[patch 11/14] No Reclaim LRU Infrastructure

From: Rik van Riel
Date: Fri May 16 2008 - 14:48:58 EST

From: Lee Schermerhorn <Lee.Schermerhorn@xxxxxx>

Infrastructure to manage pages excluded from reclaim--i.e., hidden
from vmscan. Based on a patch by Larry Woodman of Red Hat. Reworked
to maintain "nonreclaimable" pages on a separate per-zone LRU list,
to "hide" them from vmscan. A separate noreclaim pagevec is provided
for shrink_active_list() to move nonreclaimable pages to the noreclaim
list without over burdening the zone lru_lock.

Pages on the noreclaim list have both PG_noreclaim and PG_lru set.
Thus, PG_noreclaim is analogous to and mutually exclusive with
PG_active--it specifies which LRU list the page is on.

The noreclaim infrastructure is enabled by a new mm Kconfig option
[CONFIG_]NORECLAIM_LRU.

A new function 'page_reclaimable(page, vma)' in vmscan.c tests whether
or not a page is reclaimable. Subsequent patches will add the various
!reclaimable tests. We'll want to keep these tests light-weight for
use in shrink_active_list() and, possibly, the fault path.

Signed-off-by: Lee Schermerhorn <lee.schermerhorn@xxxxxx>
Signed-off-by: Rik van Riel <riel@xxxxxxxxxx>

---
V3 -> V6:
+ remove lru_cache_add_active_or_noreclaim(). Only used by
optional patch to cull nonreclaimable pages in fault path.
Will add back to that patch.
+ misc cleanup pointed out by review of V5

V1 -> V3:
+ rebase to 23-mm1 atop RvR's split LRU series
+ define NR_NORECLAIM and LRU_NORECLAIM to avoid errors when not
configured.

V1 -> V2:
+ handle review comments -- various typos and errors.
+ extract "putback_all_noreclaim_pages()" into a separate patch
and rework as "scan_all_zones_noreclaim_pages().

include/linux/mm_inline.h | 33 +++++++++++-
include/linux/mmzone.h | 24 +++++++++
include/linux/page-flags.h | 17 ++++++
include/linux/pagevec.h | 6 ++
include/linux/swap.h | 22 ++++++++
mm/Kconfig | 10 +++
mm/mempolicy.c | 2
mm/migrate.c | 6 +-
mm/page_alloc.c | 9 +++
mm/swap.c | 30 ++++++++---
mm/vmscan.c | 115 ++++++++++++++++++++++++++++++++++++++-------
11 files changed, 242 insertions(+), 32 deletions(-)

Index: linux-2.6.26-rc2-mm1/mm/Kconfig
===================================================================
--- linux-2.6.26-rc2-mm1.orig/mm/Kconfig 2008-05-15 11:20:57.000000000 -0400
+++ linux-2.6.26-rc2-mm1/mm/Kconfig 2008-05-16 14:05:09.000000000 -0400
@@ -205,3 +205,13 @@ config NR_QUICK
config VIRT_TO_BUS
def_bool y
depends on !ARCH_NO_VIRT_TO_BUS
+
+config NORECLAIM_LRU
+ bool "Add LRU list to track non-reclaimable pages (EXPERIMENTAL, 64BIT only)"
+ depends on EXPERIMENTAL && 64BIT
+ help
+ Supports tracking of non-reclaimable pages off the [in]active lists
+ to avoid excessive reclaim overhead on large memory systems. Pages
+ may be non-reclaimable because: they are locked into memory, they
+ are anonymous pages for which no swap space exists, or they are anon
+ pages that are expensive to unmap [long anon_vma "related vma" list.]
Index: linux-2.6.26-rc2-mm1/include/linux/page-flags.h
===================================================================
--- linux-2.6.26-rc2-mm1.orig/include/linux/page-flags.h 2008-05-16 13:31:54.000000000 -0400
+++ linux-2.6.26-rc2-mm1/include/linux/page-flags.h 2008-05-16 14:05:09.000000000 -0400
@@ -94,6 +94,9 @@ enum pageflags {
PG_reclaim, /* To be reclaimed asap */
PG_buddy, /* Page is free, on buddy lists */
PG_swapbacked, /* Page is backed by RAM/swap */
+#ifdef CONFIG_NORECLAIM_LRU
+ PG_noreclaim, /* Page is "non-reclaimable" */
+#endif
#ifdef CONFIG_IA64_UNCACHED_ALLOCATOR
PG_uncached, /* Page has been mapped as uncached */
#endif
@@ -155,6 +158,7 @@ PAGEFLAG(Referenced, referenced) TESTCLE
PAGEFLAG(Dirty, dirty) TESTSCFLAG(Dirty, dirty) __CLEARPAGEFLAG(Dirty, dirty)
PAGEFLAG(LRU, lru) __CLEARPAGEFLAG(LRU, lru)
PAGEFLAG(Active, active) __CLEARPAGEFLAG(Active, active)
+ TESTCLEARFLAG(Active, active)
__PAGEFLAG(Slab, slab)
PAGEFLAG(Checked, owner_priv_1) /* Used by some filesystems */
PAGEFLAG(Pinned, owner_priv_1) TESTSCFLAG(Pinned, owner_priv_1) /* Xen */
@@ -191,6 +195,17 @@ PAGEFLAG(SwapCache, swapcache)
PAGEFLAG_FALSE(SwapCache)
#endif

+#ifdef CONFIG_NORECLAIM_LRU
+PAGEFLAG(Noreclaim, noreclaim) __CLEARPAGEFLAG(Noreclaim, noreclaim)
+TESTCLEARFLAG(Noreclaim, noreclaim)
+#else
+PAGEFLAG_FALSE(Noreclaim)
+#define SetPageNoreclaim(page)
+#define ClearPageNoreclaim(page)
+#define __ClearPageNoreclaim(page)
+#define TestClearPageNoreclaim(page) 0
+#endif
+
#ifdef CONFIG_IA64_UNCACHED_ALLOCATOR
PAGEFLAG(Uncached, uncached)
#else
Index: linux-2.6.26-rc2-mm1/include/linux/mmzone.h
===================================================================
--- linux-2.6.26-rc2-mm1.orig/include/linux/mmzone.h 2008-05-16 14:04:57.000000000 -0400
+++ linux-2.6.26-rc2-mm1/include/linux/mmzone.h 2008-05-16 14:05:09.000000000 -0400
@@ -85,6 +85,11 @@ enum zone_stat_item {
NR_ACTIVE_ANON, /* " " " " " */
NR_INACTIVE_FILE, /* " " " " " */
NR_ACTIVE_FILE, /* " " " " " */
+#ifdef CONFIG_NORECLAIM_LRU
+ NR_NORECLAIM, /* " " " " " */
+#else
+ NR_NORECLAIM = NR_ACTIVE_FILE, /* avoid compiler errors in dead code */
+#endif
NR_ANON_PAGES, /* Mapped anonymous pages */
NR_FILE_MAPPED, /* pagecache pages mapped into pagetables.
only modified from process context */
@@ -124,10 +129,18 @@ enum lru_list {
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 };
+#ifdef CONFIG_NORECLAIM_LRU
+ LRU_NORECLAIM,
+#else
+ LRU_NORECLAIM = LRU_ACTIVE_FILE, /* avoid compiler errors in dead code */
+#endif
+ NR_LRU_LISTS
+};

#define for_each_lru(l) for (l = 0; l < NR_LRU_LISTS; l++)

+#define for_each_reclaimable_lru(l) for (l = 0; l <= LRU_ACTIVE_FILE; l++)
+
static inline int is_file_lru(enum lru_list l)
{
return (l == LRU_INACTIVE_FILE || l == LRU_ACTIVE_FILE);
@@ -138,6 +151,15 @@ static inline int is_active_lru(enum lru
return (l == LRU_ACTIVE_ANON || l == LRU_ACTIVE_FILE);
}

+static inline int is_noreclaim_lru(enum lru_list l)
+{
+#ifdef CONFIG_NORECLAIM_LRU
+ return (l == LRU_NORECLAIM);
+#else
+ return 0;
+#endif
+}
+
enum lru_list page_lru(struct page *page);

struct per_cpu_pages {
Index: linux-2.6.26-rc2-mm1/mm/page_alloc.c
===================================================================
--- linux-2.6.26-rc2-mm1.orig/mm/page_alloc.c 2008-05-16 14:04:57.000000000 -0400
+++ linux-2.6.26-rc2-mm1/mm/page_alloc.c 2008-05-16 14:05:09.000000000 -0400
@@ -256,6 +256,9 @@ static void bad_page(struct page *page)
1 << PG_private |
1 << PG_locked |
1 << PG_active |
+#ifdef CONFIG_NORECLAIM_LRU
+ 1 << PG_noreclaim |
+#endif
1 << PG_dirty |
1 << PG_reclaim |
1 << PG_slab |
@@ -491,6 +494,9 @@ static inline int free_pages_check(struc
1 << PG_swapcache |
1 << PG_writeback |
1 << PG_reserved |
+#ifdef CONFIG_NORECLAIM_LRU
+ 1 << PG_noreclaim |
+#endif
1 << PG_buddy ))))
bad_page(page);
if (PageDirty(page))
@@ -642,6 +648,9 @@ static int prep_new_page(struct page *pa
1 << PG_private |
1 << PG_locked |
1 << PG_active |
+#ifdef CONFIG_NORECLAIM_LRU
+ 1 << PG_noreclaim |
+#endif
1 << PG_dirty |
1 << PG_slab |
1 << PG_swapcache |
Index: linux-2.6.26-rc2-mm1/include/linux/mm_inline.h
===================================================================
--- linux-2.6.26-rc2-mm1.orig/include/linux/mm_inline.h 2008-05-16 14:03:56.000000000 -0400
+++ linux-2.6.26-rc2-mm1/include/linux/mm_inline.h 2008-05-16 14:05:09.000000000 -0400
@@ -83,17 +83,42 @@ del_page_from_active_file_list(struct zo
del_page_from_lru_list(zone, page, LRU_INACTIVE_FILE);
}

+#ifdef CONFIG_NORECLAIM_LRU
+static inline void
+add_page_to_noreclaim_list(struct zone *zone, struct page *page)
+{
+ add_page_to_lru_list(zone, page, LRU_NORECLAIM);
+}
+
+static inline void
+del_page_from_noreclaim_list(struct zone *zone, struct page *page)
+{
+ del_page_from_lru_list(zone, page, LRU_NORECLAIM);
+}
+#else
+static inline void
+add_page_to_noreclaim_list(struct zone *zone, struct page *page) { }
+
+static inline void
+del_page_from_noreclaim_list(struct zone *zone, struct page *page) { }
+#endif
+
static inline void
del_page_from_lru(struct zone *zone, struct page *page)
{
enum lru_list l = LRU_INACTIVE_ANON;

list_del(&page->lru);
- if (PageActive(page)) {
- __ClearPageActive(page);
- l += LRU_ACTIVE;
+ if (PageNoreclaim(page)) {
+ __ClearPageNoreclaim(page);
+ l = LRU_NORECLAIM;
+ } else {
+ if (PageActive(page)) {
+ __ClearPageActive(page);
+ l += LRU_ACTIVE;
+ }
+ l += page_file_cache(page);
}
- l += page_file_cache(page);
__dec_zone_state(zone, NR_INACTIVE_ANON + l);
}

Index: linux-2.6.26-rc2-mm1/include/linux/swap.h
===================================================================
--- linux-2.6.26-rc2-mm1.orig/include/linux/swap.h 2008-05-16 13:53:09.000000000 -0400
+++ linux-2.6.26-rc2-mm1/include/linux/swap.h 2008-05-16 14:05:09.000000000 -0400
@@ -204,6 +204,18 @@ static inline void lru_cache_add_active_
__lru_cache_add(page, LRU_ACTIVE_FILE);
}

+#ifdef CONFIG_NORECLAIM_LRU
+static inline void lru_cache_add_noreclaim(struct page *page)
+{
+ __lru_cache_add(page, LRU_NORECLAIM);
+}
+#else
+static inline void lru_cache_add_noreclaim(struct page *page)
+{
+ BUG();
+}
+#endif
+
/* linux/mm/vmscan.c */
extern unsigned long try_to_free_pages(struct zonelist *zonelist, int order,
gfp_t gfp_mask);
@@ -228,6 +240,16 @@ static inline int zone_reclaim(struct zo
}
#endif

+#ifdef CONFIG_NORECLAIM_LRU
+extern int page_reclaimable(struct page *page, struct vm_area_struct *vma);
+#else
+static inline int page_reclaimable(struct page *page,
+ struct vm_area_struct *vma)
+{
+ return 1;
+}
+#endif
+
extern int kswapd_run(int nid);

#ifdef CONFIG_MMU
Index: linux-2.6.26-rc2-mm1/include/linux/pagevec.h
===================================================================
--- linux-2.6.26-rc2-mm1.orig/include/linux/pagevec.h 2008-05-16 13:53:09.000000000 -0400
+++ linux-2.6.26-rc2-mm1/include/linux/pagevec.h 2008-05-16 14:05:09.000000000 -0400
@@ -101,6 +101,12 @@ static inline void __pagevec_lru_add_act
____pagevec_lru_add(pvec, LRU_ACTIVE_FILE);
}

+#ifdef CONFIG_NORECLAIM_LRU
+static inline void __pagevec_lru_add_noreclaim(struct pagevec *pvec)
+{
+ ____pagevec_lru_add(pvec, LRU_NORECLAIM);
+}
+#endif

static inline void pagevec_lru_add_file(struct pagevec *pvec)
{
Index: linux-2.6.26-rc2-mm1/mm/swap.c
===================================================================
--- linux-2.6.26-rc2-mm1.orig/mm/swap.c 2008-05-16 14:04:57.000000000 -0400
+++ linux-2.6.26-rc2-mm1/mm/swap.c 2008-05-16 14:05:09.000000000 -0400
@@ -106,9 +106,13 @@ enum lru_list page_lru(struct page *page
{
enum lru_list lru = LRU_BASE;

- if (PageActive(page))
- lru += LRU_ACTIVE;
- lru += page_file_cache(page);
+ if (PageNoreclaim(page))
+ lru = LRU_NORECLAIM;
+ else {
+ if (PageActive(page))
+ lru += LRU_ACTIVE;
+ lru += page_file_cache(page);
+ }

return lru;
}
@@ -133,7 +137,8 @@ static void pagevec_move_tail(struct pag
zone = pagezone;
spin_lock(&zone->lru_lock);
}
- if (PageLRU(page) && !PageActive(page)) {
+ if (PageLRU(page) && !PageActive(page) &&
+ !PageNoreclaim(page)) {
int lru = page_file_cache(page);
list_move_tail(&page->lru, &zone->list[lru]);
pgmoved++;
@@ -154,7 +159,7 @@ static void pagevec_move_tail(struct pag
void rotate_reclaimable_page(struct page *page)
{
if (!PageLocked(page) && !PageDirty(page) && !PageActive(page) &&
- PageLRU(page)) {
+ !PageNoreclaim(page) && PageLRU(page)) {
struct pagevec *pvec;
unsigned long flags;

@@ -175,7 +180,7 @@ void activate_page(struct page *page)
struct zone *zone = page_zone(page);

spin_lock_irq(&zone->lru_lock);
- if (PageLRU(page) && !PageActive(page)) {
+ if (PageLRU(page) && !PageActive(page) && !PageNoreclaim(page)) {
int file = page_file_cache(page);
int lru = LRU_BASE + file;
del_page_from_lru_list(zone, page, lru);
@@ -207,7 +212,8 @@ void activate_page(struct page *page)
*/
void mark_page_accessed(struct page *page)
{
- if (!PageActive(page) && PageReferenced(page) && PageLRU(page)) {
+ if (!PageActive(page) && !PageNoreclaim(page) &&
+ PageReferenced(page) && PageLRU(page)) {
activate_page(page);
ClearPageReferenced(page);
} else if (!PageReferenced(page)) {
@@ -235,10 +241,14 @@ void __lru_cache_add(struct page *page,
void lru_cache_add_lru(struct page *page, enum lru_list lru)
{
if (PageActive(page)) {
+ VM_BUG_ON(PageNoreclaim(page));
ClearPageActive(page);
+ } else if (PageNoreclaim(page)) {
+ VM_BUG_ON(PageActive(page));
+ ClearPageNoreclaim(page);
}

- VM_BUG_ON(PageLRU(page) || PageActive(page));
+ VM_BUG_ON(PageLRU(page) || PageActive(page) || PageNoreclaim(page));
__lru_cache_add(page, lru);
}

@@ -339,6 +349,7 @@ void release_pages(struct page **pages,

if (PageLRU(page)) {
struct zone *pagezone = page_zone(page);
+
if (pagezone != zone) {
if (zone)
spin_unlock_irqrestore(&zone->lru_lock,
@@ -426,10 +437,13 @@ void ____pagevec_lru_add(struct pagevec
zone = pagezone;
spin_lock_irq(&zone->lru_lock);
}
+ VM_BUG_ON(PageActive(page) || PageNoreclaim(page));
VM_BUG_ON(PageLRU(page));
SetPageLRU(page);
if (is_active_lru(lru))
SetPageActive(page);
+ else if (is_noreclaim_lru(lru))
+ SetPageNoreclaim(page);
add_page_to_lru_list(zone, page, lru);
}
if (zone)
Index: linux-2.6.26-rc2-mm1/mm/migrate.c
===================================================================
--- linux-2.6.26-rc2-mm1.orig/mm/migrate.c 2008-05-16 13:31:54.000000000 -0400
+++ linux-2.6.26-rc2-mm1/mm/migrate.c 2008-05-16 14:05:09.000000000 -0400
@@ -340,8 +340,11 @@ static void migrate_page_copy(struct pag
SetPageReferenced(newpage);
if (PageUptodate(page))
SetPageUptodate(newpage);
- if (PageActive(page))
+ if (TestClearPageActive(page)) {
+ VM_BUG_ON(PageNoreclaim(page));
SetPageActive(newpage);
+ } else if (TestClearPageNoreclaim(page))
+ SetPageNoreclaim(newpage);
if (PageChecked(page))
SetPageChecked(newpage);
if (PageMappedToDisk(page))
@@ -362,7 +365,6 @@ static void migrate_page_copy(struct pag
#ifdef CONFIG_SWAP
ClearPageSwapCache(page);
#endif
- ClearPageActive(page);
ClearPagePrivate(page);
set_page_private(page, 0);
page->mapping = NULL;
Index: linux-2.6.26-rc2-mm1/mm/vmscan.c
===================================================================
--- linux-2.6.26-rc2-mm1.orig/mm/vmscan.c 2008-05-16 14:05:05.000000000 -0400
+++ linux-2.6.26-rc2-mm1/mm/vmscan.c 2008-05-16 14:05:09.000000000 -0400
@@ -470,6 +470,11 @@ static unsigned long shrink_page_list(st

sc->nr_scanned++;

+ if (!page_reclaimable(page, NULL)) {
+ SetPageNoreclaim(page);
+ goto keep_locked;
+ }
+
if (!sc->may_swap && page_mapped(page))
goto keep_locked;

@@ -566,7 +571,7 @@ static unsigned long shrink_page_list(st
* possible for a page to have PageDirty set, but it is actually
* clean (all its buffers are clean). This happens if the
* buffers were written out directly, with submit_bh(). ext3
- * will do this, as well as the blockdev mapping.
+ * will do this, as well as the blockdev mapping.
* try_to_release_page() will discover that cleanness and will
* drop the buffers and mark the page clean - it can be freed.
*
@@ -598,6 +603,7 @@ activate_locked:
/* Not a candidate for swapping, so reclaim swap space. */
if (PageSwapCache(page) && vm_swap_full())
remove_exclusive_swap_page_ref(page);
+ VM_BUG_ON(PageActive(page));
SetPageActive(page);
pgactivate++;
keep_locked:
@@ -647,6 +653,14 @@ int __isolate_lru_page(struct page *page
if (mode != ISOLATE_BOTH && (!page_file_cache(page) != !file))
return ret;

+ /*
+ * Non-reclaimable pages shouldn't make it onto either the active
+ * nor the inactive list. However, when doing lumpy reclaim of
+ * higher order pages we can still run into them.
+ */
+ if (PageNoreclaim(page))
+ return ret;
+
ret = -EBUSY;
if (likely(get_page_unless_zero(page))) {
/*
@@ -758,7 +772,7 @@ static unsigned long isolate_lru_pages(u
/* else it is being freed elsewhere */
list_move(&cursor_page->lru, src);
default:
- break;
+ break; /* ! on LRU or wrong list */
}
}
}
@@ -818,8 +832,9 @@ static unsigned long clear_active_flags(
* Returns -EBUSY if the page was not on an LRU list.
*
* The returned page will have PageLRU() cleared. If it was found on
- * the active list, it will have PageActive set. That flag may need
- * to be cleared by the caller before letting the page go.
+ * the active list, it will have PageActive set. If it was found on
+ * the noreclaim list, it will have the PageNoreclaim bit set. That flag
+ * may need to be cleared by the caller before letting the page go.
*
* The vmstat statistic corresponding to the list on which the page was
* found will be decremented.
@@ -844,7 +859,13 @@ int isolate_lru_page(struct page *page)
ret = 0;
ClearPageLRU(page);

+ /* Calculate the LRU list for normal pages ... */
lru += page_file_cache(page) + !!PageActive(page);
+
+ /* ... except NoReclaim, which has its own list. */
+ if (PageNoreclaim(page))
+ lru = LRU_NORECLAIM;
+
del_page_from_lru_list(zone, page, lru);
}
spin_unlock_irq(&zone->lru_lock);
@@ -961,16 +982,21 @@ static unsigned long shrink_inactive_lis
VM_BUG_ON(PageLRU(page));
SetPageLRU(page);
list_del(&page->lru);
- if (page_file_cache(page))
- lru += LRU_FILE;
- if (scan_global_lru(sc)) {
+ if (PageNoreclaim(page)) {
+ VM_BUG_ON(PageActive(page));
+ lru = LRU_NORECLAIM;
+ } else {
if (page_file_cache(page))
- zone->recent_rotated_file++;
- else
- zone->recent_rotated_anon++;
+ lru += LRU_FILE;
+ 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;
}
- if (PageActive(page))
- lru += LRU_ACTIVE;
add_page_to_lru_list(zone, page, lru);
if (!pagevec_add(&pvec, page)) {
spin_unlock_irq(&zone->lru_lock);
@@ -1033,6 +1059,7 @@ static void shrink_active_list(unsigned
LIST_HEAD(l_hold); /* The pages which were snipped off */
LIST_HEAD(l_active);
LIST_HEAD(l_inactive);
+ LIST_HEAD(l_noreclaim);
struct page *page;
struct pagevec pvec;
enum lru_list lru;
@@ -1064,6 +1091,13 @@ static void shrink_active_list(unsigned
cond_resched();
page = lru_to_page(&l_hold);
list_del(&page->lru);
+
+ if (!page_reclaimable(page, NULL)) {
+ /* Non-reclaimable pages go onto their own list. */
+ list_add(&page->lru, &l_noreclaim);
+ continue;
+ }
+
if (page_referenced(page, 0, sc->mem_cgroup) && file) {
/* Referenced file pages stay active. */
list_add(&page->lru, &l_active);
@@ -1151,6 +1185,32 @@ static void shrink_active_list(unsigned
zone->recent_rotated_anon += pgmoved;
}

+#ifdef CONFIG_NORECLAIM_LRU
+ pgmoved = 0;
+ while (!list_empty(&l_noreclaim)) {
+ page = lru_to_page(&l_noreclaim);
+ prefetchw_prev_lru_page(page, &l_noreclaim, flags);
+
+ VM_BUG_ON(PageLRU(page));
+ SetPageLRU(page);
+ VM_BUG_ON(!PageActive(page));
+ ClearPageActive(page);
+ VM_BUG_ON(PageNoreclaim(page));
+ SetPageNoreclaim(page);
+
+ list_move(&page->lru, &zone->list[LRU_NORECLAIM]);
+ pgmoved++;
+ if (!pagevec_add(&pvec, page)) {
+ __mod_zone_page_state(zone, NR_NORECLAIM, pgmoved);
+ pgmoved = 0;
+ spin_unlock_irq(&zone->lru_lock);
+ __pagevec_release(&pvec);
+ spin_lock_irq(&zone->lru_lock);
+ }
+ }
+ __mod_zone_page_state(zone, NR_NORECLAIM, pgmoved);
+#endif
+
__count_zone_vm_events(PGREFILL, zone, pgscanned);
__count_vm_events(PGDEACTIVATE, pgdeactivate);
spin_unlock_irq(&zone->lru_lock);
@@ -1267,7 +1327,7 @@ static unsigned long shrink_zone(int pri

get_scan_ratio(zone, sc, percent);

- for_each_lru(l) {
+ for_each_reclaimable_lru(l) {
if (scan_global_lru(sc)) {
int file = is_file_lru(l);
int scan;
@@ -1298,7 +1358,7 @@ static unsigned long shrink_zone(int pri

while (nr[LRU_INACTIVE_ANON] || nr[LRU_ACTIVE_FILE] ||
nr[LRU_INACTIVE_FILE]) {
- for_each_lru(l) {
+ for_each_reclaimable_lru(l) {
if (nr[l]) {
nr_to_scan = min(nr[l],
(unsigned long)sc->swap_cluster_max);
@@ -1849,8 +1909,8 @@ static unsigned long shrink_all_zones(un
if (zone_is_all_unreclaimable(zone) && prio != DEF_PRIORITY)
continue;

- for_each_lru(l) {
- /* For pass = 0 we don't shrink the active list */
+ for_each_reclaimable_lru(l) {
+ /* For pass = 0, we don't shrink the active list */
if (pass == 0 &&
(l == LRU_ACTIVE_ANON || l == LRU_ACTIVE_FILE))
continue;
@@ -2187,3 +2247,26 @@ int zone_reclaim(struct zone *zone, gfp_
return ret;
}
#endif
+
+#ifdef CONFIG_NORECLAIM_LRU
+/*
+ * page_reclaimable - test whether a page is reclaimable
+ * @page: the page to test
+ * @vma: the VMA in which the page is or will be mapped, may be NULL
+ *
+ * Test whether page is reclaimable--i.e., should be placed on active/inactive
+ * lists vs noreclaim list.
+ *
+ * Reasons page might not be reclaimable:
+ * TODO - later patches
+ */
+int page_reclaimable(struct page *page, struct vm_area_struct *vma)
+{
+
+ VM_BUG_ON(PageNoreclaim(page));
+
+ /* TODO: test page [!]reclaimable conditions */
+
+ return 1;
+}
+#endif
Index: linux-2.6.26-rc2-mm1/mm/mempolicy.c
===================================================================
--- linux-2.6.26-rc2-mm1.orig/mm/mempolicy.c 2008-05-15 16:07:44.000000000 -0400
+++ linux-2.6.26-rc2-mm1/mm/mempolicy.c 2008-05-16 14:05:09.000000000 -0400
@@ -2199,7 +2199,7 @@ static void gather_stats(struct page *pa
if (PageSwapCache(page))
md->swapcache++;

- if (PageActive(page))
+ if (PageActive(page) || PageNoreclaim(page))
md->active++;

if (PageWriteback(page))

--
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