Commit 4da2ce25 authored by Michal Hocko's avatar Michal Hocko Committed by Linus Torvalds

mm: distinguish CMA and MOVABLE isolation in has_unmovable_pages()

Joonsoo has noticed that "mm: drop migrate type checks from
has_unmovable_pages" would break CMA allocator because it relies on
has_unmovable_pages returning false even for CMA pageblocks which in
fact don't have to be movable:


This is a result of the code sharing between CMA and memory hotplug
while each one has a different idea of what has_unmovable_pages should
return.  This is unfortunate but fixing it properly would require a lot
of code duplication.

Fix the issue by introducing the requested migrate type argument and
special case MIGRATE_CMA case where CMA page blocks are handled
properly.  This will work for memory hotplug because it requires

Link: default avatarMichal Hocko <>
Reported-by: default avatarJoonsoo Kim <>
Tested-by: default avatarStefan Wahren <>
Tested-by: default avatarRan Wang <>
Cc: Michael Ellerman <>
Cc: Vlastimil Babka <>
Cc: Igor Mammedov <>
Cc: KAMEZAWA Hiroyuki <>
Cc: Reza Arbab <>
Cc: Vitaly Kuznetsov <>
Cc: Xishi Qiu <>
Cc: Yasuaki Ishimatsu <>
Signed-off-by: default avatarAndrew Morton <>
Signed-off-by: default avatarLinus Torvalds <>
parent d7b236e1
......@@ -31,7 +31,7 @@ static inline bool is_migrate_isolate(int migratetype)
bool has_unmovable_pages(struct zone *zone, struct page *page, int count,
bool skip_hwpoisoned_pages);
int migratetype, bool skip_hwpoisoned_pages);
void set_pageblock_migratetype(struct page *page, int migratetype);
int move_freepages_block(struct zone *zone, struct page *page,
int migratetype, int *num_movable);
......@@ -7353,6 +7353,7 @@ void *__init alloc_large_system_hash(const char *tablename,
* race condition. So you can't expect this function should be exact.
bool has_unmovable_pages(struct zone *zone, struct page *page, int count,
int migratetype,
bool skip_hwpoisoned_pages)
unsigned long pfn, iter, found;
......@@ -7364,6 +7365,15 @@ bool has_unmovable_pages(struct zone *zone, struct page *page, int count,
if (zone_idx(zone) == ZONE_MOVABLE)
return false;
* CMA allocations (alloc_contig_range) really need to mark isolate
* CMA pageblocks even when they are not movable in fact so consider
* them movable here.
if (is_migrate_cma(migratetype) &&
return false;
pfn = page_to_pfn(page);
for (found = 0, iter = 0; iter < pageblock_nr_pages; iter++) {
unsigned long check = pfn + iter;
......@@ -7446,7 +7456,7 @@ bool is_pageblock_removable_nolock(struct page *page)
if (!zone_spans_pfn(zone, pfn))
return false;
return !has_unmovable_pages(zone, page, 0, true);
return !has_unmovable_pages(zone, page, 0, MIGRATE_MOVABLE, true);
......@@ -15,7 +15,7 @@
#include <trace/events/page_isolation.h>
static int set_migratetype_isolate(struct page *page,
static int set_migratetype_isolate(struct page *page, int migratetype,
bool skip_hwpoisoned_pages)
struct zone *zone;
......@@ -52,7 +52,7 @@ static int set_migratetype_isolate(struct page *page,
* 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,
if (!has_unmovable_pages(zone, page, arg.pages_found, migratetype,
ret = 0;
......@@ -64,14 +64,14 @@ static int set_migratetype_isolate(struct page *page,
if (!ret) {
unsigned long nr_pages;
int migratetype = get_pageblock_migratetype(page);
int mt = get_pageblock_migratetype(page);
set_pageblock_migratetype(page, MIGRATE_ISOLATE);
nr_pages = move_freepages_block(zone, page, MIGRATE_ISOLATE,
__mod_zone_freepage_state(zone, -nr_pages, migratetype);
__mod_zone_freepage_state(zone, -nr_pages, mt);
spin_unlock_irqrestore(&zone->lock, flags);
......@@ -183,7 +183,7 @@ int start_isolate_page_range(unsigned long start_pfn, unsigned long end_pfn,
pfn += pageblock_nr_pages) {
page = __first_valid_page(pfn, pageblock_nr_pages);
if (page &&
set_migratetype_isolate(page, skip_hwpoisoned_pages)) {
set_migratetype_isolate(page, migratetype, skip_hwpoisoned_pages)) {
undo_pfn = pfn;
goto undo;
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