linux-kernel - Re: [PATCH v3] drm/etnaviv: Request pages from DMA32 zone on addressing

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Message-ID: <CAH9NwWczgAmgRbHiKD1614Yc1fAXRYV2ZDUeuEunPDUcRmPwgA@mail.gmail.com>
Date: Wed, 11 Sep 2024 19:35:44 +0200
From: Christian Gmeiner <christian.gmeiner@...il.com>
To: Xiaolei Wang <xiaolei.wang@...driver.com>
Cc: sui.jingfeng@...ux.dev, l.stach@...gutronix.de, 
	linux+etnaviv@...linux.org.uk, airlied@...il.com, daniel@...ll.ch, 
	etnaviv@...ts.freedesktop.org, dri-devel@...ts.freedesktop.org, 
	linux-kernel@...r.kernel.org
Subject: Re: [PATCH v3] drm/etnaviv: Request pages from DMA32 zone on addressing_limited

Am Di., 3. Sept. 2024 um 04:09 Uhr schrieb Xiaolei Wang
<xiaolei.wang@...driver.com>:
>
> Remove __GFP_HIGHMEM when requesting a page from DMA32 zone,
> and since all vivante GPUs in the system will share the same
> DMA constraints, move the check of whether to get a page from
> DMA32 to etnaviv_bind().
>
> Fixes: b72af445cd38 ("drm/etnaviv: request pages from DMA32 zone when needed")
> Suggested-by: Sui Jingfeng <sui.jingfeng@...ux.dev>
> Signed-off-by: Xiaolei Wang <xiaolei.wang@...driver.com>

Reviewed-by: Christian Gmeiner <cgmeiner@...lia.com>

> ---
>
> change log
>
> v1:
>   https://patchwork.kernel.org/project/dri-devel/patch/20240806104733.2018783-1-xiaolei.wang@windriver.com/
>
> v2:
>   Modify the issue of not retaining GFP_USER in v1 and update the commit log.
>
> v3:
>   Use "priv->shm_gfp_mask = GFP_USER | __GFP_RETRY_MAYFAIL | __GFP_NOWARN;"
> instead of
>   "priv->shm_gfp_mask = GFP_HIGHUSER | __GFP_RETRY_MAYFAIL | __GFP_NOWARN;"
> and move the check of whether to get a page from DMA32 to etnaviv_bind().
>
>  drivers/gpu/drm/etnaviv/etnaviv_drv.c | 10 +++++++++-
>  drivers/gpu/drm/etnaviv/etnaviv_gpu.c |  8 --------
>  2 files changed, 9 insertions(+), 9 deletions(-)
>
> diff --git a/drivers/gpu/drm/etnaviv/etnaviv_drv.c b/drivers/gpu/drm/etnaviv/etnaviv_drv.c
> index 6500f3999c5f..8cb2c3ec8e5d 100644
> --- a/drivers/gpu/drm/etnaviv/etnaviv_drv.c
> +++ b/drivers/gpu/drm/etnaviv/etnaviv_drv.c
> @@ -536,7 +536,15 @@ static int etnaviv_bind(struct device *dev)
>         mutex_init(&priv->gem_lock);
>         INIT_LIST_HEAD(&priv->gem_list);
>         priv->num_gpus = 0;
> -       priv->shm_gfp_mask = GFP_HIGHUSER | __GFP_RETRY_MAYFAIL | __GFP_NOWARN;
> +       priv->shm_gfp_mask = GFP_USER | __GFP_RETRY_MAYFAIL | __GFP_NOWARN;
> +
> +       /*
> +        * If the GPU is part of a system with DMA addressing limitations,
> +        * request pages for our SHM backend buffers from the DMA32 zone to
> +        * hopefully avoid performance killing SWIOTLB bounce buffering.
> +        */
> +       if (dma_addressing_limited(dev))
> +               priv->shm_gfp_mask |= GFP_DMA32;
>
>         priv->cmdbuf_suballoc = etnaviv_cmdbuf_suballoc_new(drm->dev);
>         if (IS_ERR(priv->cmdbuf_suballoc)) {
> diff --git a/drivers/gpu/drm/etnaviv/etnaviv_gpu.c b/drivers/gpu/drm/etnaviv/etnaviv_gpu.c
> index 7c7f97793ddd..5e753dd42f72 100644
> --- a/drivers/gpu/drm/etnaviv/etnaviv_gpu.c
> +++ b/drivers/gpu/drm/etnaviv/etnaviv_gpu.c
> @@ -839,14 +839,6 @@ int etnaviv_gpu_init(struct etnaviv_gpu *gpu)
>         if (ret)
>                 goto fail;
>
> -       /*
> -        * If the GPU is part of a system with DMA addressing limitations,
> -        * request pages for our SHM backend buffers from the DMA32 zone to
> -        * hopefully avoid performance killing SWIOTLB bounce buffering.
> -        */
> -       if (dma_addressing_limited(gpu->dev))
> -               priv->shm_gfp_mask |= GFP_DMA32;
> -
>         /* Create buffer: */
>         ret = etnaviv_cmdbuf_init(priv->cmdbuf_suballoc, &gpu->buffer,
>                                   PAGE_SIZE);
> --
> 2.25.1
>


-- 
greets
--
Christian Gmeiner, MSc

https://christian-gmeiner.info/privacypolicy