diff options
Diffstat (limited to 'kernel/arch/powerpc/platforms/pseries/cmm.c')
| -rw-r--r-- | kernel/arch/powerpc/platforms/pseries/cmm.c | 739 |
1 files changed, 739 insertions, 0 deletions
diff --git a/kernel/arch/powerpc/platforms/pseries/cmm.c b/kernel/arch/powerpc/platforms/pseries/cmm.c new file mode 100644 index 000000000..fc44ad047 --- /dev/null +++ b/kernel/arch/powerpc/platforms/pseries/cmm.c @@ -0,0 +1,739 @@ +/* + * 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/gfp.h> +#include <linux/kthread.h> +#include <linux/module.h> +#include <linux/oom.h> +#include <linux/reboot.h> +#include <linux/sched.h> +#include <linux/stringify.h> +#include <linux/swap.h> +#include <linux/device.h> +#include <asm/firmware.h> +#include <asm/hvcall.h> +#include <asm/mmu.h> +#include <asm/pgalloc.h> +#include <asm/uaccess.h> +#include <linux/memory.h> +#include <asm/plpar_wrappers.h> + +#define CMM_DRIVER_VERSION "1.0.0" +#define CMM_DEFAULT_DELAY 1 +#define CMM_HOTPLUG_DELAY 5 +#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)) +/* + * The priority level tries to ensure that this notifier is called as + * late as possible to reduce thrashing in the shared memory pool. + */ +#define CMM_MEM_HOTPLUG_PRI 1 +#define CMM_MEM_ISOLATE_PRI 15 + +static unsigned int delay = CMM_DEFAULT_DELAY; +static unsigned int hotplug_delay = CMM_HOTPLUG_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 device cmm_dev; + +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(hotplug_delay, hotplug_delay, uint, S_IRUGO | S_IWUSR); +MODULE_PARM_DESC(delay, "Delay (in seconds) after memory hotplug remove " + "before loaning resumes. " + "[Default=" __stringify(CMM_HOTPLUG_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 DEFINE_MUTEX(hotplug_mutex); +static int hotplug_occurred; /* protected by the hotplug mutex */ + +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) { + /* Exit if a hotplug operation is in progress or occurred */ + if (mutex_trylock(&hotplug_mutex)) { + if (hotplug_occurred) { + mutex_unlock(&hotplug_mutex); + break; + } + mutex_unlock(&hotplug_mutex); + } else { + break; + } + + 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; + signed long active_pages_target, page_loan_request, target; + signed long total_pages = totalram_pages + loaned_pages; + signed long min_mem_pages = (min_mem_mb * 1024 * 1024) / PAGE_SIZE; + + rc = h_get_mpp(&mpp_data); + + if (rc != H_SUCCESS) + return; + + page_loan_request = div_s64((s64)mpp_data.loan_request, PAGE_SIZE); + target = page_loan_request + (signed long)loaned_pages; + + if (target < 0 || total_pages < min_mem_pages) + target = 0; + + if (target > oom_freed_pages) + target -= oom_freed_pages; + else + target = 0; + + active_pages_target = total_pages - target; + + if (min_mem_pages > active_pages_target) + target = total_pages - min_mem_pages; + + if (target < 0) + target = 0; + + loaned_pages_target = target; + + 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) + break; + + if (mutex_trylock(&hotplug_mutex)) { + if (hotplug_occurred) { + hotplug_occurred = 0; + mutex_unlock(&hotplug_mutex); + cmm_dbg("Hotplug operation has occurred, " + "loaning activity suspended " + "for %d seconds.\n", + hotplug_delay); + timeleft = msleep_interruptible(hotplug_delay * + 1000); + if (kthread_should_stop() || timeleft) + break; + continue; + } + mutex_unlock(&hotplug_mutex); + } else { + cmm_dbg("Hotplug operation in progress, activity " + "suspended\n"); + continue; + } + + 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 device *dev, \ + struct device_attribute *attr, \ + char *buf) \ + { \ + return sprintf(buf, format, ##args); \ + } \ + static DEVICE_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 device *dev, + struct device_attribute *attr, char *buf) +{ + return sprintf(buf, "%lu\n", PAGES2KB(oom_freed_pages)); +} + +static ssize_t store_oom_pages(struct device *dev, + struct device_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 DEVICE_ATTR(oom_freed_kb, S_IWUSR | S_IRUGO, + show_oom_pages, store_oom_pages); + +static struct device_attribute *cmm_attrs[] = { + &dev_attr_loaned_kb, + &dev_attr_loaned_target_kb, + &dev_attr_oom_freed_kb, +}; + +static struct bus_type cmm_subsys = { + .name = "cmm", + .dev_name = "cmm", +}; + +/** + * cmm_sysfs_register - Register with sysfs + * + * Return value: + * 0 on success / other on failure + **/ +static int cmm_sysfs_register(struct device *dev) +{ + int i, rc; + + if ((rc = subsys_system_register(&cmm_subsys, NULL))) + return rc; + + dev->id = 0; + dev->bus = &cmm_subsys; + + if ((rc = device_register(dev))) + goto subsys_unregister; + + for (i = 0; i < ARRAY_SIZE(cmm_attrs); i++) { + if ((rc = device_create_file(dev, cmm_attrs[i]))) + goto fail; + } + + return 0; + +fail: + while (--i >= 0) + device_remove_file(dev, cmm_attrs[i]); + device_unregister(dev); +subsys_unregister: + bus_unregister(&cmm_subsys); + return rc; +} + +/** + * cmm_unregister_sysfs - Unregister from sysfs + * + **/ +static void cmm_unregister_sysfs(struct device *dev) +{ + int i; + + for (i = 0; i < ARRAY_SIZE(cmm_attrs); i++) + device_remove_file(dev, cmm_attrs[i]); + device_unregister(dev); + bus_unregister(&cmm_subsys); +} + +/** + * cmm_reboot_notifier - Make sure pages are not still marked as "loaned" + * + **/ +static int cmm_reboot_notifier(struct notifier_block *nb, + unsigned long action, void *unused) +{ + if (action == SYS_RESTART) { + if (cmm_thread_ptr) + kthread_stop(cmm_thread_ptr); + cmm_thread_ptr = NULL; + cmm_free_pages(loaned_pages); + } + return NOTIFY_DONE; +} + +static struct notifier_block cmm_reboot_nb = { + .notifier_call = cmm_reboot_notifier, +}; + +/** + * cmm_count_pages - Count the number of pages loaned in a particular range. + * + * @arg: memory_isolate_notify structure with address range and count + * + * Return value: + * 0 on success + **/ +static unsigned long cmm_count_pages(void *arg) +{ + struct memory_isolate_notify *marg = arg; + struct cmm_page_array *pa; + unsigned long start = (unsigned long)pfn_to_kaddr(marg->start_pfn); + unsigned long end = start + (marg->nr_pages << PAGE_SHIFT); + unsigned long idx; + + spin_lock(&cmm_lock); + pa = cmm_page_list; + while (pa) { + if ((unsigned long)pa >= start && (unsigned long)pa < end) + marg->pages_found++; + for (idx = 0; idx < pa->index; idx++) + if (pa->page[idx] >= start && pa->page[idx] < end) + marg->pages_found++; + pa = pa->next; + } + spin_unlock(&cmm_lock); + return 0; +} + +/** + * cmm_memory_isolate_cb - Handle memory isolation notifier calls + * @self: notifier block struct + * @action: action to take + * @arg: struct memory_isolate_notify data for handler + * + * Return value: + * NOTIFY_OK or notifier error based on subfunction return value + **/ +static int cmm_memory_isolate_cb(struct notifier_block *self, + unsigned long action, void *arg) +{ + int ret = 0; + + if (action == MEM_ISOLATE_COUNT) + ret = cmm_count_pages(arg); + + return notifier_from_errno(ret); +} + +static struct notifier_block cmm_mem_isolate_nb = { + .notifier_call = cmm_memory_isolate_cb, + .priority = CMM_MEM_ISOLATE_PRI +}; + +/** + * cmm_mem_going_offline - Unloan pages where memory is to be removed + * @arg: memory_notify structure with page range to be offlined + * + * Return value: + * 0 on success + **/ +static int cmm_mem_going_offline(void *arg) +{ + struct memory_notify *marg = arg; + unsigned long start_page = (unsigned long)pfn_to_kaddr(marg->start_pfn); + unsigned long end_page = start_page + (marg->nr_pages << PAGE_SHIFT); + struct cmm_page_array *pa_curr, *pa_last, *npa; + unsigned long idx; + unsigned long freed = 0; + + cmm_dbg("Memory going offline, searching 0x%lx (%ld pages).\n", + start_page, marg->nr_pages); + spin_lock(&cmm_lock); + + /* Search the page list for pages in the range to be offlined */ + pa_last = pa_curr = cmm_page_list; + while (pa_curr) { + for (idx = (pa_curr->index - 1); (idx + 1) > 0; idx--) { + if ((pa_curr->page[idx] < start_page) || + (pa_curr->page[idx] >= end_page)) + continue; + + plpar_page_set_active(__pa(pa_curr->page[idx])); + free_page(pa_curr->page[idx]); + freed++; + loaned_pages--; + totalram_pages++; + pa_curr->page[idx] = pa_last->page[--pa_last->index]; + if (pa_last->index == 0) { + if (pa_curr == pa_last) + pa_curr = pa_last->next; + pa_last = pa_last->next; + free_page((unsigned long)cmm_page_list); + cmm_page_list = pa_last; + } + } + pa_curr = pa_curr->next; + } + + /* Search for page list structures in the range to be offlined */ + pa_last = NULL; + pa_curr = cmm_page_list; + while (pa_curr) { + if (((unsigned long)pa_curr >= start_page) && + ((unsigned long)pa_curr < end_page)) { + npa = (struct cmm_page_array *)__get_free_page( + GFP_NOIO | __GFP_NOWARN | + __GFP_NORETRY | __GFP_NOMEMALLOC); + if (!npa) { + spin_unlock(&cmm_lock); + cmm_dbg("Failed to allocate memory for list " + "management. Memory hotplug " + "failed.\n"); + return ENOMEM; + } + memcpy(npa, pa_curr, PAGE_SIZE); + if (pa_curr == cmm_page_list) + cmm_page_list = npa; + if (pa_last) + pa_last->next = npa; + free_page((unsigned long) pa_curr); + freed++; + pa_curr = npa; + } + + pa_last = pa_curr; + pa_curr = pa_curr->next; + } + + spin_unlock(&cmm_lock); + cmm_dbg("Released %ld pages in the search range.\n", freed); + + return 0; +} + +/** + * cmm_memory_cb - Handle memory hotplug notifier calls + * @self: notifier block struct + * @action: action to take + * @arg: struct memory_notify data for handler + * + * Return value: + * NOTIFY_OK or notifier error based on subfunction return value + * + **/ +static int cmm_memory_cb(struct notifier_block *self, + unsigned long action, void *arg) +{ + int ret = 0; + + switch (action) { + case MEM_GOING_OFFLINE: + mutex_lock(&hotplug_mutex); + hotplug_occurred = 1; + ret = cmm_mem_going_offline(arg); + break; + case MEM_OFFLINE: + case MEM_CANCEL_OFFLINE: + mutex_unlock(&hotplug_mutex); + cmm_dbg("Memory offline operation complete.\n"); + break; + case MEM_GOING_ONLINE: + case MEM_ONLINE: + case MEM_CANCEL_ONLINE: + break; + } + + return notifier_from_errno(ret); +} + +static struct notifier_block cmm_mem_nb = { + .notifier_call = cmm_memory_cb, + .priority = CMM_MEM_HOTPLUG_PRI +}; + +/** + * 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 = register_reboot_notifier(&cmm_reboot_nb))) + goto out_oom_notifier; + + if ((rc = cmm_sysfs_register(&cmm_dev))) + goto out_reboot_notifier; + + if (register_memory_notifier(&cmm_mem_nb) || + register_memory_isolate_notifier(&cmm_mem_isolate_nb)) + goto out_unregister_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_notifier; + } + + return rc; + +out_unregister_notifier: + unregister_memory_notifier(&cmm_mem_nb); + unregister_memory_isolate_notifier(&cmm_mem_isolate_nb); + cmm_unregister_sysfs(&cmm_dev); +out_reboot_notifier: + unregister_reboot_notifier(&cmm_reboot_nb); +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); + unregister_reboot_notifier(&cmm_reboot_nb); + unregister_memory_notifier(&cmm_mem_nb); + unregister_memory_isolate_notifier(&cmm_mem_isolate_nb); + cmm_free_pages(loaned_pages); + cmm_unregister_sysfs(&cmm_dev); +} + +/** + * 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); |