diff mbox series

[v2,01/20] mm/zsmalloc: add zpdesc memory descriptor for zswap.zpool

Message ID 20240703040613.681396-2-alexs@kernel.org (mailing list archive)
State New
Headers show
Series mm/zsmalloc: add zpdesc memory descriptor for zswap.zpool | expand

Commit Message

alexs@kernel.org July 3, 2024, 4:05 a.m. UTC 
From: Alex Shi <alexs@kernel.org>

The 1st patch introduces new memory decriptor zpdesc and rename
zspage.first_page to zspage.first_zpdesc, no functional change.

We removed PG_owner_priv_1 since it was moved to zspage after
commit a41ec880aa7b ("zsmalloc: move huge compressed obj from
page to zspage").

And keep the memcg_data member, since as Yosry pointed out:
"When the pages are freed, put_page() -> folio_put() -> __folio_put() will call
mem_cgroup_uncharge(). The latter will call folio_memcg() (which reads
folio->memcg_data) to figure out if uncharging needs to be done.

There are also other similar code paths that will check
folio->memcg_data. It is currently expected to be present for all
folios. So until we have custom code paths per-folio type for
allocation/freeing/etc, we need to keep folio->memcg_data present and
properly initialized."

Originally-by: Hyeonggon Yoo <42.hyeyoo@gmail.com>
Signed-off-by: Alex Shi <alexs@kernel.org>
---
 mm/zpdesc.h   | 64 +++++++++++++++++++++++++++++++++++++++++++++++++++
 mm/zsmalloc.c | 21 ++++++++---------
 2 files changed, 74 insertions(+), 11 deletions(-)
 create mode 100644 mm/zpdesc.h

Comments

kernel test robot July 5, 2024, 1:41 p.m. UTC | #1 
Hi,

kernel test robot noticed the following build errors:

[auto build test ERROR on akpm-mm/mm-everything]

url:    https://github.com/intel-lab-lkp/linux/commits/alexs-kernel-org/mm-zsmalloc-add-zpdesc-memory-descriptor-for-zswap-zpool/20240703-182314
base:   https://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm.git mm-everything
patch link:    https://lore.kernel.org/r/20240703040613.681396-2-alexs%40kernel.org
patch subject: [PATCH v2 01/20] mm/zsmalloc: add zpdesc memory descriptor for zswap.zpool
config: i386-buildonly-randconfig-004-20240705 (https://download.01.org/0day-ci/archive/20240705/202407052121.e5LTYhXc-lkp@intel.com/config)
compiler: clang version 18.1.5 (https://github.com/llvm/llvm-project 617a15a9eac96088ae5e9134248d8236e34b91b1)
reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20240705/202407052121.e5LTYhXc-lkp@intel.com/reproduce)

If you fix the issue in a separate patch/commit (i.e. not just a new version of
the same patch/commit), kindly add following tags
| Reported-by: kernel test robot <lkp@intel.com>
| Closes: https://lore.kernel.org/oe-kbuild-all/202407052121.e5LTYhXc-lkp@intel.com/

All errors (new ones prefixed by >>):

   In file included from mm/zsmalloc.c:65:
>> mm/zpdesc.h:48:1: error: no member named 'memcg_data' in 'page'
      48 | ZPDESC_MATCH(memcg_data, memcg_data);
         | ^            ~~~~~~~~~~
   mm/zpdesc.h:40:16: note: expanded from macro 'ZPDESC_MATCH'
      40 |         static_assert(offsetof(struct page, pg) == offsetof(struct zpdesc, zp))
         |                       ^                     ~~
   include/linux/stddef.h:16:32: note: expanded from macro 'offsetof'
      16 | #define offsetof(TYPE, MEMBER)  __builtin_offsetof(TYPE, MEMBER)
         |                                 ^                        ~~~~~~
   include/linux/build_bug.h:77:50: note: expanded from macro 'static_assert'
      77 | #define static_assert(expr, ...) __static_assert(expr, ##__VA_ARGS__, #expr)
         |                                                  ^~~~
   include/linux/build_bug.h:78:56: note: expanded from macro '__static_assert'
      78 | #define __static_assert(expr, msg, ...) _Static_assert(expr, msg)
         |                                                        ^~~~
   In file included from mm/zsmalloc.c:65:
>> mm/zpdesc.h:48:1: error: no member named 'memcg_data' in 'zpdesc'
      48 | ZPDESC_MATCH(memcg_data, memcg_data);
         | ^                        ~~~~~~~~~~
   mm/zpdesc.h:40:45: note: expanded from macro 'ZPDESC_MATCH'
      40 |         static_assert(offsetof(struct page, pg) == offsetof(struct zpdesc, zp))
         |                                                    ^                       ~~
   include/linux/stddef.h:16:32: note: expanded from macro 'offsetof'
      16 | #define offsetof(TYPE, MEMBER)  __builtin_offsetof(TYPE, MEMBER)
         |                                 ^                        ~~~~~~
   include/linux/build_bug.h:77:50: note: expanded from macro 'static_assert'
      77 | #define static_assert(expr, ...) __static_assert(expr, ##__VA_ARGS__, #expr)
         |                                                  ^~~~
   include/linux/build_bug.h:78:56: note: expanded from macro '__static_assert'
      78 | #define __static_assert(expr, msg, ...) _Static_assert(expr, msg)
         |                                                        ^~~~
   2 errors generated.


vim +48 mm/zpdesc.h

     9	
    10	/*
    11	 * struct zpdesc -	Memory descriptor for zpool memory, now is for zsmalloc
    12	 * @flags:		Page flags, PG_private: identifies the first component page
    13	 * @lru:		Indirectly used by page migration
    14	 * @mops:		Used by page migration
    15	 * @next:		Next zpdesc in a zspage in zsmalloc zpool
    16	 * @handle:		For huge zspage in zsmalloc zpool
    17	 * @zspage:		Pointer to zspage in zsmalloc
    18	 * @memcg_data:		Memory Control Group data.
    19	 *
    20	 * This struct overlays struct page for now. Do not modify without a good
    21	 * understanding of the issues.
    22	 */
    23	struct zpdesc {
    24		unsigned long flags;
    25		struct list_head lru;
    26		struct movable_operations *mops;
    27		union {
    28			/* Next zpdescs in a zspage in zsmalloc zpool */
    29			struct zpdesc *next;
    30			/* For huge zspage in zsmalloc zpool */
    31			unsigned long handle;
    32		};
    33		struct zspage *zspage;
    34		unsigned long _zp_pad_1;
    35	#ifdef CONFIG_SLAB_OBJ_EXT
    36		unsigned long memcg_data;
    37	#endif
    38	};
    39	#define ZPDESC_MATCH(pg, zp) \
    40		static_assert(offsetof(struct page, pg) == offsetof(struct zpdesc, zp))
    41	
    42	ZPDESC_MATCH(flags, flags);
    43	ZPDESC_MATCH(lru, lru);
    44	ZPDESC_MATCH(mapping, mops);
    45	ZPDESC_MATCH(index, next);
    46	ZPDESC_MATCH(index, handle);
    47	ZPDESC_MATCH(private, zspage);
  > 48	ZPDESC_MATCH(memcg_data, memcg_data);
    49	#undef ZPDESC_MATCH
    50	static_assert(sizeof(struct zpdesc) <= sizeof(struct page));
    51
kernel test robot July 5, 2024, 2:02 p.m. UTC | #2 
Hi,

kernel test robot noticed the following build errors:

[auto build test ERROR on akpm-mm/mm-everything]

url:    https://github.com/intel-lab-lkp/linux/commits/alexs-kernel-org/mm-zsmalloc-add-zpdesc-memory-descriptor-for-zswap-zpool/20240703-182314
base:   https://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm.git mm-everything
patch link:    https://lore.kernel.org/r/20240703040613.681396-2-alexs%40kernel.org
patch subject: [PATCH v2 01/20] mm/zsmalloc: add zpdesc memory descriptor for zswap.zpool
config: i386-buildonly-randconfig-001-20240705 (https://download.01.org/0day-ci/archive/20240705/202407052114.eLXLN20k-lkp@intel.com/config)
compiler: gcc-13 (Ubuntu 13.2.0-4ubuntu3) 13.2.0
reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20240705/202407052114.eLXLN20k-lkp@intel.com/reproduce)

If you fix the issue in a separate patch/commit (i.e. not just a new version of
the same patch/commit), kindly add following tags
| Reported-by: kernel test robot <lkp@intel.com>
| Closes: https://lore.kernel.org/oe-kbuild-all/202407052114.eLXLN20k-lkp@intel.com/

All errors (new ones prefixed by >>):

   In file included from include/linux/container_of.h:5,
                    from include/linux/list.h:5,
                    from include/linux/module.h:12,
                    from mm/zsmalloc.c:40:
>> include/linux/stddef.h:16:33: error: 'struct page' has no member named 'memcg_data'
      16 | #define offsetof(TYPE, MEMBER)  __builtin_offsetof(TYPE, MEMBER)
         |                                 ^~~~~~~~~~~~~~~~~~
   include/linux/build_bug.h:78:56: note: in definition of macro '__static_assert'
      78 | #define __static_assert(expr, msg, ...) _Static_assert(expr, msg)
         |                                                        ^~~~
   mm/zpdesc.h:40:9: note: in expansion of macro 'static_assert'
      40 |         static_assert(offsetof(struct page, pg) == offsetof(struct zpdesc, zp))
         |         ^~~~~~~~~~~~~
   mm/zpdesc.h:40:23: note: in expansion of macro 'offsetof'
      40 |         static_assert(offsetof(struct page, pg) == offsetof(struct zpdesc, zp))
         |                       ^~~~~~~~
   mm/zpdesc.h:48:1: note: in expansion of macro 'ZPDESC_MATCH'
      48 | ZPDESC_MATCH(memcg_data, memcg_data);
         | ^~~~~~~~~~~~
>> include/linux/stddef.h:16:33: error: 'struct zpdesc' has no member named 'memcg_data'
      16 | #define offsetof(TYPE, MEMBER)  __builtin_offsetof(TYPE, MEMBER)
         |                                 ^~~~~~~~~~~~~~~~~~
   include/linux/build_bug.h:78:56: note: in definition of macro '__static_assert'
      78 | #define __static_assert(expr, msg, ...) _Static_assert(expr, msg)
         |                                                        ^~~~
   mm/zpdesc.h:40:9: note: in expansion of macro 'static_assert'
      40 |         static_assert(offsetof(struct page, pg) == offsetof(struct zpdesc, zp))
         |         ^~~~~~~~~~~~~
   mm/zpdesc.h:40:52: note: in expansion of macro 'offsetof'
      40 |         static_assert(offsetof(struct page, pg) == offsetof(struct zpdesc, zp))
         |                                                    ^~~~~~~~
   mm/zpdesc.h:48:1: note: in expansion of macro 'ZPDESC_MATCH'
      48 | ZPDESC_MATCH(memcg_data, memcg_data);
         | ^~~~~~~~~~~~
>> include/linux/stddef.h:16:33: error: expression in static assertion is not an integer
      16 | #define offsetof(TYPE, MEMBER)  __builtin_offsetof(TYPE, MEMBER)
         |                                 ^~~~~~~~~~~~~~~~~~
   include/linux/build_bug.h:78:56: note: in definition of macro '__static_assert'
      78 | #define __static_assert(expr, msg, ...) _Static_assert(expr, msg)
         |                                                        ^~~~
   mm/zpdesc.h:40:9: note: in expansion of macro 'static_assert'
      40 |         static_assert(offsetof(struct page, pg) == offsetof(struct zpdesc, zp))
         |         ^~~~~~~~~~~~~
   mm/zpdesc.h:40:23: note: in expansion of macro 'offsetof'
      40 |         static_assert(offsetof(struct page, pg) == offsetof(struct zpdesc, zp))
         |                       ^~~~~~~~
   mm/zpdesc.h:48:1: note: in expansion of macro 'ZPDESC_MATCH'
      48 | ZPDESC_MATCH(memcg_data, memcg_data);
         | ^~~~~~~~~~~~


vim +16 include/linux/stddef.h

6e2182874324727 Richard Knutsson 2006-09-30  14  
^1da177e4c3f415 Linus Torvalds   2005-04-16  15  #undef offsetof
14e83077d55ff4b Rasmus Villemoes 2022-03-23 @16  #define offsetof(TYPE, MEMBER)	__builtin_offsetof(TYPE, MEMBER)
3876488444e7123 Denys Vlasenko   2015-03-09  17
diff mbox series

Patch

diff --git a/mm/zpdesc.h b/mm/zpdesc.h
new file mode 100644
index 000000000000..4455a663ee84
--- /dev/null
+++ b/mm/zpdesc.h
@@ -0,0 +1,64 @@ 
+/* SPDX-License-Identifier: GPL-2.0 */
+/* zpdesc.h: zswap.zpool memory descriptor
+ *
+ * Written by Alex Shi <alexs@kernel.org>
+ *	      Hyeonggon Yoo <42.hyeyoo@gmail.com>
+ */
+#ifndef __MM_ZPDESC_H__
+#define __MM_ZPDESC_H__
+
+/*
+ * struct zpdesc -	Memory descriptor for zpool memory, now is for zsmalloc
+ * @flags:		Page flags, PG_private: identifies the first component page
+ * @lru:		Indirectly used by page migration
+ * @mops:		Used by page migration
+ * @next:		Next zpdesc in a zspage in zsmalloc zpool
+ * @handle:		For huge zspage in zsmalloc zpool
+ * @zspage:		Pointer to zspage in zsmalloc
+ * @memcg_data:		Memory Control Group data.
+ *
+ * This struct overlays struct page for now. Do not modify without a good
+ * understanding of the issues.
+ */
+struct zpdesc {
+	unsigned long flags;
+	struct list_head lru;
+	struct movable_operations *mops;
+	union {
+		/* Next zpdescs in a zspage in zsmalloc zpool */
+		struct zpdesc *next;
+		/* For huge zspage in zsmalloc zpool */
+		unsigned long handle;
+	};
+	struct zspage *zspage;
+	unsigned long _zp_pad_1;
+#ifdef CONFIG_SLAB_OBJ_EXT
+	unsigned long memcg_data;
+#endif
+};
+#define ZPDESC_MATCH(pg, zp) \
+	static_assert(offsetof(struct page, pg) == offsetof(struct zpdesc, zp))
+
+ZPDESC_MATCH(flags, flags);
+ZPDESC_MATCH(lru, lru);
+ZPDESC_MATCH(mapping, mops);
+ZPDESC_MATCH(index, next);
+ZPDESC_MATCH(index, handle);
+ZPDESC_MATCH(private, zspage);
+ZPDESC_MATCH(memcg_data, memcg_data);
+#undef ZPDESC_MATCH
+static_assert(sizeof(struct zpdesc) <= sizeof(struct page));
+
+#define zpdesc_page(zp)			(_Generic((zp),			\
+	const struct zpdesc *:		(const struct page *)(zp),	\
+	struct zpdesc *:		(struct page *)(zp)))
+
+#define zpdesc_folio(zp)		(_Generic((zp),			\
+	const struct zpdesc *:		(const struct folio *)(zp),	\
+	struct zpdesc *:		(struct folio *)(zp)))
+
+#define page_zpdesc(p)			(_Generic((p),			\
+	const struct page *:		(const struct zpdesc *)(p),	\
+	struct page *:			(struct zpdesc *)(p)))
+
+#endif
diff --git a/mm/zsmalloc.c b/mm/zsmalloc.c
index 5d6581ab7c07..a532851025f9 100644
--- a/mm/zsmalloc.c
+++ b/mm/zsmalloc.c
@@ -13,20 +13,18 @@ 
 
 /*
  * Following is how we use various fields and flags of underlying
- * struct page(s) to form a zspage.
+ * struct zpdesc(page) to form a zspage.
  *
- * Usage of struct page fields:
- *	page->private: points to zspage
- *	page->index: links together all component pages of a zspage
+ * Usage of struct zpdesc fields:
+ *	zpdesc->zspage: points to zspage
+ *	zpdesc->next: links together all component pages of a zspage
  *		For the huge page, this is always 0, so we use this field
  *		to store handle.
  *	page->page_type: PG_zsmalloc, lower 16 bit locate the first object
  *		offset in a subpage of a zspage
  *
- * Usage of struct page flags:
+ * Usage of struct zpdesc(page) flags:
  *	PG_private: identifies the first component page
- *	PG_owner_priv_1: identifies the huge component page
- *
  */
 
 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
@@ -64,6 +62,7 @@ 
 #include <linux/pagemap.h>
 #include <linux/fs.h>
 #include <linux/local_lock.h>
+#include "zpdesc.h"
 
 #define ZSPAGE_MAGIC	0x58
 
@@ -253,7 +252,7 @@  struct zspage {
 	};
 	unsigned int inuse;
 	unsigned int freeobj;
-	struct page *first_page;
+	struct zpdesc *first_zpdesc;
 	struct list_head list; /* fullness list */
 	struct zs_pool *pool;
 	rwlock_t lock;
@@ -448,7 +447,7 @@  static inline void mod_zspage_inuse(struct zspage *zspage, int val)
 
 static inline struct page *get_first_page(struct zspage *zspage)
 {
-	struct page *first_page = zspage->first_page;
+	struct page *first_page = zpdesc_page(zspage->first_zpdesc);
 
 	VM_BUG_ON_PAGE(!is_first_page(first_page), first_page);
 	return first_page;
@@ -948,7 +947,7 @@  static void create_page_chain(struct size_class *class, struct zspage *zspage,
 		set_page_private(page, (unsigned long)zspage);
 		page->index = 0;
 		if (i == 0) {
-			zspage->first_page = page;
+			zspage->first_zpdesc = page_zpdesc(page);
 			SetPagePrivate(page);
 			if (unlikely(class->objs_per_zspage == 1 &&
 					class->pages_per_zspage == 1))
@@ -1324,7 +1323,7 @@  static unsigned long obj_malloc(struct zs_pool *pool,
 		link->handle = handle | OBJ_ALLOCATED_TAG;
 	else
 		/* record handle to page->index */
-		zspage->first_page->index = handle | OBJ_ALLOCATED_TAG;
+		zspage->first_zpdesc->handle = handle | OBJ_ALLOCATED_TAG;
 
 	kunmap_atomic(vaddr);
 	mod_zspage_inuse(zspage, 1);