linux/include/trace/events/swiotlb.h
Zoltan Kiss 2b2b614dd2 tracing/events: Add bounce tracing to swiotbl
Ftrace is currently not able to detect when SWIOTLB has to do double buffering.
Under Xen you can only see it indirectly in function_graph, when
xen_swiotlb_map_page() doesn't stop after range_straddles_page_boundary(), but
calls spinlock functions, memcpy() and xen_phys_to_bus() as well. This patch
introduces the swiotlb:swiotlb_bounced event, which also prints out the
following informations to help you find out why bouncing happened:

dev_name: 0000:08:00.0 dma_mask=ffffffffffffffff dev_addr=9149f000 size=32768
swiotlb_force=0

If you use Xen, and (dev_addr + size + 1) > dma_mask, the buffer is out of the
device's DMA range. If swiotlb_force == 1, you should really change the kernel
parameters. Otherwise, the buffer is not contiguous in mfn space.

Signed-off-by: Zoltan Kiss <zoltan.kiss@citrix.com>
[v1: Don't print 'swiotlb_force=X', just print swiotlb_force if it is enabled]
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
2013-10-02 12:53:26 -04:00

47 lines
1.1 KiB
C

#undef TRACE_SYSTEM
#define TRACE_SYSTEM swiotlb
#if !defined(_TRACE_SWIOTLB_H) || defined(TRACE_HEADER_MULTI_READ)
#define _TRACE_SWIOTLB_H
#include <linux/tracepoint.h>
TRACE_EVENT(swiotlb_bounced,
TP_PROTO(struct device *dev,
dma_addr_t dev_addr,
size_t size,
int swiotlb_force),
TP_ARGS(dev, dev_addr, size, swiotlb_force),
TP_STRUCT__entry(
__string( dev_name, dev_name(dev) )
__field( u64, dma_mask )
__field( dma_addr_t, dev_addr )
__field( size_t, size )
__field( int, swiotlb_force )
),
TP_fast_assign(
__assign_str(dev_name, dev_name(dev));
__entry->dma_mask = (dev->dma_mask ? *dev->dma_mask : 0);
__entry->dev_addr = dev_addr;
__entry->size = size;
__entry->swiotlb_force = swiotlb_force;
),
TP_printk("dev_name: %s dma_mask=%llx dev_addr=%llx "
"size=%zu %s",
__get_str(dev_name),
__entry->dma_mask,
(unsigned long long)__entry->dev_addr,
__entry->size,
__entry->swiotlb_force ? "swiotlb_force" : "" )
);
#endif /* _TRACE_SWIOTLB_H */
/* This part must be outside protection */
#include <trace/define_trace.h>