[-mm PATCH 4/8] Memory controller memory accounting (v2)

[Balbir Singh]

Add the accounting hooks. The accounting is carried out for RSS and Page
Cache (unmapped) pages. There is now a common limit and accounting for both.
The RSS accounting is accounted at page_add_*_rmap() and page_remove_rmap()
time. Page cache is accounted at add_to_page_cache(),
__delete_from_page_cache(). Swap cache is also accounted for.

Each page's meta_page is protected with a bit in page flags, this makes
handling of race conditions involving simultaneous mappings of a page easier.
A reference count is kept in the meta_page to deal with cases where a page
might be unmapped from the RSS of all tasks, but still lives in the page
cache.

Signed-off-by: Balbir Singh <balbir@xxxxxxxxxxxxxxxxxx>
---

 fs/exec.c                  |    1 
 include/linux/memcontrol.h |   11 +++
 include/linux/page-flags.h |    3 +
 mm/filemap.c               |    8 ++
 mm/memcontrol.c            |  132 ++++++++++++++++++++++++++++++++++++++++++++-
 mm/memory.c                |   22 +++++++
 mm/migrate.c               |    6 ++
 mm/page_alloc.c            |    3 +
 mm/rmap.c                  |    2 
 mm/swap_state.c            |    8 ++
 mm/swapfile.c              |   40 +++++++------
 11 files changed, 218 insertions(+), 18 deletions(-)

diff -puN fs/exec.c~mem-control-accounting fs/exec.c
--- linux-2.6.22-rc6/fs/exec.c~mem-control-accounting	2007-07-05 13:45:18.000000000 -0700
+++ linux-2.6.22-rc6-balbir/fs/exec.c	2007-07-05 13:45:18.000000000 -0700
@@ -51,6 +51,7 @@
 #include <linux/cn_proc.h>
 #include <linux/audit.h>
 #include <linux/signalfd.h>
+#include <linux/memcontrol.h>
 
 #include <asm/uaccess.h>
 #include <asm/mmu_context.h>
diff -puN include/linux/memcontrol.h~mem-control-accounting include/linux/memcontrol.h
--- linux-2.6.22-rc6/include/linux/memcontrol.h~mem-control-accounting	2007-07-05 13:45:18.000000000 -0700
+++ linux-2.6.22-rc6-balbir/include/linux/memcontrol.h	2007-07-05 18:27:26.000000000 -0700
@@ -24,6 +24,8 @@ extern void mm_init_container(struct mm_
 extern void mm_free_container(struct mm_struct *mm);
 extern void page_assign_meta_page(struct page *page, struct meta_page *mp);
 extern struct meta_page *page_get_meta_page(struct page *page);
+extern int mem_container_charge(struct page *page, struct mm_struct *mm);
+extern void mem_container_uncharge(struct meta_page *mp);
 
 #else /* CONFIG_CONTAINER_MEM_CONT */
 static inline void mm_init_container(struct mm_struct *mm,
@@ -45,6 +47,15 @@ static inline struct meta_page *page_get
 	return NULL;
 }
 
+static inline int mem_container_charge(struct page *page, struct mm_struct *mm)
+{
+	return 0;
+}
+
+static inline void mem_container_uncharge(struct meta_page *mp)
+{
+}
+
 #endif /* CONFIG_CONTAINER_MEM_CONT */
 
 #endif /* _LINUX_MEMCONTROL_H */
diff -puN include/linux/page-flags.h~mem-control-accounting include/linux/page-flags.h
--- linux-2.6.22-rc6/include/linux/page-flags.h~mem-control-accounting	2007-07-05 13:45:18.000000000 -0700
+++ linux-2.6.22-rc6-balbir/include/linux/page-flags.h	2007-07-05 13:45:18.000000000 -0700
@@ -98,6 +98,9 @@
 #define PG_checked		PG_owner_priv_1 /* Used by some filesystems */
 #define PG_pinned		PG_owner_priv_1	/* Xen pinned pagetable */
 
+#define PG_metapage		21	/* Used for checking if a meta_page */
+					/* is associated with a page	    */
+
 #if (BITS_PER_LONG > 32)
 /*
  * 64-bit-only flags build down from bit 31
diff -puN mm/filemap.c~mem-control-accounting mm/filemap.c
--- linux-2.6.22-rc6/mm/filemap.c~mem-control-accounting	2007-07-05 13:45:18.000000000 -0700
+++ linux-2.6.22-rc6-balbir/mm/filemap.c	2007-07-05 18:26:29.000000000 -0700
@@ -31,6 +31,7 @@
 #include <linux/syscalls.h>
 #include <linux/cpuset.h>
 #include <linux/hardirq.h> /* for BUG_ON(!in_atomic()) only */
+#include <linux/memcontrol.h>
 #include "internal.h"
 
 /*
@@ -116,6 +117,7 @@ void __remove_from_page_cache(struct pag
 {
 	struct address_space *mapping = page->mapping;
 
+	mem_container_uncharge(page_get_meta_page(page));
 	radix_tree_delete(&mapping->page_tree, page->index);
 	page->mapping = NULL;
 	mapping->nrpages--;
@@ -442,6 +444,11 @@ int add_to_page_cache(struct page *page,
 	int error = radix_tree_preload(gfp_mask & ~__GFP_HIGHMEM);
 
 	if (error == 0) {
+
+		error = mem_container_charge(page, current->mm);
+		if (error)
+			goto out;
+
 		write_lock_irq(&mapping->tree_lock);
 		error = radix_tree_insert(&mapping->page_tree, offset, page);
 		if (!error) {
@@ -455,6 +462,7 @@ int add_to_page_cache(struct page *page,
 		write_unlock_irq(&mapping->tree_lock);
 		radix_tree_preload_end();
 	}
+out:
 	return error;
 }
 EXPORT_SYMBOL(add_to_page_cache);
diff -puN mm/memcontrol.c~mem-control-accounting mm/memcontrol.c
--- linux-2.6.22-rc6/mm/memcontrol.c~mem-control-accounting	2007-07-05 13:45:18.000000000 -0700
+++ linux-2.6.22-rc6-balbir/mm/memcontrol.c	2007-07-05 18:27:29.000000000 -0700
@@ -16,6 +16,9 @@
 #include <linux/memcontrol.h>
 #include <linux/container.h>
 #include <linux/mm.h>
+#include <linux/page-flags.h>
+#include <linux/bit_spinlock.h>
+#include <linux/rcupdate.h>
 
 struct container_subsys mem_container_subsys;
 
@@ -26,7 +29,9 @@ struct container_subsys mem_container_su
  * to help the administrator determine what knobs to tune.
  *
  * TODO: Add a water mark for the memory controller. Reclaim will begin when
- * we hit the water mark.
+ * we hit the water mark. May be even add a low water mark, such that
+ * no reclaim occurs from a container at it's low water mark, this is
+ * a feature that will be implemented much later in the future.
  */
 struct mem_container {
 	struct container_subsys_state css;
@@ -51,6 +56,7 @@ struct meta_page {
 	struct list_head list;		/* per container LRU list */
 	struct page *page;
 	struct mem_container *mem_container;
+	atomic_t ref_cnt;
 };
 
 
@@ -87,6 +93,128 @@ struct meta_page *page_get_meta_page(str
 	return page->meta_page;
 }
 
+void __always_inline lock_meta_page(struct page *page)
+{
+	bit_spin_lock(PG_metapage, &page->flags);
+}
+
+void __always_inline unlock_meta_page(struct page *page)
+{
+	bit_spin_unlock(PG_metapage, &page->flags);
+}
+
+/*
+ * Charge the memory controller for page usage.
+ * Return
+ * 0 if the charge was successful
+ * < 0 if the container is over its limit
+ */
+int mem_container_charge(struct page *page, struct mm_struct *mm)
+{
+	struct mem_container *mem;
+	struct meta_page *mp;
+
+	/*
+	 * Should meta_page's go to their own slab?
+	 * One could optimize the performance of the charging routine
+	 * by saving a bit in the page_flags and using it as a lock
+	 * to see if the container page already has a meta_page associated
+	 * with it
+	 */
+	lock_meta_page(page);
+	mp = page_get_meta_page(page);
+	/*
+	 * The meta_page exists and the page has already been accounted
+	 */
+	if (mp) {
+		atomic_inc(&mp->ref_cnt);
+		goto done;
+	}
+
+	unlock_meta_page(page);
+
+	mp = kzalloc(sizeof(struct meta_page), GFP_KERNEL);
+	if (mp == NULL)
+		goto err;
+
+	rcu_read_lock();
+	/*
+	 * We always charge the container the mm_struct belongs to
+	 * the mm_struct's mem_container changes on task migration if the
+	 * thread group leader migrates. It's possible that mm is not
+	 * set, if so charge the init_mm (happens for pagecache usage).
+	 */
+	if (!mm)
+		mm = &init_mm;
+
+	mem = rcu_dereference(mm->mem_container);
+	/*
+	 * For every charge from the container, increment reference
+	 * count
+	 */
+	css_get(&mem->css);
+	rcu_read_unlock();
+
+	/*
+	 * If we created the meta_page, we should free it on exceeding
+	 * the container limit.
+	 */
+	if (res_counter_charge(&mem->res, 1))
+		goto free_mp;
+
+	lock_meta_page(page);
+	/*
+	 * Check if somebody else beat us to allocating the meta_page
+	 */
+	if (page_get_meta_page(page)) {
+		atomic_inc(&mp->ref_cnt);
+		res_counter_uncharge(&mem->res, 1);
+		goto done;
+	}
+
+	atomic_set(&mp->ref_cnt, 1);
+	mp->mem_container = mem;
+	mp->page = page;
+	page_assign_meta_page(page, mp);
+
+done:
+	unlock_meta_page(page);
+	return 0;
+free_mp:
+	kfree(mp);
+	return -ENOMEM;
+err:
+	unlock_meta_page(page);
+	return -ENOMEM;
+}
+
+/*
+ * Uncharging is always a welcome operation, we never complain, simply
+ * uncharge.
+ */
+void mem_container_uncharge(struct meta_page *mp)
+{
+	struct mem_container *mem;
+	struct page *page;
+
+	/*
+	 * This can happen for PAGE_ZERO
+	 */
+	if (!mp)
+		return;
+
+	if (atomic_dec_and_test(&mp->ref_cnt)) {
+		page = mp->page;
+		lock_meta_page(page);
+		mem = mp->mem_container;
+		css_put(&mem->css);
+		page_assign_meta_page(page, NULL);
+		unlock_meta_page(page);
+		res_counter_uncharge(&mem->res, 1);
+		kfree(mp);
+	}
+}
+
 static ssize_t mem_container_read(struct container *cont, struct cftype *cft,
 			struct file *file, char __user *userbuf, size_t nbytes,
 			loff_t *ppos)
@@ -142,6 +270,8 @@ static int mem_container_create(struct c
 	res_counter_init(&mem->res);
 	cont->subsys[mem_container_subsys_id] = &mem->css;
 	mem->css.container = cont;
+	INIT_LIST_HEAD(&mem->active_list);
+	INIT_LIST_HEAD(&mem->inactive_list);
 	return 0;
 }
 
diff -puN mm/memory.c~mem-control-accounting mm/memory.c
--- linux-2.6.22-rc6/mm/memory.c~mem-control-accounting	2007-07-05 13:45:18.000000000 -0700
+++ linux-2.6.22-rc6-balbir/mm/memory.c	2007-07-05 13:45:18.000000000 -0700
@@ -50,6 +50,7 @@
 #include <linux/delayacct.h>
 #include <linux/init.h>
 #include <linux/writeback.h>
+#include <linux/memcontrol.h>
 
 #include <asm/pgalloc.h>
 #include <asm/uaccess.h>
@@ -1226,6 +1227,10 @@ static int insert_page(struct mm_struct 
 	pte_t *pte;
 	spinlock_t *ptl;  
 
+	retval = mem_container_charge(page, mm);
+	if (retval)
+		goto out;
+
 	retval = -EINVAL;
 	if (PageAnon(page))
 		goto out;
@@ -1731,6 +1736,9 @@ gotten:
 		cow_user_page(new_page, old_page, address, vma);
 	}
 
+	if (mem_container_charge(new_page, mm))
+		goto oom;
+
 	/*
 	 * Re-check the pte - we dropped the lock
 	 */
@@ -2188,6 +2196,11 @@ static int do_swap_page(struct mm_struct
 	}
 
 	delayacct_clear_flag(DELAYACCT_PF_SWAPIN);
+	if (mem_container_charge(page, mm)) {
+		ret = VM_FAULT_OOM;
+		goto out;
+	}
+
 	mark_page_accessed(page);
 	lock_page(page);
 
@@ -2255,6 +2268,7 @@ static int do_anonymous_page(struct mm_s
 	pte_t entry;
 
 	if (write_access) {
+
 		/* Allocate our own private page. */
 		pte_unmap(page_table);
 
@@ -2264,6 +2278,9 @@ static int do_anonymous_page(struct mm_s
 		if (!page)
 			goto oom;
 
+		if (mem_container_charge(page, mm))
+			goto oom;
+
 		entry = mk_pte(page, vma->vm_page_prot);
 		entry = maybe_mkwrite(pte_mkdirty(entry), vma);
 
@@ -2397,6 +2414,11 @@ static int __do_fault(struct mm_struct *
 
 	}
 
+	if (mem_container_charge(page, mm)) {
+		fdata.type = VM_FAULT_OOM;
+		goto out;
+	}
+
 	page_table = pte_offset_map_lock(mm, pmd, address, &ptl);
 
 	/*
diff -puN mm/migrate.c~mem-control-accounting mm/migrate.c
--- linux-2.6.22-rc6/mm/migrate.c~mem-control-accounting	2007-07-05 13:45:18.000000000 -0700
+++ linux-2.6.22-rc6-balbir/mm/migrate.c	2007-07-05 13:45:18.000000000 -0700
@@ -28,6 +28,7 @@
 #include <linux/mempolicy.h>
 #include <linux/vmalloc.h>
 #include <linux/security.h>
+#include <linux/memcontrol.h>
 
 #include "internal.h"
 
@@ -157,6 +158,11 @@ static void remove_migration_pte(struct 
  		return;
  	}
 
+	if (mem_container_charge(new, mm)) {
+		pte_unmap(ptep);
+		return;
+	}
+
  	ptl = pte_lockptr(mm, pmd);
  	spin_lock(ptl);
 	pte = *ptep;
diff -puN mm/page_alloc.c~mem-control-accounting mm/page_alloc.c
--- linux-2.6.22-rc6/mm/page_alloc.c~mem-control-accounting	2007-07-05 13:45:18.000000000 -0700
+++ linux-2.6.22-rc6-balbir/mm/page_alloc.c	2007-07-05 13:45:18.000000000 -0700
@@ -41,6 +41,7 @@
 #include <linux/pfn.h>
 #include <linux/backing-dev.h>
 #include <linux/fault-inject.h>
+#include <linux/memcontrol.h>
 
 #include <asm/tlbflush.h>
 #include <asm/div64.h>
@@ -1015,6 +1016,7 @@ static void fastcall free_hot_cold_page(
 
 	if (!PageHighMem(page))
 		debug_check_no_locks_freed(page_address(page), PAGE_SIZE);
+	page_assign_meta_page(page, NULL);
 	arch_free_page(page, 0);
 	kernel_map_pages(page, 1, 0);
 
@@ -2576,6 +2578,7 @@ void __meminit memmap_init_zone(unsigned
 		set_page_links(page, zone, nid, pfn);
 		init_page_count(page);
 		reset_page_mapcount(page);
+		page_assign_meta_page(page, NULL);
 		SetPageReserved(page);
 
 		/*
diff -puN mm/rmap.c~mem-control-accounting mm/rmap.c
--- linux-2.6.22-rc6/mm/rmap.c~mem-control-accounting	2007-07-05 13:45:18.000000000 -0700
+++ linux-2.6.22-rc6-balbir/mm/rmap.c	2007-07-05 13:45:18.000000000 -0700
@@ -643,6 +643,8 @@ void page_remove_rmap(struct page *page,
 			page_clear_dirty(page);
 			set_page_dirty(page);
 		}
+
+		mem_container_uncharge(page_get_meta_page(page));
 		__dec_zone_page_state(page,
 				PageAnon(page) ? NR_ANON_PAGES : NR_FILE_MAPPED);
 	}
diff -puN mm/swapfile.c~mem-control-accounting mm/swapfile.c
--- linux-2.6.22-rc6/mm/swapfile.c~mem-control-accounting	2007-07-05 13:45:18.000000000 -0700
+++ linux-2.6.22-rc6-balbir/mm/swapfile.c	2007-07-05 13:45:18.000000000 -0700
@@ -506,9 +506,12 @@ unsigned int count_swap_pages(int type, 
  * just let do_wp_page work it out if a write is requested later - to
  * force COW, vm_page_prot omits write permission from any private vma.
  */
-static void unuse_pte(struct vm_area_struct *vma, pte_t *pte,
+static int unuse_pte(struct vm_area_struct *vma, pte_t *pte,
 		unsigned long addr, swp_entry_t entry, struct page *page)
 {
+	if (mem_container_charge(page, vma->vm_mm))
+		return -ENOMEM;
+
 	inc_mm_counter(vma->vm_mm, anon_rss);
 	get_page(page);
 	set_pte_at(vma->vm_mm, addr, pte,
@@ -520,6 +523,7 @@ static void unuse_pte(struct vm_area_str
 	 * immediately swapped out again after swapon.
 	 */
 	activate_page(page);
+	return 1;
 }
 
 static int unuse_pte_range(struct vm_area_struct *vma, pmd_t *pmd,
@@ -529,7 +533,7 @@ static int unuse_pte_range(struct vm_are
 	pte_t swp_pte = swp_entry_to_pte(entry);
 	pte_t *pte;
 	spinlock_t *ptl;
-	int found = 0;
+	int ret = 0;
 
 	pte = pte_offset_map_lock(vma->vm_mm, pmd, addr, &ptl);
 	do {
@@ -538,13 +542,12 @@ static int unuse_pte_range(struct vm_are
 		 * Test inline before going to call unuse_pte.
 		 */
 		if (unlikely(pte_same(*pte, swp_pte))) {
-			unuse_pte(vma, pte++, addr, entry, page);
-			found = 1;
+			ret = unuse_pte(vma, pte++, addr, entry, page);
 			break;
 		}
 	} while (pte++, addr += PAGE_SIZE, addr != end);
 	pte_unmap_unlock(pte - 1, ptl);
-	return found;
+	return ret;
 }
 
 static inline int unuse_pmd_range(struct vm_area_struct *vma, pud_t *pud,
@@ -553,14 +556,16 @@ static inline int unuse_pmd_range(struct
 {
 	pmd_t *pmd;
 	unsigned long next;
+	int ret;
 
 	pmd = pmd_offset(pud, addr);
 	do {
 		next = pmd_addr_end(addr, end);
 		if (pmd_none_or_clear_bad(pmd))
 			continue;
-		if (unuse_pte_range(vma, pmd, addr, next, entry, page))
-			return 1;
+		ret = unuse_pte_range(vma, pmd, addr, next, entry, page);
+		if (ret)
+			return ret;
 	} while (pmd++, addr = next, addr != end);
 	return 0;
 }
@@ -571,14 +576,16 @@ static inline int unuse_pud_range(struct
 {
 	pud_t *pud;
 	unsigned long next;
+	int ret;
 
 	pud = pud_offset(pgd, addr);
 	do {
 		next = pud_addr_end(addr, end);
 		if (pud_none_or_clear_bad(pud))
 			continue;
-		if (unuse_pmd_range(vma, pud, addr, next, entry, page))
-			return 1;
+		ret = unuse_pmd_range(vma, pud, addr, next, entry, page);
+		if (ret)
+			return ret;
 	} while (pud++, addr = next, addr != end);
 	return 0;
 }
@@ -588,6 +595,7 @@ static int unuse_vma(struct vm_area_stru
 {
 	pgd_t *pgd;
 	unsigned long addr, end, next;
+	int ret;
 
 	if (page->mapping) {
 		addr = page_address_in_vma(page, vma);
@@ -605,8 +613,9 @@ static int unuse_vma(struct vm_area_stru
 		next = pgd_addr_end(addr, end);
 		if (pgd_none_or_clear_bad(pgd))
 			continue;
-		if (unuse_pud_range(vma, pgd, addr, next, entry, page))
-			return 1;
+		ret = unuse_pud_range(vma, pgd, addr, next, entry, page);
+		if (ret)
+			return ret;
 	} while (pgd++, addr = next, addr != end);
 	return 0;
 }
@@ -615,6 +624,7 @@ static int unuse_mm(struct mm_struct *mm
 				swp_entry_t entry, struct page *page)
 {
 	struct vm_area_struct *vma;
+	int ret = 0;
 
 	if (!down_read_trylock(&mm->mmap_sem)) {
 		/*
@@ -627,15 +637,11 @@ static int unuse_mm(struct mm_struct *mm
 		lock_page(page);
 	}
 	for (vma = mm->mmap; vma; vma = vma->vm_next) {
-		if (vma->anon_vma && unuse_vma(vma, entry, page))
+		if (vma->anon_vma && (ret = unuse_vma(vma, entry, page)))
 			break;
 	}
 	up_read(&mm->mmap_sem);
-	/*
-	 * Currently unuse_mm cannot fail, but leave error handling
-	 * at call sites for now, since we change it from time to time.
-	 */
-	return 0;
+	return ret;
 }
 
 /*
diff -puN mm/swap_state.c~mem-control-accounting mm/swap_state.c
--- linux-2.6.22-rc6/mm/swap_state.c~mem-control-accounting	2007-07-05 13:45:18.000000000 -0700
+++ linux-2.6.22-rc6-balbir/mm/swap_state.c	2007-07-05 18:28:08.000000000 -0700
@@ -17,6 +17,7 @@
 #include <linux/backing-dev.h>
 #include <linux/pagevec.h>
 #include <linux/migrate.h>
+#include <linux/memcontrol.h>
 
 #include <asm/pgtable.h>
 
@@ -79,6 +80,11 @@ static int __add_to_swap_cache(struct pa
 	BUG_ON(PagePrivate(page));
 	error = radix_tree_preload(gfp_mask);
 	if (!error) {
+
+		error = mem_container_charge(page, current->mm);
+		if (error)
+			goto out;
+
 		write_lock_irq(&swapper_space.tree_lock);
 		error = radix_tree_insert(&swapper_space.page_tree,
 						entry.val, page);
@@ -93,6 +99,7 @@ static int __add_to_swap_cache(struct pa
 		write_unlock_irq(&swapper_space.tree_lock);
 		radix_tree_preload_end();
 	}
+out:
 	return error;
 }
 
@@ -129,6 +136,7 @@ void __delete_from_swap_cache(struct pag
 	BUG_ON(PageWriteback(page));
 	BUG_ON(PagePrivate(page));
 
+	mem_container_uncharge(page_get_meta_page(page));
 	radix_tree_delete(&swapper_space.page_tree, page_private(page));
 	set_page_private(page, 0);
 	ClearPageSwapCache(page);
_

-- 
	Warm Regards,
	Balbir Singh
	Linux Technology Center
	IBM, ISTL
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