/**
* 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_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_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);
}
/**
* 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;
}
/**
* 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);
}
/**
* 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);
}
/**
* 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;
}
