linux-kernel - Re: [PATCH 3/3] cma: add functions to get region pages counters

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Message-ID: <xa1twq5ez914.fsf@mina86.com>
Date:	Fri, 26 Dec 2014 17:10:47 +0100
From:	Michal Nazarewicz <mina86@...a86.com>
To:	"Stefan I. Strogin" <s.strogin@...tner.samsung.com>,
	linux-mm@...ck.org, linux-kernel@...r.kernel.org
Cc:	Dmitry Safonov <d.safonov@...tner.samsung.com>,
	s.strogin@...tner.samsung.com,
	Joonsoo Kim <iamjoonsoo.kim@....com>,
	Andrew Morton <akpm@...ux-foundation.org>,
	Marek Szyprowski <m.szyprowski@...sung.com>,
	aneesh.kumar@...ux.vnet.ibm.com,
	Laurent Pinchart <laurent.pinchart@...asonboard.com>,
	Pintu Kumar <pintu.k@...sung.com>,
	Weijie Yang <weijie.yang@...sung.com>,
	Laura Abbott <lauraa@...eaurora.org>,
	SeongJae Park <sj38.park@...il.com>,
	Hui Zhu <zhuhui@...omi.com>, Minchan Kim <minchan@...nel.org>,
	Dyasly Sergey <s.dyasly@...sung.com>,
	Vyacheslav Tyrtov <v.tyrtov@...sung.com>
Subject: Re: [PATCH 3/3] cma: add functions to get region pages counters

On Fri, Dec 26 2014, "Stefan I. Strogin" <s.strogin@...tner.samsung.com> wrote:
> From: Dmitry Safonov <d.safonov@...tner.samsung.com>
>
> Here are two functions that provide interface to compute/get used size
> and size of biggest free chunk in cma region.
> Added that information in cmainfo.
>
> Signed-off-by: Dmitry Safonov <d.safonov@...tner.samsung.com>

Acked-by: Michal Nazarewicz <mina86@...a86.com>

> ---
>  include/linux/cma.h |  2 ++
>  mm/cma.c            | 34 ++++++++++++++++++++++++++++++++++
>  2 files changed, 36 insertions(+)
>
> diff --git a/include/linux/cma.h b/include/linux/cma.h
> index 9384ba6..855e6f2 100644
> --- a/include/linux/cma.h
> +++ b/include/linux/cma.h
> @@ -18,6 +18,8 @@ struct cma;
>  extern unsigned long totalcma_pages;
>  extern phys_addr_t cma_get_base(struct cma *cma);
>  extern unsigned long cma_get_size(struct cma *cma);
> +extern unsigned long cma_get_used(struct cma *cma);
> +extern unsigned long cma_get_maxchunk(struct cma *cma);
>  
>  extern int __init cma_declare_contiguous(phys_addr_t base,
>  			phys_addr_t size, phys_addr_t limit,
> diff --git a/mm/cma.c b/mm/cma.c
> index ffaea26..5e560ed 100644
> --- a/mm/cma.c
> +++ b/mm/cma.c
> @@ -78,6 +78,36 @@ unsigned long cma_get_size(struct cma *cma)
>  	return cma->count << PAGE_SHIFT;
>  }
>  
> +unsigned long cma_get_used(struct cma *cma)
> +{
> +	unsigned long ret = 0;
> +
> +	mutex_lock(&cma->lock);
> +	/* pages counter is smaller than sizeof(int) */
> +	ret = bitmap_weight(cma->bitmap, (int)cma->count);
> +	mutex_unlock(&cma->lock);
> +
> +	return ret << (PAGE_SHIFT + cma->order_per_bit);
> +}
> +
> +unsigned long cma_get_maxchunk(struct cma *cma)
> +{
> +	unsigned long maxchunk = 0;
> +	unsigned long start, end = 0;
> +
> +	mutex_lock(&cma->lock);
> +	for (;;) {
> +		start = find_next_zero_bit(cma->bitmap, cma->count, end);
> +		if (start >= cma->count)
> +			break;
> +		end = find_next_bit(cma->bitmap, cma->count, start);
> +		maxchunk = max(end - start, maxchunk);
> +	}
> +	mutex_unlock(&cma->lock);
> +
> +	return maxchunk << (PAGE_SHIFT + cma->order_per_bit);
> +}
> +
>  static unsigned long cma_bitmap_aligned_mask(struct cma *cma, int align_order)
>  {
>  	if (align_order <= cma->order_per_bit)
> @@ -591,6 +621,10 @@ static int s_show(struct seq_file *m, void *p)
>  	struct cma_buffer *cmabuf;
>  	struct stack_trace trace;
>  
> +	seq_printf(m, "CMARegion stat: %8lu kB total, %8lu kB used, %8lu kB max contiguous chunk\n\n",
> +		   cma_get_size(cma) >> 10,
> +		   cma_get_used(cma) >> 10,
> +		   cma_get_maxchunk(cma) >> 10);
>  	mutex_lock(&cma->list_lock);
>  
>  	list_for_each_entry(cmabuf, &cma->buffers_list, list) {
> -- 
> 2.1.0
>

-- 
Best regards,                                         _     _
.o. | Liege of Serenely Enlightened Majesty of      o' \,=./ `o
..o | Computer Science,  Michał “mina86” Nazarewicz    (o o)
ooo +--<mpn@...gle.com>--<xmpp:mina86@...ber.org>--ooO--(_)--Ooo--
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