From 4da2ce250f986060750fcc5b29112914e31803ba Mon Sep 17 00:00:00 2001 From: Michal Hocko Date: Wed, 15 Nov 2017 17:33:26 -0800 Subject: [PATCH] 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: alloc_contig_range start_isolate_page_range set_migratetype_isolate has_unmovable_pages 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 MIGRATE_MOVABLE. Link: http://lkml.kernel.org/r/20171019122118.y6cndierwl2vnguj@dhcp22.suse.cz Signed-off-by: Michal Hocko Reported-by: Joonsoo Kim Tested-by: Stefan Wahren Tested-by: Ran 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: Andrew Morton Signed-off-by: Linus Torvalds --- include/linux/page-isolation.h | 2 +- mm/page_alloc.c | 12 +++++++++++- mm/page_isolation.c | 10 +++++----- 3 files changed, 17 insertions(+), 7 deletions(-) diff --git a/include/linux/page-isolation.h b/include/linux/page-isolation.h index 05a04e6..cdad58b 100644 --- a/include/linux/page-isolation.h +++ b/include/linux/page-isolation.h @@ -31,7 +31,7 @@ static inline bool is_migrate_isolate(int migratetype) #endif 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); diff --git a/mm/page_alloc.c b/mm/page_alloc.c index e6d4234..755f35f 100644 --- a/mm/page_alloc.c +++ b/mm/page_alloc.c @@ -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) && + is_migrate_cma(get_pageblock_migratetype(page))) + 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); } #if (defined(CONFIG_MEMORY_ISOLATION) && defined(CONFIG_COMPACTION)) || defined(CONFIG_CMA) diff --git a/mm/page_isolation.c b/mm/page_isolation.c index 44f2139..165ed81 100644 --- a/mm/page_isolation.c +++ b/mm/page_isolation.c @@ -15,7 +15,7 @@ #define CREATE_TRACE_POINTS #include -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, skip_hwpoisoned_pages)) ret = 0; @@ -64,14 +64,14 @@ static int set_migratetype_isolate(struct page *page, out: if (!ret) { unsigned long nr_pages; - int migratetype = get_pageblock_migratetype(page); + int mt = get_pageblock_migratetype(page); set_pageblock_migratetype(page, MIGRATE_ISOLATE); zone->nr_isolate_pageblock++; nr_pages = move_freepages_block(zone, page, MIGRATE_ISOLATE, NULL); - __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; } -- 2.7.4