#include <linux/errno.h>
#include <linux/fs.h>
#include <linux/init.h>
#include <linux/module.h>
#include <linux/moduleparam.h>
#include <linux/gfp.h>
#include <linux/sched.h>
#include <linux/string_helpers.h>
#include <linux/sysctl.h>
#include <linux/swap.h>
#include <linux/kthread.h>
#include <linux/oom.h>
#include <linux/uaccess.h>
#include <asm/diag.h>
#ifdef CONFIG_CMM_IUCV
static char *cmm_default_sender = "VMRMSVM";
#endif
static char *sender;
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 struct task_struct *cmm_thread_ptr;
static DECLARE_WAIT_QUEUE_HEAD(cmm_thread_wait);
static void cmm_timer_fn(struct timer_list *);
static void cmm_set_timer(void);
static DEFINE_TIMER(cmm_timer, cmm_timer_fn);
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) {
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_range(virt_to_pfn((void *)addr), 1);
pa->pages[pa->index++] = addr;
(*counter)++;
spin_unlock(&cmm_lock);
nr--;
cond_resched();
}
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 long cmm_free_pages(long nr, long *counter, struct cmm_page_array **list)
{
long inc = 0;
while (nr) {
inc = min(256L, nr);
nr -= inc;
inc = __cmm_free_pages(inc, counter, list);
if (inc)
break;
cond_resched();
}
return nr + inc;
}
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;
while (1) {
rc = wait_event_interruptible(cmm_thread_wait,
cmm_pages != cmm_pages_target ||
cmm_timed_pages != cmm_timed_pages_target ||
kthread_should_stop());
if (kthread_should_stop() || rc == -ERESTARTSYS) {
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_kick_thread(void)
{
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))
timer_delete(&cmm_timer);
return;
}
mod_timer(&cmm_timer, jiffies + secs_to_jiffies(cmm_timeout_seconds));
}
static void cmm_timer_fn(struct timer_list *unused)
{
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();
}
static void cmm_set_pages(long nr)
{
cmm_pages_target = nr;
cmm_kick_thread();
}
static long cmm_get_pages(void)
{
return cmm_pages;
}
static void cmm_add_timed_pages(long nr)
{
cmm_timed_pages_target += nr;
cmm_kick_thread();
}
static long cmm_get_timed_pages(void)
{
return cmm_timed_pages;
}
static void cmm_set_timeout(long nr, long seconds)
{
cmm_timeout_pages = nr;
cmm_timeout_seconds = seconds;
cmm_set_timer();
}
static int cmm_skip_blanks(char *cp, char **endp)
{
char *str;
for (str = cp; *str == ' ' || *str == '\t'; str++)
;
*endp = str;
return str != cp;
}
static int cmm_pages_handler(const struct ctl_table *ctl, int write,
void *buffer, size_t *lenp, loff_t *ppos)
{
long nr = cmm_get_pages();
struct ctl_table ctl_entry = {
.procname = ctl->procname,
.data = &nr,
.maxlen = sizeof(long),
};
int rc;
rc = proc_doulongvec_minmax(&ctl_entry, write, buffer, lenp, ppos);
if (rc < 0 || !write)
return rc;
cmm_set_pages(nr);
return 0;
}
static int cmm_timed_pages_handler(const struct ctl_table *ctl, int write,
void *buffer, size_t *lenp,
loff_t *ppos)
{
long nr = cmm_get_timed_pages();
struct ctl_table ctl_entry = {
.procname = ctl->procname,
.data = &nr,
.maxlen = sizeof(long),
};
int rc;
rc = proc_doulongvec_minmax(&ctl_entry, write, buffer, lenp, ppos);
if (rc < 0 || !write)
return rc;
cmm_add_timed_pages(nr);
return 0;
}
static int cmm_timeout_handler(const struct ctl_table *ctl, int write,
void *buffer, size_t *lenp, loff_t *ppos)
{
char buf[64], *p;
long nr, seconds;
unsigned int len;
if (!*lenp || (*ppos && !write)) {
*lenp = 0;
return 0;
}
if (write) {
len = min(*lenp, sizeof(buf));
memcpy(buf, buffer, len);
buf[len - 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);
*ppos += *lenp;
} else {
len = scnprintf(buf, sizeof(buf), "%ld %ld\n",
cmm_timeout_pages, cmm_timeout_seconds);
if (len > *lenp)
len = *lenp;
memcpy(buffer, buf, len);
*lenp = len;
*ppos += len;
}
return 0;
}
static const struct ctl_table cmm_table[] = {
{
.procname = "cmm_pages",
.mode = 0644,
.proc_handler = cmm_pages_handler,
},
{
.procname = "cmm_timed_pages",
.mode = 0644,
.proc_handler = cmm_timed_pages_handler,
},
{
.procname = "cmm_timeout",
.mode = 0644,
.proc_handler = cmm_timeout_handler,
},
};
#ifdef CONFIG_CMM_IUCV
#define SMSG_PREFIX "CMM"
static void cmm_smsg_target(const 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
static struct ctl_table_header *cmm_sysctl_header;
static int __init cmm_init(void)
{
int rc = -ENOMEM;
cmm_sysctl_header = register_sysctl("vm", cmm_table);
if (!cmm_sysctl_header)
goto out_sysctl;
#ifdef CONFIG_CMM_IUCV
if (sender)
string_upper(sender, sender);
else
sender = cmm_default_sender;
rc = smsg_register_callback(SMSG_PREFIX, cmm_smsg_target);
if (rc < 0)
goto out_smsg;
#endif
rc = register_oom_notifier(&cmm_oom_nb);
if (rc < 0)
goto out_oom_notify;
cmm_thread_ptr = kthread_run(cmm_thread, NULL, "cmmthread");
if (!IS_ERR(cmm_thread_ptr))
return 0;
rc = PTR_ERR(cmm_thread_ptr);
unregister_oom_notifier(&cmm_oom_nb);
out_oom_notify:
#ifdef CONFIG_CMM_IUCV
smsg_unregister_callback(SMSG_PREFIX, cmm_smsg_target);
out_smsg:
#endif
unregister_sysctl_table(cmm_sysctl_header);
out_sysctl:
timer_delete_sync(&cmm_timer);
return rc;
}
module_init(cmm_init);
static void __exit cmm_exit(void)
{
unregister_sysctl_table(cmm_sysctl_header);
#ifdef CONFIG_CMM_IUCV
smsg_unregister_callback(SMSG_PREFIX, cmm_smsg_target);
#endif
unregister_oom_notifier(&cmm_oom_nb);
kthread_stop(cmm_thread_ptr);
timer_delete_sync(&cmm_timer);
cmm_free_pages(cmm_pages, &cmm_pages, &cmm_page_list);
cmm_free_pages(cmm_timed_pages, &cmm_timed_pages, &cmm_timed_page_list);
}
module_exit(cmm_exit);
MODULE_DESCRIPTION("Cooperative memory management interface");
MODULE_LICENSE("GPL");
