linux-kernel - [PATCH 17/20] mm/zsmalloc: convert get/set_first_obj

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Date: Fri, 28 Jun 2024 11:11:32 +0800
From: alexs@...nel.org
To: Vitaly Wool <vitaly.wool@...sulko.com>,
	Miaohe Lin <linmiaohe@...wei.com>,
	Andrew Morton <akpm@...ux-foundation.org>,
	linux-kernel@...r.kernel.org,
	linux-mm@...ck.org,
	minchan@...nel.org,
	willy@...radead.org,
	senozhatsky@...omium.org,
	david@...hat.com,
	42.hyeyoo@...il.com
Cc: Alex Shi <alexs@...nel.org>
Subject: [PATCH 17/20] mm/zsmalloc: convert get/set_first_obj_offset() to take zpdesc

From: Hyeonggon Yoo <42.hyeyoo@...il.com>

Now that all users of get/set_first_obj_offset() are converted
to use zpdesc, convert them to take zpdesc.

Signed-off-by: Hyeonggon Yoo <42.hyeyoo@...il.com>
Signed-off-by: Alex Shi <alexs@...nel.org>
---
 mm/zpdesc.h   |  3 +++
 mm/zsmalloc.c | 32 ++++++++++++++++----------------
 2 files changed, 19 insertions(+), 16 deletions(-)

diff --git a/mm/zpdesc.h b/mm/zpdesc.h
index 186ff9711ffb..17941774c46e 100644
--- a/mm/zpdesc.h
+++ b/mm/zpdesc.h
@@ -14,6 +14,7 @@
  * @next:		Next zpdesc in a zspage in zsmalloc zpool
  * @handle:		For huge zspage in zsmalloc zpool
  * @zspage:		Pointer to zspage in zsmalloc
+ * @first_obj_offset:	First object offset in zsmalloc zpool
  *
  * This struct overlays struct page for now. Do not modify without a good
  * understanding of the issues.
@@ -29,6 +30,7 @@ struct zpdesc {
 		unsigned long handle;
 	};
 	struct zspage *zspage;
+	unsigned int first_obj_offset;
 };
 #define ZPDESC_MATCH(pg, zp) \
 	static_assert(offsetof(struct page, pg) == offsetof(struct zpdesc, zp))
@@ -38,6 +40,7 @@ ZPDESC_MATCH(lru, lru);
 ZPDESC_MATCH(index, next);
 ZPDESC_MATCH(index, handle);
 ZPDESC_MATCH(private, zspage);
+ZPDESC_MATCH(page_type, first_obj_offset);
 #undef ZPDESC_MATCH
 static_assert(sizeof(struct zpdesc) <= sizeof(struct page));
 
diff --git a/mm/zsmalloc.c b/mm/zsmalloc.c
index 951292dbcae4..3ce49f0372cc 100644
--- a/mm/zsmalloc.c
+++ b/mm/zsmalloc.c
@@ -496,26 +496,26 @@ static struct zpdesc *get_first_zpdesc(struct zspage *zspage)
 
 #define FIRST_OBJ_PAGE_TYPE_MASK	0xffff
 
-static inline void reset_first_obj_offset(struct page *page)
+static inline void reset_first_obj_offset(struct zpdesc *zpdesc)
 {
-	VM_WARN_ON_ONCE(!PageZsmalloc(page));
-	page->page_type |= FIRST_OBJ_PAGE_TYPE_MASK;
+	VM_WARN_ON_ONCE(!PageZsmalloc(zpdesc_page(zpdesc)));
+	zpdesc->first_obj_offset |= FIRST_OBJ_PAGE_TYPE_MASK;
 }
 
-static inline unsigned int get_first_obj_offset(struct page *page)
+static inline unsigned int get_first_obj_offset(struct zpdesc *zpdesc)
 {
-	VM_WARN_ON_ONCE(!PageZsmalloc(page));
-	return page->page_type & FIRST_OBJ_PAGE_TYPE_MASK;
+	VM_WARN_ON_ONCE(!PageZsmalloc(zpdesc_page(zpdesc)));
+	return zpdesc->first_obj_offset & FIRST_OBJ_PAGE_TYPE_MASK;
 }
 
-static inline void set_first_obj_offset(struct page *page, unsigned int offset)
+static inline void set_first_obj_offset(struct zpdesc *zpdesc, unsigned int offset)
 {
 	/* With 16 bit available, we can support offsets into 64 KiB pages. */
 	BUILD_BUG_ON(PAGE_SIZE > SZ_64K);
-	VM_WARN_ON_ONCE(!PageZsmalloc(page));
+	VM_WARN_ON_ONCE(!PageZsmalloc(zpdesc_page(zpdesc)));
 	VM_WARN_ON_ONCE(offset & ~FIRST_OBJ_PAGE_TYPE_MASK);
-	page->page_type &= ~FIRST_OBJ_PAGE_TYPE_MASK;
-	page->page_type |= offset & FIRST_OBJ_PAGE_TYPE_MASK;
+	zpdesc->first_obj_offset &= ~FIRST_OBJ_PAGE_TYPE_MASK;
+	zpdesc->first_obj_offset |= offset & FIRST_OBJ_PAGE_TYPE_MASK;
 }
 
 static inline unsigned int get_freeobj(struct zspage *zspage)
@@ -852,7 +852,7 @@ static void reset_zpdesc(struct zpdesc *zpdesc)
 	ClearPagePrivate(page);
 	zpdesc->zspage = NULL;
 	zpdesc->next = NULL;
-	reset_first_obj_offset(page);
+	reset_first_obj_offset(zpdesc);
 	__ClearPageZsmalloc(page);
 }
 
@@ -936,7 +936,7 @@ static void init_zspage(struct size_class *class, struct zspage *zspage)
 		struct link_free *link;
 		void *vaddr;
 
-		set_first_obj_offset(zpdesc_page(zpdesc), off);
+		set_first_obj_offset(zpdesc, off);
 
 		vaddr = zpdesc_kmap_atomic(zpdesc);
 		link = (struct link_free *)vaddr + off / sizeof(*link);
@@ -1593,7 +1593,7 @@ static unsigned long find_alloced_obj(struct size_class *class,
 	unsigned long handle = 0;
 	void *addr = zpdesc_kmap_atomic(zpdesc);
 
-	offset = get_first_obj_offset(zpdesc_page(zpdesc));
+	offset = get_first_obj_offset(zpdesc);
 	offset += class->size * index;
 
 	while (offset < PAGE_SIZE) {
@@ -1789,8 +1789,8 @@ static void replace_sub_page(struct size_class *class, struct zspage *zspage,
 	} while ((zpdesc = get_next_zpdesc(zpdesc)) != NULL);
 
 	create_page_chain(class, zspage, zpdescs);
-	first_obj_offset = get_first_obj_offset(zpdesc_page(oldzpdesc));
-	set_first_obj_offset(zpdesc_page(newzpdesc), first_obj_offset);
+	first_obj_offset = get_first_obj_offset(oldzpdesc);
+	set_first_obj_offset(newzpdesc, first_obj_offset);
 	if (unlikely(ZsHugePage(zspage)))
 		newzpdesc->handle = oldzpdesc->handle;
 	__zpdesc_set_movable(newzpdesc, &zsmalloc_mops);
@@ -1845,7 +1845,7 @@ static int zs_page_migrate(struct page *newpage, struct page *page,
 	/* the migrate_write_lock protects zpage access via zs_map_object */
 	migrate_write_lock(zspage);
 
-	offset = get_first_obj_offset(zpdesc_page(zpdesc));
+	offset = get_first_obj_offset(zpdesc);
 	s_addr = zpdesc_kmap_atomic(zpdesc);
 
 	/*
-- 
2.43.0