diff options
Diffstat (limited to 'arch/s390/mm/cmm.c')
| -rw-r--r-- | arch/s390/mm/cmm.c | 431 |
1 files changed, 431 insertions, 0 deletions
diff --git a/arch/s390/mm/cmm.c b/arch/s390/mm/cmm.c new file mode 100644 index 000000000..f47515313 --- /dev/null +++ b/arch/s390/mm/cmm.c @@ -0,0 +1,431 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * Collaborative memory management interface. + * + * Copyright IBM Corp 2003, 2010 + * Author(s): Martin Schwidefsky <schwidefsky@de.ibm.com>, + * + */ + +#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) { + /* 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_range(virt_to_pfn((void *)addr), 1); + 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; + + 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)) + del_timer(&cmm_timer); + return; + } + mod_timer(&cmm_timer, jiffies + msecs_to_jiffies(cmm_timeout_seconds * MSEC_PER_SEC)); +} + +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(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(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(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 = sprintf(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 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 + /* convert sender to uppercase characters */ + 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: + del_timer_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); + del_timer_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_LICENSE("GPL"); |