the following patch:
- puts min_free_pages, free_pages_[low,high] in a struct, so the
sysctl control is free from compiler reorders (just take a look
at the old sysctl.c :-) and we're freed from three global variables
- implements sysctl tunable disk cache memory limitations:
buffer_mem.min_percent; /* minimum amount of buffer + cache */
buffer_mem.borrow_percent; /* when there's more than this, kswapd
* only steals from us */
buffer_mem.max_percent; /* the maximum amount of buffer + cache */
- removes the swap= and buff= startup options, since things are
sysctl tunable now and nobody uses the old options
- cleans up the swapctl_t struct (v6 now :-)
- updates the documentation (Yes, sir!)
It patches cleanly against 2.1.89. The reason I send this to
David is that I had to change asm/sparc(64)/mm/init.c because
of min_free_pages et al...
Rik.
+-------------------------------------------+--------------------------+
| Linux: - LinuxHQ MM-patches page | Scouting webmaster |
| - kswapd ask-him & complain-to guy | Vries cubscout leader |
| http://www.fys.ruu.nl/~riel/ | <H.H.vanRiel@fys.ruu.nl> |
+-------------------------------------------+--------------------------+
--- linux.89.orig/include/linux/swapctl.h Sat Mar 7 06:02:12 1998
+++ linux-2.1.89/include/linux/swapctl.h Thu Mar 12 15:13:45 1998
@@ -6,29 +6,18 @@
/* Swap tuning control */
-/* First, enumerate the different reclaim policies */
-enum RCL_POLICY {RCL_ROUND_ROBIN, RCL_BUFF_FIRST, RCL_PERSIST};
-
-typedef struct swap_control_v5
+typedef struct swap_control_v6
{
unsigned int sc_max_page_age;
unsigned int sc_page_advance;
unsigned int sc_page_decline;
unsigned int sc_page_initial_age;
- unsigned int sc_max_buff_age;
- unsigned int sc_buff_advance;
- unsigned int sc_buff_decline;
- unsigned int sc_buff_initial_age;
unsigned int sc_age_cluster_fract;
unsigned int sc_age_cluster_min;
unsigned int sc_pageout_weight;
unsigned int sc_bufferout_weight;
- unsigned int sc_buffer_grace;
- unsigned int sc_nr_buffs_to_free;
- unsigned int sc_nr_pages_to_free;
- enum RCL_POLICY sc_policy;
-} swap_control_v5;
-typedef struct swap_control_v5 swap_control_t;
+} swap_control_v6;
+typedef struct swap_control_v6 swap_control_t;
extern swap_control_t swap_control;
typedef struct swapstat_v1
@@ -42,7 +31,23 @@
typedef swapstat_v1 swapstat_t;
extern swapstat_t swapstats;
-extern int min_free_pages, free_pages_low, free_pages_high;
+typedef struct buffer_mem_v1
+{
+ unsigned int min_percent;
+ unsigned int borrow_percent;
+ unsigned int max_percent;
+} buffer_mem_v1;
+typedef buffer_mem_v1 buffer_mem_t;
+extern buffer_mem_t buffer_mem;
+
+typedef struct freepages_v1
+{
+ unsigned int min;
+ unsigned int low;
+ unsigned int high;
+} freepages_v1;
+typedef freepages_v1 freepages_t;
+extern freepages_t freepages;
#define SC_VERSION 1
#define SC_MAX_VERSION 1
@@ -55,28 +60,17 @@
failure to free a resource at any priority */
#define RCL_FAILURE (RCL_MAXPRI + 1)
-#define RCL_POLICY (swap_control.sc_policy)
#define AGE_CLUSTER_FRACT (swap_control.sc_age_cluster_fract)
#define AGE_CLUSTER_MIN (swap_control.sc_age_cluster_min)
#define PAGEOUT_WEIGHT (swap_control.sc_pageout_weight)
#define BUFFEROUT_WEIGHT (swap_control.sc_bufferout_weight)
-#define NR_BUFFS_TO_FREE (swap_control.sc_nr_buffs_to_free)
-#define NR_PAGES_TO_FREE (swap_control.sc_nr_pages_to_free)
-
-#define BUFFERMEM_GRACE (swap_control.sc_buffer_grace)
-
/* Page aging (see mm/swap.c) */
#define MAX_PAGE_AGE (swap_control.sc_max_page_age)
#define PAGE_ADVANCE (swap_control.sc_page_advance)
#define PAGE_DECLINE (swap_control.sc_page_decline)
#define PAGE_INITIAL_AGE (swap_control.sc_page_initial_age)
-
-#define MAX_BUFF_AGE (swap_control.sc_max_buff_age)
-#define BUFF_ADVANCE (swap_control.sc_buff_advance)
-#define BUFF_DECLINE (swap_control.sc_buff_decline)
-#define BUFF_INITIAL_AGE (swap_control.sc_buff_initial_age)
/* Given a resource of N units (pages or buffers etc), we only try to
* age and reclaim AGE_CLUSTER_FRACT per 1024 resources each time we
--- linux.89.orig/mm/swap.c Wed May 14 07:41:20 1997
+++ linux-2.1.89/mm/swap.c Thu Mar 12 15:18:17 1998
@@ -5,10 +5,12 @@
*/
/*
- * This file should contain most things doing the swapping from/to disk.
+ * This file contains the default values for the opereation of the
+ * Linux VM subsystem. Finetuning documentation can be found in
+ * linux/Documentation/sysctl/vm.txt.
* Started 18.12.91
- *
* Swap aging added 23.2.95, Stephen Tweedie.
+ * Buffermem limits added 12.3.98, Rik van Riel.
*/
#include <linux/mm.h>
@@ -33,15 +35,18 @@
/*
* We identify three levels of free memory. We never let free mem
- * fall below the min_free_pages except for atomic allocations. We
- * start background swapping if we fall below free_pages_high free
- * pages, and we begin intensive swapping below free_pages_low.
+ * fall below the freepages.min except for atomic allocations. We
+ * start background swapping if we fall below freepages.high free
+ * pages, and we begin intensive swapping below freepages.low.
*
- * Keep these three variables contiguous for sysctl(2).
+ * These values are there to keep GCC from complaining. Actual
+ * initialization is done in mm/page_alloc.c or arch/sparc(64)/mm/init.c.
*/
-int min_free_pages = 48;
-int free_pages_low = 72;
-int free_pages_high = 96;
+freepages_t freepages = {
+ 48, /* freepages.min */
+ 72, /* freepages.low */
+ 96 /* freepages.high */
+};
/* We track the number of pages currently being asynchronously swapped
out, so that we don't try to swap TOO many pages out at once */
@@ -55,53 +60,15 @@
swap_control_t swap_control = {
20, 3, 1, 3, /* Page aging */
- 10, 2, 2, 4, /* Buffer aging */
32, 4, /* Aging cluster */
8192, 8192, /* Pageout and bufferout weights */
- -200, /* Buffer grace */
- 1, 1, /* Buffs/pages to free */
- RCL_ROUND_ROBIN /* Balancing policy */
};
swapstat_t swapstats = {0};
-/* General swap control */
-
-/* Parse the kernel command line "swap=" option at load time: */
-__initfunc(void swap_setup(char *str, int *ints))
-{
- int * swap_vars[8] = {
- &MAX_PAGE_AGE,
- &PAGE_ADVANCE,
- &PAGE_DECLINE,
- &PAGE_INITIAL_AGE,
- &AGE_CLUSTER_FRACT,
- &AGE_CLUSTER_MIN,
- &PAGEOUT_WEIGHT,
- &BUFFEROUT_WEIGHT
- };
- int i;
- for (i=0; i < ints[0] && i < 8; i++) {
- if (ints[i+1])
- *(swap_vars[i]) = ints[i+1];
- }
-}
-
-/* Parse the kernel command line "buff=" option at load time: */
-__initfunc(void buff_setup(char *str, int *ints))
-{
- int * buff_vars[6] = {
- &MAX_BUFF_AGE,
- &BUFF_ADVANCE,
- &BUFF_DECLINE,
- &BUFF_INITIAL_AGE,
- &BUFFEROUT_WEIGHT,
- &BUFFERMEM_GRACE
- };
- int i;
- for (i=0; i < ints[0] && i < 6; i++) {
- if (ints[i+1])
- *(buff_vars[i]) = ints[i+1];
- }
-}
+buffer_mem_t buffer_mem = {
+ 6, /* minimum percent buffer + cache memory */
+ 20, /* borrow percent buffer + cache memory */
+ 90 /* maximum percent buffer + cache memory */
+};
--- linux.89.orig/fs/buffer.c Wed Mar 4 06:22:19 1998
+++ linux-2.1.89/fs/buffer.c Thu Mar 12 15:48:30 1998
@@ -731,7 +731,8 @@
/* We are going to try to locate this much memory. */
needed = bdf_prm.b_un.nrefill * size;
- while ((nr_free_pages > min_free_pages*2) &&
+ while ((nr_free_pages > freepages.min*2) &&
+ BUFFER_MEM < (buffer_mem.max_percent * num_physpages / 100) &&
grow_buffers(GFP_BUFFER, size)) {
obtained += PAGE_SIZE;
if (obtained >= needed)
@@ -815,7 +816,8 @@
* are _any_ free buffers.
*/
while (obtained < (needed >> 1) &&
- nr_free_pages > min_free_pages + 5 &&
+ nr_free_pages > freepages.min + 5 &&
+ BUFFER_MEM < (buffer_mem.max_percent * num_physpages / 100) &&
grow_buffers(GFP_BUFFER, size))
obtained += PAGE_SIZE;
--- linux.89.orig/arch/sparc/mm/init.c Tue Jan 13 00:15:43 1998
+++ linux-2.1.89/arch/sparc/mm/init.c Thu Mar 12 15:16:32 1998
@@ -17,6 +17,7 @@
#include <linux/mman.h>
#include <linux/mm.h>
#include <linux/swap.h>
+#include <linux/swapctl.h>
#ifdef CONFIG_BLK_DEV_INITRD
#include <linux/blk.h>
#endif
@@ -172,9 +173,6 @@
struct cache_palias *sparc_aliases;
-extern int min_free_pages;
-extern int free_pages_low;
-extern int free_pages_high;
extern void srmmu_frob_mem_map(unsigned long);
int physmem_mapped_contig = 1;
@@ -265,11 +263,11 @@
initpages << (PAGE_SHIFT-10),
PAGE_OFFSET, end_mem);
- min_free_pages = nr_free_pages >> 7;
- if(min_free_pages < 16)
- min_free_pages = 16;
- free_pages_low = min_free_pages + (min_free_pages >> 1);
- free_pages_high = min_free_pages + min_free_pages;
+ freepages.min = nr_free_pages >> 7;
+ if(freepages.min < 16)
+ freepages.min = 16;
+ freepages.low = freepages.min + (freepages.min >> 1);
+ freepages.high = freepages.min + freepages.min;
}
void free_initmem (void)
--- linux.89.orig/arch/sparc64/mm/init.c Sat Jan 17 05:34:00 1998
+++ linux-2.1.89/arch/sparc64/mm/init.c Thu Mar 12 15:17:03 1998
@@ -10,6 +10,7 @@
#include <linux/init.h>
#include <linux/blk.h>
#include <linux/swap.h>
+#include <linux/swapctl.h>
#include <asm/head.h>
#include <asm/system.h>
@@ -864,10 +865,6 @@
return device_scan (PAGE_ALIGN (start_mem));
}
-extern int min_free_pages;
-extern int free_pages_low;
-extern int free_pages_high;
-
__initfunc(static void taint_real_pages(unsigned long start_mem, unsigned long end_mem))
{
unsigned long addr, tmp2 = 0;
@@ -946,11 +943,11 @@
initpages << (PAGE_SHIFT-10),
PAGE_OFFSET, end_mem);
- min_free_pages = nr_free_pages >> 7;
- if(min_free_pages < 16)
- min_free_pages = 16;
- free_pages_low = min_free_pages + (min_free_pages >> 1);
- free_pages_high = min_free_pages + min_free_pages;
+ freepages.low = nr_free_pages >> 7;
+ if(freepages.low < 16)
+ freepages.low = 16;
+ freepages.low = freepages.low + (freepages.low >> 1);
+ freepages.high = freepages.low + freepages.low;
}
void free_initmem (void)
--- linux.89.orig/kernel/sysctl.c Sat Feb 21 22:27:56 1998
+++ linux-2.1.89/kernel/sysctl.c Thu Mar 12 15:21:03 1998
@@ -183,12 +183,14 @@
{VM_SWAPOUT, "swapout_interval",
&swapout_interval, sizeof(int), 0600, NULL, &proc_dointvec_jiffies},
{VM_FREEPG, "freepages",
- &min_free_pages, 3*sizeof(int), 0600, NULL, &proc_dointvec},
+ &freepages, sizeof(freepages_t), 0600, NULL, &proc_dointvec},
{VM_BDFLUSH, "bdflush", &bdf_prm, 9*sizeof(int), 0600, NULL,
&proc_dointvec_minmax, &sysctl_intvec, NULL,
&bdflush_min, &bdflush_max},
{VM_OVERCOMMIT_MEMORY, "overcommit_memory", &sysctl_overcommit_memory,
sizeof(sysctl_overcommit_memory), 0644, NULL, &proc_dointvec},
+ {VM_BUFFERMEM, "buffermem",
+ &buffer_mem, sizeof(buffer_mem_t), 0600, NULL, &proc_dointvec},
{0}
};
--- linux.89.orig/include/linux/swap.h Tue Feb 24 00:24:32 1998
+++ linux-2.1.89/include/linux/swap.h Thu Mar 12 15:39:55 1998
@@ -36,10 +36,10 @@
extern int nr_swap_pages;
extern int nr_free_pages;
extern atomic_t nr_async_pages;
-extern int min_free_pages;
-extern int free_pages_low;
-extern int free_pages_high;
extern struct inode swapper_inode;
+extern unsigned long page_cache_size;
+extern int buffermem;
+#define BUFFER_MEM ((buffermem >> PAGE_SHIFT) + page_cache_size)
/* Incomplete types for prototype declarations: */
struct task_struct;
--- linux.89.orig/include/linux/sysctl.h Sun Mar 1 23:40:40 1998
+++ linux-2.1.89/include/linux/sysctl.h Thu Mar 12 14:22:39 1998
@@ -82,6 +82,7 @@
VM_FREEPG, /* struct: Set free page thresholds */
VM_BDFLUSH, /* struct: Control buffer cache flushing */
VM_OVERCOMMIT_MEMORY, /* Turn off the virtual memory safety limit */
+ VM_BUFFERMEM /* struct: Set cache memory thresholds */
};
--- linux.89.orig/mm/vmscan.c Thu Mar 5 03:00:09 1998
+++ linux-2.1.89/mm/vmscan.c Thu Mar 12 16:54:24 1998
@@ -6,7 +6,7 @@
* Swap reorganised 29.12.95, Stephen Tweedie.
* kswapd added: 7.1.96 sct
* Removed kswapd_ctl limits, and swap out as many pages as needed
- * to bring the system back to free_pages_high: 2.4.97, Rik van Riel.
+ * to bring the system back to freepages.high: 2.4.97, Rik van Riel.
* Version: $Id: vmscan.c,v 1.5 1998/02/23 22:14:28 sct Exp $
*/
@@ -22,6 +22,8 @@
#include <linux/smp_lock.h>
#include <linux/slab.h>
#include <linux/dcache.h>
+#include <linux/fs.h>
+#include <linux/pagemap.h>
#include <asm/bitops.h>
#include <asm/pgtable.h>
@@ -454,11 +456,14 @@
stop = 3;
if (gfp_mask & __GFP_WAIT)
stop = 0;
+ if (BUFFER_MEM > buffer_mem.borrow_percent * num_physpages / 100)
+ state = 0;
switch (state) {
do {
case 0:
- if (shrink_mmap(i, gfp_mask))
+ if (BUFFER_MEM > (buffer_mem.min_percent * num_physpages /100) &&
+ shrink_mmap(i, gfp_mask))
return 1;
state = 1;
case 1:
@@ -511,7 +516,6 @@
printk ("Starting kswapd v%.*s\n", i, s);
}
-#define MAX_SWAP_FAIL 3
/*
* The background pageout daemon.
* Started as a kernel thread from the init process.
@@ -551,28 +555,25 @@
swapstats.wakeups++;
/* Do the background pageout:
* When we've got loads of memory, we try
- * (free_pages_high - nr_free_pages) times to
+ * (freepages.high - nr_free_pages) times to
* free memory. As memory gets tighter, kswapd
* gets more and more agressive. -- Rik.
*/
- tries = free_pages_high - nr_free_pages;
- if (tries < min_free_pages) {
- tries = min_free_pages;
+ tries = freepages.high - nr_free_pages;
+ if (tries < freepages.min) {
+ tries = freepages.min;
}
- else if (nr_free_pages < (free_pages_high + free_pages_low) / 2) {
+ if (nr_free_pages < freepages.high + freepages.low)
tries <<= 1;
- if (nr_free_pages < free_pages_low) {
- tries <<= 1;
- if (nr_free_pages <= min_free_pages) {
- tries <<= 1;
- }
- }
- }
while (tries--) {
int gfp_mask;
- if (free_memory_available())
- break;
+ if (BUFFER_MEM < (buffer_mem.max_percent * num_physpages / 100)) {
+ if (free_memory_available())
+ break;
+ if (nr_free_pages + atomic_read(&nr_async_pages) > freepages.high * 4)
+ break;
+ }
gfp_mask = __GFP_IO;
try_to_free_page(gfp_mask);
/*
@@ -585,11 +586,11 @@
}
#if 0
/*
- * Report failure if we couldn't even reach min_free_pages.
+ * Report failure if we couldn't even reach freepages.min.
*/
- if (nr_free_pages < min_free_pages)
+ if (nr_free_pages < freepages.min)
printk("kswapd: failed, got %d of %d\n",
- nr_free_pages, min_free_pages);
+ nr_free_pages, freepages.min);
#endif
}
/* As if we could ever get here - maybe we want to make this killable */
@@ -606,9 +607,10 @@
int want_wakeup = 0, memory_low = 0;
int pages = nr_free_pages + atomic_read(&nr_async_pages);
- if (pages < free_pages_low)
+ if (pages < freepages.low)
memory_low = want_wakeup = 1;
- else if (pages < free_pages_high && jiffies >= next_swap_jiffies)
+ else if ((pages < freepages.high || BUFFER_MEM > (num_physpages * buffer_mem.max_percent / 100))
+ && jiffies >= next_swap_jiffies)
want_wakeup = 1;
if (want_wakeup) {
--- linux.89.orig/init/main.c Tue Feb 10 01:12:56 1998
+++ linux-2.1.89/init/main.c Thu Mar 12 15:05:00 1998
@@ -78,8 +78,6 @@
extern void smp_setup(char *str, int *ints);
extern void ioapic_pirq_setup(char *str, int *ints);
extern void no_scroll(char *str, int *ints);
-extern void swap_setup(char *str, int *ints);
-extern void buff_setup(char *str, int *ints);
extern void panic_setup(char *str, int *ints);
extern void bmouse_setup(char *str, int *ints);
extern void msmouse_setup(char *str, int *ints);
@@ -490,8 +488,6 @@
#if defined (CONFIG_AMIGA) || defined (CONFIG_ATARI)
{ "video=", video_setup },
#endif
- { "swap=", swap_setup },
- { "buff=", buff_setup },
{ "panic=", panic_setup },
{ "console=", console_setup },
#ifdef CONFIG_VT
--- linux.89.orig/Documentation/sysctl/vm.txt Thu Feb 26 20:09:16 1998
+++ linux-2.1.89/Documentation/sysctl/vm.txt Thu Mar 12 16:19:39 1998
@@ -16,6 +16,7 @@
Currently, these files are in /proc/sys/vm:
- bdflush
+- buffermem
- freepages
- overcommit_memory
- swapctl
@@ -88,11 +89,27 @@
age_super is for filesystem metadata.
==============================================================
+buffermem:
+The three values in this file correspond to the values in
+the struct buffer_mem. It controls how much memory should
+be used for buffer and cache memory. Note that memorymapped
+files are also counted as cache memory...
+
+The values are:
+min_percent -- this is the minumum percentage of memory
+ that should be spent on buffer + page cache
+borrow_percent -- when Linux is short on memory, and buffer
+ and cache use more than this percentage of
+ memory, free pages are stolen from them
+max_percent -- this is the maximum amount of memory that
+ can be used for buffer and cache memory
+
+==============================================================
freepages:
-This file contains three values: min_free_pages, free_pages_low
-and free_pages_high in order.
+This file contains the values in the struct freepages. That
+struct contains three members: min, low and high.
These numbers are used by the VM subsystem to keep a reasonable
number of pages on the free page list, so that programs can
@@ -100,25 +117,23 @@
free used pages first. The actual freeing of pages is done
by kswapd, a kernel daemon.
-min_free_pages -- when the number of free pages reaches this
- level, only the kernel can allocate memory
- for _critical_ tasks only
-free_pages_low -- when the number of free pages drops below
- this level, kswapd is woken up immediately
-free_pages_high -- this is kswapd's target, when more than
- free_pages_high pages are free, kswapd will
- stop swapping.
-
-When the number of free pages is between free_pages_low and
-free_pages_high, and kswapd hasn't run for swapout_interval
-jiffies, then kswapd is woken up too. See swapout_interval
-for more info.
+min -- when the number of free pages reaches this
+ level, only the kernel can allocate memory
+ for _critical_ tasks only
+low -- when the number of free pages drops below
+ this level, kswapd is woken up immediately
+high -- this is kswapd's target, when more than <high>
+ pages are free, kswapd will stop swapping.
+
+When the number of free pages is between low and high,
+and kswapd hasn't run for swapout_interval jiffies, then
+kswapd is woken up too. See swapout_interval for more info.
When free memory is always low on your system, and kswapd has
trouble keeping up with allocations, you might want to
-increase these values, especially free_pages_high and perhaps
-free_pages_low. I've found that a 1:2:4 relation for these
-values tend to work rather well in a heavily loaded system.
+increase these values, especially high and perhaps low.
+I've found that a 1:2:4 relation for these values tend to work
+rather well in a heavily loaded system.
==============================================================
@@ -163,9 +178,7 @@
swapctl:
-This file contains no less than 16 variables, of which about
-half is actually used :-) In the listing below, the unused
-variables are marked as such.
+This file contains no less than 8 variables.
All of these values are used by kswapd, and the usage can be
found in linux/mm/vmscan.c.
@@ -177,18 +190,10 @@
unsigned int sc_page_advance;
unsigned int sc_page_decline;
unsigned int sc_page_initial_age;
- unsigned int sc_max_buff_age; /* unused */
- unsigned int sc_buff_advance; /* unused */
- unsigned int sc_buff_decline; /* unused */
- unsigned int sc_buff_initial_age; /* unused */
unsigned int sc_age_cluster_fract;
unsigned int sc_age_cluster_min;
unsigned int sc_pageout_weight;
unsigned int sc_bufferout_weight;
- unsigned int sc_buffer_grace; /* unused */
- unsigned int sc_nr_buffs_to_free; /* unused */
- unsigned int sc_nr_pages_to_free; /* unused */
- enum RCL_POLICY sc_policy; /* RCL_PERSIST hardcoded */
} swap_control_v5;
--------------------------------------------------------------
@@ -207,9 +212,8 @@
(default 1)
And when a page reaches age 0, it's ready to be swapped out.
-The variables sc_age_cluster_fract till sc_bufferout_weight
-have to do with the amount of scanning kswapd is doing on
-each call to try_to_swap_out().
+The next four variables can be used to control kswapd's
+agressiveness in swapping out pages.
sc_age_cluster_fract is used to calculate how many pages from
a process are to be scanned by kswapd. The formula used is
@@ -221,9 +225,12 @@
The values of sc_pageout_weight and sc_bufferout_weight are
used to control the how many tries kswapd will do in order
-to swapout one page / buffer. As with sc_age_cluster_fract,
-the actual value is calculated by several more or less complex
-formulae and the default value is good for every purpose.
+to swapout one page / buffer. These values can be used to
+finetune the ratio between user pages and buffer/cache memory.
+When you find that your Linux system is swapping out too much
+process pages in order to satisfy buffer memory demands, you
+might want to either increase sc_bufferout_weight, or decrease
+the value of sc_pageout_weight.
==============================================================
-
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