| /* |
| * Collaborative memory management interface. |
| * |
| * Copyright (C) 2008 IBM Corporation |
| * Author(s): Brian King (brking@linux.vnet.ibm.com), |
| * |
| * This program is free software; you can redistribute it and/or modify |
| * it under the terms of the GNU General Public License as published by |
| * the Free Software Foundation; either version 2 of the License, or |
| * (at your option) any later version. |
| * |
| * This program is distributed in the hope that it will be useful, |
| * but WITHOUT ANY WARRANTY; without even the implied warranty of |
| * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
| * GNU General Public License for more details. |
| * |
| * You should have received a copy of the GNU General Public License |
| * along with this program; if not, write to the Free Software |
| * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA |
| * |
| */ |
| |
| #include <linux/ctype.h> |
| #include <linux/delay.h> |
| #include <linux/errno.h> |
| #include <linux/fs.h> |
| #include <linux/init.h> |
| #include <linux/kthread.h> |
| #include <linux/module.h> |
| #include <linux/oom.h> |
| #include <linux/sched.h> |
| #include <linux/stringify.h> |
| #include <linux/swap.h> |
| #include <linux/sysdev.h> |
| #include <asm/firmware.h> |
| #include <asm/hvcall.h> |
| #include <asm/mmu.h> |
| #include <asm/pgalloc.h> |
| #include <asm/uaccess.h> |
| |
| #include "plpar_wrappers.h" |
| |
| #define CMM_DRIVER_VERSION "1.0.0" |
| #define CMM_DEFAULT_DELAY 1 |
| #define CMM_DEBUG 0 |
| #define CMM_DISABLE 0 |
| #define CMM_OOM_KB 1024 |
| #define CMM_MIN_MEM_MB 256 |
| #define KB2PAGES(_p) ((_p)>>(PAGE_SHIFT-10)) |
| #define PAGES2KB(_p) ((_p)<<(PAGE_SHIFT-10)) |
| |
| static unsigned int delay = CMM_DEFAULT_DELAY; |
| static unsigned int oom_kb = CMM_OOM_KB; |
| static unsigned int cmm_debug = CMM_DEBUG; |
| static unsigned int cmm_disabled = CMM_DISABLE; |
| static unsigned long min_mem_mb = CMM_MIN_MEM_MB; |
| static struct sys_device cmm_sysdev; |
| |
| MODULE_AUTHOR("Brian King <brking@linux.vnet.ibm.com>"); |
| MODULE_DESCRIPTION("IBM System p Collaborative Memory Manager"); |
| MODULE_LICENSE("GPL"); |
| MODULE_VERSION(CMM_DRIVER_VERSION); |
| |
| module_param_named(delay, delay, uint, S_IRUGO | S_IWUSR); |
| MODULE_PARM_DESC(delay, "Delay (in seconds) between polls to query hypervisor paging requests. " |
| "[Default=" __stringify(CMM_DEFAULT_DELAY) "]"); |
| module_param_named(oom_kb, oom_kb, uint, S_IRUGO | S_IWUSR); |
| MODULE_PARM_DESC(oom_kb, "Amount of memory in kb to free on OOM. " |
| "[Default=" __stringify(CMM_OOM_KB) "]"); |
| module_param_named(min_mem_mb, min_mem_mb, ulong, S_IRUGO | S_IWUSR); |
| MODULE_PARM_DESC(min_mem_mb, "Minimum amount of memory (in MB) to not balloon. " |
| "[Default=" __stringify(CMM_MIN_MEM_MB) "]"); |
| module_param_named(debug, cmm_debug, uint, S_IRUGO | S_IWUSR); |
| MODULE_PARM_DESC(debug, "Enable module debugging logging. Set to 1 to enable. " |
| "[Default=" __stringify(CMM_DEBUG) "]"); |
| |
| #define CMM_NR_PAGES ((PAGE_SIZE - sizeof(void *) - sizeof(unsigned long)) / sizeof(unsigned long)) |
| |
| #define cmm_dbg(...) if (cmm_debug) { printk(KERN_INFO "cmm: "__VA_ARGS__); } |
| |
| struct cmm_page_array { |
| struct cmm_page_array *next; |
| unsigned long index; |
| unsigned long page[CMM_NR_PAGES]; |
| }; |
| |
| static unsigned long loaned_pages; |
| static unsigned long loaned_pages_target; |
| static unsigned long oom_freed_pages; |
| |
| static struct cmm_page_array *cmm_page_list; |
| static DEFINE_SPINLOCK(cmm_lock); |
| |
| static struct task_struct *cmm_thread_ptr; |
| |
| /** |
| * cmm_alloc_pages - Allocate pages and mark them as loaned |
| * @nr: number of pages to allocate |
| * |
| * Return value: |
| * number of pages requested to be allocated which were not |
| **/ |
| static long cmm_alloc_pages(long nr) |
| { |
| struct cmm_page_array *pa, *npa; |
| unsigned long addr; |
| long rc; |
| |
| cmm_dbg("Begin request for %ld pages\n", nr); |
| |
| while (nr) { |
| addr = __get_free_page(GFP_NOIO | __GFP_NOWARN | |
| __GFP_NORETRY | __GFP_NOMEMALLOC); |
| if (!addr) |
| break; |
| spin_lock(&cmm_lock); |
| pa = cmm_page_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 | __GFP_NOWARN | |
| __GFP_NORETRY | __GFP_NOMEMALLOC); |
| if (!npa) { |
| pr_info("%s: Can not allocate new page list\n", __func__); |
| free_page(addr); |
| break; |
| } |
| spin_lock(&cmm_lock); |
| pa = cmm_page_list; |
| |
| if (!pa || pa->index >= CMM_NR_PAGES) { |
| npa->next = pa; |
| npa->index = 0; |
| pa = npa; |
| cmm_page_list = pa; |
| } else |
| free_page((unsigned long) npa); |
| } |
| |
| if ((rc = plpar_page_set_loaned(__pa(addr)))) { |
| pr_err("%s: Can not set page to loaned. rc=%ld\n", __func__, rc); |
| spin_unlock(&cmm_lock); |
| free_page(addr); |
| break; |
| } |
| |
| pa->page[pa->index++] = addr; |
| loaned_pages++; |
| totalram_pages--; |
| spin_unlock(&cmm_lock); |
| nr--; |
| } |
| |
| cmm_dbg("End request with %ld pages unfulfilled\n", nr); |
| return nr; |
| } |
| |
| /** |
| * cmm_free_pages - Free pages and mark them as active |
| * @nr: number of pages to free |
| * |
| * Return value: |
| * number of pages requested to be freed which were not |
| **/ |
| static long cmm_free_pages(long nr) |
| { |
| struct cmm_page_array *pa; |
| unsigned long addr; |
| |
| cmm_dbg("Begin free of %ld pages.\n", nr); |
| spin_lock(&cmm_lock); |
| pa = cmm_page_list; |
| while (nr) { |
| if (!pa || pa->index <= 0) |
| break; |
| addr = pa->page[--pa->index]; |
| |
| if (pa->index == 0) { |
| pa = pa->next; |
| free_page((unsigned long) cmm_page_list); |
| cmm_page_list = pa; |
| } |
| |
| plpar_page_set_active(__pa(addr)); |
| free_page(addr); |
| loaned_pages--; |
| nr--; |
| totalram_pages++; |
| } |
| spin_unlock(&cmm_lock); |
| cmm_dbg("End request with %ld pages unfulfilled\n", nr); |
| return nr; |
| } |
| |
| /** |
| * cmm_oom_notify - OOM notifier |
| * @self: notifier block struct |
| * @dummy: not used |
| * @parm: returned - number of pages freed |
| * |
| * Return value: |
| * NOTIFY_OK |
| **/ |
| static int cmm_oom_notify(struct notifier_block *self, |
| unsigned long dummy, void *parm) |
| { |
| unsigned long *freed = parm; |
| long nr = KB2PAGES(oom_kb); |
| |
| cmm_dbg("OOM processing started\n"); |
| nr = cmm_free_pages(nr); |
| loaned_pages_target = loaned_pages; |
| *freed += KB2PAGES(oom_kb) - nr; |
| oom_freed_pages += KB2PAGES(oom_kb) - nr; |
| cmm_dbg("OOM processing complete\n"); |
| return NOTIFY_OK; |
| } |
| |
| /** |
| * cmm_get_mpp - Read memory performance parameters |
| * |
| * Makes hcall to query the current page loan request from the hypervisor. |
| * |
| * Return value: |
| * nothing |
| **/ |
| static void cmm_get_mpp(void) |
| { |
| int rc; |
| struct hvcall_mpp_data mpp_data; |
| unsigned long active_pages_target; |
| signed long page_loan_request; |
| |
| rc = h_get_mpp(&mpp_data); |
| |
| if (rc != H_SUCCESS) |
| return; |
| |
| page_loan_request = div_s64((s64)mpp_data.loan_request, PAGE_SIZE); |
| loaned_pages_target = page_loan_request + loaned_pages; |
| if (loaned_pages_target > oom_freed_pages) |
| loaned_pages_target -= oom_freed_pages; |
| else |
| loaned_pages_target = 0; |
| |
| active_pages_target = totalram_pages + loaned_pages - loaned_pages_target; |
| |
| if ((min_mem_mb * 1024 * 1024) > (active_pages_target * PAGE_SIZE)) |
| loaned_pages_target = totalram_pages + loaned_pages - |
| ((min_mem_mb * 1024 * 1024) / PAGE_SIZE); |
| |
| cmm_dbg("delta = %ld, loaned = %lu, target = %lu, oom = %lu, totalram = %lu\n", |
| page_loan_request, loaned_pages, loaned_pages_target, |
| oom_freed_pages, totalram_pages); |
| } |
| |
| static struct notifier_block cmm_oom_nb = { |
| .notifier_call = cmm_oom_notify |
| }; |
| |
| /** |
| * cmm_thread - CMM task thread |
| * @dummy: not used |
| * |
| * Return value: |
| * 0 |
| **/ |
| static int cmm_thread(void *dummy) |
| { |
| unsigned long timeleft; |
| |
| while (1) { |
| timeleft = msleep_interruptible(delay * 1000); |
| |
| if (kthread_should_stop() || timeleft) { |
| loaned_pages_target = loaned_pages; |
| break; |
| } |
| |
| cmm_get_mpp(); |
| |
| if (loaned_pages_target > loaned_pages) { |
| if (cmm_alloc_pages(loaned_pages_target - loaned_pages)) |
| loaned_pages_target = loaned_pages; |
| } else if (loaned_pages_target < loaned_pages) |
| cmm_free_pages(loaned_pages - loaned_pages_target); |
| } |
| return 0; |
| } |
| |
| #define CMM_SHOW(name, format, args...) \ |
| static ssize_t show_##name(struct sys_device *dev, \ |
| struct sysdev_attribute *attr, \ |
| char *buf) \ |
| { \ |
| return sprintf(buf, format, ##args); \ |
| } \ |
| static SYSDEV_ATTR(name, S_IRUGO, show_##name, NULL) |
| |
| CMM_SHOW(loaned_kb, "%lu\n", PAGES2KB(loaned_pages)); |
| CMM_SHOW(loaned_target_kb, "%lu\n", PAGES2KB(loaned_pages_target)); |
| |
| static ssize_t show_oom_pages(struct sys_device *dev, |
| struct sysdev_attribute *attr, char *buf) |
| { |
| return sprintf(buf, "%lu\n", PAGES2KB(oom_freed_pages)); |
| } |
| |
| static ssize_t store_oom_pages(struct sys_device *dev, |
| struct sysdev_attribute *attr, |
| const char *buf, size_t count) |
| { |
| unsigned long val = simple_strtoul (buf, NULL, 10); |
| |
| if (!capable(CAP_SYS_ADMIN)) |
| return -EPERM; |
| if (val != 0) |
| return -EBADMSG; |
| |
| oom_freed_pages = 0; |
| return count; |
| } |
| |
| static SYSDEV_ATTR(oom_freed_kb, S_IWUSR| S_IRUGO, |
| show_oom_pages, store_oom_pages); |
| |
| static struct sysdev_attribute *cmm_attrs[] = { |
| &attr_loaned_kb, |
| &attr_loaned_target_kb, |
| &attr_oom_freed_kb, |
| }; |
| |
| static struct sysdev_class cmm_sysdev_class = { |
| .name = "cmm", |
| }; |
| |
| /** |
| * cmm_sysfs_register - Register with sysfs |
| * |
| * Return value: |
| * 0 on success / other on failure |
| **/ |
| static int cmm_sysfs_register(struct sys_device *sysdev) |
| { |
| int i, rc; |
| |
| if ((rc = sysdev_class_register(&cmm_sysdev_class))) |
| return rc; |
| |
| sysdev->id = 0; |
| sysdev->cls = &cmm_sysdev_class; |
| |
| if ((rc = sysdev_register(sysdev))) |
| goto class_unregister; |
| |
| for (i = 0; i < ARRAY_SIZE(cmm_attrs); i++) { |
| if ((rc = sysdev_create_file(sysdev, cmm_attrs[i]))) |
| goto fail; |
| } |
| |
| return 0; |
| |
| fail: |
| while (--i >= 0) |
| sysdev_remove_file(sysdev, cmm_attrs[i]); |
| sysdev_unregister(sysdev); |
| class_unregister: |
| sysdev_class_unregister(&cmm_sysdev_class); |
| return rc; |
| } |
| |
| /** |
| * cmm_unregister_sysfs - Unregister from sysfs |
| * |
| **/ |
| static void cmm_unregister_sysfs(struct sys_device *sysdev) |
| { |
| int i; |
| |
| for (i = 0; i < ARRAY_SIZE(cmm_attrs); i++) |
| sysdev_remove_file(sysdev, cmm_attrs[i]); |
| sysdev_unregister(sysdev); |
| sysdev_class_unregister(&cmm_sysdev_class); |
| } |
| |
| /** |
| * cmm_init - Module initialization |
| * |
| * Return value: |
| * 0 on success / other on failure |
| **/ |
| static int cmm_init(void) |
| { |
| int rc = -ENOMEM; |
| |
| if (!firmware_has_feature(FW_FEATURE_CMO)) |
| return -EOPNOTSUPP; |
| |
| if ((rc = register_oom_notifier(&cmm_oom_nb)) < 0) |
| return rc; |
| |
| if ((rc = cmm_sysfs_register(&cmm_sysdev))) |
| goto out_oom_notifier; |
| |
| if (cmm_disabled) |
| return rc; |
| |
| cmm_thread_ptr = kthread_run(cmm_thread, NULL, "cmmthread"); |
| if (IS_ERR(cmm_thread_ptr)) { |
| rc = PTR_ERR(cmm_thread_ptr); |
| goto out_unregister_sysfs; |
| } |
| |
| return rc; |
| |
| out_unregister_sysfs: |
| cmm_unregister_sysfs(&cmm_sysdev); |
| out_oom_notifier: |
| unregister_oom_notifier(&cmm_oom_nb); |
| return rc; |
| } |
| |
| /** |
| * cmm_exit - Module exit |
| * |
| * Return value: |
| * nothing |
| **/ |
| static void cmm_exit(void) |
| { |
| if (cmm_thread_ptr) |
| kthread_stop(cmm_thread_ptr); |
| unregister_oom_notifier(&cmm_oom_nb); |
| cmm_free_pages(loaned_pages); |
| cmm_unregister_sysfs(&cmm_sysdev); |
| } |
| |
| /** |
| * cmm_set_disable - Disable/Enable CMM |
| * |
| * Return value: |
| * 0 on success / other on failure |
| **/ |
| static int cmm_set_disable(const char *val, struct kernel_param *kp) |
| { |
| int disable = simple_strtoul(val, NULL, 10); |
| |
| if (disable != 0 && disable != 1) |
| return -EINVAL; |
| |
| if (disable && !cmm_disabled) { |
| if (cmm_thread_ptr) |
| kthread_stop(cmm_thread_ptr); |
| cmm_thread_ptr = NULL; |
| cmm_free_pages(loaned_pages); |
| } else if (!disable && cmm_disabled) { |
| cmm_thread_ptr = kthread_run(cmm_thread, NULL, "cmmthread"); |
| if (IS_ERR(cmm_thread_ptr)) |
| return PTR_ERR(cmm_thread_ptr); |
| } |
| |
| cmm_disabled = disable; |
| return 0; |
| } |
| |
| module_param_call(disable, cmm_set_disable, param_get_uint, |
| &cmm_disabled, S_IRUGO | S_IWUSR); |
| MODULE_PARM_DESC(disable, "Disable CMM. Set to 1 to disable. " |
| "[Default=" __stringify(CMM_DISABLE) "]"); |
| |
| module_init(cmm_init); |
| module_exit(cmm_exit); |