498 lines
11 KiB
C
498 lines
11 KiB
C
/*
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* Collaborative memory management interface.
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*
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* Copyright IBM Corp 2003,2010
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* Author(s): Martin Schwidefsky <schwidefsky@de.ibm.com>,
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*
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*/
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#include <linux/errno.h>
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#include <linux/fs.h>
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#include <linux/init.h>
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#include <linux/module.h>
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#include <linux/gfp.h>
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#include <linux/sched.h>
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#include <linux/sysctl.h>
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#include <linux/ctype.h>
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#include <linux/swap.h>
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#include <linux/kthread.h>
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#include <linux/oom.h>
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#include <linux/suspend.h>
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#include <linux/uaccess.h>
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#include <asm/pgalloc.h>
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#include <asm/diag.h>
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#ifdef CONFIG_CMM_IUCV
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static char *cmm_default_sender = "VMRMSVM";
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#endif
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static char *sender;
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module_param(sender, charp, 0400);
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MODULE_PARM_DESC(sender,
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"Guest name that may send SMSG messages (default VMRMSVM)");
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#include "../../../drivers/s390/net/smsgiucv.h"
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#define CMM_NR_PAGES ((PAGE_SIZE / sizeof(unsigned long)) - 2)
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struct cmm_page_array {
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struct cmm_page_array *next;
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unsigned long index;
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unsigned long pages[CMM_NR_PAGES];
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};
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static long cmm_pages;
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static long cmm_timed_pages;
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static volatile long cmm_pages_target;
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static volatile long cmm_timed_pages_target;
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static long cmm_timeout_pages;
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static long cmm_timeout_seconds;
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static int cmm_suspended;
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static struct cmm_page_array *cmm_page_list;
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static struct cmm_page_array *cmm_timed_page_list;
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static DEFINE_SPINLOCK(cmm_lock);
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static struct task_struct *cmm_thread_ptr;
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static DECLARE_WAIT_QUEUE_HEAD(cmm_thread_wait);
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static DEFINE_TIMER(cmm_timer, NULL, 0, 0);
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static void cmm_timer_fn(unsigned long);
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static void cmm_set_timer(void);
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static long cmm_alloc_pages(long nr, long *counter,
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struct cmm_page_array **list)
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{
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struct cmm_page_array *pa, *npa;
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unsigned long addr;
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while (nr) {
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addr = __get_free_page(GFP_NOIO);
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if (!addr)
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break;
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spin_lock(&cmm_lock);
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pa = *list;
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if (!pa || pa->index >= CMM_NR_PAGES) {
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/* Need a new page for the page list. */
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spin_unlock(&cmm_lock);
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npa = (struct cmm_page_array *)
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__get_free_page(GFP_NOIO);
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if (!npa) {
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free_page(addr);
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break;
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}
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spin_lock(&cmm_lock);
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pa = *list;
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if (!pa || pa->index >= CMM_NR_PAGES) {
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npa->next = pa;
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npa->index = 0;
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pa = npa;
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*list = pa;
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} else
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free_page((unsigned long) npa);
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}
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diag10(addr);
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pa->pages[pa->index++] = addr;
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(*counter)++;
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spin_unlock(&cmm_lock);
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nr--;
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}
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return nr;
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}
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static long cmm_free_pages(long nr, long *counter, struct cmm_page_array **list)
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{
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struct cmm_page_array *pa;
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unsigned long addr;
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spin_lock(&cmm_lock);
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pa = *list;
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while (nr) {
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if (!pa || pa->index <= 0)
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break;
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addr = pa->pages[--pa->index];
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if (pa->index == 0) {
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pa = pa->next;
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free_page((unsigned long) *list);
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*list = pa;
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}
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free_page(addr);
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(*counter)--;
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nr--;
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}
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spin_unlock(&cmm_lock);
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return nr;
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}
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static int cmm_oom_notify(struct notifier_block *self,
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unsigned long dummy, void *parm)
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{
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unsigned long *freed = parm;
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long nr = 256;
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nr = cmm_free_pages(nr, &cmm_timed_pages, &cmm_timed_page_list);
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if (nr > 0)
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nr = cmm_free_pages(nr, &cmm_pages, &cmm_page_list);
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cmm_pages_target = cmm_pages;
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cmm_timed_pages_target = cmm_timed_pages;
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*freed += 256 - nr;
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return NOTIFY_OK;
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}
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static struct notifier_block cmm_oom_nb = {
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.notifier_call = cmm_oom_notify,
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};
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static int cmm_thread(void *dummy)
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{
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int rc;
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while (1) {
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rc = wait_event_interruptible(cmm_thread_wait,
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(!cmm_suspended && (cmm_pages != cmm_pages_target ||
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cmm_timed_pages != cmm_timed_pages_target)) ||
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kthread_should_stop());
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if (kthread_should_stop() || rc == -ERESTARTSYS) {
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cmm_pages_target = cmm_pages;
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cmm_timed_pages_target = cmm_timed_pages;
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break;
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}
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if (cmm_pages_target > cmm_pages) {
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if (cmm_alloc_pages(1, &cmm_pages, &cmm_page_list))
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cmm_pages_target = cmm_pages;
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} else if (cmm_pages_target < cmm_pages) {
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cmm_free_pages(1, &cmm_pages, &cmm_page_list);
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}
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if (cmm_timed_pages_target > cmm_timed_pages) {
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if (cmm_alloc_pages(1, &cmm_timed_pages,
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&cmm_timed_page_list))
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cmm_timed_pages_target = cmm_timed_pages;
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} else if (cmm_timed_pages_target < cmm_timed_pages) {
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cmm_free_pages(1, &cmm_timed_pages,
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&cmm_timed_page_list);
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}
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if (cmm_timed_pages > 0 && !timer_pending(&cmm_timer))
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cmm_set_timer();
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}
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return 0;
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}
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static void cmm_kick_thread(void)
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{
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wake_up(&cmm_thread_wait);
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}
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static void cmm_set_timer(void)
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{
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if (cmm_timed_pages_target <= 0 || cmm_timeout_seconds <= 0) {
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if (timer_pending(&cmm_timer))
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del_timer(&cmm_timer);
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return;
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}
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if (timer_pending(&cmm_timer)) {
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if (mod_timer(&cmm_timer, jiffies + cmm_timeout_seconds*HZ))
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return;
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}
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cmm_timer.function = cmm_timer_fn;
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cmm_timer.data = 0;
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cmm_timer.expires = jiffies + cmm_timeout_seconds*HZ;
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add_timer(&cmm_timer);
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}
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static void cmm_timer_fn(unsigned long ignored)
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{
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long nr;
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nr = cmm_timed_pages_target - cmm_timeout_pages;
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if (nr < 0)
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cmm_timed_pages_target = 0;
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else
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cmm_timed_pages_target = nr;
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cmm_kick_thread();
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cmm_set_timer();
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}
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static void cmm_set_pages(long nr)
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{
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cmm_pages_target = nr;
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cmm_kick_thread();
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}
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static long cmm_get_pages(void)
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{
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return cmm_pages;
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}
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static void cmm_add_timed_pages(long nr)
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{
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cmm_timed_pages_target += nr;
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cmm_kick_thread();
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}
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static long cmm_get_timed_pages(void)
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{
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return cmm_timed_pages;
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}
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static void cmm_set_timeout(long nr, long seconds)
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{
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cmm_timeout_pages = nr;
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cmm_timeout_seconds = seconds;
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cmm_set_timer();
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}
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static int cmm_skip_blanks(char *cp, char **endp)
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{
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char *str;
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for (str = cp; *str == ' ' || *str == '\t'; str++)
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;
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*endp = str;
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return str != cp;
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}
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static struct ctl_table cmm_table[];
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static int cmm_pages_handler(ctl_table *ctl, int write, void __user *buffer,
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size_t *lenp, loff_t *ppos)
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{
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char buf[16], *p;
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long nr;
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int len;
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if (!*lenp || (*ppos && !write)) {
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*lenp = 0;
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return 0;
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}
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if (write) {
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len = *lenp;
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if (copy_from_user(buf, buffer,
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len > sizeof(buf) ? sizeof(buf) : len))
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return -EFAULT;
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buf[sizeof(buf) - 1] = '\0';
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cmm_skip_blanks(buf, &p);
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nr = simple_strtoul(p, &p, 0);
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if (ctl == &cmm_table[0])
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cmm_set_pages(nr);
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else
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cmm_add_timed_pages(nr);
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} else {
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if (ctl == &cmm_table[0])
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nr = cmm_get_pages();
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else
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nr = cmm_get_timed_pages();
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len = sprintf(buf, "%ld\n", nr);
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if (len > *lenp)
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len = *lenp;
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if (copy_to_user(buffer, buf, len))
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return -EFAULT;
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}
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*lenp = len;
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*ppos += len;
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return 0;
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}
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static int cmm_timeout_handler(ctl_table *ctl, int write, void __user *buffer,
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size_t *lenp, loff_t *ppos)
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{
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char buf[64], *p;
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long nr, seconds;
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int len;
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if (!*lenp || (*ppos && !write)) {
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*lenp = 0;
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return 0;
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}
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if (write) {
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len = *lenp;
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if (copy_from_user(buf, buffer,
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len > sizeof(buf) ? sizeof(buf) : len))
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return -EFAULT;
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buf[sizeof(buf) - 1] = '\0';
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cmm_skip_blanks(buf, &p);
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nr = simple_strtoul(p, &p, 0);
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cmm_skip_blanks(p, &p);
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seconds = simple_strtoul(p, &p, 0);
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cmm_set_timeout(nr, seconds);
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} else {
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len = sprintf(buf, "%ld %ld\n",
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cmm_timeout_pages, cmm_timeout_seconds);
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if (len > *lenp)
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len = *lenp;
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if (copy_to_user(buffer, buf, len))
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return -EFAULT;
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}
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*lenp = len;
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*ppos += len;
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return 0;
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}
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static struct ctl_table cmm_table[] = {
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{
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.procname = "cmm_pages",
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.mode = 0644,
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.proc_handler = cmm_pages_handler,
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},
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{
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.procname = "cmm_timed_pages",
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.mode = 0644,
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.proc_handler = cmm_pages_handler,
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},
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{
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.procname = "cmm_timeout",
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.mode = 0644,
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.proc_handler = cmm_timeout_handler,
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},
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{ }
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};
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static struct ctl_table cmm_dir_table[] = {
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{
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.procname = "vm",
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.maxlen = 0,
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.mode = 0555,
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.child = cmm_table,
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},
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{ }
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};
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#ifdef CONFIG_CMM_IUCV
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#define SMSG_PREFIX "CMM"
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static void cmm_smsg_target(const char *from, char *msg)
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{
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long nr, seconds;
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if (strlen(sender) > 0 && strcmp(from, sender) != 0)
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return;
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if (!cmm_skip_blanks(msg + strlen(SMSG_PREFIX), &msg))
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return;
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if (strncmp(msg, "SHRINK", 6) == 0) {
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if (!cmm_skip_blanks(msg + 6, &msg))
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return;
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nr = simple_strtoul(msg, &msg, 0);
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cmm_skip_blanks(msg, &msg);
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if (*msg == '\0')
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cmm_set_pages(nr);
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} else if (strncmp(msg, "RELEASE", 7) == 0) {
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if (!cmm_skip_blanks(msg + 7, &msg))
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return;
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nr = simple_strtoul(msg, &msg, 0);
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cmm_skip_blanks(msg, &msg);
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if (*msg == '\0')
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cmm_add_timed_pages(nr);
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} else if (strncmp(msg, "REUSE", 5) == 0) {
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if (!cmm_skip_blanks(msg + 5, &msg))
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return;
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nr = simple_strtoul(msg, &msg, 0);
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if (!cmm_skip_blanks(msg, &msg))
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return;
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seconds = simple_strtoul(msg, &msg, 0);
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cmm_skip_blanks(msg, &msg);
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if (*msg == '\0')
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cmm_set_timeout(nr, seconds);
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}
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}
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#endif
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static struct ctl_table_header *cmm_sysctl_header;
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static int cmm_suspend(void)
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{
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cmm_suspended = 1;
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cmm_free_pages(cmm_pages, &cmm_pages, &cmm_page_list);
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cmm_free_pages(cmm_timed_pages, &cmm_timed_pages, &cmm_timed_page_list);
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return 0;
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}
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static int cmm_resume(void)
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{
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cmm_suspended = 0;
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cmm_kick_thread();
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return 0;
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}
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static int cmm_power_event(struct notifier_block *this,
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unsigned long event, void *ptr)
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{
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switch (event) {
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case PM_POST_HIBERNATION:
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return cmm_resume();
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case PM_HIBERNATION_PREPARE:
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return cmm_suspend();
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default:
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return NOTIFY_DONE;
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}
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}
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static struct notifier_block cmm_power_notifier = {
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.notifier_call = cmm_power_event,
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};
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static int __init cmm_init(void)
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{
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int rc = -ENOMEM;
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cmm_sysctl_header = register_sysctl_table(cmm_dir_table);
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if (!cmm_sysctl_header)
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goto out_sysctl;
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#ifdef CONFIG_CMM_IUCV
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/* convert sender to uppercase characters */
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if (sender) {
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int len = strlen(sender);
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while (len--)
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sender[len] = toupper(sender[len]);
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} else {
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sender = cmm_default_sender;
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}
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rc = smsg_register_callback(SMSG_PREFIX, cmm_smsg_target);
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if (rc < 0)
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goto out_smsg;
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#endif
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rc = register_oom_notifier(&cmm_oom_nb);
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if (rc < 0)
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goto out_oom_notify;
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rc = register_pm_notifier(&cmm_power_notifier);
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if (rc)
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goto out_pm;
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cmm_thread_ptr = kthread_run(cmm_thread, NULL, "cmmthread");
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rc = IS_ERR(cmm_thread_ptr) ? PTR_ERR(cmm_thread_ptr) : 0;
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if (rc)
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goto out_kthread;
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return 0;
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out_kthread:
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unregister_pm_notifier(&cmm_power_notifier);
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out_pm:
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unregister_oom_notifier(&cmm_oom_nb);
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out_oom_notify:
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#ifdef CONFIG_CMM_IUCV
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smsg_unregister_callback(SMSG_PREFIX, cmm_smsg_target);
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out_smsg:
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#endif
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unregister_sysctl_table(cmm_sysctl_header);
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out_sysctl:
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del_timer_sync(&cmm_timer);
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return rc;
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}
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module_init(cmm_init);
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static void __exit cmm_exit(void)
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{
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unregister_sysctl_table(cmm_sysctl_header);
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#ifdef CONFIG_CMM_IUCV
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smsg_unregister_callback(SMSG_PREFIX, cmm_smsg_target);
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#endif
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unregister_pm_notifier(&cmm_power_notifier);
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unregister_oom_notifier(&cmm_oom_nb);
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kthread_stop(cmm_thread_ptr);
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del_timer_sync(&cmm_timer);
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cmm_free_pages(cmm_pages, &cmm_pages, &cmm_page_list);
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cmm_free_pages(cmm_timed_pages, &cmm_timed_pages, &cmm_timed_page_list);
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}
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module_exit(cmm_exit);
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MODULE_LICENSE("GPL");
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