diff options
| -rw-r--r-- | arch/powerpc/platforms/pseries/cmm.c | 254 |
1 files changed, 248 insertions, 6 deletions
diff --git a/arch/powerpc/platforms/pseries/cmm.c b/arch/powerpc/platforms/pseries/cmm.c index bcdcf0ccc8d..a277f2e28db 100644 --- a/arch/powerpc/platforms/pseries/cmm.c +++ b/arch/powerpc/platforms/pseries/cmm.c @@ -38,19 +38,28 @@ #include <asm/mmu.h> #include <asm/pgalloc.h> #include <asm/uaccess.h> +#include <linux/memory.h> #include "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; @@ -65,6 +74,10 @@ 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) "]"); @@ -92,6 +105,9 @@ 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; /** @@ -110,6 +126,17 @@ static long cmm_alloc_pages(long nr) 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) @@ -119,8 +146,9 @@ static long cmm_alloc_pages(long nr) 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); + 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); @@ -282,9 +310,28 @@ static int cmm_thread(void *dummy) while (1) { timeleft = msleep_interruptible(delay * 1000); - if (kthread_should_stop() || timeleft) { - loaned_pages_target = loaned_pages; + 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(); @@ -414,6 +461,193 @@ static struct notifier_block cmm_reboot_nb = { }; /** + * 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); + + if (ret) + ret = notifier_from_errno(ret); + else + ret = NOTIFY_OK; + + return 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; + continue; + } + } + 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; + } + + if (ret) + ret = notifier_from_errno(ret); + else + ret = NOTIFY_OK; + + return ret; +} + +static struct notifier_block cmm_mem_nb = { + .notifier_call = cmm_memory_cb, + .priority = CMM_MEM_HOTPLUG_PRI +}; + +/** * cmm_init - Module initialization * * Return value: @@ -435,18 +669,24 @@ static int cmm_init(void) if ((rc = cmm_sysfs_register(&cmm_sysdev))) 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_sysfs; + goto out_unregister_notifier; } return rc; -out_unregister_sysfs: +out_unregister_notifier: + unregister_memory_notifier(&cmm_mem_nb); + unregister_memory_isolate_notifier(&cmm_mem_isolate_nb); cmm_unregister_sysfs(&cmm_sysdev); out_reboot_notifier: unregister_reboot_notifier(&cmm_reboot_nb); @@ -467,6 +707,8 @@ static void cmm_exit(void) 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_sysdev); } |