Re: [PATCH v3 5/6] mm/cma: remove MIGRATE_CMA
From: Chen Feng
Date: Thu May 26 2016 - 21:47:26 EST
Hi Joonsoo,
On 2016/5/26 14:22, js1304@xxxxxxxxx wrote:
> From: Joonsoo Kim <iamjoonsoo.kim@xxxxxxx>
>
> Now, all reserved pages for CMA region are belong to the ZONE_CMA
> and there is no other type of pages. Therefore, we don't need to
> use MIGRATE_CMA to distinguish and handle differently for CMA pages
> and ordinary pages. Remove MIGRATE_CMA.
>
> Unfortunately, this patch make free CMA counter incorrect because
> we count it when pages are on the MIGRATE_CMA. It will be fixed
> by next patch. I can squash next patch here but it makes changes
> complicated and hard to review so I separate that.
>
> Signed-off-by: Joonsoo Kim <iamjoonsoo.kim@xxxxxxx>
> ---
> include/linux/gfp.h | 3 +-
> include/linux/mmzone.h | 22 -------------
> include/linux/vmstat.h | 8 -----
> mm/cma.c | 2 +-
> mm/compaction.c | 10 ++----
> mm/hugetlb.c | 2 +-
> mm/page_alloc.c | 87 +++++++++++++-------------------------------------
> mm/page_isolation.c | 5 ++-
> mm/vmstat.c | 5 +--
> 9 files changed, 31 insertions(+), 113 deletions(-)
>
> diff --git a/include/linux/gfp.h b/include/linux/gfp.h
> index 4d6c008..1a3b869 100644
> --- a/include/linux/gfp.h
> +++ b/include/linux/gfp.h
> @@ -559,8 +559,7 @@ static inline bool pm_suspended_storage(void)
>
> #if (defined(CONFIG_MEMORY_ISOLATION) && defined(CONFIG_COMPACTION)) || defined(CONFIG_CMA)
> /* The below functions must be run on a range from a single zone. */
> -extern int alloc_contig_range(unsigned long start, unsigned long end,
> - unsigned migratetype);
> +extern int alloc_contig_range(unsigned long start, unsigned long end);
> extern void free_contig_range(unsigned long pfn, unsigned nr_pages);
> #endif
>
> diff --git a/include/linux/mmzone.h b/include/linux/mmzone.h
> index 54c92a6..236d0bd 100644
> --- a/include/linux/mmzone.h
> +++ b/include/linux/mmzone.h
> @@ -41,22 +41,6 @@ enum {
> MIGRATE_RECLAIMABLE,
> MIGRATE_PCPTYPES, /* the number of types on the pcp lists */
> MIGRATE_HIGHATOMIC = MIGRATE_PCPTYPES,
> -#ifdef CONFIG_CMA
> - /*
> - * MIGRATE_CMA migration type is designed to mimic the way
> - * ZONE_MOVABLE works. Only movable pages can be allocated
> - * from MIGRATE_CMA pageblocks and page allocator never
> - * implicitly change migration type of MIGRATE_CMA pageblock.
> - *
> - * The way to use it is to change migratetype of a range of
> - * pageblocks to MIGRATE_CMA which can be done by
> - * __free_pageblock_cma() function. What is important though
> - * is that a range of pageblocks must be aligned to
> - * MAX_ORDER_NR_PAGES should biggest page be bigger then
> - * a single pageblock.
> - */
> - MIGRATE_CMA,
> -#endif
> #ifdef CONFIG_MEMORY_ISOLATION
> MIGRATE_ISOLATE, /* can't allocate from here */
> #endif
> @@ -66,12 +50,6 @@ enum {
> /* In mm/page_alloc.c; keep in sync also with show_migration_types() there */
> extern char * const migratetype_names[MIGRATE_TYPES];
>
> -#ifdef CONFIG_CMA
> -# define is_migrate_cma(migratetype) unlikely((migratetype) == MIGRATE_CMA)
> -#else
> -# define is_migrate_cma(migratetype) false
> -#endif
> -
> #define for_each_migratetype_order(order, type) \
> for (order = 0; order < MAX_ORDER; order++) \
> for (type = 0; type < MIGRATE_TYPES; type++)
> diff --git a/include/linux/vmstat.h b/include/linux/vmstat.h
> index 0aa613d..e0eb3e5 100644
> --- a/include/linux/vmstat.h
> +++ b/include/linux/vmstat.h
> @@ -264,14 +264,6 @@ static inline void drain_zonestat(struct zone *zone,
> struct per_cpu_pageset *pset) { }
> #endif /* CONFIG_SMP */
>
> -static inline void __mod_zone_freepage_state(struct zone *zone, int nr_pages,
> - int migratetype)
> -{
> - __mod_zone_page_state(zone, NR_FREE_PAGES, nr_pages);
> - if (is_migrate_cma(migratetype))
> - __mod_zone_page_state(zone, NR_FREE_CMA_PAGES, nr_pages);
> -}
> -
> extern const char * const vmstat_text[];
>
> #endif /* _LINUX_VMSTAT_H */
> diff --git a/mm/cma.c b/mm/cma.c
> index 8684f50..bd436e4 100644
> --- a/mm/cma.c
> +++ b/mm/cma.c
> @@ -444,7 +444,7 @@ struct page *cma_alloc(struct cma *cma, size_t count, unsigned int align)
>
> pfn = cma->base_pfn + (bitmap_no << cma->order_per_bit);
> mutex_lock(&cma_mutex);
> - ret = alloc_contig_range(pfn, pfn + count, MIGRATE_CMA);
> + ret = alloc_contig_range(pfn, pfn + count);
> mutex_unlock(&cma_mutex);
> if (ret == 0) {
> page = pfn_to_page(pfn);
> diff --git a/mm/compaction.c b/mm/compaction.c
> index 1427366..acb1d1a 100644
> --- a/mm/compaction.c
> +++ b/mm/compaction.c
> @@ -76,7 +76,7 @@ static void map_pages(struct list_head *list)
>
> static inline bool migrate_async_suitable(int migratetype)
> {
> - return is_migrate_cma(migratetype) || migratetype == MIGRATE_MOVABLE;
> + return migratetype == MIGRATE_MOVABLE;
> }
>
> #ifdef CONFIG_COMPACTION
> @@ -953,7 +953,7 @@ static bool suitable_migration_target(struct page *page)
> return false;
> }
>
> - /* If the block is MIGRATE_MOVABLE or MIGRATE_CMA, allow migration */
> + /* If the block is MIGRATE_MOVABLE, allow migration */
> if (migrate_async_suitable(get_pageblock_migratetype(page)))
> return true;
>
> @@ -1277,12 +1277,6 @@ static enum compact_result __compact_finished(struct zone *zone, struct compact_
> if (!list_empty(&area->free_list[migratetype]))
> return COMPACT_PARTIAL;
>
> -#ifdef CONFIG_CMA
> - /* MIGRATE_MOVABLE can fallback on MIGRATE_CMA */
> - if (migratetype == MIGRATE_MOVABLE &&
> - !list_empty(&area->free_list[MIGRATE_CMA]))
> - return COMPACT_PARTIAL;
> -#endif
> /*
> * Job done if allocation would steal freepages from
> * other migratetype buddy lists.
> diff --git a/mm/hugetlb.c b/mm/hugetlb.c
> index d26162e..a081f15 100644
> --- a/mm/hugetlb.c
> +++ b/mm/hugetlb.c
> @@ -1029,7 +1029,7 @@ static int __alloc_gigantic_page(unsigned long start_pfn,
> unsigned long nr_pages)
> {
> unsigned long end_pfn = start_pfn + nr_pages;
> - return alloc_contig_range(start_pfn, end_pfn, MIGRATE_MOVABLE);
> + return alloc_contig_range(start_pfn, end_pfn);
> }
>
> static bool pfn_range_valid_gigantic(struct zone *z,
> diff --git a/mm/page_alloc.c b/mm/page_alloc.c
> index bab3698..e1c17d15 100644
> --- a/mm/page_alloc.c
> +++ b/mm/page_alloc.c
> @@ -124,8 +124,8 @@ gfp_t gfp_allowed_mask __read_mostly = GFP_BOOT_MASK;
> * put on a pcplist. Used to avoid the pageblock migratetype lookup when
> * freeing from pcplists in most cases, at the cost of possibly becoming stale.
> * Also the migratetype set in the page does not necessarily match the pcplist
> - * index, e.g. page might have MIGRATE_CMA set but be on a pcplist with any
> - * other index - this ensures that it will be put on the correct CMA freelist.
> + * index, e.g. page might have MIGRATE_MOVABLE set but be on a pcplist with any
> + * other index - this ensures that it will be put on the correct freelist.
> */
> static inline int get_pcppage_migratetype(struct page *page)
> {
> @@ -234,9 +234,6 @@ char * const migratetype_names[MIGRATE_TYPES] = {
> "Movable",
> "Reclaimable",
> "HighAtomic",
> -#ifdef CONFIG_CMA
> - "CMA",
> -#endif
> #ifdef CONFIG_MEMORY_ISOLATION
> "Isolate",
> #endif
> @@ -670,7 +667,7 @@ static inline void set_page_guard(struct zone *zone, struct page *page,
> INIT_LIST_HEAD(&page->lru);
> set_page_private(page, order);
> /* Guard pages are not available for any usage */
> - __mod_zone_freepage_state(zone, -(1 << order), migratetype);
> + __mod_zone_page_state(zone, NR_FREE_PAGES, -(1 << order));
> }
>
> static inline void clear_page_guard(struct zone *zone, struct page *page,
> @@ -689,7 +686,7 @@ static inline void clear_page_guard(struct zone *zone, struct page *page,
>
> set_page_private(page, 0);
> if (!is_migrate_isolate(migratetype))
> - __mod_zone_freepage_state(zone, (1 << order), migratetype);
> + __mod_zone_page_state(zone, NR_FREE_PAGES, (1 << order));
> }
> #else
> struct page_ext_operations debug_guardpage_ops = { NULL, };
> @@ -800,7 +797,7 @@ static inline void __free_one_page(struct page *page,
>
> VM_BUG_ON(migratetype == -1);
> if (likely(!is_migrate_isolate(migratetype)))
> - __mod_zone_freepage_state(zone, 1 << order, migratetype);
> + __mod_zone_page_state(zone, NR_FREE_PAGES, 1 << order);
>
> page_idx = pfn & ((1 << MAX_ORDER) - 1);
>
> @@ -1580,7 +1577,7 @@ static void __init adjust_present_page_count(struct page *page, long count)
> zone->present_pages += count;
> }
>
> -/* Free whole pageblock and set its migration type to MIGRATE_CMA. */
> +/* Free whole pageblock and set its migration type to MIGRATE_MOVABLE. */
> void __init init_cma_reserved_pageblock(struct page *page)
> {
> unsigned i = pageblock_nr_pages;
> @@ -1605,7 +1602,7 @@ void __init init_cma_reserved_pageblock(struct page *page)
>
> adjust_present_page_count(page, pageblock_nr_pages);
>
> - set_pageblock_migratetype(page, MIGRATE_CMA);
> + set_pageblock_migratetype(page, MIGRATE_MOVABLE);
I have a question here, if the ZONE_CMA pages are all movable.
Then the unmovable alloc will also use CMA memory. Is this right?
How can the cma memory be migrate?
>
> if (pageblock_order >= MAX_ORDER) {
> i = pageblock_nr_pages;
> @@ -1830,25 +1827,11 @@ static int fallbacks[MIGRATE_TYPES][4] = {
> [MIGRATE_UNMOVABLE] = { MIGRATE_RECLAIMABLE, MIGRATE_MOVABLE, MIGRATE_TYPES },
> [MIGRATE_RECLAIMABLE] = { MIGRATE_UNMOVABLE, MIGRATE_MOVABLE, MIGRATE_TYPES },
> [MIGRATE_MOVABLE] = { MIGRATE_RECLAIMABLE, MIGRATE_UNMOVABLE, MIGRATE_TYPES },
> -#ifdef CONFIG_CMA
> - [MIGRATE_CMA] = { MIGRATE_TYPES }, /* Never used */
> -#endif
> #ifdef CONFIG_MEMORY_ISOLATION
> [MIGRATE_ISOLATE] = { MIGRATE_TYPES }, /* Never used */
> #endif
> };
>
> -#ifdef CONFIG_CMA
> -static struct page *__rmqueue_cma_fallback(struct zone *zone,
> - unsigned int order)
> -{
> - return __rmqueue_smallest(zone, order, MIGRATE_CMA);
> -}
> -#else
> -static inline struct page *__rmqueue_cma_fallback(struct zone *zone,
> - unsigned int order) { return NULL; }
> -#endif
> -
> /*
> * Move the free pages in a range to the free lists of the requested type.
> * Note that start_page and end_pages are not aligned on a pageblock
> @@ -2053,7 +2036,7 @@ static void reserve_highatomic_pageblock(struct page *page, struct zone *zone,
> /* Yoink! */
> mt = get_pageblock_migratetype(page);
> if (mt != MIGRATE_HIGHATOMIC &&
> - !is_migrate_isolate(mt) && !is_migrate_cma(mt)) {
> + !is_migrate_isolate(mt)) {
> zone->nr_reserved_highatomic += pageblock_nr_pages;
> set_pageblock_migratetype(page, MIGRATE_HIGHATOMIC);
> move_freepages_block(zone, page, MIGRATE_HIGHATOMIC);
> @@ -2156,9 +2139,7 @@ __rmqueue_fallback(struct zone *zone, unsigned int order, int start_migratetype)
> /*
> * The pcppage_migratetype may differ from pageblock's
> * migratetype depending on the decisions in
> - * find_suitable_fallback(). This is OK as long as it does not
> - * differ for MIGRATE_CMA pageblocks. Those can be used as
> - * fallback only via special __rmqueue_cma_fallback() function
> + * find_suitable_fallback(). This is OK.
> */
> set_pcppage_migratetype(page, start_migratetype);
>
> @@ -2181,13 +2162,8 @@ static struct page *__rmqueue(struct zone *zone, unsigned int order,
> struct page *page;
>
> page = __rmqueue_smallest(zone, order, migratetype);
> - if (unlikely(!page)) {
> - if (migratetype == MIGRATE_MOVABLE)
> - page = __rmqueue_cma_fallback(zone, order);
> -
> - if (!page)
> - page = __rmqueue_fallback(zone, order, migratetype);
> - }
> + if (unlikely(!page))
> + page = __rmqueue_fallback(zone, order, migratetype);
>
> trace_mm_page_alloc_zone_locked(page, order, migratetype);
> return page;
> @@ -2227,9 +2203,6 @@ static int rmqueue_bulk(struct zone *zone, unsigned int order,
> else
> list_add_tail(&page->lru, list);
> list = &page->lru;
> - if (is_migrate_cma(get_pcppage_migratetype(page)))
> - __mod_zone_page_state(zone, NR_FREE_CMA_PAGES,
> - -(1 << order));
> }
> __mod_zone_page_state(zone, NR_FREE_PAGES, -(i << order));
> spin_unlock(&zone->lock);
> @@ -2527,7 +2500,7 @@ int __isolate_free_page(struct page *page, unsigned int order)
> if (!zone_watermark_ok(zone, 0, watermark, 0, 0))
> return 0;
>
> - __mod_zone_freepage_state(zone, -(1UL << order), mt);
> + __mod_zone_page_state(zone, NR_FREE_PAGES, -(1UL << order));
> }
>
> /* Remove page from free list */
> @@ -2542,7 +2515,7 @@ int __isolate_free_page(struct page *page, unsigned int order)
> struct page *endpage = page + (1 << order) - 1;
> for (; page < endpage; page += pageblock_nr_pages) {
> int mt = get_pageblock_migratetype(page);
> - if (!is_migrate_isolate(mt) && !is_migrate_cma(mt))
> + if (!is_migrate_isolate(mt))
> set_pageblock_migratetype(page,
> MIGRATE_MOVABLE);
> }
> @@ -2670,8 +2643,7 @@ struct page *buffered_rmqueue(struct zone *preferred_zone,
> if (!page)
> goto failed;
> __mod_zone_page_state(zone, NR_ALLOC_BATCH, -(1 << order));
> - __mod_zone_freepage_state(zone, -(1 << order),
> - get_pcppage_migratetype(page));
> + __mod_zone_page_state(zone, NR_FREE_PAGES, -(1 << order));
> }
>
> if (atomic_long_read(&zone->vm_stat[NR_ALLOC_BATCH]) <= 0 &&
> @@ -2825,11 +2797,6 @@ bool __zone_watermark_ok(struct zone *z, unsigned int order, unsigned long mark,
> if (!list_empty(&area->free_list[mt]))
> return true;
> }
> -
> -#ifdef CONFIG_CMA
> - if (!list_empty(&area->free_list[MIGRATE_CMA]))
> - return true;
> -#endif
> }
> return false;
> }
> @@ -4320,9 +4287,6 @@ static void show_migration_types(unsigned char type)
> [MIGRATE_MOVABLE] = 'M',
> [MIGRATE_RECLAIMABLE] = 'E',
> [MIGRATE_HIGHATOMIC] = 'H',
> -#ifdef CONFIG_CMA
> - [MIGRATE_CMA] = 'C',
> -#endif
> #ifdef CONFIG_MEMORY_ISOLATION
> [MIGRATE_ISOLATE] = 'I',
> #endif
> @@ -7244,7 +7208,7 @@ bool has_unmovable_pages(struct zone *zone, struct page *page, int count,
> return false;
>
> mt = get_pageblock_migratetype(page);
> - if (mt == MIGRATE_MOVABLE || is_migrate_cma(mt))
> + if (mt == MIGRATE_MOVABLE)
> return false;
>
> pfn = page_to_pfn(page);
> @@ -7392,15 +7356,11 @@ static int __alloc_contig_migrate_range(struct compact_control *cc,
> * alloc_contig_range() -- tries to allocate given range of pages
> * @start: start PFN to allocate
> * @end: one-past-the-last PFN to allocate
> - * @migratetype: migratetype of the underlaying pageblocks (either
> - * #MIGRATE_MOVABLE or #MIGRATE_CMA). All pageblocks
> - * in range must have the same migratetype and it must
> - * be either of the two.
> *
> * The PFN range does not have to be pageblock or MAX_ORDER_NR_PAGES
> * aligned, however it's the caller's responsibility to guarantee that
> * we are the only thread that changes migrate type of pageblocks the
> - * pages fall in.
> + * pages fall in and it should be MIGRATE_MOVABLE.
> *
> * The PFN range must belong to a single zone.
> *
> @@ -7408,8 +7368,7 @@ static int __alloc_contig_migrate_range(struct compact_control *cc,
> * pages which PFN is in [start, end) are allocated for the caller and
> * need to be freed with free_contig_range().
> */
> -int alloc_contig_range(unsigned long start, unsigned long end,
> - unsigned migratetype)
> +int alloc_contig_range(unsigned long start, unsigned long end)
> {
> unsigned long outer_start, outer_end;
> unsigned int order;
> @@ -7442,14 +7401,14 @@ int alloc_contig_range(unsigned long start, unsigned long end,
> * allocator removing them from the buddy system. This way
> * page allocator will never consider using them.
> *
> - * This lets us mark the pageblocks back as
> - * MIGRATE_CMA/MIGRATE_MOVABLE so that free pages in the
> - * aligned range but not in the unaligned, original range are
> - * put back to page allocator so that buddy can use them.
> + * This lets us mark the pageblocks back as MIGRATE_MOVABLE
> + * so that free pages in the aligned range but not in the
> + * unaligned, original range are put back to page allocator
> + * so that buddy can use them.
> */
>
> ret = start_isolate_page_range(pfn_max_align_down(start),
> - pfn_max_align_up(end), migratetype,
> + pfn_max_align_up(end), MIGRATE_MOVABLE,
> false);
> if (ret)
> return ret;
> @@ -7528,7 +7487,7 @@ int alloc_contig_range(unsigned long start, unsigned long end,
>
> done:
> undo_isolate_page_range(pfn_max_align_down(start),
> - pfn_max_align_up(end), migratetype);
> + pfn_max_align_up(end), MIGRATE_MOVABLE);
> return ret;
> }
>
> diff --git a/mm/page_isolation.c b/mm/page_isolation.c
> index 612122b..5708649 100644
> --- a/mm/page_isolation.c
> +++ b/mm/page_isolation.c
> @@ -61,13 +61,12 @@ static int set_migratetype_isolate(struct page *page,
> out:
> if (!ret) {
> unsigned long nr_pages;
> - int migratetype = get_pageblock_migratetype(page);
>
> set_pageblock_migratetype(page, MIGRATE_ISOLATE);
> zone->nr_isolate_pageblock++;
> nr_pages = move_freepages_block(zone, page, MIGRATE_ISOLATE);
>
> - __mod_zone_freepage_state(zone, -nr_pages, migratetype);
> + __mod_zone_page_state(zone, NR_FREE_PAGES, -nr_pages);
> }
>
> spin_unlock_irqrestore(&zone->lock, flags);
> @@ -122,7 +121,7 @@ static void unset_migratetype_isolate(struct page *page, unsigned migratetype)
> */
> if (!isolated_page) {
> nr_pages = move_freepages_block(zone, page, migratetype);
> - __mod_zone_freepage_state(zone, nr_pages, migratetype);
> + __mod_zone_page_state(zone, NR_FREE_PAGES, nr_pages);
> }
> set_pageblock_migratetype(page, migratetype);
> zone->nr_isolate_pageblock--;
> diff --git a/mm/vmstat.c b/mm/vmstat.c
> index 48c4942..8d18d1e 100644
> --- a/mm/vmstat.c
> +++ b/mm/vmstat.c
> @@ -1088,10 +1088,7 @@ static void pagetypeinfo_showmixedcount_print(struct seq_file *m,
>
> page_mt = gfpflags_to_migratetype(page_ext->gfp_mask);
> if (pageblock_mt != page_mt) {
> - if (is_migrate_cma(pageblock_mt))
> - count[MIGRATE_MOVABLE]++;
> - else
> - count[pageblock_mt]++;
> + count[pageblock_mt]++;
>
> pfn = block_end_pfn;
> break;
>