Re: [PATCH v3 3/5] cma: count free CMA pages

[Minchan Kim <minchan@kernel.org>]

On Tue, Sep 04, 2012 at 03:26:23PM +0200, Bartlomiej Zolnierkiewicz wrote:
> Add NR_FREE_CMA_PAGES counter to be later used for checking watermark
> in __zone_watermark_ok().  For simplicity and to avoid #ifdef hell make
> this counter always available (not only when CONFIG_CMA=y).

I would like to hide it in case of !CONFIG_CMA.
Otherwise, does it really make ifdef hell?

Many part of your code uses below pattern.

                       __mod_zone_page_state(zone, NR_FREE_PAGES, 1 << order);
                       if (is_migrate_cma(migratetype))
                               __mod_zone_page_state(zone, NR_FREE_CMA_PAGES,
                                                     1 << order);

So how about this?

        NR_ANON_TRANSPARENT_HUGEPAGES,
+#ifdef CONFIG_CMA
+       NR_FREE_CMA_PAGES,
+#endif
        NR_VM_ZONE_STAT_ITEMS };

#ifdef CONFIG_CMA
#  define is_migrate_cma(migratetype) unlikely((migratetype) == MIGRATE_CMA)
#  define cma_wmark_pages(zone) zone->min_cma_pages
#else
#  define is_migrate_cma(migratetype) false
#  define cma_wmark_pages(zone) 0
#  define NR_FREE_CMA_PAGES     0
#endif

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);
}


> 
> Cc: Marek Szyprowski <m.szyprowski@samsung.com>
> Cc: Michal Nazarewicz <mina86@mina86.com>
> Cc: Minchan Kim <minchan@kernel.org>
> Cc: Mel Gorman <mgorman@suse.de>
> Cc: Hugh Dickins <hughd@google.com>
> Signed-off-by: Bartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com>
> Signed-off-by: Kyungmin Park <kyungmin.park@samsung.com>
> ---
>  include/linux/mmzone.h |  1 +
>  mm/page_alloc.c        | 36 ++++++++++++++++++++++++++++++++----
>  mm/page_isolation.c    |  7 +++++++
>  mm/vmstat.c            |  1 +
>  4 files changed, 41 insertions(+), 4 deletions(-)
> 
> diff --git a/include/linux/mmzone.h b/include/linux/mmzone.h
> index ca034a1..904889d 100644
> --- a/include/linux/mmzone.h
> +++ b/include/linux/mmzone.h
> @@ -140,6 +140,7 @@ enum zone_stat_item {
>  	NUMA_OTHER,		/* allocation from other node */
>  #endif
>  	NR_ANON_TRANSPARENT_HUGEPAGES,
> +	NR_FREE_CMA_PAGES,
>  	NR_VM_ZONE_STAT_ITEMS };
>  
>  /*
> diff --git a/mm/page_alloc.c b/mm/page_alloc.c
> index 3acdf0f..5bb0cda 100644
> --- a/mm/page_alloc.c
> +++ b/mm/page_alloc.c
> @@ -559,6 +559,9 @@ static inline void __free_one_page(struct page *page,
>  			clear_page_guard_flag(buddy);
>  			set_page_private(page, 0);
>  			__mod_zone_page_state(zone, NR_FREE_PAGES, 1 << order);
> +			if (is_migrate_cma(migratetype))
> +				__mod_zone_page_state(zone, NR_FREE_CMA_PAGES,
> +						      1 << order);
>  		} else {
>  			list_del(&buddy->lru);
>  			zone->free_area[order].nr_free--;
> @@ -677,6 +680,8 @@ static void free_pcppages_bulk(struct zone *zone, int count,
>  			/* MIGRATE_MOVABLE list may include MIGRATE_RESERVEs */
>  			__free_one_page(page, zone, 0, mt);
>  			trace_mm_page_pcpu_drain(page, 0, mt);
> +			if (is_migrate_cma(mt))
> +				__mod_zone_page_state(zone, NR_FREE_CMA_PAGES, 1);
>  		} while (--to_free && --batch_free && !list_empty(list));
>  	}
>  	__mod_zone_page_state(zone, NR_FREE_PAGES, count);
> @@ -691,8 +696,12 @@ static void free_one_page(struct zone *zone, struct page *page, int order,
>  	zone->pages_scanned = 0;
>  
>  	__free_one_page(page, zone, order, migratetype);
> -	if (migratetype != MIGRATE_ISOLATE)
> +	if (migratetype != MIGRATE_ISOLATE) {
>  		__mod_zone_page_state(zone, NR_FREE_PAGES, 1 << order);
> +		if (is_migrate_cma(migratetype))
> +			__mod_zone_page_state(zone, NR_FREE_CMA_PAGES,
> +					      1 << order);
> +	}
>  	spin_unlock(&zone->lock);
>  }
>  
> @@ -816,6 +825,9 @@ static inline void expand(struct zone *zone, struct page *page,
>  			set_page_private(&page[size], high);
>  			/* Guard pages are not available for any usage */
>  			__mod_zone_page_state(zone, NR_FREE_PAGES, -(1 << high));
> +			if (is_migrate_cma(migratetype))
> +				__mod_zone_page_state(zone, NR_FREE_CMA_PAGES,
> +						      -(1 << high));
>  			continue;
>  		}
>  #endif
> @@ -1141,6 +1153,9 @@ static int rmqueue_bulk(struct zone *zone, unsigned int order,
>  		}
>  		set_page_private(page, mt);
>  		list = &page->lru;
> +		if (is_migrate_cma(mt))
> +			__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);
> @@ -1398,6 +1413,7 @@ int split_free_page(struct page *page, bool check_wmark)
>  	unsigned int order;
>  	unsigned long watermark;
>  	struct zone *zone;
> +	int mt;
>  
>  	BUG_ON(!PageBuddy(page));
>  
> @@ -1416,8 +1432,13 @@ int split_free_page(struct page *page, bool check_wmark)
>  	zone->free_area[order].nr_free--;
>  	rmv_page_order(page);
>  
> -	if (get_pageblock_migratetype(page) != MIGRATE_ISOLATE)
> +	mt = get_pageblock_migratetype(page);
> +	if (mt != MIGRATE_ISOLATE) {
>  		__mod_zone_page_state(zone, NR_FREE_PAGES, -(1UL << order));
> +		if (is_migrate_cma(mt))
> +			__mod_zone_page_state(zone, NR_FREE_CMA_PAGES,
> +					      -(1UL << order));
> +	}
>  
>  	/* Split into individual pages */
>  	set_page_refcounted(page);
> @@ -1492,6 +1513,9 @@ again:
>  		spin_unlock(&zone->lock);
>  		if (!page)
>  			goto failed;
> +		if (is_migrate_cma(get_pageblock_migratetype(page)))
> +			__mod_zone_page_state(zone, NR_FREE_CMA_PAGES,
> +					      -(1 << order));
>  		__mod_zone_page_state(zone, NR_FREE_PAGES, -(1 << order));
>  	}
>  
> @@ -2860,7 +2884,8 @@ void show_free_areas(unsigned int filter)
>  		" unevictable:%lu"
>  		" dirty:%lu writeback:%lu unstable:%lu\n"
>  		" free:%lu slab_reclaimable:%lu slab_unreclaimable:%lu\n"
> -		" mapped:%lu shmem:%lu pagetables:%lu bounce:%lu\n",
> +		" mapped:%lu shmem:%lu pagetables:%lu bounce:%lu\n"
> +		" free_cma:%lu\n",
>  		global_page_state(NR_ACTIVE_ANON),
>  		global_page_state(NR_INACTIVE_ANON),
>  		global_page_state(NR_ISOLATED_ANON),
> @@ -2877,7 +2902,8 @@ void show_free_areas(unsigned int filter)
>  		global_page_state(NR_FILE_MAPPED),
>  		global_page_state(NR_SHMEM),
>  		global_page_state(NR_PAGETABLE),
> -		global_page_state(NR_BOUNCE));
> +		global_page_state(NR_BOUNCE),
> +		global_page_state(NR_FREE_CMA_PAGES));
>  
>  	for_each_populated_zone(zone) {
>  		int i;
> @@ -2909,6 +2935,7 @@ void show_free_areas(unsigned int filter)
>  			" pagetables:%lukB"
>  			" unstable:%lukB"
>  			" bounce:%lukB"
> +			" free_cma:%lukB"
>  			" writeback_tmp:%lukB"
>  			" pages_scanned:%lu"
>  			" all_unreclaimable? %s"
> @@ -2938,6 +2965,7 @@ void show_free_areas(unsigned int filter)
>  			K(zone_page_state(zone, NR_PAGETABLE)),
>  			K(zone_page_state(zone, NR_UNSTABLE_NFS)),
>  			K(zone_page_state(zone, NR_BOUNCE)),
> +			K(zone_page_state(zone, NR_FREE_CMA_PAGES)),
>  			K(zone_page_state(zone, NR_WRITEBACK_TEMP)),
>  			zone->pages_scanned,
>  			(zone->all_unreclaimable ? "yes" : "no")
> diff --git a/mm/page_isolation.c b/mm/page_isolation.c
> index d210cc8..6ead34d 100644
> --- a/mm/page_isolation.c
> +++ b/mm/page_isolation.c
> @@ -77,11 +77,15 @@ int set_migratetype_isolate(struct page *page)
>  out:
>  	if (!ret) {
>  		unsigned long nr_pages;
> +		int mt = get_pageblock_migratetype(page);
>  
>  		set_pageblock_isolate(page);
>  		nr_pages = move_freepages_block(zone, page, MIGRATE_ISOLATE);
>  
>  		__mod_zone_page_state(zone, NR_FREE_PAGES, -nr_pages);
> +		if (is_migrate_cma(mt))
> +			__mod_zone_page_state(zone, NR_FREE_CMA_PAGES,
> +					      -nr_pages);
>  	}
>  
>  	spin_unlock_irqrestore(&zone->lock, flags);
> @@ -102,6 +106,9 @@ void unset_migratetype_isolate(struct page *page, unsigned migratetype)
>  		goto out;
>  	nr_pages = move_freepages_block(zone, page, 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);
>  	restore_pageblock_isolate(page, migratetype);
>  out:
>  	spin_unlock_irqrestore(&zone->lock, flags);
> diff --git a/mm/vmstat.c b/mm/vmstat.c
> index df7a674..7c102e6 100644
> --- a/mm/vmstat.c
> +++ b/mm/vmstat.c
> @@ -722,6 +722,7 @@ const char * const vmstat_text[] = {
>  	"numa_other",
>  #endif
>  	"nr_anon_transparent_hugepages",
> +	"nr_free_cma",
>  	"nr_dirty_threshold",
>  	"nr_dirty_background_threshold",
>  
> -- 
> 1.7.11.3
> 
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-- 
Kind regards,
Minchan Kim

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