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From: Minchan Kim <minchan@kernel.org>
To: Seth Jennings <sjenning@linux.vnet.ibm.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
	Andrew Morton <akpm@linux-foundation.org>,
	Dan Magenheimer <dan.magenheimer@oracle.com>,
	Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>,
	Nitin Gupta <ngupta@vflare.org>,
	Robert Jennings <rcj@linux.vnet.ibm.com>,
	linux-mm@kvack.org, devel@driverdev.osuosl.org,
	linux-kernel@vger.kernel.org
Subject: Re: [PATCH 2/4] zsmalloc: add single-page object fastpath in unmap
Date: Tue, 10 Jul 2012 11:25:45 +0900	[thread overview]
Message-ID: <4FFB92A9.4090203@kernel.org> (raw)
In-Reply-To: <1341263752-10210-3-git-send-email-sjenning@linux.vnet.ibm.com>

On 07/03/2012 06:15 AM, Seth Jennings wrote:
> Improve zs_unmap_object() performance by adding a fast path for
> objects that don't span pages.
> 
> Signed-off-by: Seth Jennings <sjenning@linux.vnet.ibm.com>
> ---
>  drivers/staging/zsmalloc/zsmalloc-main.c |   15 ++++++++++-----
>  1 file changed, 10 insertions(+), 5 deletions(-)
> 
> diff --git a/drivers/staging/zsmalloc/zsmalloc-main.c b/drivers/staging/zsmalloc/zsmalloc-main.c
> index a7a6f22..4942d41 100644
> --- a/drivers/staging/zsmalloc/zsmalloc-main.c
> +++ b/drivers/staging/zsmalloc/zsmalloc-main.c
> @@ -774,6 +774,7 @@ void *zs_map_object(struct zs_pool *pool, unsigned long handle)
>  	}
>  
>  	zs_copy_map_object(area->vm_buf, page, off, class->size);
> +	area->vm_addr = NULL;
>  	return area->vm_buf;
>  }
>  EXPORT_SYMBOL_GPL(zs_map_object);
> @@ -788,6 +789,14 @@ void zs_unmap_object(struct zs_pool *pool, unsigned long handle)
>  	struct size_class *class;
>  	struct mapping_area *area;
>  
> +	area = &__get_cpu_var(zs_map_area);
> +	if (area->vm_addr) {
> +		/* single-page object fastpath */
> +		kunmap_atomic(area->vm_addr);
> +		put_cpu_var(zs_map_area);
> +		return;
> +	}
> +

Please locate this after below BUG_ON.
The BUG check is still effective regardless of your fast path patch.

>  	BUG_ON(!handle);
>  
>  	obj_handle_to_location(handle, &page, &obj_idx);
> @@ -795,11 +804,7 @@ void zs_unmap_object(struct zs_pool *pool, unsigned long handle)
>  	class = &pool->size_class[class_idx];
>  	off = obj_idx_to_offset(page, obj_idx, class->size);
>  
> -	area = &__get_cpu_var(zs_map_area);
> -	if (off + class->size <= PAGE_SIZE)
> -		kunmap_atomic(area->vm_addr);
> -	else
> -		zs_copy_unmap_object(area->vm_buf, page, off, class->size);
> +	zs_copy_unmap_object(area->vm_buf, page, off, class->size);
>  	put_cpu_var(zs_map_area);
>  }
>  EXPORT_SYMBOL_GPL(zs_unmap_object);
> 


-- 
Kind regards,
Minchan Kim



WARNING: multiple messages have this Message-ID
From: Minchan Kim <minchan@kernel.org>
To: Seth Jennings <sjenning@linux.vnet.ibm.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
	Andrew Morton <akpm@linux-foundation.org>,
	Dan Magenheimer <dan.magenheimer@oracle.com>,
	Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>,
	Nitin Gupta <ngupta@vflare.org>,
	Robert Jennings <rcj@linux.vnet.ibm.com>,
	linux-mm@kvack.org, devel@driverdev.osuosl.org,
	linux-kernel@vger.kernel.org
Subject: Re: [PATCH 2/4] zsmalloc: add single-page object fastpath in unmap
Date: Tue, 10 Jul 2012 11:25:45 +0900	[thread overview]
Message-ID: <4FFB92A9.4090203@kernel.org> (raw)
In-Reply-To: <1341263752-10210-3-git-send-email-sjenning@linux.vnet.ibm.com>

On 07/03/2012 06:15 AM, Seth Jennings wrote:
> Improve zs_unmap_object() performance by adding a fast path for
> objects that don't span pages.
> 
> Signed-off-by: Seth Jennings <sjenning@linux.vnet.ibm.com>
> ---
>  drivers/staging/zsmalloc/zsmalloc-main.c |   15 ++++++++++-----
>  1 file changed, 10 insertions(+), 5 deletions(-)
> 
> diff --git a/drivers/staging/zsmalloc/zsmalloc-main.c b/drivers/staging/zsmalloc/zsmalloc-main.c
> index a7a6f22..4942d41 100644
> --- a/drivers/staging/zsmalloc/zsmalloc-main.c
> +++ b/drivers/staging/zsmalloc/zsmalloc-main.c
> @@ -774,6 +774,7 @@ void *zs_map_object(struct zs_pool *pool, unsigned long handle)
>  	}
>  
>  	zs_copy_map_object(area->vm_buf, page, off, class->size);
> +	area->vm_addr = NULL;
>  	return area->vm_buf;
>  }
>  EXPORT_SYMBOL_GPL(zs_map_object);
> @@ -788,6 +789,14 @@ void zs_unmap_object(struct zs_pool *pool, unsigned long handle)
>  	struct size_class *class;
>  	struct mapping_area *area;
>  
> +	area = &__get_cpu_var(zs_map_area);
> +	if (area->vm_addr) {
> +		/* single-page object fastpath */
> +		kunmap_atomic(area->vm_addr);
> +		put_cpu_var(zs_map_area);
> +		return;
> +	}
> +

Please locate this after below BUG_ON.
The BUG check is still effective regardless of your fast path patch.

>  	BUG_ON(!handle);
>  
>  	obj_handle_to_location(handle, &page, &obj_idx);
> @@ -795,11 +804,7 @@ void zs_unmap_object(struct zs_pool *pool, unsigned long handle)
>  	class = &pool->size_class[class_idx];
>  	off = obj_idx_to_offset(page, obj_idx, class->size);
>  
> -	area = &__get_cpu_var(zs_map_area);
> -	if (off + class->size <= PAGE_SIZE)
> -		kunmap_atomic(area->vm_addr);
> -	else
> -		zs_copy_unmap_object(area->vm_buf, page, off, class->size);
> +	zs_copy_unmap_object(area->vm_buf, page, off, class->size);
>  	put_cpu_var(zs_map_area);
>  }
>  EXPORT_SYMBOL_GPL(zs_unmap_object);
> 


-- 
Kind regards,
Minchan Kim


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  reply	other threads:[~2012-07-10  2:25 UTC|newest]

Thread overview: 62+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2012-07-02 21:15 [PATCH 0/4] zsmalloc improvements Seth Jennings
2012-07-02 21:15 ` Seth Jennings
2012-07-02 21:15 ` [PATCH 1/4] zsmalloc: remove x86 dependency Seth Jennings
2012-07-02 21:15   ` Seth Jennings
2012-07-10  2:21   ` Minchan Kim
2012-07-10  2:21     ` Minchan Kim
2012-07-10 15:29     ` Seth Jennings
2012-07-10 15:29       ` Seth Jennings
2012-07-11  7:27       ` Minchan Kim
2012-07-11  7:27         ` Minchan Kim
2012-07-11 18:26   ` Nitin Gupta
2012-07-11 18:26     ` Nitin Gupta
2012-07-11 20:32     ` Seth Jennings
2012-07-11 20:32       ` Seth Jennings
2012-07-11 22:42       ` Nitin Gupta
2012-07-11 22:42         ` Nitin Gupta
2012-07-12  0:23         ` Seth Jennings
2012-07-12  0:23           ` Seth Jennings
2012-07-02 21:15 ` [PATCH 2/4] zsmalloc: add single-page object fastpath in unmap Seth Jennings
2012-07-02 21:15   ` Seth Jennings
2012-07-10  2:25   ` Minchan Kim [this message]
2012-07-10  2:25     ` Minchan Kim
2012-07-02 21:15 ` [PATCH 3/4] zsmalloc: add details to zs_map_object boiler plate Seth Jennings
2012-07-02 21:15   ` Seth Jennings
2012-07-10  2:35   ` Minchan Kim
2012-07-10  2:35     ` Minchan Kim
2012-07-10 15:17     ` Seth Jennings
2012-07-10 15:17       ` Seth Jennings
2012-07-11  7:42       ` Minchan Kim
2012-07-11  7:42         ` Minchan Kim
2012-07-11 14:15         ` Seth Jennings
2012-07-11 14:15           ` Seth Jennings
2012-07-12  1:15           ` Minchan Kim
2012-07-12  1:15             ` Minchan Kim
2012-07-12 19:54             ` Dan Magenheimer
2012-07-12 19:54               ` Dan Magenheimer
2012-07-12 22:46               ` Dan Magenheimer
2012-07-12 22:46                 ` Dan Magenheimer
2012-07-02 21:15 ` [PATCH 4/4] zsmalloc: add mapping modes Seth Jennings
2012-07-02 21:15   ` Seth Jennings
2012-07-04  5:33 ` [PATCH 0/4] zsmalloc improvements Minchan Kim
2012-07-04  5:33   ` Minchan Kim
2012-07-04 20:43 ` Konrad Rzeszutek Wilk
2012-07-04 20:43   ` Konrad Rzeszutek Wilk
2012-07-06 15:07   ` Seth Jennings
2012-07-06 15:07     ` Seth Jennings
2012-07-09 13:58     ` Seth Jennings
2012-07-09 13:58       ` Seth Jennings
2012-07-11 19:42       ` Konrad Rzeszutek Wilk
2012-07-11 19:42         ` Konrad Rzeszutek Wilk
2012-07-11 20:48         ` Seth Jennings
2012-07-11 20:48           ` Seth Jennings
2012-07-12 10:40           ` Konrad Rzeszutek Wilk
2012-07-12 10:40             ` Konrad Rzeszutek Wilk
2012-07-11  7:03 ` Minchan Kim
2012-07-11  7:03   ` Minchan Kim
2012-07-11 14:00   ` Seth Jennings
2012-07-11 14:00     ` Seth Jennings
2012-07-12  1:01     ` Minchan Kim
2012-07-12  1:01       ` Minchan Kim
2012-07-11 19:16   ` Seth Jennings
2012-07-11 19:16     ` Seth Jennings

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