From 7fd2b5b42e728c988142f17e2185d85ae23bb439 Mon Sep 17 00:00:00 2001
From: "Matthew Wilcox (Oracle)" <willy@infradead.org>
Date: Wed, 29 Sep 2021 23:10:53 -0400
Subject: [PATCH] mm: Remove slab from struct page

All members of struct slab can now be removed from struct page.
This shrinks the definition of struct page by 30 LOC, making
it easier to understand.

Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
---
 include/linux/mm_types.h   | 34 ----------------------------------
 include/linux/page-flags.h | 37 -------------------------------------
 2 files changed, 71 deletions(-)

diff --git a/include/linux/mm_types.h b/include/linux/mm_types.h
index c2ea71aba84e..417c5e8a3371 100644
--- a/include/linux/mm_types.h
+++ b/include/linux/mm_types.h
@@ -117,33 +117,6 @@ struct page {
 				atomic_long_t pp_frag_count;
 			};
 		};
-		struct {	/* slab, slob and slub */
-			union {
-				struct list_head slab_list;
-				struct {	/* Partial pages */
-					struct page *next;
-#ifdef CONFIG_64BIT
-					int pages;	/* Nr of pages left */
-					int pobjects;	/* Approximate count */
-#else
-					short int pages;
-					short int pobjects;
-#endif
-				};
-			};
-			struct kmem_cache *slab_cache; /* not slob */
-			/* Double-word boundary */
-			void *freelist;		/* first free object */
-			union {
-				void *s_mem;	/* slab: first object */
-				unsigned long counters;		/* SLUB */
-				struct {			/* SLUB */
-					unsigned inuse:16;
-					unsigned objects:15;
-					unsigned frozen:1;
-				};
-			};
-		};
 		struct {	/* Tail pages of compound page */
 			unsigned long compound_head;	/* Bit zero is set */
 
@@ -207,9 +180,6 @@ struct page {
 		 * which are currently stored here.
 		 */
 		unsigned int page_type;
-
-		unsigned int active;		/* SLAB */
-		int units;			/* SLOB */
 	};
 
 	/* Usage count. *DO NOT USE DIRECTLY*. See page_ref.h */
@@ -283,11 +253,7 @@ struct slab {
 	static_assert(offsetof(struct page, pg) == offsetof(struct slab, sl))
 SLAB_MATCH(flags, flags);
 SLAB_MATCH(compound_head, slab_list);	/* Ensure bit 0 is clear */
-SLAB_MATCH(slab_list, slab_list);
 SLAB_MATCH(rcu_head, rcu_head);
-SLAB_MATCH(slab_cache, slab_cache);
-SLAB_MATCH(s_mem, s_mem);
-SLAB_MATCH(active, active);
 SLAB_MATCH(_refcount, _refcount);
 #ifdef CONFIG_MEMCG
 SLAB_MATCH(memcg_data, memcg_data);
diff --git a/include/linux/page-flags.h b/include/linux/page-flags.h
index 57bdb1eb2f29..d3d0806c1535 100644
--- a/include/linux/page-flags.h
+++ b/include/linux/page-flags.h
@@ -799,43 +799,6 @@ extern bool is_free_buddy_page(struct page *page);
 
 __PAGEFLAG(Isolated, isolated, PF_ANY);
 
-/*
- * If network-based swap is enabled, sl*b must keep track of whether pages
- * were allocated from pfmemalloc reserves.
- */
-static inline int PageSlabPfmemalloc(struct page *page)
-{
-	VM_BUG_ON_PAGE(!PageSlab(page), page);
-	return PageActive(page);
-}
-
-/*
- * A version of PageSlabPfmemalloc() for opportunistic checks where the page
- * might have been freed under us and not be a PageSlab anymore.
- */
-static inline int __PageSlabPfmemalloc(struct page *page)
-{
-	return PageActive(page);
-}
-
-static inline void SetPageSlabPfmemalloc(struct page *page)
-{
-	VM_BUG_ON_PAGE(!PageSlab(page), page);
-	SetPageActive(page);
-}
-
-static inline void __ClearPageSlabPfmemalloc(struct page *page)
-{
-	VM_BUG_ON_PAGE(!PageSlab(page), page);
-	__ClearPageActive(page);
-}
-
-static inline void ClearPageSlabPfmemalloc(struct page *page)
-{
-	VM_BUG_ON_PAGE(!PageSlab(page), page);
-	ClearPageActive(page);
-}
-
 #ifdef CONFIG_MMU
 #define __PG_MLOCKED		(1UL << PG_mlocked)
 #else
-- 
2.49.0