From 83ca259489409a1fe8a83dad83a82f32174d4f31 Mon Sep 17 00:00:00 2001 From: Dongli Zhang Date: Fri, 5 Apr 2019 09:15:25 +0800 Subject: 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 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 Signed-off-by: Konrad Rzeszutek Wilk --- kernel/dma/swiotlb.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) (limited to 'kernel') diff --git a/kernel/dma/swiotlb.c b/kernel/dma/swiotlb.c index 2b0c8fd9658e..82c767374c70 100644 --- a/kernel/dma/swiotlb.c +++ b/kernel/dma/swiotlb.c @@ -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; -- cgit v1.2.3-59-g8ed1b From 53b29c336830db48ad3dc737f88b8c065b1f0851 Mon Sep 17 00:00:00 2001 From: Dongli Zhang Date: Fri, 12 Apr 2019 19:38:26 +0800 Subject: swiotlb: save io_tlb_used to local variable before leaving critical section MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit When swiotlb is full, the kernel would print io_tlb_used. However, the result might be inaccurate at that time because we have left the critical section protected by spinlock. Therefore, we backup the io_tlb_used into local variable before leaving critical section. Fixes: 83ca25948940 ("swiotlb: dump used and total slots when swiotlb buffer is full") Suggested-by: Håkon Bugge Signed-off-by: Dongli Zhang Signed-off-by: Konrad Rzeszutek Wilk --- kernel/dma/swiotlb.c | 7 +++++-- 1 file changed, 5 insertions(+), 2 deletions(-) (limited to 'kernel') diff --git a/kernel/dma/swiotlb.c b/kernel/dma/swiotlb.c index 82c767374c70..38d57218809c 100644 --- a/kernel/dma/swiotlb.c +++ b/kernel/dma/swiotlb.c @@ -445,6 +445,7 @@ phys_addr_t swiotlb_tbl_map_single(struct device *hwdev, unsigned long mask; unsigned long offset_slots; unsigned long max_slots; + unsigned long tmp_io_tlb_used; if (no_iotlb_memory) panic("Can not allocate SWIOTLB buffer earlier and can't now provide you with the DMA bounce buffer"); @@ -531,10 +532,12 @@ phys_addr_t swiotlb_tbl_map_single(struct device *hwdev, } while (index != wrap); not_found: + tmp_io_tlb_used = io_tlb_used; + 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), total %lu, used %lu\n", - size, io_tlb_nslabs, io_tlb_used); + dev_warn(hwdev, "swiotlb buffer is full (sz: %zd bytes), total %lu (slots), used %lu (slots)\n", + size, io_tlb_nslabs, tmp_io_tlb_used); return DMA_MAPPING_ERROR; found: io_tlb_used += nslots; -- cgit v1.2.3-59-g8ed1b