From: Matthew Dobson <colpatch@us.ibm.com>
Documentation/kernel-parameters.txt | 2
Documentation/sysctl/vm.txt | 9 +++
include/linux/mmzone.h | 19 +++++++
include/linux/sysctl.h | 1
init/main.c | 1
kernel/sysctl.c | 11 ++++
mm/page_alloc.c | 89 +++++++++++++++++++++++++-----------
7 files changed, 104 insertions(+), 28 deletions(-)
diff -puN Documentation/kernel-parameters.txt~min_free_kbytes Documentation/kernel-parameters.txt
--- 25/Documentation/kernel-parameters.txt~min_free_kbytes 2003-06-03 20:32:25.000000000 -0700
+++ 25-akpm/Documentation/kernel-parameters.txt 2003-06-03 20:32:25.000000000 -0700
@@ -540,8 +540,6 @@ running once the system is up.
[KNL,ACPI] Mark specific memory as reserved.
Region of memory to be used, from ss to ss+nn.
- memfrac= [KNL]
-
meye= [HW] Set MotionEye Camera parameters
See Documentation/video4linux/meye.txt.
diff -puN Documentation/sysctl/vm.txt~min_free_kbytes Documentation/sysctl/vm.txt
--- 25/Documentation/sysctl/vm.txt~min_free_kbytes 2003-06-03 20:32:25.000000000 -0700
+++ 25-akpm/Documentation/sysctl/vm.txt 2003-06-03 20:32:25.000000000 -0700
@@ -22,6 +22,7 @@ Currently, these files are in /proc/sys/
- dirty_background_ratio
- dirty_expire_centisecs
- dirty_writeback_centisecs
+- min_free_kbytes
==============================================================
@@ -74,3 +75,11 @@ The number of pages the kernel reads in
2 ^ page-cluster. Values above 2 ^ 5 don't make much sense
for swap because we only cluster swap data in 32-page groups.
+==============================================================
+
+min_free_kbytes:
+
+This is used to force the Linux VM to keep a minimum number
+of kilobytes free. The VM uses this number to compute a pages_min
+value for each lowmem zone in the system. Each lowmem zone gets
+a number of reserved free pages based proportionally on its size.
diff -puN include/linux/mmzone.h~min_free_kbytes include/linux/mmzone.h
--- 25/include/linux/mmzone.h~min_free_kbytes 2003-06-03 20:32:25.000000000 -0700
+++ 25-akpm/include/linux/mmzone.h 2003-06-03 20:32:25.000000000 -0700
@@ -249,6 +249,25 @@ static inline struct zone *next_zone(str
#define for_each_zone(zone) \
for (zone = pgdat_list->node_zones; zone; zone = next_zone(zone))
+/**
+ * is_highmem - helper function to quickly check if a struct zone is a
+ * highmem zone or not. This is an attempt to keep references
+ * to ZONE_{DMA/NORMAL/HIGHMEM/etc} in general code to a minimum.
+ * @zone - pointer to struct zone variable
+ */
+static inline int is_highmem(struct zone *zone)
+{
+ return (zone - zone->zone_pgdat->node_zones == ZONE_HIGHMEM);
+}
+
+/* These two functions are used to setup the per zone pages min values */
+struct ctl_table;
+struct file;
+int min_free_kbytes_sysctl_handler(struct ctl_table *, int, struct file *,
+ void *, size_t *);
+extern void setup_per_zone_pages_min(void);
+
+
#ifdef CONFIG_NUMA
#define MAX_NR_MEMBLKS BITS_PER_LONG /* Max number of Memory Blocks */
#else /* !CONFIG_NUMA */
diff -puN include/linux/sysctl.h~min_free_kbytes include/linux/sysctl.h
--- 25/include/linux/sysctl.h~min_free_kbytes 2003-06-03 20:32:25.000000000 -0700
+++ 25-akpm/include/linux/sysctl.h 2003-06-03 20:32:25.000000000 -0700
@@ -156,6 +156,7 @@ enum
VM_HUGETLB_PAGES=18, /* int: Number of available Huge Pages */
VM_SWAPPINESS=19, /* Tendency to steal mapped memory */
VM_LOWER_ZONE_PROTECTION=20,/* Amount of protection of lower zones */
+ VM_MIN_FREE_KBYTES=21, /* Minimum free kilobytes to maintain */
};
diff -puN init/main.c~min_free_kbytes init/main.c
--- 25/init/main.c~min_free_kbytes 2003-06-03 20:32:25.000000000 -0700
+++ 25-akpm/init/main.c 2003-06-03 20:32:25.000000000 -0700
@@ -390,6 +390,7 @@ asmlinkage void __init start_kernel(void
lock_kernel();
printk(linux_banner);
setup_arch(&command_line);
+ setup_per_zone_pages_min();
setup_per_cpu_areas();
/*
diff -puN kernel/sysctl.c~min_free_kbytes kernel/sysctl.c
--- 25/kernel/sysctl.c~min_free_kbytes 2003-06-03 20:32:25.000000000 -0700
+++ 25-akpm/kernel/sysctl.c 2003-06-03 20:34:13.000000000 -0700
@@ -57,6 +57,7 @@ extern char core_pattern[];
extern int cad_pid;
extern int pid_max;
extern int sysctl_lower_zone_protection;
+extern int min_free_kbytes;
/* this is needed for the proc_dointvec_minmax for [fs_]overflow UID and GID */
static int maxolduid = 65535;
@@ -661,6 +662,16 @@ static ctl_table vm_table[] = {
.strategy = &sysctl_intvec,
.extra1 = &zero,
},
+ {
+ .ctl_name = VM_MIN_FREE_KBYTES,
+ .procname = "min_free_kbytes",
+ .data = &min_free_kbytes,
+ .maxlen = sizeof(min_free_kbytes),
+ .mode = 0644,
+ .proc_handler = &min_free_kbytes_sysctl_handler,
+ .strategy = &sysctl_intvec,
+ .extra1 = &zero,
+ },
{ .ctl_name = 0 }
};
diff -puN mm/page_alloc.c~min_free_kbytes mm/page_alloc.c
--- 25/mm/page_alloc.c~min_free_kbytes 2003-06-03 20:32:25.000000000 -0700
+++ 25-akpm/mm/page_alloc.c 2003-06-03 20:32:25.000000000 -0700
@@ -29,6 +29,7 @@
#include <linux/slab.h>
#include <linux/notifier.h>
#include <linux/topology.h>
+#include <linux/sysctl.h>
#include <asm/tlbflush.h>
@@ -49,9 +50,7 @@ struct zone *zone_table[MAX_NR_ZONES*MAX
EXPORT_SYMBOL(zone_table);
static char *zone_names[MAX_NR_ZONES] = { "DMA", "Normal", "HighMem" };
-static int zone_balance_ratio[MAX_NR_ZONES] __initdata = { 128, 128, 128, };
-static int zone_balance_min[MAX_NR_ZONES] __initdata = { 20 , 20, 20, };
-static int zone_balance_max[MAX_NR_ZONES] __initdata = { 255 , 255, 255, };
+int min_free_kbytes = 1024;
/*
* Temporary debugging check for pages not lying within a given zone.
@@ -1212,7 +1211,6 @@ static void __init free_area_init_core(s
for (j = 0; j < MAX_NR_ZONES; j++) {
struct zone *zone = pgdat->node_zones + j;
- unsigned long mask;
unsigned long size, realsize;
unsigned long batch;
@@ -1286,15 +1284,6 @@ static void __init free_area_init_core(s
pgdat->nr_zones = j+1;
- mask = (realsize / zone_balance_ratio[j]);
- if (mask < zone_balance_min[j])
- mask = zone_balance_min[j];
- else if (mask > zone_balance_max[j])
- mask = zone_balance_max[j];
- zone->pages_min = mask;
- zone->pages_low = mask*2;
- zone->pages_high = mask*3;
-
zone->zone_mem_map = lmem_map;
zone->zone_start_pfn = zone_start_pfn;
@@ -1379,19 +1368,6 @@ void __init free_area_init(unsigned long
}
#endif
-static int __init setup_mem_frac(char *str)
-{
- int j = 0;
-
- while (get_option(&str, &zone_balance_ratio[j++]) == 2);
- printk("setup_mem_frac: ");
- for (j = 0; j < MAX_NR_ZONES; j++) printk("%d ", zone_balance_ratio[j]);
- printk("\n");
- return 1;
-}
-
-__setup("memfrac=", setup_mem_frac);
-
#ifdef CONFIG_PROC_FS
#include <linux/seq_file.h>
@@ -1568,3 +1544,64 @@ void __init page_alloc_init(void)
init_page_alloc_cpu(smp_processor_id());
register_cpu_notifier(&page_alloc_nb);
}
+
+/*
+ * setup_per_zone_pages_min - called when min_free_kbytes changes. Ensures
+ * that the pages_{min,low,high} values for each zone are set correctly
+ * with respect to min_free_kbytes.
+ */
+void setup_per_zone_pages_min(void)
+{
+ unsigned long pages_min = min_free_kbytes >> (PAGE_SHIFT - 10);
+ unsigned long lowmem_pages = 0;
+ struct zone *zone;
+ unsigned long flags;
+
+ /* Calculate total number of !ZONE_HIGHMEM pages */
+ for_each_zone(zone)
+ if (!is_highmem(zone))
+ lowmem_pages += zone->present_pages;
+
+ for_each_zone(zone) {
+ spin_lock_irqsave(&zone->lru_lock, flags);
+ if (is_highmem(zone)) {
+ /*
+ * Often, highmem doesn't need to reserve any pages.
+ * But the pages_min/low/high values are also used for
+ * batching up page reclaim activity so we need a
+ * decent value here.
+ */
+ int min_pages;
+
+ min_pages = zone->present_pages / 1024;
+ if (min_pages < SWAP_CLUSTER_MAX)
+ min_pages = SWAP_CLUSTER_MAX;
+ if (min_pages > 128)
+ min_pages = 128;
+ zone->pages_min = min_pages;
+ } else {
+ /* if it's a lowmem zone, reserve a number of pages
+ * proportionate to the zone's size.
+ */
+ zone->pages_min = (pages_min * zone->present_pages) /
+ lowmem_pages;
+ }
+
+ zone->pages_low = zone->pages_min * 2;
+ zone->pages_high = zone->pages_min * 3;
+ spin_unlock_irqrestore(&zone->lru_lock, flags);
+ }
+}
+
+/*
+ * min_free_kbytes_sysctl_handler - just a wrapper around proc_dointvec() so
+ * that we can call setup_per_zone_pages_min() whenever min_free_kbytes
+ * changes.
+ */
+int min_free_kbytes_sysctl_handler(ctl_table *table, int write,
+ struct file *file, void *buffer, size_t *length)
+{
+ proc_dointvec(table, write, file, buffer, length);
+ setup_per_zone_pages_min();
+ return 0;
+}
_