Commit 83ca2594 authored Apr 05, 2019 by Dongli Zhang Committed by Konrad Rzeszutek Wilk Apr 10, 2019

swiotlb: dump used and total slots when swiotlb buffer is full



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 71602fe6 ("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.zhang@oracle.com>
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>

parent 22cb45d7

kernel/dma/swiotlb.c

+2 −1

Original line number	Diff line number	Diff line
		@@ -533,7 +533,8 @@ 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;

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