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powerpc/pseries/cmm: Rip out memory isolate notifier

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The memory isolate notifier was added to allow to offline memory
blocks that contain inflated/"loaned" pages. We can achieve the same
using the balloon compaction framework.

Get rid of the memory isolate notifier. Also, we can get rid of
cmm_mem_going_offline(), as we will never reach that code path now
when we have allocated memory in the balloon (allocated pages are
unmovable and will no longer be special-cased using the memory
isolation notifier).

Leave the memory notifier in place, so we can still back off in case
memory gets offlined.

Signed-off-by: David Hildenbrand <david@redhat.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20191031142933.10779-7-david@redhat.com
This commit is contained in:
David Hildenbrand 2019-10-31 15:29:27 +01:00 committed by Michael Ellerman
parent 287b89773d
commit 7659f5d644
1 changed files with 1 additions and 96 deletions
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97
arch/powerpc/platforms/pseries/cmm.c
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@ -38,12 +38,8 @@
#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;
@ -446,90 +442,6 @@ 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 page *page;
spin_lock(&cmm_lock);
list_for_each_entry(page, &cmm_page_list, lru) {
if (page_to_pfn(page) >= marg->start_pfn &&
page_to_pfn(page) < marg->start_pfn + marg->nr_pages)
marg->pages_found++;
}
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;
struct page *page, *tmp;
unsigned long freed = 0;
cmm_dbg("Memory going offline, searching PFN 0x%lx (%ld pages).\n",
marg->start_pfn, marg->nr_pages);
spin_lock(&cmm_lock);
/* Search the page list for pages in the range to be offlined */
list_for_each_entry_safe(page, tmp, &cmm_page_list, lru) {
if (page_to_pfn(page) < marg->start_pfn ||
page_to_pfn(page) >= marg->start_pfn + marg->nr_pages)
continue;
plpar_page_set_active(page);
list_del(&page->lru);
adjust_managed_page_count(page, 1);
__free_page(page);
freed++;
loaned_pages--;
}
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
@ -549,7 +461,6 @@ static int cmm_memory_cb(struct notifier_block *self,
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:
@ -596,10 +507,6 @@ static int cmm_init(void)
if (rc)
goto out_unregister_notifier;
rc = register_memory_isolate_notifier(&cmm_mem_isolate_nb);
if (rc)
goto out_unregister_notifier;
if (cmm_disabled)
return 0;
@ -612,7 +519,6 @@ static int cmm_init(void)
return 0;
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);
@ -634,7 +540,6 @@ static void cmm_exit(void)
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);
}