android_kernel_motorola_sm6225/arch/s390/mm/cmm.c
Martin Schwidefsky 8bc719d3ca [PATCH] out of memory notifier
Add a notifer chain to the out of memory killer.  If one of the registered
callbacks could release some memory, do not kill the process but return and
retry the allocation that forced the oom killer to run.

The purpose of the notifier is to add a safety net in the presence of
memory ballooners.  If the resource manager inflated the balloon to a size
where memory allocations can not be satisfied anymore, it is better to
deflate the balloon a bit instead of killing processes.

The implementation for the s390 ballooner is included.

[akpm@osdl.org: cleanups]
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-09-26 08:48:47 -07:00

468 lines
9.8 KiB
C

/*
* arch/s390/mm/cmm.c
*
* S390 version
* Copyright (C) 2003 IBM Deutschland Entwicklung GmbH, IBM Corporation
* Author(s): Martin Schwidefsky (schwidefsky@de.ibm.com)
*
* Collaborative memory management interface.
*/
#include <linux/errno.h>
#include <linux/fs.h>
#include <linux/init.h>
#include <linux/module.h>
#include <linux/sched.h>
#include <linux/sysctl.h>
#include <linux/ctype.h>
#include <linux/swap.h>
#include <asm/pgalloc.h>
#include <asm/uaccess.h>
static char *sender = "VMRMSVM";
module_param(sender, charp, 0400);
MODULE_PARM_DESC(sender,
"Guest name that may send SMSG messages (default VMRMSVM)");
#include "../../../drivers/s390/net/smsgiucv.h"
#define CMM_NR_PAGES ((PAGE_SIZE / sizeof(unsigned long)) - 2)
struct cmm_page_array {
struct cmm_page_array *next;
unsigned long index;
unsigned long pages[CMM_NR_PAGES];
};
static long cmm_pages;
static long cmm_timed_pages;
static volatile long cmm_pages_target;
static volatile long cmm_timed_pages_target;
static long cmm_timeout_pages;
static long cmm_timeout_seconds;
static struct cmm_page_array *cmm_page_list;
static struct cmm_page_array *cmm_timed_page_list;
static DEFINE_SPINLOCK(cmm_lock);
static unsigned long cmm_thread_active;
static struct work_struct cmm_thread_starter;
static wait_queue_head_t cmm_thread_wait;
static struct timer_list cmm_timer;
static void cmm_timer_fn(unsigned long);
static void cmm_set_timer(void);
static long
cmm_alloc_pages(long nr, long *counter, struct cmm_page_array **list)
{
struct cmm_page_array *pa, *npa;
unsigned long addr;
while (nr) {
addr = __get_free_page(GFP_NOIO);
if (!addr)
break;
spin_lock(&cmm_lock);
pa = *list;
if (!pa || pa->index >= CMM_NR_PAGES) {
/* Need a new page for the page list. */
spin_unlock(&cmm_lock);
npa = (struct cmm_page_array *)
__get_free_page(GFP_NOIO);
if (!npa) {
free_page(addr);
break;
}
spin_lock(&cmm_lock);
pa = *list;
if (!pa || pa->index >= CMM_NR_PAGES) {
npa->next = pa;
npa->index = 0;
pa = npa;
*list = pa;
} else
free_page((unsigned long) npa);
}
diag10(addr);
pa->pages[pa->index++] = addr;
(*counter)++;
spin_unlock(&cmm_lock);
nr--;
}
return nr;
}
static long
cmm_free_pages(long nr, long *counter, struct cmm_page_array **list)
{
struct cmm_page_array *pa;
unsigned long addr;
spin_lock(&cmm_lock);
pa = *list;
while (nr) {
if (!pa || pa->index <= 0)
break;
addr = pa->pages[--pa->index];
if (pa->index == 0) {
pa = pa->next;
free_page((unsigned long) *list);
*list = pa;
}
free_page(addr);
(*counter)--;
nr--;
}
spin_unlock(&cmm_lock);
return nr;
}
static int cmm_oom_notify(struct notifier_block *self,
unsigned long dummy, void *parm)
{
unsigned long *freed = parm;
long nr = 256;
nr = cmm_free_pages(nr, &cmm_timed_pages, &cmm_timed_page_list);
if (nr > 0)
nr = cmm_free_pages(nr, &cmm_pages, &cmm_page_list);
cmm_pages_target = cmm_pages;
cmm_timed_pages_target = cmm_timed_pages;
*freed += 256 - nr;
return NOTIFY_OK;
}
static struct notifier_block cmm_oom_nb = {
.notifier_call = cmm_oom_notify
};
static int
cmm_thread(void *dummy)
{
int rc;
daemonize("cmmthread");
while (1) {
rc = wait_event_interruptible(cmm_thread_wait,
(cmm_pages != cmm_pages_target ||
cmm_timed_pages != cmm_timed_pages_target));
if (rc == -ERESTARTSYS) {
/* Got kill signal. End thread. */
clear_bit(0, &cmm_thread_active);
cmm_pages_target = cmm_pages;
cmm_timed_pages_target = cmm_timed_pages;
break;
}
if (cmm_pages_target > cmm_pages) {
if (cmm_alloc_pages(1, &cmm_pages, &cmm_page_list))
cmm_pages_target = cmm_pages;
} else if (cmm_pages_target < cmm_pages) {
cmm_free_pages(1, &cmm_pages, &cmm_page_list);
}
if (cmm_timed_pages_target > cmm_timed_pages) {
if (cmm_alloc_pages(1, &cmm_timed_pages,
&cmm_timed_page_list))
cmm_timed_pages_target = cmm_timed_pages;
} else if (cmm_timed_pages_target < cmm_timed_pages) {
cmm_free_pages(1, &cmm_timed_pages,
&cmm_timed_page_list);
}
if (cmm_timed_pages > 0 && !timer_pending(&cmm_timer))
cmm_set_timer();
}
return 0;
}
static void
cmm_start_thread(void)
{
kernel_thread(cmm_thread, NULL, 0);
}
static void
cmm_kick_thread(void)
{
if (!test_and_set_bit(0, &cmm_thread_active))
schedule_work(&cmm_thread_starter);
wake_up(&cmm_thread_wait);
}
static void
cmm_set_timer(void)
{
if (cmm_timed_pages_target <= 0 || cmm_timeout_seconds <= 0) {
if (timer_pending(&cmm_timer))
del_timer(&cmm_timer);
return;
}
if (timer_pending(&cmm_timer)) {
if (mod_timer(&cmm_timer, jiffies + cmm_timeout_seconds*HZ))
return;
}
cmm_timer.function = cmm_timer_fn;
cmm_timer.data = 0;
cmm_timer.expires = jiffies + cmm_timeout_seconds*HZ;
add_timer(&cmm_timer);
}
static void
cmm_timer_fn(unsigned long ignored)
{
long nr;
nr = cmm_timed_pages_target - cmm_timeout_pages;
if (nr < 0)
cmm_timed_pages_target = 0;
else
cmm_timed_pages_target = nr;
cmm_kick_thread();
cmm_set_timer();
}
void
cmm_set_pages(long nr)
{
cmm_pages_target = nr;
cmm_kick_thread();
}
long
cmm_get_pages(void)
{
return cmm_pages;
}
void
cmm_add_timed_pages(long nr)
{
cmm_timed_pages_target += nr;
cmm_kick_thread();
}
long
cmm_get_timed_pages(void)
{
return cmm_timed_pages;
}
void
cmm_set_timeout(long nr, long seconds)
{
cmm_timeout_pages = nr;
cmm_timeout_seconds = seconds;
cmm_set_timer();
}
static inline int
cmm_skip_blanks(char *cp, char **endp)
{
char *str;
for (str = cp; *str == ' ' || *str == '\t'; str++);
*endp = str;
return str != cp;
}
#ifdef CONFIG_CMM_PROC
/* These will someday get removed. */
#define VM_CMM_PAGES 1111
#define VM_CMM_TIMED_PAGES 1112
#define VM_CMM_TIMEOUT 1113
static struct ctl_table cmm_table[];
static int
cmm_pages_handler(ctl_table *ctl, int write, struct file *filp,
void __user *buffer, size_t *lenp, loff_t *ppos)
{
char buf[16], *p;
long nr;
int len;
if (!*lenp || (*ppos && !write)) {
*lenp = 0;
return 0;
}
if (write) {
len = *lenp;
if (copy_from_user(buf, buffer,
len > sizeof(buf) ? sizeof(buf) : len))
return -EFAULT;
buf[sizeof(buf) - 1] = '\0';
cmm_skip_blanks(buf, &p);
nr = simple_strtoul(p, &p, 0);
if (ctl == &cmm_table[0])
cmm_set_pages(nr);
else
cmm_add_timed_pages(nr);
} else {
if (ctl == &cmm_table[0])
nr = cmm_get_pages();
else
nr = cmm_get_timed_pages();
len = sprintf(buf, "%ld\n", nr);
if (len > *lenp)
len = *lenp;
if (copy_to_user(buffer, buf, len))
return -EFAULT;
}
*lenp = len;
*ppos += len;
return 0;
}
static int
cmm_timeout_handler(ctl_table *ctl, int write, struct file *filp,
void __user *buffer, size_t *lenp, loff_t *ppos)
{
char buf[64], *p;
long nr, seconds;
int len;
if (!*lenp || (*ppos && !write)) {
*lenp = 0;
return 0;
}
if (write) {
len = *lenp;
if (copy_from_user(buf, buffer,
len > sizeof(buf) ? sizeof(buf) : len))
return -EFAULT;
buf[sizeof(buf) - 1] = '\0';
cmm_skip_blanks(buf, &p);
nr = simple_strtoul(p, &p, 0);
cmm_skip_blanks(p, &p);
seconds = simple_strtoul(p, &p, 0);
cmm_set_timeout(nr, seconds);
} else {
len = sprintf(buf, "%ld %ld\n",
cmm_timeout_pages, cmm_timeout_seconds);
if (len > *lenp)
len = *lenp;
if (copy_to_user(buffer, buf, len))
return -EFAULT;
}
*lenp = len;
*ppos += len;
return 0;
}
static struct ctl_table cmm_table[] = {
{
.ctl_name = VM_CMM_PAGES,
.procname = "cmm_pages",
.mode = 0644,
.proc_handler = &cmm_pages_handler,
},
{
.ctl_name = VM_CMM_TIMED_PAGES,
.procname = "cmm_timed_pages",
.mode = 0644,
.proc_handler = &cmm_pages_handler,
},
{
.ctl_name = VM_CMM_TIMEOUT,
.procname = "cmm_timeout",
.mode = 0644,
.proc_handler = &cmm_timeout_handler,
},
{ .ctl_name = 0 }
};
static struct ctl_table cmm_dir_table[] = {
{
.ctl_name = CTL_VM,
.procname = "vm",
.maxlen = 0,
.mode = 0555,
.child = cmm_table,
},
{ .ctl_name = 0 }
};
#endif
#ifdef CONFIG_CMM_IUCV
#define SMSG_PREFIX "CMM"
static void
cmm_smsg_target(char *from, char *msg)
{
long nr, seconds;
if (strlen(sender) > 0 && strcmp(from, sender) != 0)
return;
if (!cmm_skip_blanks(msg + strlen(SMSG_PREFIX), &msg))
return;
if (strncmp(msg, "SHRINK", 6) == 0) {
if (!cmm_skip_blanks(msg + 6, &msg))
return;
nr = simple_strtoul(msg, &msg, 0);
cmm_skip_blanks(msg, &msg);
if (*msg == '\0')
cmm_set_pages(nr);
} else if (strncmp(msg, "RELEASE", 7) == 0) {
if (!cmm_skip_blanks(msg + 7, &msg))
return;
nr = simple_strtoul(msg, &msg, 0);
cmm_skip_blanks(msg, &msg);
if (*msg == '\0')
cmm_add_timed_pages(nr);
} else if (strncmp(msg, "REUSE", 5) == 0) {
if (!cmm_skip_blanks(msg + 5, &msg))
return;
nr = simple_strtoul(msg, &msg, 0);
if (!cmm_skip_blanks(msg, &msg))
return;
seconds = simple_strtoul(msg, &msg, 0);
cmm_skip_blanks(msg, &msg);
if (*msg == '\0')
cmm_set_timeout(nr, seconds);
}
}
#endif
struct ctl_table_header *cmm_sysctl_header;
static int
cmm_init (void)
{
#ifdef CONFIG_CMM_PROC
cmm_sysctl_header = register_sysctl_table(cmm_dir_table, 1);
#endif
#ifdef CONFIG_CMM_IUCV
smsg_register_callback(SMSG_PREFIX, cmm_smsg_target);
#endif
register_oom_notifier(&cmm_oom_nb);
INIT_WORK(&cmm_thread_starter, (void *) cmm_start_thread, NULL);
init_waitqueue_head(&cmm_thread_wait);
init_timer(&cmm_timer);
return 0;
}
static void
cmm_exit(void)
{
unregister_oom_notifier(&cmm_oom_nb);
cmm_free_pages(cmm_pages, &cmm_pages, &cmm_page_list);
cmm_free_pages(cmm_timed_pages, &cmm_timed_pages, &cmm_timed_page_list);
#ifdef CONFIG_CMM_PROC
unregister_sysctl_table(cmm_sysctl_header);
#endif
#ifdef CONFIG_CMM_IUCV
smsg_unregister_callback(SMSG_PREFIX, cmm_smsg_target);
#endif
}
module_init(cmm_init);
module_exit(cmm_exit);
EXPORT_SYMBOL(cmm_set_pages);
EXPORT_SYMBOL(cmm_get_pages);
EXPORT_SYMBOL(cmm_add_timed_pages);
EXPORT_SYMBOL(cmm_get_timed_pages);
EXPORT_SYMBOL(cmm_set_timeout);
MODULE_LICENSE("GPL");