[PATCH] mm: compare MIGRATE_ISOLATE selectively

From: Minchan Kim
Date: Thu Dec 20 2012 - 00:25:53 EST


Now mm several functions test MIGRATE_ISOLATE and some of those
are hotpath but MIGRATE_ISOLATE is used only if we enable
CONFIG_MEMORY_ISOLATION(ie, CMA, memory-hotplug and memory-failure)
which are not common config option. So let's not add unnecessary
overhead and code.

Signed-off-by: Minchan Kim <minchan@xxxxxxxxxx>
---
include/linux/mmzone.h | 2 ++
include/linux/page-isolation.h | 19 +++++++++++++++++++
mm/compaction.c | 6 +++++-
mm/page_alloc.c | 16 ++++++++++------
mm/vmstat.c | 2 ++
5 files changed, 38 insertions(+), 7 deletions(-)

diff --git a/include/linux/mmzone.h b/include/linux/mmzone.h
index 73b64a3..4f4c8c2 100644
--- a/include/linux/mmzone.h
+++ b/include/linux/mmzone.h
@@ -57,7 +57,9 @@ enum {
*/
MIGRATE_CMA,
#endif
+#ifdef CONFIG_MEMORY_ISOLATION
MIGRATE_ISOLATE, /* can't allocate from here */
+#endif
MIGRATE_TYPES
};

diff --git a/include/linux/page-isolation.h b/include/linux/page-isolation.h
index a92061e..4ada4ef 100644
--- a/include/linux/page-isolation.h
+++ b/include/linux/page-isolation.h
@@ -1,6 +1,25 @@
#ifndef __LINUX_PAGEISOLATION_H
#define __LINUX_PAGEISOLATION_H

+#ifdef CONFIG_MEMORY_ISOLATION
+static inline bool page_isolated_pageblock(struct page *page)
+{
+ return get_pageblock_migratetype(page) == MIGRATE_ISOLATE;
+}
+static inline bool mt_isolated_pageblock(int migratetype)
+{
+ return migratetype == MIGRATE_ISOLATE;
+}
+#else
+static inline bool page_isolated_pageblock(struct page *page)
+{
+ return false;
+}
+static inline bool mt_isolated_pageblock(int migratetype)
+{
+ return false;
+}
+#endif

bool has_unmovable_pages(struct zone *zone, struct page *page, int count,
bool skip_hwpoisoned_pages);
diff --git a/mm/compaction.c b/mm/compaction.c
index 70f4443..dc2a6c7 100644
--- a/mm/compaction.c
+++ b/mm/compaction.c
@@ -15,6 +15,7 @@
#include <linux/sysctl.h>
#include <linux/sysfs.h>
#include <linux/balloon_compaction.h>
+#include <linux/page-isolation.h>
#include "internal.h"

#ifdef CONFIG_COMPACTION
@@ -215,7 +216,10 @@ static bool suitable_migration_target(struct page *page)
int migratetype = get_pageblock_migratetype(page);

/* Don't interfere with memory hot-remove or the min_free_kbytes blocks */
- if (migratetype == MIGRATE_ISOLATE || migratetype == MIGRATE_RESERVE)
+ if (migratetype == MIGRATE_RESERVE)
+ return false;
+
+ if (mt_isolated_pageblock(migratetype))
return false;

/* If the page is a large free page, then allow migration */
diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index 0939417..5450815 100644
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -668,7 +668,7 @@ static void free_pcppages_bulk(struct zone *zone, int count,
/* MIGRATE_MOVABLE list may include MIGRATE_RESERVEs */
__free_one_page(page, zone, 0, mt);
trace_mm_page_pcpu_drain(page, 0, mt);
- if (likely(get_pageblock_migratetype(page) != MIGRATE_ISOLATE)) {
+ if (likely(!page_isolated_pageblock(page))) {
__mod_zone_page_state(zone, NR_FREE_PAGES, 1);
if (is_migrate_cma(mt))
__mod_zone_page_state(zone, NR_FREE_CMA_PAGES, 1);
@@ -686,7 +686,7 @@ static void free_one_page(struct zone *zone, struct page *page, int order,
zone->pages_scanned = 0;

__free_one_page(page, zone, order, migratetype);
- if (unlikely(migratetype != MIGRATE_ISOLATE))
+ if (unlikely(!mt_isolated_pageblock(migratetype)))
__mod_zone_freepage_state(zone, 1 << order, migratetype);
spin_unlock(&zone->lock);
}
@@ -914,7 +914,9 @@ static int fallbacks[MIGRATE_TYPES][4] = {
[MIGRATE_MOVABLE] = { MIGRATE_RECLAIMABLE, MIGRATE_UNMOVABLE, MIGRATE_RESERVE },
#endif
[MIGRATE_RESERVE] = { MIGRATE_RESERVE }, /* Never used */
+#ifdef CONFIG_MEMORY_ISOLATION
[MIGRATE_ISOLATE] = { MIGRATE_RESERVE }, /* Never used */
+#endif
};

/*
@@ -1140,7 +1142,7 @@ static int rmqueue_bulk(struct zone *zone, unsigned int order,
list_add_tail(&page->lru, list);
if (IS_ENABLED(CONFIG_CMA)) {
mt = get_pageblock_migratetype(page);
- if (!is_migrate_cma(mt) && mt != MIGRATE_ISOLATE)
+ if (!is_migrate_cma(mt) && !mt_isolated_pageblock(mt))
mt = migratetype;
}
set_freepage_migratetype(page, mt);
@@ -1324,7 +1326,7 @@ void free_hot_cold_page(struct page *page, int cold)
* excessively into the page allocator
*/
if (migratetype >= MIGRATE_PCPTYPES) {
- if (unlikely(migratetype == MIGRATE_ISOLATE)) {
+ if (unlikely(mt_isolated_pageblock(migratetype))) {
free_one_page(zone, page, 0, migratetype);
goto out;
}
@@ -1405,7 +1407,7 @@ int capture_free_page(struct page *page, int alloc_order, int migratetype)
order = page_order(page);
mt = get_pageblock_migratetype(page);

- if (mt != MIGRATE_ISOLATE) {
+ if (!mt_isolated_pageblock(mt)) {
/* Obey watermarks as if the page was being allocated */
watermark = low_wmark_pages(zone) + (1 << order);
if (!zone_watermark_ok(zone, 0, watermark, 0, 0))
@@ -1428,7 +1430,7 @@ int capture_free_page(struct page *page, int alloc_order, int migratetype)
struct page *endpage = page + (1 << order) - 1;
for (; page < endpage; page += pageblock_nr_pages) {
int mt = get_pageblock_migratetype(page);
- if (mt != MIGRATE_ISOLATE && !is_migrate_cma(mt))
+ if (!mt_isolated_pageblock(mt) && !is_migrate_cma(mt))
set_pageblock_migratetype(page,
MIGRATE_MOVABLE);
}
@@ -2937,7 +2939,9 @@ static void show_migration_types(unsigned char type)
#ifdef CONFIG_CMA
[MIGRATE_CMA] = 'C',
#endif
+#ifdef CONFIG_MEMORY_ISOLATION
[MIGRATE_ISOLATE] = 'I',
+#endif
};
char tmp[MIGRATE_TYPES + 1];
char *p = tmp;
diff --git a/mm/vmstat.c b/mm/vmstat.c
index 58e3da5..2e6094f 100644
--- a/mm/vmstat.c
+++ b/mm/vmstat.c
@@ -629,7 +629,9 @@ static char * const migratetype_names[MIGRATE_TYPES] = {
#ifdef CONFIG_CMA
"CMA",
#endif
+#ifdef CONFIG_MEMORY_ISOLATION
"Isolate",
+#endif
};

static void *frag_start(struct seq_file *m, loff_t *pos)
--
1.7.9.5

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