linux-kernel - Re: [PATCH] dma-buf: system_heap: Avoid warning on mid-order allocations

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Date:   Tue, 14 Sep 2021 15:56:37 +0200
From:   Daniel Vetter <daniel@...ll.ch>
To:     John Stultz <john.stultz@...aro.org>
Cc:     lkml <linux-kernel@...r.kernel.org>,
        Daniel Vetter <daniel@...ll.ch>,
        Christian Koenig <christian.koenig@....com>,
        Sumit Semwal <sumit.semwal@...aro.org>,
        Liam Mark <lmark@...eaurora.org>,
        Chris Goldsworthy <cgoldswo@...eaurora.org>,
        Laura Abbott <labbott@...nel.org>,
        Brian Starkey <Brian.Starkey@....com>,
        Hridya Valsaraju <hridya@...gle.com>,
        Suren Baghdasaryan <surenb@...gle.com>,
        Sandeep Patil <sspatil@...gle.com>,
        Daniel Mentz <danielmentz@...gle.com>,
        Ørjan Eide <orjan.eide@....com>,
        Robin Murphy <robin.murphy@....com>,
        Simon Ser <contact@...rsion.fr>,
        James Jones <jajones@...dia.com>, Leo Yan <leo.yan@...aro.org>,
        linux-media@...r.kernel.org, dri-devel@...ts.freedesktop.org
Subject: Re: [PATCH] dma-buf: system_heap: Avoid warning on mid-order
 allocations

On Thu, Sep 09, 2021 at 02:37:41AM +0000, John Stultz wrote:
> When trying to do mid-order allocations, set __GFP_NOWARN to
> avoid warning messages if the allocation fails, as we will
> still fall back to single page allocatitions in that case.
> This is the similar to what we already do for large order
> allocations.
> 
> Cc: Daniel Vetter <daniel@...ll.ch>
> Cc: Christian Koenig <christian.koenig@....com>
> Cc: Sumit Semwal <sumit.semwal@...aro.org>
> Cc: Liam Mark <lmark@...eaurora.org>
> Cc: Chris Goldsworthy <cgoldswo@...eaurora.org>
> Cc: Laura Abbott <labbott@...nel.org>
> Cc: Brian Starkey <Brian.Starkey@....com>
> Cc: Hridya Valsaraju <hridya@...gle.com>
> Cc: Suren Baghdasaryan <surenb@...gle.com>
> Cc: Sandeep Patil <sspatil@...gle.com>
> Cc: Daniel Mentz <danielmentz@...gle.com>
> Cc: Ørjan Eide <orjan.eide@....com>
> Cc: Robin Murphy <robin.murphy@....com>
> Cc: Simon Ser <contact@...rsion.fr>
> Cc: James Jones <jajones@...dia.com>
> Cc: Leo Yan <leo.yan@...aro.org>
> Cc: linux-media@...r.kernel.org
> Cc: dri-devel@...ts.freedesktop.org
> Signed-off-by: John Stultz <john.stultz@...aro.org>

Acked-by: Daniel Vetter <daniel.vetter@...ll.ch>

> ---
>  drivers/dma-buf/heaps/system_heap.c | 5 +++--
>  1 file changed, 3 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/dma-buf/heaps/system_heap.c b/drivers/dma-buf/heaps/system_heap.c
> index 23a7e74ef966..f57a39ddd063 100644
> --- a/drivers/dma-buf/heaps/system_heap.c
> +++ b/drivers/dma-buf/heaps/system_heap.c
> @@ -40,11 +40,12 @@ struct dma_heap_attachment {
>  	bool mapped;
>  };
>  
> +#define LOW_ORDER_GFP (GFP_HIGHUSER | __GFP_ZERO | __GFP_COMP)
> +#define MID_ORDER_GFP (LOW_ORDER_GFP | __GFP_NOWARN)
>  #define HIGH_ORDER_GFP  (((GFP_HIGHUSER | __GFP_ZERO | __GFP_NOWARN \
>  				| __GFP_NORETRY) & ~__GFP_RECLAIM) \
>  				| __GFP_COMP)
> -#define LOW_ORDER_GFP (GFP_HIGHUSER | __GFP_ZERO | __GFP_COMP)
> -static gfp_t order_flags[] = {HIGH_ORDER_GFP, LOW_ORDER_GFP, LOW_ORDER_GFP};
> +static gfp_t order_flags[] = {HIGH_ORDER_GFP, MID_ORDER_GFP, LOW_ORDER_GFP};
>  /*
>   * The selection of the orders used for allocation (1MB, 64K, 4K) is designed
>   * to match with the sizes often found in IOMMUs. Using order 4 pages instead
> -- 
> 2.25.1
> 

-- 
Daniel Vetter
Software Engineer, Intel Corporation
http://blog.ffwll.ch