1

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