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VM pageout scalability improvements (V9)

PATCH In review Rik van Riel 2 participants 15 messages May 29, 2008 – Jun 1, 2008

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cover VM pageout scalability improvements (V9)

On large memory systems, the VM can spend way too much time scanning through pages that it cannot (or should not) evict from memory. Not only does it use up CPU time, but it also provokes lock contention and can leave large systems under memory presure in a catatonic state.

Against 2.6.26-rc2-mm1

This patch series improves VM scalability by:

1) putting filesystem backed, swap backed and non-reclaimable pages onto their own LRUs, so the system only scans the pages that it can/should evict from memory

2) switching to two handed clock replacement for the anonymous LRUs, so the number of pages that need to be scanned when the system starts swapping is bound to a reasonable number

3) keeping non-reclaimable pages off the LRU completely, so the VM does not waste CPU time scanning them. Currently only ramfs and SHM_LOCKED pages are kept on the noreclaim list, mlock()ed VMAs will be added later

More info on the overall design can be found at:

http://linux-mm.org/PageReplacementDesign

An all-in-one patch can be found at:

http://people.redhat.com/riel/splitvm/

Changelog:
- fix shrink_list memcgroup balancing (KOSAKI Motohiro)
- fix balancing stats in shrink_active_list (Daisuke Nishimura)

- make sure previously active pagecache pages get reactivated on the first access (Rik van Riel)
- compile fix when !CONFIG_SWAP (MinChan Kim)
- clean up page-flags.h defines when !CONFIG_NORECLAIM_LRU (Lee Schermerhorn)
- fix some race conditions around moving pages to and from the noreclaim list (Lee Schermerhorn, KOSAKI Motohiro)
- use putback_lru_page() for page migration (Lee Schermerhorn)
- fix potential SHM_UNLOCK race in scan_mapping_noreclaim_pages() (Lee Schermerhorn, KOSAKI Motohiro)

- improve swap space freeing to deal with COW shared space
(Lee Schermerhorn, Daisuke Nishimura & Minchan Kim)
- clean up PG_swapbacked setting in swapin path (Minchan Kim)
- properly invoke shrink_active_list for background aging (Minchan Kim)
- add authorship info to all patches (Rik van Riel)
- clean up (or move below ---) the comments for the commit logs (Rik van Riel)
- after some tests, reduce default swappiness to 20 for now (Rik van Riel)

- several code cleanups (minchan Kim)
- noreclaim patch refactoring and improvements (Lee Schermerhorn)
- several PROT_NONE and vma merging fixes (KOSAKI Motohiro)
- SMP bugfixes and efficiency improvements (Rik van Riel, Lee Schermerhorn)
- fix NUMA node stats printing (Lee Schermerhorn)
- remove the mlocked-VMA-noreclaim code for now, it still has bugs on IA64 and is holding up the merge (Rik van Riel)

- make page_alloc.c compile without CONFIG_NORECLAIM_MLOCK (minchan Kim)
- BUG() does not take an argument (minchan Kim)
- clean up is_active_lru and is_file_lru (Andy Whitcroft)
- clean up shrink_active_list temp list names (KOSAKI Motohiro)
- add total active & inactive memory totals for vmstat -a (KOSAKI Motohiro)
- only try global anon page aging on global lru scans (KOSAKI Motohiro)
- make function descriptions follow the kernel-doc format (Rik van Riel)
- simplify mlock_vma_pages_range and munlock_vma_pages_range (Lee Schermerhorn)
- remove some more arguments, rename to mlock_vma_pages_all (Lee Schermerhorn)
- many code cleanups (Lee Schermerhorn)
- pass correct vma arg to mlock_vma_pages_range from do_brk (Rik van Riel)
- port to 2.6.25-rc3-mm1

- pull the memcontrol lru arrayification earlier into the patch series
- use a pagevec array similar to the lru array
- clean up the code in various places
- improved pageout balancing and reduced pageout cpu use

- fix compilation on PPC and without memcontrol
- make page_is_pagecache more readable
- replace get_scan_ratio with correct version

- merge memcontroller split LRU code into the main split LRU patch, since it is not functionally different (it was split up only to help people who had seen the last version of the patch series review it)
- drop the page_file_cache debugging patch, since it never triggered
- reintroduce code to not scan anon list if swap is full
- add code to scan anon list if page cache is very small already
- use lumpy reclaim more aggressively for smaller order > 1 allocations

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#1 lore raw

PATCH 1/12 move isolate_lru_page() to vmscan.c

From: Nick Piggin <[email protected]>

isolate_lru_page logically belongs to be in vmscan.c than migrate.c.

It is tough, because we don't need that function without memory migration so there is a valid argument to have it in migrate.c. However a subsequent patch needs to make use of it in the core mm, so we can happily move it to vmscan.c.

Also, make the function a little more generic by not requiring that it adds an isolated page to a given list. Callers can do that.

Note that we now have '__isolate_lru_page()', that does something quite different, visible outside of vmscan.c for use with memory controller. Methinks we need to
rationalize these names/purposes. --lts

---

V1 -> V2 [lts]:
+ fix botched merge -- add back "get_page_unless_zero()"

From: Nick Piggin <[email protected]>
To: Linux Memory Management <[email protected]>
Subject: [patch 1/4] mm: move and rework isolate_lru_page
Date: Mon, 12 Mar 2007 07:38:44 +0100 (CET)

 include/linux/migrate.h |    3 ---
 mm/internal.h           |    2 ++
 mm/mempolicy.c          |    9 +++++++--
 mm/migrate.c            |   34 +++-------------------------------
 mm/vmscan.c             |   45 +++++++++++++++++++++++++++++++++++++++++++++
 5 files changed, 57 insertions(+), 36 deletions(-)
include/linux/migrate.h +0 -3
Index: linux-2.6.26-rc2-mm1/include/linux/migrate.h
===================================================================
@@ -25,7 +25,6 @@ static inline int vma_migratable(struct 
 	return 1;
 }
 
-extern int isolate_lru_page(struct page *p, struct list_head *pagelist);
 extern int putback_lru_pages(struct list_head *l);
 extern int migrate_page(struct address_space *,
 			struct page *, struct page *);
@@ -42,8 +41,6 @@ extern int migrate_vmas(struct mm_struct
 static inline int vma_migratable(struct vm_area_struct *vma)
 					{ return 0; }
 
-static inline int isolate_lru_page(struct page *p, struct list_head *list)
-					{ return -ENOSYS; }
 static inline int putback_lru_pages(struct list_head *l) { return 0; }
 static inline int migrate_pages(struct list_head *l, new_page_t x,
 		unsigned long private) { return -ENOSYS; }
mm/internal.h +2 -0
Index: linux-2.6.26-rc2-mm1/mm/internal.h
===================================================================
@@ -34,6 +34,8 @@ static inline void __put_page(struct pag
 	atomic_dec(&page->_count);
 }
 
+extern int isolate_lru_page(struct page *page);
+
 extern void __free_pages_bootmem(struct page *page, unsigned int order);
 
 /*
mm/migrate.c +3 -31
Index: linux-2.6.26-rc2-mm1/mm/migrate.c
===================================================================
@@ -37,36 +37,6 @@
 #define lru_to_page(_head) (list_entry((_head)->prev, struct page, lru))
 
 /*
- * Isolate one page from the LRU lists. If successful put it onto
- * the indicated list with elevated page count.
- *
- * Result:
- *  -EBUSY: page not on LRU list
- *  0: page removed from LRU list and added to the specified list.
- */
-int isolate_lru_page(struct page *page, struct list_head *pagelist)
-{
-	int ret = -EBUSY;
-
-	if (PageLRU(page)) {
-		struct zone *zone = page_zone(page);
-
-		spin_lock_irq(&zone->lru_lock);
-		if (PageLRU(page) && get_page_unless_zero(page)) {
-			ret = 0;
-			ClearPageLRU(page);
-			if (PageActive(page))
-				del_page_from_active_list(zone, page);
-			else
-				del_page_from_inactive_list(zone, page);
-			list_add_tail(&page->lru, pagelist);
-		}
-		spin_unlock_irq(&zone->lru_lock);
-	}
-	return ret;
-}
-
-/*
  * migrate_prep() needs to be called before we start compiling a list of pages
  * to be migrated using isolate_lru_page().
  */
@@ -895,7 +865,9 @@ static int do_move_pages(struct mm_struc
 				!migrate_all)
 			goto put_and_set;
 
-		err = isolate_lru_page(page, &pagelist);
+		err = isolate_lru_page(page);
+		if (!err)
+			list_add_tail(&page->lru, &pagelist);
 put_and_set:
 		/*
 		 * Either remove the duplicate refcount from
mm/vmscan.c +45 -0

51 lines not on this page · raw message

mm/mempolicy.c +7 -2
Index: linux-2.6.26-rc2-mm1/mm/mempolicy.c
===================================================================
@@ -93,6 +93,8 @@
 #include <asm/tlbflush.h>
 #include <asm/uaccess.h>
 
+#include "internal.h"
+
 /* Internal flags */
 #define MPOL_MF_DISCONTIG_OK (MPOL_MF_INTERNAL << 0)	/* Skip checks for continuous vmas */
 #define MPOL_MF_INVERT (MPOL_MF_INTERNAL << 1)		/* Invert check for nodemask */
@@ -758,8 +760,11 @@ static void migrate_page_add(struct page
 	/*
 	 * Avoid migrating a page that is shared with others.
 	 */
-	if ((flags & MPOL_MF_MOVE_ALL) || page_mapcount(page) == 1)
-		isolate_lru_page(page, pagelist);
+	if ((flags & MPOL_MF_MOVE_ALL) || page_mapcount(page) == 1) {
+		if (!isolate_lru_page(page)) {
+			list_add_tail(&page->lru, pagelist);
+		}
+	}
 }
 
 static struct page *new_node_page(struct page *page, unsigned long node, int **x)
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#2 lore raw

PATCH 2/12 Use an indexed array for LRU variables

In reply to Rik van Riel

From: Christoph Lameter <[email protected]>

Currently we are defining explicit variables for the inactive and active list. An indexed array can be more generic and avoid repeating similar code in several places in the reclaim code.

We are saving a few bytes in terms of code size:

Before:

text data bss dec hex filename
4097753 573120 4092484 8763357 85b7dd vmlinux

After:

text data bss dec hex filename
4097729 573120 4092484 8763333 85b7c5 vmlinux

Having an easy way to add new lru lists may ease future work on the reclaim code.

---
V3 [riel]: memcontrol LRU arrayification

V1 -> V2 [lts]:
+ Remove extraneous __dec_zone_state(zone, NR_ACTIVE) pointed out by Mel G.

 include/linux/memcontrol.h |   17 +-----
 include/linux/mm_inline.h  |   33 ++++++++----
 include/linux/mmzone.h     |   17 ++++--
 mm/memcontrol.c            |  115 ++++++++++++++++---------------------------
 mm/page_alloc.c            |    9 +--
 mm/swap.c                  |    2 
 mm/vmscan.c                |  120 +++++++++++++++++++++------------------------
 mm/vmstat.c                |    3 -
 8 files changed, 146 insertions(+), 170 deletions(-)
include/linux/mmzone.h +11 -6
Index: linux-2.6.26-rc2-mm1/include/linux/mmzone.h
===================================================================
@@ -81,8 +81,8 @@ struct zone_padding {
 enum zone_stat_item {
 	/* First 128 byte cacheline (assuming 64 bit words) */
 	NR_FREE_PAGES,
-	NR_INACTIVE,
-	NR_ACTIVE,
+	NR_INACTIVE,	/* must match order of LRU_[IN]ACTIVE */
+	NR_ACTIVE,	/*  "     "     "   "       "         */
 	NR_ANON_PAGES,	/* Mapped anonymous pages */
 	NR_FILE_MAPPED,	/* pagecache pages mapped into pagetables.
 			   only modified from process context */
@@ -107,6 +107,13 @@ enum zone_stat_item {
 #endif
 	NR_VM_ZONE_STAT_ITEMS };
 
+enum lru_list {
+	LRU_INACTIVE,	/* must match order of NR_[IN]ACTIVE */
+	LRU_ACTIVE,	/*  "     "     "   "       "        */
+	NR_LRU_LISTS };
+
+#define for_each_lru(l) for (l = 0; l < NR_LRU_LISTS; l++)
+
 struct per_cpu_pages {
 	int count;		/* number of pages in the list */
 	int high;		/* high watermark, emptying needed */
@@ -251,10 +258,8 @@ struct zone {
 
 	/* Fields commonly accessed by the page reclaim scanner */
 	spinlock_t		lru_lock;	
-	struct list_head	active_list;
-	struct list_head	inactive_list;
-	unsigned long		nr_scan_active;
-	unsigned long		nr_scan_inactive;
+	struct list_head	list[NR_LRU_LISTS];
+	unsigned long		nr_scan[NR_LRU_LISTS];
 	unsigned long		pages_scanned;	   /* since last reclaim */
 	unsigned long		flags;		   /* zone flags, see below */
 
include/linux/mm_inline.h +22 -11
Index: linux-2.6.26-rc2-mm1/include/linux/mm_inline.h
===================================================================
@@ -1,40 +1,51 @@
 static inline void
+add_page_to_lru_list(struct zone *zone, struct page *page, enum lru_list l)
+{
+	list_add(&page->lru, &zone->list[l]);
+	__inc_zone_state(zone, NR_INACTIVE + l);
+}
+
+static inline void
+del_page_from_lru_list(struct zone *zone, struct page *page, enum lru_list l)
+{
+	list_del(&page->lru);
+	__dec_zone_state(zone, NR_INACTIVE + l);
+}
+
+static inline void
 add_page_to_active_list(struct zone *zone, struct page *page)
 {
-	list_add(&page->lru, &zone->active_list);
-	__inc_zone_state(zone, NR_ACTIVE);
+	add_page_to_lru_list(zone, page, LRU_ACTIVE);
 }
 
 static inline void
 add_page_to_inactive_list(struct zone *zone, struct page *page)
 {
-	list_add(&page->lru, &zone->inactive_list);
-	__inc_zone_state(zone, NR_INACTIVE);
+	add_page_to_lru_list(zone, page, LRU_INACTIVE);
 }
 
 static inline void
 del_page_from_active_list(struct zone *zone, struct page *page)
 {
-	list_del(&page->lru);
-	__dec_zone_state(zone, NR_ACTIVE);
+	del_page_from_lru_list(zone, page, LRU_ACTIVE);
 }
 
 static inline void
 del_page_from_inactive_list(struct zone *zone, struct page *page)
 {
-	list_del(&page->lru);
-	__dec_zone_state(zone, NR_INACTIVE);
+	del_page_from_lru_list(zone, page, LRU_INACTIVE);
 }
 
 static inline void
 del_page_from_lru(struct zone *zone, struct page *page)
 {
+	enum lru_list l = LRU_INACTIVE;
+
 	list_del(&page->lru);
 	if (PageActive(page)) {
 		__ClearPageActive(page);
-		__dec_zone_state(zone, NR_ACTIVE);
-	} else {
-		__dec_zone_state(zone, NR_INACTIVE);
+		l = LRU_ACTIVE;
 	}
+	__dec_zone_state(zone, NR_INACTIVE + l);
 }
 
mm/page_alloc.c +5 -4
Index: linux-2.6.26-rc2-mm1/mm/page_alloc.c
===================================================================
@@ -3444,6 +3444,7 @@ static void __paginginit free_area_init_
 	for (j = 0; j < MAX_NR_ZONES; j++) {
 		struct zone *zone = pgdat->node_zones + j;
 		unsigned long size, realsize, memmap_pages;
+		enum lru_list l;
 
 		size = zone_spanned_pages_in_node(nid, j, zones_size);
 		realsize = size - zone_absent_pages_in_node(nid, j,
@@ -3494,10 +3495,10 @@ static void __paginginit free_area_init_
 		zone->prev_priority = DEF_PRIORITY;
 
 		zone_pcp_init(zone);
-		INIT_LIST_HEAD(&zone->active_list);
-		INIT_LIST_HEAD(&zone->inactive_list);
-		zone->nr_scan_active = 0;
-		zone->nr_scan_inactive = 0;
+		for_each_lru(l) {
+			INIT_LIST_HEAD(&zone->list[l]);
+			zone->nr_scan[l] = 0;
+		}
 		zap_zone_vm_stats(zone);
 		zone->flags = 0;
 		if (!size)
mm/swap.c +1 -1
Index: linux-2.6.26-rc2-mm1/mm/swap.c
===================================================================
@@ -117,7 +117,7 @@ static void pagevec_move_tail(struct pag
 			spin_lock(&zone->lru_lock);
 		}
 		if (PageLRU(page) && !PageActive(page)) {
-			list_move_tail(&page->lru, &zone->inactive_list);
+			list_move_tail(&page->lru, &zone->list[LRU_INACTIVE]);
 			pgmoved++;
 		}
 	}
mm/vmscan.c +57 -63

198 lines not on this page · raw message

mm/vmstat.c +2 -1
Index: linux-2.6.26-rc2-mm1/mm/vmstat.c
===================================================================
@@ -772,7 +772,8 @@ static void zoneinfo_show_print(struct s
 		   zone->pages_low,
 		   zone->pages_high,
 		   zone->pages_scanned,
-		   zone->nr_scan_active, zone->nr_scan_inactive,
+		   zone->nr_scan[LRU_ACTIVE],
+		   zone->nr_scan[LRU_INACTIVE],
 		   zone->spanned_pages,
 		   zone->present_pages);
 
include/linux/memcontrol.h +5 -12
Index: linux-2.6.26-rc2-mm1/include/linux/memcontrol.h
===================================================================
@@ -67,10 +67,8 @@ extern void mem_cgroup_note_reclaim_prio
 extern void mem_cgroup_record_reclaim_priority(struct mem_cgroup *mem,
 							int priority);
 
-extern long mem_cgroup_calc_reclaim_active(struct mem_cgroup *mem,
-				struct zone *zone, int priority);
-extern long mem_cgroup_calc_reclaim_inactive(struct mem_cgroup *mem,
-				struct zone *zone, int priority);
+extern long mem_cgroup_calc_reclaim(struct mem_cgroup *mem, struct zone *zone,
+					int priority, enum lru_list lru);
 
 #else /* CONFIG_CGROUP_MEM_RES_CTLR */
 static inline void page_reset_bad_cgroup(struct page *page)
@@ -152,14 +150,9 @@ static inline void mem_cgroup_record_rec
 {
 }
 
-static inline long mem_cgroup_calc_reclaim_active(struct mem_cgroup *mem,
-					struct zone *zone, int priority)
-{
-	return 0;
-}
-
-static inline long mem_cgroup_calc_reclaim_inactive(struct mem_cgroup *mem,
-					struct zone *zone, int priority)
+static inline long mem_cgroup_calc_reclaim(struct mem_cgroup *mem,
+					struct zone *zone, int priority,
+					enum lru_list lru)
 {
 	return 0;
 }
mm/memcontrol.c +43 -72

228 lines not on this page · raw message

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#3 lore raw

PATCH 3/12 use an array for the LRU pagevecs

In reply to Rik van Riel

From: KOSAKI Motohiro <[email protected]>

Turn the pagevecs into an array just like the LRUs. This significantly cleans up the source code and reduces the size of the kernel by about 13kB after all the LRU lists have been created further down in the split VM patch series.

---
 include/linux/mmzone.h  |   13 +++++-
 include/linux/pagevec.h |   13 +++++-
 include/linux/swap.h    |   18 ++++++++-
 mm/migrate.c            |   11 -----
 mm/swap.c               |   96 ++++++++++++++++++++++--------------------------
 5 files changed, 83 insertions(+), 68 deletions(-)
include/linux/mmzone.h +11 -2
Index: linux-2.6.26-rc2-mm1/include/linux/mmzone.h
===================================================================
@@ -107,13 +107,22 @@ enum zone_stat_item {
 #endif
 	NR_VM_ZONE_STAT_ITEMS };
 
+#define LRU_BASE 0
+
 enum lru_list {
-	LRU_INACTIVE,	/* must match order of NR_[IN]ACTIVE */
-	LRU_ACTIVE,	/*  "     "     "   "       "        */
+	LRU_INACTIVE = LRU_BASE,	/* must match order of NR_[IN]ACTIVE */
+	LRU_ACTIVE,			/*  "     "     "   "       "        */
 	NR_LRU_LISTS };
 
 #define for_each_lru(l) for (l = 0; l < NR_LRU_LISTS; l++)
 
+static inline int is_active_lru(enum lru_list l)
+{
+	return (l == LRU_ACTIVE);
+}
+
+enum lru_list page_lru(struct page *page);
+
 struct per_cpu_pages {
 	int count;		/* number of pages in the list */
 	int high;		/* high watermark, emptying needed */
mm/swap.c +44 -52

149 lines not on this page · raw message

include/linux/pagevec.h +11 -2
Index: linux-2.6.26-rc2-mm1/include/linux/pagevec.h
===================================================================
@@ -23,8 +23,7 @@ struct pagevec {
 void __pagevec_release(struct pagevec *pvec);
 void __pagevec_release_nonlru(struct pagevec *pvec);
 void __pagevec_free(struct pagevec *pvec);
-void __pagevec_lru_add(struct pagevec *pvec);
-void __pagevec_lru_add_active(struct pagevec *pvec);
+void ____pagevec_lru_add(struct pagevec *pvec, enum lru_list lru);
 void pagevec_strip(struct pagevec *pvec);
 unsigned pagevec_lookup(struct pagevec *pvec, struct address_space *mapping,
 		pgoff_t start, unsigned nr_pages);
@@ -81,6 +80,16 @@ static inline void pagevec_free(struct p
 		__pagevec_free(pvec);
 }
 
+static inline void __pagevec_lru_add(struct pagevec *pvec)
+{
+	____pagevec_lru_add(pvec, LRU_INACTIVE);
+}
+
+static inline void __pagevec_lru_add_active(struct pagevec *pvec)
+{
+	____pagevec_lru_add(pvec, LRU_ACTIVE);
+}
+
 static inline void pagevec_lru_add(struct pagevec *pvec)
 {
 	if (pagevec_count(pvec))
include/linux/swap.h +16 -2
Index: linux-2.6.26-rc2-mm1/include/linux/swap.h
===================================================================
@@ -171,8 +171,8 @@ extern unsigned int nr_free_pagecache_pa
 
 
 /* linux/mm/swap.c */
-extern void lru_cache_add(struct page *);
-extern void lru_cache_add_active(struct page *);
+extern void __lru_cache_add(struct page *, enum lru_list lru);
+extern void lru_cache_add_lru(struct page *, enum lru_list lru);
 extern void activate_page(struct page *);
 extern void mark_page_accessed(struct page *);
 extern void lru_add_drain(void);
@@ -180,6 +180,20 @@ extern int lru_add_drain_all(void);
 extern void rotate_reclaimable_page(struct page *page);
 extern void swap_setup(void);
 
+/**
+ * lru_cache_add: add a page to the page lists
+ * @page: the page to add
+ */
+static inline void lru_cache_add(struct page *page)
+{
+	__lru_cache_add(page, LRU_INACTIVE);
+}
+
+static inline void lru_cache_add_active(struct page *page)
+{
+	__lru_cache_add(page, LRU_ACTIVE);
+}
+
 /* linux/mm/vmscan.c */
 extern unsigned long try_to_free_pages(struct zonelist *zonelist, int order,
 					gfp_t gfp_mask);
mm/migrate.c +1 -10
Index: linux-2.6.26-rc2-mm1/mm/migrate.c
===================================================================
@@ -55,16 +55,7 @@ int migrate_prep(void)
 
 static inline void move_to_lru(struct page *page)
 {
-	if (PageActive(page)) {
-		/*
-		 * lru_cache_add_active checks that
-		 * the PG_active bit is off.
-		 */
-		ClearPageActive(page);
-		lru_cache_add_active(page);
-	} else {
-		lru_cache_add(page);
-	}
+	lru_cache_add_lru(page, page_lru(page));
 	put_page(page);
 }
 
Signature · 1 line
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#4 lore raw

PATCH 4/12 free swap space on swap-in/activation

In reply to Rik van Riel

From: Rik van Riel <[email protected]>

Free swap cache entries when swapping in pages if vm_swap_full() [swap space > 1/2 used]. Uses new pagevec to reduce pressure on locks.

---
 include/linux/pagevec.h |    1 +
 include/linux/swap.h    |    6 ++++++
 mm/swap.c               |   18 ++++++++++++++++++
 mm/swapfile.c           |   25 ++++++++++++++++++++++---
 mm/vmscan.c             |    7 +++++++
 5 files changed, 54 insertions(+), 3 deletions(-)
mm/vmscan.c +7 -0
Index: linux-2.6.26-rc2-mm1/mm/vmscan.c
===================================================================
@@ -619,6 +619,9 @@ free_it:
 		continue;
 
 activate_locked:
+		/* Not a candidate for swapping, so reclaim swap space. */
+		if (PageSwapCache(page) && vm_swap_full())
+			remove_exclusive_swap_page_ref(page);
 		SetPageActive(page);
 		pgactivate++;
 keep_locked:
@@ -1203,6 +1206,8 @@ static void shrink_active_list(unsigned 
 			__mod_zone_page_state(zone, NR_ACTIVE, pgmoved);
 			pgmoved = 0;
 			spin_unlock_irq(&zone->lru_lock);
+			if (vm_swap_full())
+				pagevec_swap_free(&pvec);
 			__pagevec_release(&pvec);
 			spin_lock_irq(&zone->lru_lock);
 		}
@@ -1212,6 +1217,8 @@ static void shrink_active_list(unsigned 
 	__count_zone_vm_events(PGREFILL, zone, pgscanned);
 	__count_vm_events(PGDEACTIVATE, pgdeactivate);
 	spin_unlock_irq(&zone->lru_lock);
+	if (vm_swap_full())
+		pagevec_swap_free(&pvec);
 
 	pagevec_release(&pvec);
 }
mm/swap.c +18 -0
Index: linux-2.6.26-rc2-mm1/mm/swap.c
===================================================================
@@ -443,6 +443,24 @@ void pagevec_strip(struct pagevec *pvec)
 	}
 }
 
+/*
+ * Try to free swap space from the pages in a pagevec
+ */
+void pagevec_swap_free(struct pagevec *pvec)
+{
+	int i;
+
+	for (i = 0; i < pagevec_count(pvec); i++) {
+		struct page *page = pvec->pages[i];
+
+		if (PageSwapCache(page) && !TestSetPageLocked(page)) {
+			if (PageSwapCache(page))
+				remove_exclusive_swap_page_ref(page);
+			unlock_page(page);
+		}
+	}
+}
+
 /**
  * pagevec_lookup - gang pagecache lookup
  * @pvec:	Where the resulting pages are placed
include/linux/pagevec.h +1 -0
Index: linux-2.6.26-rc2-mm1/include/linux/pagevec.h
===================================================================
@@ -25,6 +25,7 @@ void __pagevec_release_nonlru(struct pag
 void __pagevec_free(struct pagevec *pvec);
 void ____pagevec_lru_add(struct pagevec *pvec, enum lru_list lru);
 void pagevec_strip(struct pagevec *pvec);
+void pagevec_swap_free(struct pagevec *pvec);
 unsigned pagevec_lookup(struct pagevec *pvec, struct address_space *mapping,
 		pgoff_t start, unsigned nr_pages);
 unsigned pagevec_lookup_tag(struct pagevec *pvec,
include/linux/swap.h +6 -0
Index: linux-2.6.26-rc2-mm1/include/linux/swap.h
===================================================================
@@ -265,6 +265,7 @@ extern sector_t swapdev_block(int, pgoff
 extern struct swap_info_struct *get_swap_info_struct(unsigned);
 extern int can_share_swap_page(struct page *);
 extern int remove_exclusive_swap_page(struct page *);
+extern int remove_exclusive_swap_page_ref(struct page *);
 struct backing_dev_info;
 
 /* linux/mm/thrash.c */
@@ -353,6 +354,11 @@ static inline int remove_exclusive_swap_
 	return 0;
 }
 
+static inline int remove_exclusive_swap_page_ref(struct page *page)
+{
+	return 0;
+}
+
 static inline swp_entry_t get_swap_page(void)
 {
 	swp_entry_t entry;
mm/swapfile.c +22 -3
Index: linux-2.6.26-rc2-mm1/mm/swapfile.c
===================================================================
@@ -343,7 +343,7 @@ int can_share_swap_page(struct page *pag
  * Work out if there are any other processes sharing this
  * swap cache page. Free it if you can. Return success.
  */
-int remove_exclusive_swap_page(struct page *page)
+static int remove_exclusive_swap_page_count(struct page *page, int count)
 {
 	int retval;
 	struct swap_info_struct * p;
@@ -356,7 +356,7 @@ int remove_exclusive_swap_page(struct pa
 		return 0;
 	if (PageWriteback(page))
 		return 0;
-	if (page_count(page) != 2) /* 2: us + cache */
+	if (page_count(page) != count) /* us + cache + ptes */
 		return 0;
 
 	entry.val = page_private(page);
@@ -369,7 +369,7 @@ int remove_exclusive_swap_page(struct pa
 	if (p->swap_map[swp_offset(entry)] == 1) {
 		/* Recheck the page count with the swapcache lock held.. */
 		write_lock_irq(&swapper_space.tree_lock);
-		if ((page_count(page) == 2) && !PageWriteback(page)) {
+		if ((page_count(page) == count) && !PageWriteback(page)) {
 			__delete_from_swap_cache(page);
 			SetPageDirty(page);
 			retval = 1;
@@ -387,6 +387,25 @@ int remove_exclusive_swap_page(struct pa
 }
 
 /*
+ * Most of the time the page should have two references: one for the
+ * process and one for the swap cache.
+ */
+int remove_exclusive_swap_page(struct page *page)
+{
+	return remove_exclusive_swap_page_count(page, 2);
+}
+
+/*
+ * The pageout code holds an extra reference to the page.  That raises
+ * the reference count to test for to 2 for a page that is only in the
+ * swap cache plus 1 for each process that maps the page.
+ */
+int remove_exclusive_swap_page_ref(struct page *page)
+{
+	return remove_exclusive_swap_page_count(page, 2 + page_mapcount(page));
+}
+
+/*
  * Free the swap entry like above, but also try to
  * free the page cache entry if it is the last user.
  */
Signature · 1 line
All Rights Reversed
#5 lore raw

PATCH 5/12 define page_file_cache() function

In reply to Rik van Riel

From: Rik van Riel <[email protected]>

Define page_file_cache() function to answer the question:
is page backed by a file?

Originally part of Rik van Riel's split-lru patch. Extracted to make available for other, independent reclaim patches.

Moved inline function to linux/mm_inline.h where it will be needed by subsequent "split LRU" and "noreclaim" patches.

Unfortunately this needs to use a page flag, since the PG_swapbacked state needs to be preserved all the way to the point where the page is last removed from the LRU. Trying to derive the status from other info in the page resulted in wrong VM statistics in earlier split VM patchsets.

---
 include/linux/mm_inline.h  |   24 ++++++++++++++++++++++++
 include/linux/page-flags.h |    2 ++
 mm/memory.c                |    3 +++
 mm/migrate.c               |    2 ++
 mm/page_alloc.c            |    4 ++++
 mm/shmem.c                 |    1 +
 mm/swap_state.c            |    3 +++
 7 files changed, 39 insertions(+)
include/linux/mm_inline.h +24 -0
Index: linux-2.6.26-rc2-mm1/include/linux/mm_inline.h
===================================================================
@@ -1,3 +1,26 @@
+#ifndef LINUX_MM_INLINE_H
+#define LINUX_MM_INLINE_H
+
+/**
+ * page_file_cache - should the page be on a file LRU or anon LRU?
+ * @page: the page to test
+ *
+ * Returns !0 if @page is page cache page backed by a regular filesystem,
+ * or 0 if @page is anonymous, tmpfs or otherwise ram or swap backed.
+ *
+ * We would like to get this info without a page flag, but the state
+ * needs to survive until the page is last deleted from the LRU, which
+ * could be as far down as __page_cache_release.
+ */
+static inline int page_file_cache(struct page *page)
+{
+	if (PageSwapBacked(page))
+		return 0;
+
+	/* The page is page cache backed by a normal filesystem. */
+	return 2;
+}
+
 static inline void
 add_page_to_lru_list(struct zone *zone, struct page *page, enum lru_list l)
 {
@@ -49,3 +72,4 @@ del_page_from_lru(struct zone *zone, str
 	__dec_zone_state(zone, NR_INACTIVE + l);
 }
 
+#endif
mm/shmem.c +1 -0
Index: linux-2.6.26-rc2-mm1/mm/shmem.c
===================================================================
@@ -1378,6 +1378,7 @@ repeat:
 				goto failed;
 			}
 
+			SetPageSwapBacked(filepage);
 			spin_lock(&info->lock);
 			entry = shmem_swp_alloc(info, idx, sgp);
 			if (IS_ERR(entry))
include/linux/page-flags.h +2 -0
Index: linux-2.6.26-rc2-mm1/include/linux/page-flags.h
===================================================================
@@ -93,6 +93,7 @@ enum pageflags {
 	PG_mappedtodisk,	/* Has blocks allocated on-disk */
 	PG_reclaim,		/* To be reclaimed asap */
 	PG_buddy,		/* Page is free, on buddy lists */
+	PG_swapbacked,		/* Page is backed by RAM/swap */
 #ifdef CONFIG_IA64_UNCACHED_ALLOCATOR
 	PG_uncached,		/* Page has been mapped as uncached */
 #endif
@@ -160,6 +161,7 @@ PAGEFLAG(Pinned, owner_priv_1) TESTSCFLA
 PAGEFLAG(Reserved, reserved) __CLEARPAGEFLAG(Reserved, reserved)
 PAGEFLAG(Private, private) __CLEARPAGEFLAG(Private, private)
 	__SETPAGEFLAG(Private, private)
+PAGEFLAG(SwapBacked, swapbacked) __CLEARPAGEFLAG(SwapBacked, swapbacked)
 
 /*
  * Only test-and-set exist for PG_writeback.  The unconditional operators are
mm/memory.c +3 -0
Index: linux-2.6.26-rc2-mm1/mm/memory.c
===================================================================
@@ -1765,6 +1765,7 @@ gotten:
 		ptep_clear_flush(vma, address, page_table);
 		set_pte_at(mm, address, page_table, entry);
 		update_mmu_cache(vma, address, entry);
+		SetPageSwapBacked(new_page);
 		lru_cache_add_active(new_page);
 		page_add_new_anon_rmap(new_page, vma, address);
 
@@ -2233,6 +2234,7 @@ static int do_anonymous_page(struct mm_s
 	if (!pte_none(*page_table))
 		goto release;
 	inc_mm_counter(mm, anon_rss);
+	SetPageSwapBacked(page);
 	lru_cache_add_active(page);
 	page_add_new_anon_rmap(page, vma, address);
 	set_pte_at(mm, address, page_table, entry);
@@ -2374,6 +2376,7 @@ static int __do_fault(struct mm_struct *
 		set_pte_at(mm, address, page_table, entry);
 		if (anon) {
                         inc_mm_counter(mm, anon_rss);
+			SetPageSwapBacked(page);
                         lru_cache_add_active(page);
                         page_add_new_anon_rmap(page, vma, address);
 		} else {
mm/swap_state.c +3 -0
Index: linux-2.6.26-rc2-mm1/mm/swap_state.c
===================================================================
@@ -74,6 +74,7 @@ int add_to_swap_cache(struct page *page,
 	BUG_ON(!PageLocked(page));
 	BUG_ON(PageSwapCache(page));
 	BUG_ON(PagePrivate(page));
+	BUG_ON(!PageSwapBacked(page));
 	error = radix_tree_preload(gfp_mask);
 	if (!error) {
 		write_lock_irq(&swapper_space.tree_lock);
@@ -295,6 +296,7 @@ struct page *read_swap_cache_async(swp_e
 		 * May fail (-ENOMEM) if radix-tree node allocation failed.
 		 */
 		SetPageLocked(new_page);
+		SetPageSwapBacked(new_page);
 		err = add_to_swap_cache(new_page, entry, gfp_mask & GFP_KERNEL);
 		if (!err) {
 			/*
@@ -304,6 +306,7 @@ struct page *read_swap_cache_async(swp_e
 			swap_readpage(NULL, new_page);
 			return new_page;
 		}
+		ClearPageSwapBacked(new_page);
 		ClearPageLocked(new_page);
 		swap_free(entry);
 	} while (err != -ENOMEM);
mm/migrate.c +2 -0
Index: linux-2.6.26-rc2-mm1/mm/migrate.c
===================================================================
@@ -558,6 +558,8 @@ static int move_to_new_page(struct page 
 	/* Prepare mapping for the new page.*/
 	newpage->index = page->index;
 	newpage->mapping = page->mapping;
+	if (PageSwapBacked(page))
+		SetPageSwapBacked(newpage);
 
 	mapping = page_mapping(page);
 	if (!mapping)
mm/page_alloc.c +4 -0
Index: linux-2.6.26-rc2-mm1/mm/page_alloc.c
===================================================================
@@ -261,6 +261,7 @@ static void bad_page(struct page *page)
 			1 << PG_slab    |
 			1 << PG_swapcache |
 			1 << PG_writeback |
+			1 << PG_swapbacked |
 			1 << PG_buddy );
 	set_page_count(page, 0);
 	reset_page_mapcount(page);
@@ -494,6 +495,8 @@ static inline int free_pages_check(struc
 		bad_page(page);
 	if (PageDirty(page))
 		__ClearPageDirty(page);
+	if (PageSwapBacked(page))
+		__ClearPageSwapBacked(page);
 	/*
 	 * For now, we report if PG_reserved was found set, but do not
 	 * clear it, and do not free the page.  But we shall soon need
@@ -644,6 +647,7 @@ static int prep_new_page(struct page *pa
 			1 << PG_swapcache |
 			1 << PG_writeback |
 			1 << PG_reserved |
+			1 << PG_swapbacked |
 			1 << PG_buddy ))))
 		bad_page(page);
 
Signature · 1 line
All Rights Reversed
#6 lore raw

PATCH 6/12 split LRU lists into anon & file sets

In reply to Rik van Riel

From: Rik van Riel <[email protected]>

Split the LRU lists in two, one set for pages that are backed by real file systems ("file") and one for pages that are backed by memory and swap ("anon"). The latter includes tmpfs.

Eventually mlocked pages will be taken off the LRUs alltogether. A patch for that already exists and just needs to be integrated into this series.

This patch mostly has the infrastructure and a basic policy to balance how much we scan the anon lists and how much we scan the file lists. The big policy changes are in separate patches.

---
 drivers/base/node.c        |   56 +++--
 fs/cifs/file.c             |    4 
 fs/nfs/dir.c               |    2 
 fs/ntfs/file.c             |    4 
 fs/proc/proc_misc.c        |   81 +++++---
 fs/ramfs/file-nommu.c      |    4 
 include/linux/memcontrol.h |    2 
 include/linux/mm_inline.h  |   55 ++++-
 include/linux/mmzone.h     |   33 ++-
 include/linux/pagevec.h    |   29 ++-
 include/linux/swap.h       |   20 +-
 include/linux/vmstat.h     |   10 +
 mm/filemap.c               |    9 
 mm/memcontrol.c            |   73 +++----
 mm/memory.c                |    6 
 mm/page-writeback.c        |    8 
 mm/page_alloc.c            |   24 +-
 mm/readahead.c             |    2 
 mm/swap.c                  |   12 -
 mm/swap_state.c            |    2 
 mm/vmscan.c                |  428 ++++++++++++++++++++-------------------------
 mm/vmstat.c                |   14 -
 22 files changed, 491 insertions(+), 387 deletions(-)
fs/proc/proc_misc.c +49 -32
Index: linux-2.6.26-rc2-mm1/fs/proc/proc_misc.c
===================================================================
@@ -132,6 +132,10 @@ static int meminfo_read_proc(char *page,
 	unsigned long allowed;
 	struct vmalloc_info vmi;
 	long cached;
+	unsigned long inactive_anon;
+	unsigned long active_anon;
+	unsigned long inactive_file;
+	unsigned long active_file;
 
 /*
  * display in kilobytes.
@@ -150,48 +154,61 @@ static int meminfo_read_proc(char *page,
 
 	get_vmalloc_info(&vmi);
 
+	inactive_anon = global_page_state(NR_INACTIVE_ANON);
+	active_anon   = global_page_state(NR_ACTIVE_ANON);
+	inactive_file = global_page_state(NR_INACTIVE_FILE);
+	active_file   = global_page_state(NR_ACTIVE_FILE);
+
 	/*
 	 * Tagged format, for easy grepping and expansion.
 	 */
 	len = sprintf(page,
-		"MemTotal:     %8lu kB\n"
-		"MemFree:      %8lu kB\n"
-		"Buffers:      %8lu kB\n"
-		"Cached:       %8lu kB\n"
-		"SwapCached:   %8lu kB\n"
-		"Active:       %8lu kB\n"
-		"Inactive:     %8lu kB\n"
+		"MemTotal:       %8lu kB\n"
+		"MemFree:        %8lu kB\n"
+		"Buffers:        %8lu kB\n"
+		"Cached:         %8lu kB\n"
+		"SwapCached:     %8lu kB\n"
+		"Active:         %8lu kB\n"
+		"Inactive:       %8lu kB\n"
+		"Active(anon):   %8lu kB\n"
+		"Inactive(anon): %8lu kB\n"
+		"Active(file):   %8lu kB\n"
+		"Inactive(file): %8lu kB\n"
 #ifdef CONFIG_HIGHMEM
-		"HighTotal:    %8lu kB\n"
-		"HighFree:     %8lu kB\n"
-		"LowTotal:     %8lu kB\n"
-		"LowFree:      %8lu kB\n"
-#endif
-		"SwapTotal:    %8lu kB\n"
-		"SwapFree:     %8lu kB\n"
-		"Dirty:        %8lu kB\n"
-		"Writeback:    %8lu kB\n"
-		"AnonPages:    %8lu kB\n"
-		"Mapped:       %8lu kB\n"
-		"Slab:         %8lu kB\n"
-		"SReclaimable: %8lu kB\n"
-		"SUnreclaim:   %8lu kB\n"
-		"PageTables:   %8lu kB\n"
-		"NFS_Unstable: %8lu kB\n"
-		"Bounce:       %8lu kB\n"
-		"WritebackTmp: %8lu kB\n"
-		"CommitLimit:  %8lu kB\n"
-		"Committed_AS: %8lu kB\n"
-		"VmallocTotal: %8lu kB\n"
-		"VmallocUsed:  %8lu kB\n"
-		"VmallocChunk: %8lu kB\n",
+		"HighTotal:      %8lu kB\n"
+		"HighFree:       %8lu kB\n"
+		"LowTotal:       %8lu kB\n"
+		"LowFree:        %8lu kB\n"
+#endif
+		"SwapTotal:      %8lu kB\n"
+		"SwapFree:       %8lu kB\n"
+		"Dirty:          %8lu kB\n"
+		"Writeback:      %8lu kB\n"
+		"AnonPages:      %8lu kB\n"
+		"Mapped:         %8lu kB\n"
+		"Slab:           %8lu kB\n"
+		"SReclaimable:   %8lu kB\n"
+		"SUnreclaim:     %8lu kB\n"
+		"PageTables:     %8lu kB\n"
+		"NFS_Unstable:   %8lu kB\n"
+		"Bounce:         %8lu kB\n"
+		"WritebackTmp:   %8lu kB\n"
+		"CommitLimit:    %8lu kB\n"
+		"Committed_AS:   %8lu kB\n"
+		"VmallocTotal:   %8lu kB\n"
+		"VmallocUsed:    %8lu kB\n"
+		"VmallocChunk:   %8lu kB\n",
 		K(i.totalram),
 		K(i.freeram),
 		K(i.bufferram),
 		K(cached),
 		K(total_swapcache_pages),
-		K(global_page_state(NR_ACTIVE)),
-		K(global_page_state(NR_INACTIVE)),
+		K(active_anon   + active_file),
+		K(inactive_anon + inactive_file),
+		K(active_anon),
+		K(inactive_anon),
+		K(active_file),
+		K(inactive_file),
 #ifdef CONFIG_HIGHMEM
 		K(i.totalhigh),
 		K(i.freehigh),
fs/cifs/file.c +2 -2
Index: linux-2.6.26-rc2-mm1/fs/cifs/file.c
===================================================================
@@ -1778,7 +1778,7 @@ static void cifs_copy_cache_pages(struct
 		SetPageUptodate(page);
 		unlock_page(page);
 		if (!pagevec_add(plru_pvec, page))
-			__pagevec_lru_add(plru_pvec);
+			__pagevec_lru_add_file(plru_pvec);
 		data += PAGE_CACHE_SIZE;
 	}
 	return;
@@ -1912,7 +1912,7 @@ static int cifs_readpages(struct file *f
 		bytes_read = 0;
 	}
 
-	pagevec_lru_add(&lru_pvec);
+	pagevec_lru_add_file(&lru_pvec);
 
 /* need to free smb_read_data buf before exit */
 	if (smb_read_data) {
fs/ntfs/file.c +2 -2
Index: linux-2.6.26-rc2-mm1/fs/ntfs/file.c
===================================================================
@@ -439,7 +439,7 @@ static inline int __ntfs_grab_cache_page
 			pages[nr] = *cached_page;
 			page_cache_get(*cached_page);
 			if (unlikely(!pagevec_add(lru_pvec, *cached_page)))
-				__pagevec_lru_add(lru_pvec);
+				__pagevec_lru_add_file(lru_pvec);
 			*cached_page = NULL;
 		}
 		index++;
@@ -2084,7 +2084,7 @@ err_out:
 						OSYNC_METADATA|OSYNC_DATA);
 		}
   	}
-	pagevec_lru_add(&lru_pvec);
+	pagevec_lru_add_file(&lru_pvec);
 	ntfs_debug("Done.  Returning %s (written 0x%lx, status %li).",
 			written ? "written" : "status", (unsigned long)written,
 			(long)status);
fs/nfs/dir.c +1 -1
Index: linux-2.6.26-rc2-mm1/fs/nfs/dir.c
===================================================================
@@ -1524,7 +1524,7 @@ static int nfs_symlink(struct inode *dir
 	if (!add_to_page_cache(page, dentry->d_inode->i_mapping, 0,
 							GFP_KERNEL)) {
 		pagevec_add(&lru_pvec, page);
-		pagevec_lru_add(&lru_pvec);
+		pagevec_lru_add_file(&lru_pvec);
 		SetPageUptodate(page);
 		unlock_page(page);
 	} else
fs/ramfs/file-nommu.c +2 -2
Index: linux-2.6.26-rc2-mm1/fs/ramfs/file-nommu.c
===================================================================
@@ -111,12 +111,12 @@ static int ramfs_nommu_expand_for_mappin
 			goto add_error;
 
 		if (!pagevec_add(&lru_pvec, page))
-			__pagevec_lru_add(&lru_pvec);
+			__pagevec_lru_add_file(&lru_pvec);
 
 		unlock_page(page);
 	}
 
-	pagevec_lru_add(&lru_pvec);
+	pagevec_lru_add_file(&lru_pvec);
 	return 0;
 
  fsize_exceeded:
drivers/base/node.c +33 -23

67 lines not on this page · raw message

mm/memory.c +3 -3
Index: linux-2.6.26-rc2-mm1/mm/memory.c
===================================================================
@@ -1766,7 +1766,7 @@ gotten:
 		set_pte_at(mm, address, page_table, entry);
 		update_mmu_cache(vma, address, entry);
 		SetPageSwapBacked(new_page);
-		lru_cache_add_active(new_page);
+		lru_cache_add_active_anon(new_page);
 		page_add_new_anon_rmap(new_page, vma, address);
 
 		/* Free the old page.. */
@@ -2235,7 +2235,7 @@ static int do_anonymous_page(struct mm_s
 		goto release;
 	inc_mm_counter(mm, anon_rss);
 	SetPageSwapBacked(page);
-	lru_cache_add_active(page);
+	lru_cache_add_active_anon(page);
 	page_add_new_anon_rmap(page, vma, address);
 	set_pte_at(mm, address, page_table, entry);
 
@@ -2377,7 +2377,7 @@ static int __do_fault(struct mm_struct *
 		if (anon) {
                         inc_mm_counter(mm, anon_rss);
 			SetPageSwapBacked(page);
-                        lru_cache_add_active(page);
+                        lru_cache_add_active_anon(page);
                         page_add_new_anon_rmap(page, vma, address);
 		} else {
 			inc_mm_counter(mm, file_rss);
mm/page_alloc.c +17 -7
Index: linux-2.6.26-rc2-mm1/mm/page_alloc.c
===================================================================
@@ -1908,10 +1908,13 @@ void show_free_areas(void)
 		}
 	}
 
-	printk("Active:%lu inactive:%lu dirty:%lu writeback:%lu unstable:%lu\n"
+	printk("Active_anon:%lu active_file:%lu inactive_anon%lu\n"
+		" inactive_file:%lu dirty:%lu writeback:%lu unstable:%lu\n"
 		" free:%lu slab:%lu mapped:%lu pagetables:%lu bounce:%lu\n",
-		global_page_state(NR_ACTIVE),
-		global_page_state(NR_INACTIVE),
+		global_page_state(NR_ACTIVE_ANON),
+		global_page_state(NR_ACTIVE_FILE),
+		global_page_state(NR_INACTIVE_ANON),
+		global_page_state(NR_INACTIVE_FILE),
 		global_page_state(NR_FILE_DIRTY),
 		global_page_state(NR_WRITEBACK),
 		global_page_state(NR_UNSTABLE_NFS),
@@ -1934,8 +1937,10 @@ void show_free_areas(void)
 			" min:%lukB"
 			" low:%lukB"
 			" high:%lukB"
-			" active:%lukB"
-			" inactive:%lukB"
+			" active_anon:%lukB"
+			" inactive_anon:%lukB"
+			" active_file:%lukB"
+			" inactive_file:%lukB"
 			" present:%lukB"
 			" pages_scanned:%lu"
 			" all_unreclaimable? %s"
@@ -1945,8 +1950,10 @@ void show_free_areas(void)
 			K(zone->pages_min),
 			K(zone->pages_low),
 			K(zone->pages_high),
-			K(zone_page_state(zone, NR_ACTIVE)),
-			K(zone_page_state(zone, NR_INACTIVE)),
+			K(zone_page_state(zone, NR_ACTIVE_ANON)),
+			K(zone_page_state(zone, NR_INACTIVE_ANON)),
+			K(zone_page_state(zone, NR_ACTIVE_FILE)),
+			K(zone_page_state(zone, NR_INACTIVE_FILE)),
 			K(zone->present_pages),
 			zone->pages_scanned,
 			(zone_is_all_unreclaimable(zone) ? "yes" : "no")
@@ -3503,6 +3510,9 @@ static void __paginginit free_area_init_
 			INIT_LIST_HEAD(&zone->list[l]);
 			zone->nr_scan[l] = 0;
 		}
+		zone->recent_rotated_anon = 0;
+		zone->recent_rotated_file = 0;
+//TODO recent_scanned_* ???
 		zap_zone_vm_stats(zone);
 		zone->flags = 0;
 		if (!size)
mm/swap.c +9 -3
Index: linux-2.6.26-rc2-mm1/mm/swap.c
===================================================================
@@ -108,6 +108,7 @@ enum lru_list page_lru(struct page *page
 
 	if (PageActive(page))
 		lru += LRU_ACTIVE;
+	lru += page_file_cache(page);
 
 	return lru;
 }
@@ -133,7 +134,8 @@ static void pagevec_move_tail(struct pag
 			spin_lock(&zone->lru_lock);
 		}
 		if (PageLRU(page) && !PageActive(page)) {
-			list_move_tail(&page->lru, &zone->list[LRU_INACTIVE]);
+			int lru = page_file_cache(page);
+			list_move_tail(&page->lru, &zone->list[lru]);
 			pgmoved++;
 		}
 	}
@@ -174,9 +176,13 @@ void activate_page(struct page *page)
 
 	spin_lock_irq(&zone->lru_lock);
 	if (PageLRU(page) && !PageActive(page)) {
-		del_page_from_inactive_list(zone, page);
+		int lru = LRU_BASE;
+		lru += page_file_cache(page);
+		del_page_from_lru_list(zone, page, lru);
+
 		SetPageActive(page);
-		add_page_to_active_list(zone, page);
+		lru += LRU_ACTIVE;
+		add_page_to_lru_list(zone, page, lru);
 		__count_vm_event(PGACTIVATE);
 		mem_cgroup_move_lists(page, true);
 	}
mm/readahead.c +1 -1
Index: linux-2.6.26-rc2-mm1/mm/readahead.c
===================================================================
@@ -229,7 +229,7 @@ int do_page_cache_readahead(struct addre
  */
 unsigned long max_sane_readahead(unsigned long nr)
 {
-	return min(nr, (node_page_state(numa_node_id(), NR_INACTIVE)
+	return min(nr, (node_page_state(numa_node_id(), NR_INACTIVE_FILE)
 		+ node_page_state(numa_node_id(), NR_FREE_PAGES)) / 2);
 }
 
mm/filemap.c +7 -2
Index: linux-2.6.26-rc2-mm1/mm/filemap.c
===================================================================
@@ -33,6 +33,7 @@
 #include <linux/cpuset.h>
 #include <linux/hardirq.h> /* for BUG_ON(!in_atomic()) only */
 #include <linux/memcontrol.h>
+#include <linux/mm_inline.h> /* for page_file_cache() */
 #include "internal.h"
 
 /*
@@ -489,8 +490,12 @@ int add_to_page_cache_lru(struct page *p
 				pgoff_t offset, gfp_t gfp_mask)
 {
 	int ret = add_to_page_cache(page, mapping, offset, gfp_mask);
-	if (ret == 0)
-		lru_cache_add(page);
+	if (ret == 0) {
+		if (page_file_cache(page))
+			lru_cache_add_file(page);
+		else
+			lru_cache_add_active_anon(page);
+	}
 	return ret;
 }
 
mm/vmstat.c +9 -5
Index: linux-2.6.26-rc2-mm1/mm/vmstat.c
===================================================================
@@ -695,8 +695,10 @@ const struct seq_operations pagetypeinfo
 static const char * const vmstat_text[] = {
 	/* Zoned VM counters */
 	"nr_free_pages",
-	"nr_inactive",
-	"nr_active",
+	"nr_inactive_anon",
+	"nr_active_anon",
+	"nr_inactive_file",
+	"nr_active_file",
 	"nr_anon_pages",
 	"nr_mapped",
 	"nr_file_pages",
@@ -764,7 +766,7 @@ static void zoneinfo_show_print(struct s
 		   "\n        min      %lu"
 		   "\n        low      %lu"
 		   "\n        high     %lu"
-		   "\n        scanned  %lu (a: %lu i: %lu)"
+		   "\n        scanned  %lu (aa: %lu ia: %lu af: %lu if: %lu)"
 		   "\n        spanned  %lu"
 		   "\n        present  %lu",
 		   zone_page_state(zone, NR_FREE_PAGES),
@@ -772,8 +774,10 @@ static void zoneinfo_show_print(struct s
 		   zone->pages_low,
 		   zone->pages_high,
 		   zone->pages_scanned,
-		   zone->nr_scan[LRU_ACTIVE],
-		   zone->nr_scan[LRU_INACTIVE],
+		   zone->nr_scan[LRU_ACTIVE_ANON],
+		   zone->nr_scan[LRU_INACTIVE_ANON],
+		   zone->nr_scan[LRU_ACTIVE_FILE],
+		   zone->nr_scan[LRU_INACTIVE_FILE],
 		   zone->spanned_pages,
 		   zone->present_pages);
 
mm/vmscan.c +199 -229

730 lines not on this page · raw message

mm/swap_state.c +1 -1
Index: linux-2.6.26-rc2-mm1/mm/swap_state.c
===================================================================
@@ -302,7 +302,7 @@ struct page *read_swap_cache_async(swp_e
 			/*
 			 * Initiate read into locked page and return.
 			 */
-			lru_cache_add_active(new_page);
+			lru_cache_add_active_anon(new_page);
 			swap_readpage(NULL, new_page);
 			return new_page;
 		}
include/linux/mmzone.h +27 -6
Index: linux-2.6.26-rc2-mm1/include/linux/mmzone.h
===================================================================
@@ -81,21 +81,23 @@ struct zone_padding {
 enum zone_stat_item {
 	/* First 128 byte cacheline (assuming 64 bit words) */
 	NR_FREE_PAGES,
-	NR_INACTIVE,	/* must match order of LRU_[IN]ACTIVE */
-	NR_ACTIVE,	/*  "     "     "   "       "         */
+	NR_INACTIVE_ANON,	/* must match order of LRU_[IN]ACTIVE_* */
+	NR_ACTIVE_ANON,		/*  "     "     "   "       "           */
+	NR_INACTIVE_FILE,	/*  "     "     "   "       "           */
+	NR_ACTIVE_FILE,		/*  "     "     "   "       "           */
 	NR_ANON_PAGES,	/* Mapped anonymous pages */
 	NR_FILE_MAPPED,	/* pagecache pages mapped into pagetables.
 			   only modified from process context */
 	NR_FILE_PAGES,
 	NR_FILE_DIRTY,
 	NR_WRITEBACK,
-	/* Second 128 byte cacheline */
 	NR_SLAB_RECLAIMABLE,
 	NR_SLAB_UNRECLAIMABLE,
 	NR_PAGETABLE,		/* used for pagetables */
 	NR_UNSTABLE_NFS,	/* NFS unstable pages */
 	NR_BOUNCE,
 	NR_VMSCAN_WRITE,
+	/* Second 128 byte cacheline */
 	NR_WRITEBACK_TEMP,	/* Writeback using temporary buffers */
 #ifdef CONFIG_NUMA
 	NUMA_HIT,		/* allocated in intended node */
@@ -107,18 +109,33 @@ enum zone_stat_item {
 #endif
 	NR_VM_ZONE_STAT_ITEMS };
 
+/*
+ * We do arithmetic on the LRU lists in various places in the code,
+ * so it is important to keep the active lists LRU_ACTIVE higher in
+ * the array than the corresponding inactive lists, and to keep
+ * the *_FILE lists LRU_FILE higher than the corresponding _ANON lists.
+ */
 #define LRU_BASE 0
+#define LRU_ACTIVE 1
+#define LRU_FILE 2
 
 enum lru_list {
-	LRU_INACTIVE = LRU_BASE,	/* must match order of NR_[IN]ACTIVE */
-	LRU_ACTIVE,			/*  "     "     "   "       "        */
+	LRU_INACTIVE_ANON = LRU_BASE,
+	LRU_ACTIVE_ANON = LRU_BASE + LRU_ACTIVE,
+	LRU_INACTIVE_FILE = LRU_BASE + LRU_FILE,
+	LRU_ACTIVE_FILE = LRU_BASE + LRU_FILE + LRU_ACTIVE,
 	NR_LRU_LISTS };
 
 #define for_each_lru(l) for (l = 0; l < NR_LRU_LISTS; l++)
 
+static inline int is_file_lru(enum lru_list l)
+{
+	return (l == LRU_INACTIVE_FILE || l == LRU_ACTIVE_FILE);
+}
+
 static inline int is_active_lru(enum lru_list l)
 {
-	return (l == LRU_ACTIVE);
+	return (l == LRU_ACTIVE_ANON || l == LRU_ACTIVE_FILE);
 }
 
 enum lru_list page_lru(struct page *page);
@@ -269,6 +286,10 @@ struct zone {
 	spinlock_t		lru_lock;	
 	struct list_head	list[NR_LRU_LISTS];
 	unsigned long		nr_scan[NR_LRU_LISTS];
+
+	unsigned long		recent_rotated_anon;
+	unsigned long		recent_rotated_file;
+
 	unsigned long		pages_scanned;	   /* since last reclaim */
 	unsigned long		flags;		   /* zone flags, see below */
 
include/linux/mm_inline.h +40 -15

105 lines not on this page · raw message

include/linux/pagevec.h +23 -6
Index: linux-2.6.26-rc2-mm1/include/linux/pagevec.h
===================================================================
@@ -81,20 +81,37 @@ static inline void pagevec_free(struct p
 		__pagevec_free(pvec);
 }
 
-static inline void __pagevec_lru_add(struct pagevec *pvec)
+static inline void __pagevec_lru_add_anon(struct pagevec *pvec)
 {
-	____pagevec_lru_add(pvec, LRU_INACTIVE);
+	____pagevec_lru_add(pvec, LRU_INACTIVE_ANON);
 }
 
-static inline void __pagevec_lru_add_active(struct pagevec *pvec)
+static inline void __pagevec_lru_add_active_anon(struct pagevec *pvec)
 {
-	____pagevec_lru_add(pvec, LRU_ACTIVE);
+	____pagevec_lru_add(pvec, LRU_ACTIVE_ANON);
 }
 
-static inline void pagevec_lru_add(struct pagevec *pvec)
+static inline void __pagevec_lru_add_file(struct pagevec *pvec)
+{
+	____pagevec_lru_add(pvec, LRU_INACTIVE_FILE);
+}
+
+static inline void __pagevec_lru_add_active_file(struct pagevec *pvec)
+{
+	____pagevec_lru_add(pvec, LRU_ACTIVE_FILE);
+}
+
+
+static inline void pagevec_lru_add_file(struct pagevec *pvec)
+{
+	if (pagevec_count(pvec))
+		__pagevec_lru_add_file(pvec);
+}
+
+static inline void pagevec_lru_add_anon(struct pagevec *pvec)
 {
 	if (pagevec_count(pvec))
-		__pagevec_lru_add(pvec);
+		__pagevec_lru_add_anon(pvec);
 }
 
 #endif /* _LINUX_PAGEVEC_H */
include/linux/vmstat.h +10 -0
Index: linux-2.6.26-rc2-mm1/include/linux/vmstat.h
===================================================================
@@ -159,6 +159,16 @@ static inline unsigned long zone_page_st
 	return x;
 }
 
+extern unsigned long global_lru_pages(void);
+
+static inline unsigned long zone_lru_pages(struct zone *zone)
+{
+	return (zone_page_state(zone, NR_ACTIVE_ANON)
+		+ zone_page_state(zone, NR_ACTIVE_FILE)
+		+ zone_page_state(zone, NR_INACTIVE_ANON)
+		+ zone_page_state(zone, NR_INACTIVE_FILE));
+}
+
 #ifdef CONFIG_NUMA
 /*
  * Determine the per node value of a stat item. This function
mm/page-writeback.c +2 -6
Index: linux-2.6.26-rc2-mm1/mm/page-writeback.c
===================================================================
@@ -331,9 +331,7 @@ static unsigned long highmem_dirtyable_m
 		struct zone *z =
 			&NODE_DATA(node)->node_zones[ZONE_HIGHMEM];
 
-		x += zone_page_state(z, NR_FREE_PAGES)
-			+ zone_page_state(z, NR_INACTIVE)
-			+ zone_page_state(z, NR_ACTIVE);
+		x += zone_page_state(z, NR_FREE_PAGES) + zone_lru_pages(z);
 	}
 	/*
 	 * Make sure that the number of highmem pages is never larger
@@ -351,9 +349,7 @@ static unsigned long determine_dirtyable
 {
 	unsigned long x;
 
-	x = global_page_state(NR_FREE_PAGES)
-		+ global_page_state(NR_INACTIVE)
-		+ global_page_state(NR_ACTIVE);
+	x = global_page_state(NR_FREE_PAGES) + global_lru_pages();
 
 	if (!vm_highmem_is_dirtyable)
 		x -= highmem_dirtyable_memory(x);
include/linux/swap.h +15 -5
Index: linux-2.6.26-rc2-mm1/include/linux/swap.h
===================================================================
@@ -184,14 +184,24 @@ extern void swap_setup(void);
  * lru_cache_add: add a page to the page lists
  * @page: the page to add
  */
-static inline void lru_cache_add(struct page *page)
+static inline void lru_cache_add_anon(struct page *page)
 {
-	__lru_cache_add(page, LRU_INACTIVE);
+	__lru_cache_add(page, LRU_INACTIVE_ANON);
 }
 
-static inline void lru_cache_add_active(struct page *page)
+static inline void lru_cache_add_active_anon(struct page *page)
 {
-	__lru_cache_add(page, LRU_ACTIVE);
+	__lru_cache_add(page, LRU_ACTIVE_ANON);
+}
+
+static inline void lru_cache_add_file(struct page *page)
+{
+	__lru_cache_add(page, LRU_INACTIVE_FILE);
+}
+
+static inline void lru_cache_add_active_file(struct page *page)
+{
+	__lru_cache_add(page, LRU_ACTIVE_FILE);
 }
 
 /* linux/mm/vmscan.c */
@@ -199,7 +209,7 @@ extern unsigned long try_to_free_pages(s
 					gfp_t gfp_mask);
 extern unsigned long try_to_free_mem_cgroup_pages(struct mem_cgroup *mem,
 							gfp_t gfp_mask);
-extern int __isolate_lru_page(struct page *page, int mode);
+extern int __isolate_lru_page(struct page *page, int mode, int file);
 extern unsigned long shrink_all_memory(unsigned long nr_pages);
 extern int vm_swappiness;
 extern int remove_mapping(struct address_space *mapping, struct page *page);
include/linux/memcontrol.h +1 -1
Index: linux-2.6.26-rc2-mm1/include/linux/memcontrol.h
===================================================================
@@ -41,7 +41,7 @@ extern unsigned long mem_cgroup_isolate_
 					unsigned long *scanned, int order,
 					int mode, struct zone *z,
 					struct mem_cgroup *mem_cont,
-					int active);
+					int active, int file);
 extern void mem_cgroup_out_of_memory(struct mem_cgroup *mem, gfp_t gfp_mask);
 int task_in_mem_cgroup(struct task_struct *task, const struct mem_cgroup *mem);
 
mm/memcontrol.c +38 -35

150 lines not on this page · raw message

Signature · 1 line
All Rights Reversed
#7 lore raw

Re: [PATCH -mm 06/12] split LRU lists into anon & file sets

Quoted 10 lines · Rik van Riel

From: Rik van Riel <[email protected]>

Split the LRU lists in two, one set for pages that are backed by real file systems ("file") and one for pages that are backed by memory and swap ("anon"). The latter includes tmpfs.

Eventually mlocked pages will be taken off the LRUs alltogether. A patch for that already exists and just needs to be integrated into this series.

Quoted 7 lines

This patch mostly has the infrastructure and a basic policy to balance how much we scan the anon lists and how much we scan the file lists. The big policy changes are in separate patches.

Hi, Rik,

My problems with OOM continue, despite the changes incorporated into memcontrol.c. While I am investigating the problem, the code below seemed incorrect.

include/linux/mm_inline.h static inline int page_file_cache(struct · line 84

Quoted 5 lines
include/linux/mm_inline.h +4 -0
+static inline void
+del_page_from_active_file_list(struct zone *zone, struct page *page)
+{
+	del_page_from_lru_list(zone, page, LRU_INACTIVE_FILE);
 }

Shouldn't this be del_page_from_lru_list(zone, page, LRU_ACTIVE_FILE)?

Signature · 4 lines
	Warm Regards,
	Balbir Singh
	Linux Technology Center
	IBM, ISTL
#8 lore raw

PATCH 7/12 second chance replacement for anonymous pages

In reply to Rik van Riel

From: Rik van Riel <[email protected]>

We avoid evicting and scanning anonymous pages for the most part, but under some workloads we can end up with most of memory filled with anonymous pages. At that point, we suddenly need to clear the referenced bits on all of memory, which can take ages on very large memory systems.

We can reduce the maximum number of pages that need to be scanned by not taking the referenced state into account when deactivating an anonymous page. After all, every anonymous page starts out referenced, so why check?

If an anonymous page gets referenced again before it reaches the end of the inactive list, we move it back to the active list.

To keep the maximum amount of necessary work reasonable, we scale the active to inactive ratio with the size of memory, using the formula active:inactive ratio = sqrt(memory in GB * 10).

Kswapd CPU use now seems to scale by the amount of pageout bandwidth, instead of by the amount of memory present in the system.

---
 include/linux/mm_inline.h |   12 ++++++++++++
 include/linux/mmzone.h    |    5 +++++
 mm/page_alloc.c           |   40 ++++++++++++++++++++++++++++++++++++++++
 mm/vmscan.c               |   38 +++++++++++++++++++++++++++++++-------
 mm/vmstat.c               |    6 ++++--
 5 files changed, 92 insertions(+), 9 deletions(-)
include/linux/mm_inline.h +12 -0
Index: linux-2.6.26-rc2-mm1/include/linux/mm_inline.h
===================================================================
@@ -97,4 +97,16 @@ del_page_from_lru(struct zone *zone, str
 	__dec_zone_state(zone, NR_INACTIVE_ANON + l);
 }
 
+static inline int inactive_anon_low(struct zone *zone)
+{
+	unsigned long active, inactive;
+
+	active = zone_page_state(zone, NR_ACTIVE_ANON);
+	inactive = zone_page_state(zone, NR_INACTIVE_ANON);
+
+	if (inactive * zone->inactive_ratio < active)
+		return 1;
+
+	return 0;
+}
 #endif
include/linux/mmzone.h +5 -0
Index: linux-2.6.26-rc2-mm1/include/linux/mmzone.h
===================================================================
@@ -311,6 +311,11 @@ struct zone {
 	 */
 	int prev_priority;
 
+	/*
+	 * The ratio of active to inactive pages.
+	 */
+	unsigned int inactive_ratio;
+
 
 	ZONE_PADDING(_pad2_)
 	/* Rarely used or read-mostly fields */
mm/page_alloc.c +40 -0
Index: linux-2.6.26-rc2-mm1/mm/page_alloc.c
===================================================================
@@ -4269,6 +4269,45 @@ void setup_per_zone_pages_min(void)
 	calculate_totalreserve_pages();
 }
 
+/**
+ * setup_per_zone_inactive_ratio - called when min_free_kbytes changes.
+ *
+ * The inactive anon list should be small enough that the VM never has to
+ * do too much work, but large enough that each inactive page has a chance
+ * to be referenced again before it is swapped out.
+ *
+ * The inactive_anon ratio is the ratio of active to inactive anonymous
+ * pages.  Ie. a ratio of 3 means 3:1 or 25% of the anonymous pages are
+ * on the inactive list.
+ *
+ * total     return    max
+ * memory    value     inactive anon
+ * -------------------------------------
+ *   10MB       1         5MB
+ *  100MB       1        50MB
+ *    1GB       3       250MB
+ *   10GB      10       0.9GB
+ *  100GB      31         3GB
+ *    1TB     101        10GB
+ *   10TB     320        32GB
+ */
+void setup_per_zone_inactive_ratio(void)
+{
+	struct zone *zone;
+
+	for_each_zone(zone) {
+		unsigned int gb, ratio;
+
+		/* Zone size in gigabytes */
+		gb = zone->present_pages >> (30 - PAGE_SHIFT);
+		ratio = int_sqrt(10 * gb);
+		if (!ratio)
+			ratio = 1;
+
+		zone->inactive_ratio = ratio;
+	}
+}
+
 /*
  * Initialise min_free_kbytes.
  *
@@ -4306,6 +4345,7 @@ static int __init init_per_zone_pages_mi
 		min_free_kbytes = 65536;
 	setup_per_zone_pages_min();
 	setup_per_zone_lowmem_reserve();
+	setup_per_zone_inactive_ratio();
 	return 0;
 }
 module_init(init_per_zone_pages_min)
mm/vmscan.c +37 -8

89 lines not on this page · raw message

mm/vmstat.c +4 -2
Index: linux-2.6.26-rc2-mm1/mm/vmstat.c
===================================================================
@@ -814,10 +814,12 @@ static void zoneinfo_show_print(struct s
 	seq_printf(m,
 		   "\n  all_unreclaimable: %u"
 		   "\n  prev_priority:     %i"
-		   "\n  start_pfn:         %lu",
+		   "\n  start_pfn:         %lu"
+		   "\n  inactive_ratio:    %u",
 			   zone_is_all_unreclaimable(zone),
 		   zone->prev_priority,
-		   zone->zone_start_pfn);
+		   zone->zone_start_pfn,
+		   zone->inactive_ratio);
 	seq_putc(m, '\n');
 }
 
Signature · 1 line
All Rights Reversed
#9 lore raw

Re: [PATCH -mm 07/12] second chance replacement for anonymous pages

mm/vmscan.c static unsigned long shrink_list(enum lr · line 1156

Quoted 7 lines · Rik van Riel

From: Rik van Riel <[email protected]>

mm/vmscan.c +2 -0
+	if (lru == LRU_ACTIVE_ANON &&
+	    (!scan_global_lru(sc) || inactive_anon_low(zone))) {
 		shrink_active_list(nr_to_scan, zone, sc, priority, file);
 		return 0;
 	}

This should do the trick. I was playing around with v8 and came up with the exact same fix, after having spent some time reviewing and playing around with the code.

Let me bundle up all of V9 and test it.

Signature · 4 lines
	Warm Regards,
	Balbir Singh
	Linux Technology Center
	IBM, ISTL
#10 lore raw

PATCH 8/12 add some sanity checks to get_scan_ratio

In reply to Rik van Riel

From: Rik van Riel <[email protected]>

The access ratio based scan rate determination in get_scan_ratio works ok in most situations, but needs to be corrected in some corner cases:
- if we run out of swap space, do not bother scanning the anon LRUs
- if we have already freed all of the page cache, we need to scan the anon LRUs
- restore the *actual* access ratio based scan rate algorithm, the previous versions of this patch series had the wrong version
- scale the number of pages added to zone->nr_scan[l]

---
 include/linux/mmzone.h |    2 
 mm/page_alloc.c        |    3 -
 mm/swap.c              |   13 +++++-
 mm/vmscan.c            |  104 ++++++++++++++++++++++++++++++++-----------------
 4 files changed, 85 insertions(+), 37 deletions(-)
mm/vmscan.c +70 -34
Index: linux-2.6.26-rc2-mm1/mm/vmscan.c
===================================================================
@@ -893,8 +893,13 @@ static unsigned long shrink_inactive_lis
 		__mod_zone_page_state(zone, NR_INACTIVE_ANON,
 						-count[LRU_INACTIVE_ANON]);
 
-		if (scan_global_lru(sc))
+		if (scan_global_lru(sc)) {
 			zone->pages_scanned += nr_scan;
+			zone->recent_scanned_anon += count[LRU_ACTIVE_ANON] +
+						     count[LRU_INACTIVE_ANON];
+			zone->recent_scanned_file += count[LRU_ACTIVE_FILE] +
+						     count[LRU_INACTIVE_FILE];
+		}
 		spin_unlock_irq(&zone->lru_lock);
 
 		nr_scanned += nr_scan;
@@ -944,11 +949,13 @@ static unsigned long shrink_inactive_lis
 			VM_BUG_ON(PageLRU(page));
 			SetPageLRU(page);
 			list_del(&page->lru);
-			if (page_file_cache(page)) {
+			if (page_file_cache(page))
 				lru += LRU_FILE;
-				zone->recent_rotated_file++;
-			} else {
-				zone->recent_rotated_anon++;
+			if (scan_global_lru(sc)) {
+				if (page_file_cache(page))
+					zone->recent_rotated_file++;
+				else
+					zone->recent_rotated_anon++;
 			}
 			if (PageActive(page))
 				lru += LRU_ACTIVE;
@@ -1027,8 +1034,13 @@ static void shrink_active_list(unsigned 
 	 * zone->pages_scanned is used for detect zone's oom
 	 * mem_cgroup remembers nr_scan by itself.
 	 */
-	if (scan_global_lru(sc))
+	if (scan_global_lru(sc)) {
 		zone->pages_scanned += pgscanned;
+		if (file)
+			zone->recent_scanned_file += pgscanned;
+		else
+			zone->recent_scanned_anon += pgscanned;
+	}
 
 	if (file)
 		__mod_zone_page_state(zone, NR_ACTIVE_FILE, -pgmoved);
@@ -1170,9 +1182,8 @@ static unsigned long shrink_list(enum lr
 static void get_scan_ratio(struct zone *zone, struct scan_control * sc,
 					unsigned long *percent)
 {
-	unsigned long anon, file;
+	unsigned long anon, file, free;
 	unsigned long anon_prio, file_prio;
-	unsigned long rotate_sum;
 	unsigned long ap, fp;
 
 	anon  = zone_page_state(zone, NR_ACTIVE_ANON) +
@@ -1180,15 +1191,19 @@ static void get_scan_ratio(struct zone *
 	file  = zone_page_state(zone, NR_ACTIVE_FILE) +
 		zone_page_state(zone, NR_INACTIVE_FILE);
 
-	rotate_sum = zone->recent_rotated_file + zone->recent_rotated_anon;
-
 	/* Keep a floating average of RECENT references. */
-	if (unlikely(rotate_sum > min(anon, file))) {
+	if (unlikely(zone->recent_scanned_anon > anon / zone->inactive_ratio)) {
 		spin_lock_irq(&zone->lru_lock);
-		zone->recent_rotated_file /= 2;
+		zone->recent_scanned_anon /= 2;
 		zone->recent_rotated_anon /= 2;
 		spin_unlock_irq(&zone->lru_lock);
-		rotate_sum /= 2;
+	}
+
+	if (unlikely(zone->recent_scanned_file > file / 4)) {
+		spin_lock_irq(&zone->lru_lock);
+		zone->recent_scanned_file /= 2;
+		zone->recent_rotated_file /= 2;
+		spin_unlock_irq(&zone->lru_lock);
 	}
 
 	/*
@@ -1201,23 +1216,33 @@ static void get_scan_ratio(struct zone *
 	/*
 	 *                  anon       recent_rotated_anon
 	 * %anon = 100 * ----------- / ------------------- * IO cost
-	 *               anon + file       rotate_sum
+	 *               anon + file   recent_scanned_anon
 	 */
-	ap = (anon_prio * anon) / (anon + file + 1);
-	ap *= rotate_sum / (zone->recent_rotated_anon + 1);
-	if (ap == 0)
-		ap = 1;
-	else if (ap > 100)
-		ap = 100;
-	percent[0] = ap;
-
-	fp = (file_prio * file) / (anon + file + 1);
-	fp *= rotate_sum / (zone->recent_rotated_file + 1);
-	if (fp == 0)
-		fp = 1;
-	else if (fp > 100)
-		fp = 100;
-	percent[1] = fp;
+	ap = (anon_prio + 1) * (zone->recent_scanned_anon + 1);
+	ap /= zone->recent_rotated_anon + 1;
+
+	fp = (file_prio + 1) * (zone->recent_scanned_file + 1);
+	fp /= zone->recent_rotated_file + 1;
+
+	/* Normalize to percentages */
+	percent[0] = 100 * ap / (ap + fp + 1);
+	percent[1] = 100 - percent[0];
+
+	free = zone_page_state(zone, NR_FREE_PAGES);
+
+	/*
+	 * If we have no swap space, do not bother scanning anon pages.
+	 */
+	if (nr_swap_pages <= 0) {
+		percent[0] = 0;
+		percent[1] = 100;
+	}
+	/*
+	 * If we already freed most file pages, scan the anon pages
+	 * regardless of the page access ratios or swappiness setting.
+	 */
+	else if (file + free <= zone->pages_high)
+		percent[0] = 100;
 }
 
 
@@ -1238,13 +1263,17 @@ static unsigned long shrink_zone(int pri
 	for_each_lru(l) {
 		if (scan_global_lru(sc)) {
 			int file = is_file_lru(l);
+			int scan;
 			/*
 			 * Add one to nr_to_scan just to make sure that the
-			 * kernel will slowly sift through the active list.
+			 * kernel will slowly sift through each list.
 			 */
-			zone->nr_scan[l] += (zone_page_state(zone,
-				NR_INACTIVE_ANON + l) >> priority) + 1;
-			nr[l] = zone->nr_scan[l] * percent[file] / 100;
+			scan = zone_page_state(zone, NR_INACTIVE_ANON + l);
+			scan >>= priority;
+			scan = (scan * percent[file]) / 100;
+
+			zone->nr_scan[l] += scan + 1;
+			nr[l] = zone->nr_scan[l];
 			if (nr[l] >= sc->swap_cluster_max)
 				zone->nr_scan[l] = 0;
 			else
@@ -1261,7 +1290,7 @@ static unsigned long shrink_zone(int pri
 	}
 
 	while (nr[LRU_INACTIVE_ANON] || nr[LRU_ACTIVE_FILE] ||
-						 nr[LRU_INACTIVE_FILE]) {
+					nr[LRU_INACTIVE_FILE]) {
 		for_each_lru(l) {
 			if (nr[l]) {
 				nr_to_scan = min(nr[l],
@@ -1274,6 +1303,13 @@ static unsigned long shrink_zone(int pri
 		}
 	}
 
+	/*
+	 * Even if we did not try to evict anon pages at all, we want to
+	 * rebalance the anon lru active/inactive ratio.
+	 */
+	if (scan_global_lru(sc) && inactive_anon_low(zone))
+		shrink_active_list(SWAP_CLUSTER_MAX, zone, sc, priority, 0);
+
 	throttle_vm_writeout(sc->gfp_mask);
 	return nr_reclaimed;
 }
include/linux/mmzone.h +2 -0
Index: linux-2.6.26-rc2-mm1/include/linux/mmzone.h
===================================================================
@@ -289,6 +289,8 @@ struct zone {
 
 	unsigned long		recent_rotated_anon;
 	unsigned long		recent_rotated_file;
+	unsigned long		recent_scanned_anon;
+	unsigned long		recent_scanned_file;
 
 	unsigned long		pages_scanned;	   /* since last reclaim */
 	unsigned long		flags;		   /* zone flags, see below */
mm/page_alloc.c +2 -1
Index: linux-2.6.26-rc2-mm1/mm/page_alloc.c
===================================================================
@@ -3512,7 +3512,8 @@ static void __paginginit free_area_init_
 		}
 		zone->recent_rotated_anon = 0;
 		zone->recent_rotated_file = 0;
-//TODO recent_scanned_* ???
+		zone->recent_scanned_anon = 0;
+		zone->recent_scanned_file = 0;
 		zap_zone_vm_stats(zone);
 		zone->flags = 0;
 		if (!size)
mm/swap.c +11 -2
Index: linux-2.6.26-rc2-mm1/mm/swap.c
===================================================================
@@ -176,8 +176,8 @@ void activate_page(struct page *page)
 
 	spin_lock_irq(&zone->lru_lock);
 	if (PageLRU(page) && !PageActive(page)) {
-		int lru = LRU_BASE;
-		lru += page_file_cache(page);
+		int file = page_file_cache(page);
+		int lru = LRU_BASE + file;
 		del_page_from_lru_list(zone, page, lru);
 
 		SetPageActive(page);
@@ -185,6 +185,15 @@ void activate_page(struct page *page)
 		add_page_to_lru_list(zone, page, lru);
 		__count_vm_event(PGACTIVATE);
 		mem_cgroup_move_lists(page, true);
+
+		if (file) {
+			zone->recent_scanned_file++;
+			zone->recent_rotated_file++;
+		} else {
+			/* Can this happen?  Maybe through tmpfs... */
+			zone->recent_scanned_anon++;
+			zone->recent_rotated_anon++;
+		}
 	}
 	spin_unlock_irq(&zone->lru_lock);
 }
Signature · 1 line
All Rights Reversed
#11 lore raw

PATCH 9/12 fix pagecache reclaim referenced bit check

In reply to Rik van Riel

From: Rik van Riel <[email protected]>

The -mm tree contains the patch vmscan-give-referenced-active-and-unmapped-pages-a-second-trip-around-the-lru.patch which gives referenced pagecache pages another trip around
the active list. This seems to help keep frequently accessed pagecache pages in memory.

However, it means that pagecache pages that get moved to the inactive list do not have their referenced bit set, and a reference to the page will not get it moved back to the active list. This patch sets the referenced bit on pagecache pages that get deactivated, so the next access to the page will promote it back to the active list.

---
 mm/vmscan.c |    4 ++++
 1 file changed, 4 insertions(+)
mm/vmscan.c +6 -1
Index: linux-2.6.26-rc2-mm1/mm/vmscan.c
===================================================================
@@ -1062,8 +1062,13 @@ static void shrink_active_list(unsigned 
 				list_add(&page->lru, &l_inactive);
 				pgmoved++;
 			}
-		} else
+		} else {
 			list_add(&page->lru, &l_inactive);
+			if (file && !page_mapped(page))
+				/* Bypass use-once, make the next access count.
+				 * See mark_page_accessed. */
+				SetPageReferenced(page);
+		}
 	}
 
 	/*
Signature · 1 line
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#12 lore raw

PATCH 10/12 add newly swapped in pages to the inactive list

In reply to Rik van Riel

From: Rik van Riel <[email protected]>

Swapin_readahead can read in a lot of data that the processes in memory never need. Adding swap cache pages to the inactive list prevents them from putting too much pressure on the working set.

This has the potential to help the programs that are already in memory, but it could also be a disadvantage to processes that are trying to get swapped in.

In short, this patch needs testing.

---
 mm/swap_state.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)
mm/swap_state.c +1 -1
Index: linux-2.6.26-rc2-mm1/mm/swap_state.c
===================================================================
@@ -302,7 +302,7 @@ struct page *read_swap_cache_async(swp_e
 			/*
 			 * Initiate read into locked page and return.
 			 */
-			lru_cache_add_active_anon(new_page);
+			lru_cache_add_anon(new_page);
 			swap_readpage(NULL, new_page);
 			return new_page;
 		}
Signature · 1 line
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#13 lore raw

PATCH 11/12 more aggressively use lumpy reclaim

In reply to Rik van Riel

From: Rik van Riel <[email protected]>

During an AIM7 run on a 16GB system, fork started failing around 32000 threads, despite the system having plenty of free swap and 15GB of pageable memory.

If normal pageout does not result in contiguous free pages for kernel stacks, fall back to lumpy reclaim instead of failing fork or doing excessive pageout IO.

I do not know whether this change is needed due to the extreme stress test or because the inactive list is a smaller fraction of system memory on huge systems.

---
 mm/vmscan.c |   20 ++++++++++++++++----
 1 file changed, 16 insertions(+), 4 deletions(-)
mm/vmscan.c +16 -4
Index: linux-2.6.26-rc2-mm1/mm/vmscan.c
===================================================================
@@ -857,7 +857,8 @@ int isolate_lru_page(struct page *page)
  * of reclaimed pages
  */
 static unsigned long shrink_inactive_list(unsigned long max_scan,
-			struct zone *zone, struct scan_control *sc, int file)
+			struct zone *zone, struct scan_control *sc,
+			int priority, int file)
 {
 	LIST_HEAD(page_list);
 	struct pagevec pvec;
@@ -875,8 +876,19 @@ static unsigned long shrink_inactive_lis
 		unsigned long nr_freed;
 		unsigned long nr_active;
 		unsigned int count[NR_LRU_LISTS] = { 0, };
-		int mode = (sc->order > PAGE_ALLOC_COSTLY_ORDER) ?
-					ISOLATE_BOTH : ISOLATE_INACTIVE;
+		int mode = ISOLATE_INACTIVE;
+
+		/*
+		 * If we need a large contiguous chunk of memory, or have
+		 * trouble getting a small set of contiguous pages, we
+		 * will reclaim both active and inactive pages.
+		 *
+		 * We use the same threshold as pageout congestion_wait below.
+		 */
+		if (sc->order > PAGE_ALLOC_COSTLY_ORDER)
+			mode = ISOLATE_BOTH;
+		else if (sc->order && priority < DEF_PRIORITY - 2)
+			mode = ISOLATE_BOTH;
 
 		nr_taken = sc->isolate_pages(sc->swap_cluster_max,
 			     &page_list, &nr_scan, sc->order, mode,
@@ -1171,7 +1183,7 @@ static unsigned long shrink_list(enum lr
 		shrink_active_list(nr_to_scan, zone, sc, priority, file);
 		return 0;
 	}
-	return shrink_inactive_list(nr_to_scan, zone, sc, file);
+	return shrink_inactive_list(nr_to_scan, zone, sc, priority, file);
 }
 
 /*
Signature · 1 line
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#14 lore raw

PATCH 12/12 pageflag helpers for configed-out flags

In reply to Rik van Riel

From: Lee Schermerhorn <[email protected]>

Define proper false/noop inline functions for noreclaim page flags when !defined(CONFIG_NORECLAIM_LRU)

---
 include/linux/page-flags.h |   12 ++++++++++++
 1 file changed, 12 insertions(+)
include/linux/page-flags.h +12 -0
Index: linux-2.6.26-rc2-mm1/include/linux/page-flags.h
===================================================================
@@ -147,6 +147,18 @@ static inline int Page##uname(struct pag
 #define TESTSCFLAG(uname, lname)					\
 	TESTSETFLAG(uname, lname) TESTCLEARFLAG(uname, lname)
 
+#define SETPAGEFLAG_NOOP(uname)						\
+static inline void SetPage##uname(struct page *page) {  }
+
+#define CLEARPAGEFLAG_NOOP(uname)					\
+static inline void ClearPage##uname(struct page *page) {  }
+
+#define __CLEARPAGEFLAG_NOOP(uname)					\
+static inline void __ClearPage##uname(struct page *page) {  }
+
+#define TESTCLEARFLAG_FALSE(uname)					\
+static inline int TestClearPage##uname(struct page *page) { return 0; }
+
 struct page;	/* forward declaration */
 
 PAGEFLAG(Locked, locked) TESTSCFLAG(Locked, locked)
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