Single Zone Optimizations
If we only have a single zone then various macros can be optimized.
We do not need to protect higher zones, we know that zones are
always present, can remove useless data from /proc etc etc.
Signed-off-by: Christoph Lameter <clameter@sgi.com>
Index: linux-2.6.18-mm2/mm/vmstat.c
===================================================================
--- linux-2.6.18-mm2.orig/mm/vmstat.c 2006-09-28 15:29:48.000000000 -0500
+++ linux-2.6.18-mm2/mm/vmstat.c 2006-09-28 16:47:53.208512202 -0500
@@ -554,7 +554,7 @@ static int zoneinfo_show(struct seq_file
for (i = 0; i < NR_VM_ZONE_STAT_ITEMS; i++)
seq_printf(m, "\n %-12s %lu", vmstat_text[i],
zone_page_state(zone, i));
-
+#ifdef MULTI_ZONE
seq_printf(m,
"\n protection: (%lu",
zone->lowmem_reserve[0]);
@@ -563,6 +563,7 @@ static int zoneinfo_show(struct seq_file
seq_printf(m,
")"
"\n pagesets");
+#endif
for_each_online_cpu(i) {
struct per_cpu_pageset *pageset;
int j;
Index: linux-2.6.18-mm2/mm/page_alloc.c
===================================================================
--- linux-2.6.18-mm2.orig/mm/page_alloc.c 2006-09-28 15:29:48.000000000 -0500
+++ linux-2.6.18-mm2/mm/page_alloc.c 2006-09-28 16:47:53.225115171 -0500
@@ -59,6 +59,7 @@ int percpu_pagelist_fraction;
static void __free_pages_ok(struct page *page, unsigned int order);
+#ifdef MULTI_ZONE
/*
* results with 256, 32 in the lowmem_reserve sysctl:
* 1G machine -> (16M dma, 800M-16M normal, 1G-800M high)
@@ -81,6 +82,7 @@ int sysctl_lowmem_reserve_ratio[MAX_NR_Z
32
#endif
};
+#endif
EXPORT_SYMBOL(totalram_pages);
@@ -920,8 +922,11 @@ int zone_watermark_ok(struct zone *z, in
min -= min / 2;
if (alloc_flags & ALLOC_HARDER)
min -= min / 4;
-
+#ifdef SINGLE_ZONE
+ if (free_pages <= min)
+#else
if (free_pages <= min + z->lowmem_reserve[classzone_idx])
+#endif
return 0;
for (o = 0; o < order; o++) {
/* At the next order, this order's pages become unavailable */
@@ -1462,10 +1467,12 @@ void show_free_areas(void)
zone->pages_scanned,
(zone->all_unreclaimable ? "yes" : "no")
);
+#ifdef MULTI_ZONE
printk("lowmem_reserve[]:");
for (i = 0; i < MAX_NR_ZONES; i++)
printk(" %lu", zone->lowmem_reserve[i]);
printk("\n");
+#endif
}
for_each_zone(zone) {
@@ -2863,12 +2870,13 @@ static void calculate_totalreserve_pages
struct zone *zone = pgdat->node_zones + i;
unsigned long max = 0;
+#ifdef MULTI_ZONE
/* Find valid and maximum lowmem_reserve in the zone */
for (j = i; j < MAX_NR_ZONES; j++) {
if (zone->lowmem_reserve[j] > max)
max = zone->lowmem_reserve[j];
}
-
+#endif
/* we treat pages_high as reserved pages. */
max += zone->pages_high;
@@ -2888,6 +2896,7 @@ static void calculate_totalreserve_pages
*/
static void setup_per_zone_lowmem_reserve(void)
{
+#ifdef MULTI_ZONE
struct pglist_data *pgdat;
enum zone_type j, idx;
@@ -2917,6 +2926,7 @@ static void setup_per_zone_lowmem_reserv
/* update totalreserve_pages */
calculate_totalreserve_pages();
+#endif
}
/*
@@ -3066,6 +3076,7 @@ int sysctl_min_slab_ratio_sysctl_handler
}
#endif
+#ifdef MULTI_ZONE
/*
* lowmem_reserve_ratio_sysctl_handler - just a wrapper around
* proc_dointvec() so that we can call setup_per_zone_lowmem_reserve()
@@ -3082,6 +3093,7 @@ int lowmem_reserve_ratio_sysctl_handler(
setup_per_zone_lowmem_reserve();
return 0;
}
+#endif
/*
* percpu_pagelist_fraction - changes the pcp->high for each zone on each
Index: linux-2.6.18-mm2/kernel/sysctl.c
===================================================================
--- linux-2.6.18-mm2.orig/kernel/sysctl.c 2006-09-28 15:29:47.000000000 -0500
+++ linux-2.6.18-mm2/kernel/sysctl.c 2006-09-28 16:47:53.245624720 -0500
@@ -900,6 +900,7 @@ static ctl_table vm_table[] = {
.proc_handler = &proc_dointvec,
},
#endif
+#ifdef MULTI_ZONE
{
.ctl_name = VM_LOWMEM_RESERVE_RATIO,
.procname = "lowmem_reserve_ratio",
@@ -909,6 +910,7 @@ static ctl_table vm_table[] = {
.proc_handler = &lowmem_reserve_ratio_sysctl_handler,
.strategy = &sysctl_intvec,
},
+#endif
{
.ctl_name = VM_DROP_PAGECACHE,
.procname = "drop_caches",
Index: linux-2.6.18-mm2/include/linux/mmzone.h
===================================================================
--- linux-2.6.18-mm2.orig/include/linux/mmzone.h 2006-09-28 15:29:43.000000000 -0500
+++ linux-2.6.18-mm2/include/linux/mmzone.h 2006-09-28 16:48:29.628588690 -0500
@@ -162,6 +162,7 @@ enum zone_type {
)
#if __ZONE_COUNT < 2
#define ZONES_SHIFT 0
+#define SINGLE_ZONE
#elif __ZONE_COUNT <= 2
#define ZONES_SHIFT 1
#elif __ZONE_COUNT <= 4
@@ -171,10 +172,15 @@ enum zone_type {
#endif
#undef __ZONE_COUNT
+#ifndef SINGLE_ZONE
+#define MULTI_ZONE
+#endif
+
struct zone {
/* Fields commonly accessed by the page allocator */
unsigned long free_pages;
unsigned long pages_min, pages_low, pages_high;
+#ifdef MULTI_ZONE
/*
* We don't know if the memory that we're going to allocate will be freeable
* or/and it will be released eventually, so to avoid totally wasting several
@@ -184,6 +190,7 @@ struct zone {
* sysctl_lowmem_reserve_ratio sysctl changes.
*/
unsigned long lowmem_reserve[MAX_NR_ZONES];
+#endif
#ifdef CONFIG_NUMA
int node;
@@ -420,11 +427,19 @@ unsigned long __init node_memmap_size_by
/*
* zone_idx() returns 0 for the ZONE_DMA zone, 1 for the ZONE_NORMAL zone, etc.
*/
+#ifdef MULTI_ZONE
#define zone_idx(zone) ((zone) - (zone)->zone_pgdat->node_zones)
+#else
+#define zone_idx(zone) ZONE_NORMAL
+#endif
static inline int populated_zone(struct zone *zone)
{
+#ifdef MULTI_ZONE
return (!!zone->present_pages);
+#else
+ return 1;
+#endif
}
static inline int is_highmem_idx(enum zone_type idx)
@@ -438,7 +453,11 @@ static inline int is_highmem_idx(enum zo
static inline int is_normal_idx(enum zone_type idx)
{
+#ifdef MULTI_ZONE
return (idx == ZONE_NORMAL);
+#else
+ return 1;
+#endif
}
/**
@@ -458,7 +477,11 @@ static inline int is_highmem(struct zone
static inline int is_normal(struct zone *zone)
{
+#ifdef MULTI_ZONE
return zone == zone->zone_pgdat->node_zones + ZONE_NORMAL;
+#else
+ return 1;
+#endif
}
static inline int is_dma32(struct zone *zone)
@@ -484,9 +507,11 @@ struct ctl_table;
struct file;
int min_free_kbytes_sysctl_handler(struct ctl_table *, int, struct file *,
void __user *, size_t *, loff_t *);
+#ifdef MULTI_ZONE
extern int sysctl_lowmem_reserve_ratio[MAX_NR_ZONES-1];
int lowmem_reserve_ratio_sysctl_handler(struct ctl_table *, int, struct file *,
void __user *, size_t *, loff_t *);
+#endif
int percpu_pagelist_fraction_sysctl_handler(struct ctl_table *, int, struct file *,
void __user *, size_t *, loff_t *);
int sysctl_min_unmapped_ratio_sysctl_handler(struct ctl_table *, int,