mm: remove the memory isolate notifier

Luckily, we have no users left, so we can get rid of it.  Cleanup
set_migratetype_isolate() a little bit.

Link: http://lkml.kernel.org/r/20191114131911.11783-2-david@redhat.com
Signed-off-by: David Hildenbrand <david@redhat.com>
Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Acked-by: Michal Hocko <mhocko@suse.com>
Cc: "Rafael J. Wysocki" <rafael@kernel.org>
Cc: Pavel Tatashin <pasha.tatashin@soleen.com>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Oscar Salvador <osalvador@suse.de>
Cc: Qian Cai <cai@lca.pw>
Cc: Anshuman Khandual <anshuman.khandual@arm.com>
Cc: Pingfan Liu <kernelfans@gmail.com>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

diff --git a/drivers/base/memory.c b/drivers/base/memory.c
index 799b431..0646439 100644 (file)
--- a/drivers/base/memory.c
+++ b/drivers/base/memory.c
@@ -70,20 +70,6 @@ void unregister_memory_notifier(struct notifier_block *nb)
 }
 EXPORT_SYMBOL(unregister_memory_notifier);
 
-static ATOMIC_NOTIFIER_HEAD(memory_isolate_chain);
-
-int register_memory_isolate_notifier(struct notifier_block *nb)
-{
-       return atomic_notifier_chain_register(&memory_isolate_chain, nb);
-}
-EXPORT_SYMBOL(register_memory_isolate_notifier);
-
-void unregister_memory_isolate_notifier(struct notifier_block *nb)
-{
-       atomic_notifier_chain_unregister(&memory_isolate_chain, nb);
-}
-EXPORT_SYMBOL(unregister_memory_isolate_notifier);
-
 static void memory_block_release(struct device *dev)
 {
        struct memory_block *mem = to_memory_block(dev);
@@ -175,11 +161,6 @@ int memory_notify(unsigned long val, void *v)
        return blocking_notifier_call_chain(&memory_chain, val, v);
 }
 
-int memory_isolate_notify(unsigned long val, void *v)
-{
-       return atomic_notifier_call_chain(&memory_isolate_chain, val, v);
-}
-
 /*
  * The probe routines leave the pages uninitialized, just as the bootmem code
  * does. Make sure we do not access them, but instead use only information from

diff --git a/include/linux/memory.h b/include/linux/memory.h
index 4c75dae..de6bccb 100644 (file)
--- a/include/linux/memory.h
+++ b/include/linux/memory.h
@@ -55,19 +55,6 @@ struct memory_notify {
        int status_change_nid;
 };
 
-/*
- * During pageblock isolation, count the number of pages within the
- * range [start_pfn, start_pfn + nr_pages) which are owned by code
- * in the notifier chain.
- */
-#define MEM_ISOLATE_COUNT      (1<<0)
-
-struct memory_isolate_notify {
-       unsigned long start_pfn;        /* Start of range to check */
-       unsigned int nr_pages;          /* # pages in range to check */
-       unsigned int pages_found;       /* # pages owned found by callbacks */
-};
-
 struct notifier_block;
 struct mem_section;
 
@@ -94,27 +81,13 @@ static inline int memory_notify(unsigned long val, void *v)
 {
        return 0;
 }
-static inline int register_memory_isolate_notifier(struct notifier_block *nb)
-{
-       return 0;
-}
-static inline void unregister_memory_isolate_notifier(struct notifier_block *nb)
-{
-}
-static inline int memory_isolate_notify(unsigned long val, void *v)
-{
-       return 0;
-}
 #else
 extern int register_memory_notifier(struct notifier_block *nb);
 extern void unregister_memory_notifier(struct notifier_block *nb);
-extern int register_memory_isolate_notifier(struct notifier_block *nb);
-extern void unregister_memory_isolate_notifier(struct notifier_block *nb);
 int create_memory_block_devices(unsigned long start, unsigned long size);
 void remove_memory_block_devices(unsigned long start, unsigned long size);
 extern void memory_dev_init(void);
 extern int memory_notify(unsigned long val, void *v);
-extern int memory_isolate_notify(unsigned long val, void *v);
 extern struct memory_block *find_memory_block(struct mem_section *);
 typedef int (*walk_memory_blocks_func_t)(struct memory_block *, void *);
 extern int walk_memory_blocks(unsigned long start, unsigned long size,

diff --git a/mm/page_isolation.c b/mm/page_isolation.c
index 04ee166..21af88b 100644 (file)
--- a/mm/page_isolation.c
+++ b/mm/page_isolation.c
@@ -18,9 +18,7 @@
 static int set_migratetype_isolate(struct page *page, int migratetype, int isol_flags)
 {
        struct zone *zone;
-       unsigned long flags, pfn;
-       struct memory_isolate_notify arg;
-       int notifier_ret;
+       unsigned long flags;
        int ret = -EBUSY;
 
        zone = page_zone(page);
@@ -35,41 +33,11 @@ static int set_migratetype_isolate(struct page *page, int migratetype, int isol_
        if (is_migrate_isolate_page(page))
                goto out;
 
-       pfn = page_to_pfn(page);
-       arg.start_pfn = pfn;
-       arg.nr_pages = pageblock_nr_pages;
-       arg.pages_found = 0;
-
-       /*
-        * It may be possible to isolate a pageblock even if the
-        * migratetype is not MIGRATE_MOVABLE. The memory isolation
-        * notifier chain is used by balloon drivers to return the
-        * number of pages in a range that are held by the balloon
-        * driver to shrink memory. If all the pages are accounted for
-        * by balloons, are free, or on the LRU, isolation can continue.
-        * Later, for example, when memory hotplug notifier runs, these
-        * pages reported as "can be isolated" should be isolated(freed)
-        * by the balloon driver through the memory notifier chain.
-        */
-       notifier_ret = memory_isolate_notify(MEM_ISOLATE_COUNT, &arg);
-       notifier_ret = notifier_to_errno(notifier_ret);
-       if (notifier_ret)
-               goto out;
        /*
         * FIXME: Now, memory hotplug doesn't call shrink_slab() by itself.
         * We just check MOVABLE pages.
         */
-       if (!has_unmovable_pages(zone, page, arg.pages_found, migratetype,
-                                isol_flags))
-               ret = 0;
-
-       /*
-        * immobile means "not-on-lru" pages. If immobile is larger than
-        * removable-by-driver pages reported by notifier, we'll fail.
-        */
-
-out:
-       if (!ret) {
+       if (!has_unmovable_pages(zone, page, 0, migratetype, isol_flags)) {
                unsigned long nr_pages;
                int mt = get_pageblock_migratetype(page);
 
@@ -79,8 +47,10 @@ out:
                                                                        NULL);
 
                __mod_zone_freepage_state(zone, -nr_pages, mt);
+               ret = 0;
        }
 
+out:
        spin_unlock_irqrestore(&zone->lock, flags);
        if (!ret)
                drain_all_pages(zone);