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SubjectRe: 2.6.0-test7-mm1
Thomas Schlichter <schlicht@uni-mannheim.de> wrote:
>
> > Scale min_free_kbytes according to machine size.
>
> This patch actually doesn't work, as is uses nr_free_buffer_pages() before the
> zonelists are set up. So min_free_kbytes is always set to 128.

Yup. I turned it into an initcall.

include/linux/mmzone.h | 2 --
init/main.c | 1 -
mm/page_alloc.c | 41 ++++++++++++++++++++++++++++++++++++++++-
3 files changed, 40 insertions(+), 4 deletions(-)
diff -puN include/linux/mmzone.h~scale-min_free_kbytes include/linux/mmzone.h
--- 25/include/linux/mmzone.h~scale-min_free_kbytes 2003-10-17 17:52:50.000000000 -0700
+++ 25-akpm/include/linux/mmzone.h 2003-10-17 21:46:55.000000000 -0700
@@ -284,8 +284,6 @@ 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 */
diff -puN init/main.c~scale-min_free_kbytes init/main.c
--- 25/init/main.c~scale-min_free_kbytes 2003-10-17 17:52:50.000000000 -0700
+++ 25-akpm/init/main.c 2003-10-17 21:47:04.000000000 -0700
@@ -396,7 +396,6 @@ 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 mm/page_alloc.c~scale-min_free_kbytes mm/page_alloc.c
--- 25/mm/page_alloc.c~scale-min_free_kbytes 2003-10-17 17:52:50.000000000 -0700
+++ 25-akpm/mm/page_alloc.c 2003-10-17 21:48:31.000000000 -0700
@@ -1589,7 +1589,7 @@ void __init page_alloc_init(void)
* 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)
+static void setup_per_zone_pages_min(void)
{
unsigned long pages_min = min_free_kbytes >> (PAGE_SHIFT - 10);
unsigned long lowmem_pages = 0;
@@ -1633,6 +1633,45 @@ void setup_per_zone_pages_min(void)
}

/*
+ * Initialise min_free_kbytes.
+ *
+ * For small machines we want it small (128k min). For large machines
+ * we want it large (16MB max). But it is not linear, because network
+ * bandwidth does not increase linearly with machine size. We use
+ *
+ * min_free_kbytes = sqrt(lowmem_kbytes)
+ *
+ * which yields
+ *
+ * 16MB: 128k
+ * 32MB: 181k
+ * 64MB: 256k
+ * 128MB: 362k
+ * 256MB: 512k
+ * 512MB: 724k
+ * 1024MB: 1024k
+ * 2048MB: 1448k
+ * 4096MB: 2048k
+ * 8192MB: 2896k
+ * 16384MB: 4096k
+ */
+static int __init init_per_zone_pages_min(void)
+{
+ unsigned long lowmem_kbytes;
+
+ lowmem_kbytes = nr_free_buffer_pages() * (PAGE_SIZE >> 10);
+
+ min_free_kbytes = int_sqrt(lowmem_kbytes);
+ if (min_free_kbytes < 128)
+ min_free_kbytes = 128;
+ if (min_free_kbytes > 16384)
+ min_free_kbytes = 16384;
+ setup_per_zone_pages_min();
+ return 0;
+}
+module_init(init_per_zone_pages_min)
+
+/*
* 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.
_

-
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