[PATCH] rmap 38 remove anonmm rmap

From: Hugh Dickins <hugh@veritas.com>

Before moving on to anon_vma rmap, remove now what's peculiar to anonmm rmap:
the anonmm handling and the mremap move cows.  Temporarily reduce
page_referenced_anon and try_to_unmap_anon to stubs, so a kernel built with
this patch will not swap anonymous at all.

3 files changed, 1 insertions, 55 deletions

diff --git a/include/linux/page-flags.h b/include/linux/page-flags.h
index 9f3864fbb5da..40028bc59127 100644
--- a/include/linux/page-flags.h
+++ b/include/linux/page-flags.h
@@ -76,7 +76,7 @@
 #define PG_reclaim		18	/* To be reclaimed asap */
 #define PG_compound		19	/* Part of a compound page */
 
-#define PG_anon			20	/* Anonymous page: anonmm in mapping */
+#define PG_anon			20	/* Anonymous: anon_vma in mapping */
 
 
 /*
diff --git a/include/linux/rmap.h b/include/linux/rmap.h
index 13e896e984aa..620987fa9607 100644
--- a/include/linux/rmap.h
+++ b/include/linux/rmap.h
@@ -35,54 +35,6 @@ static inline void page_dup_rmap(struct page *page)
 	page_map_unlock(page);
 }
 
-int mremap_move_anon_rmap(struct page *page, unsigned long addr);
-
-/**
- * mremap_moved_anon_rmap - does new address clash with that noted?
- * @page:	the page just brought back in from swap
- * @addr:	the user virtual address at which it is mapped
- *
- * Returns boolean, true if addr clashes with address already in page.
- *
- * For do_swap_page and unuse_pte: anonmm rmap cannot find the page if
- * it's at different addresses in different mms, so caller must take a
- * copy of the page to avoid that: not very clever, but too rare a case
- * to merit cleverness.
- */
-static inline int mremap_moved_anon_rmap(struct page *page, unsigned long addr)
-{
-	return page->index != (addr & PAGE_MASK);
-}
-
-/**
- * make_page_exclusive - try to make page exclusive to one mm
- * @vma		the vm_area_struct covering this address
- * @addr	the user virtual address of the page in question
- *
- * Assumes that the page at this address is anonymous (COWable),
- * and that the caller holds mmap_sem for reading or for writing.
- *
- * For mremap's move_page_tables and for swapoff's unuse_process:
- * not a general purpose routine, and in general may not succeed.
- * But move_page_tables loops until it succeeds, and unuse_process
- * holds the original page locked, which protects against races.
- */
-static inline int make_page_exclusive(struct vm_area_struct *vma,
-					unsigned long addr)
-{
-	if (handle_mm_fault(vma->vm_mm, vma, addr, 1) != VM_FAULT_OOM)
-		return 0;
-	return -ENOMEM;
-}
-
-/*
- * Called from kernel/fork.c to manage anonymous memory
- */
-void init_rmap(void);
-int exec_rmap(struct mm_struct *);
-int dup_rmap(struct mm_struct *, struct mm_struct *oldmm);
-void exit_rmap(struct mm_struct *);
-
 /*
  * Called from mm/vmscan.c to handle paging out
  */
@@ -91,11 +43,6 @@ int try_to_unmap(struct page *);
 
 #else	/* !CONFIG_MMU */
 
-#define init_rmap()		do {} while (0)
-#define exec_rmap(mm)		(0)
-#define dup_rmap(mm, oldmm)	(0)
-#define exit_rmap(mm)		do {} while (0)
-
 #define page_referenced(page)	TestClearPageReferenced(page)
 #define try_to_unmap(page)	SWAP_FAIL
 
diff --git a/include/linux/sched.h b/include/linux/sched.h
index 9cf8e5be3ed0..60e8bb20c43e 100644
--- a/include/linux/sched.h
+++ b/include/linux/sched.h
@@ -207,7 +207,6 @@ struct mm_struct {
 						 * together off init_mm.mmlist, and are protected
 						 * by mmlist_lock
 						 */
-	struct anonmm *anonmm;			/* For rmap to track anon mem */
 
 	unsigned long start_code, end_code, start_data, end_data;
 	unsigned long start_brk, brk, start_stack;