Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 23.128.96.18 as permitted sender) client-ip=23.128.96.18;
Date:   Wed, 15 Apr 2020 21:23:59 +0530
From:   Vinod Koul <vkoul@kernel.org>
To:     leonid.ravich@dell.com
Cc:     dmaengine@vger.kernel.org, lravich@gmail.com,
        Dan Williams <dan.j.williams@intel.com>,
        Dave Jiang <dave.jiang@intel.com>,
        Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        Alexios Zavras <alexios.zavras@intel.com>,
        "Alexander.Barabash@dell.com" <Alexander.Barabash@dell.com>,
        Thomas Gleixner <tglx@linutronix.de>,
        Kate Stewart <kstewart@linuxfoundation.org>,
        Jilayne Lovejoy <opensource@jilayne.com>,
        Logan Gunthorpe <logang@deltatee.com>,
        linux-kernel@vger.kernel.org
Subject: Re: [PATCH v2 2/2] dmaengine: ioat: Decreasing  allocation chunk
 size 2M -> 512K
Message-ID: <20200415155359.GT72691@vkoul-mobl>
References: <20200402092725.15121-2-leonid.ravich@dell.com>
 <20200402163356.9029-1-leonid.ravich@dell.com>
 <20200402163356.9029-2-leonid.ravich@dell.com>
MIME-Version: 1.0
Content-Type: text/plain; charset=us-ascii
Content-Disposition: inline
In-Reply-To: <20200402163356.9029-2-leonid.ravich@dell.com>
Sender: linux-kernel-owner@vger.kernel.org
Precedence: bulk

On 02-04-20, 19:33, leonid.ravich@dell.com wrote:
> From: Leonid Ravich <Leonid.Ravich@emc.com>
> 
> current IOAT driver using big (2MB) allocations chunk for its descriptors
> therefore each ioat dma engine need 2 such chunks
> (64k entres in ring  each entry 64B = 4MB)
> requiring 2 * 2M * dmaengine contiguies memory chunk
> might fail due to memory fragmention.

This is quite decent explanation :) pls use upto 72 chars to make it a
better read.

> 
> so we decreasing chunk size and using more chunks.
> 
> Acked-by: Dave Jiang <dave.jiang@intel.com>
> Signed-off-by: Leonid Ravich <Leonid.Ravich@emc.com>
> ---
>  drivers/dma/ioat/dma.h | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/drivers/dma/ioat/dma.h b/drivers/dma/ioat/dma.h
> index 5216c6b..e6b622e 100644
> --- a/drivers/dma/ioat/dma.h
> +++ b/drivers/dma/ioat/dma.h
> @@ -83,7 +83,7 @@ struct ioatdma_device {
>  
>  #define IOAT_MAX_ORDER 16
>  #define IOAT_MAX_DESCS (1 << IOAT_MAX_ORDER)
> -#define IOAT_CHUNK_SIZE (SZ_2M)
> +#define IOAT_CHUNK_SIZE (SZ_512K)
>  #define IOAT_DESCS_PER_CHUNK (IOAT_CHUNK_SIZE / IOAT_DESC_SZ)
>  
>  struct ioat_descs {
> -- 
> 1.9.3

-- 
~Vinod