On Fri, Apr 05, 2019 at 09:15:25AM +0800, Dongli Zhang wrote:
> So far the kernel only prints the requested size if swiotlb buffer if full.
> It is not possible to know whether it is simply an out of buffer, or it is
> because swiotlb cannot allocate buffer with the requested size due to
> fragmentation.
>
> As 'io_tlb_used' is available since commit 71602fe6d4e9 ("swiotlb: add
> debugfs to track swiotlb buffer usage"), both 'io_tlb_used' and
> 'io_tlb_nslabs' are printed when swiotlb buffer is full.
>
> Signed-off-by: Dongli Zhang <dongli.zh...@oracle.com>
Applied. Will send git pull shortly.
> ---
> kernel/dma/swiotlb.c | 3 ++-
> 1 file changed, 2 insertions(+), 1 deletion(-)
>
> diff --git a/kernel/dma/swiotlb.c b/kernel/dma/swiotlb.c
> index 53012db..3f43b37 100644
> --- a/kernel/dma/swiotlb.c
> +++ b/kernel/dma/swiotlb.c
> @@ -540,7 +540,8 @@ phys_addr_t swiotlb_tbl_map_single(struct device *hwdev,
> not_found:
> spin_unlock_irqrestore(&io_tlb_lock, flags);
> if (!(attrs & DMA_ATTR_NO_WARN) && printk_ratelimit())
> - dev_warn(hwdev, "swiotlb buffer is full (sz: %zd bytes)\n",
> size);
> + dev_warn(hwdev, "swiotlb buffer is full (sz: %zd bytes), total
> %lu, used %lu\n",
> + size, io_tlb_nslabs, io_tlb_used);
> return DMA_MAPPING_ERROR;
> found:
> io_tlb_used += nslots;
> --
> 2.7.4
>
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