From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754389Ab3HVVro (ORCPT ); Thu, 22 Aug 2013 17:47:44 -0400 Received: from smtp02.citrix.com ([66.165.176.63]:36662 "EHLO SMTP02.CITRIX.COM" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754161Ab3HVVrn (ORCPT ); Thu, 22 Aug 2013 17:47:43 -0400 X-IronPort-AV: E=Sophos;i="4.89,936,1367971200"; d="scan'208";a="44537798" From: Zoltan Kiss To: Konrad Rzeszutek Wilk , Jeremy Fitzhardinge , Steven Rostedt , Frederic Weisbecker , Ingo Molnar , , , CC: Zoltan Kiss Subject: [PATCH] tracing/events: Add bounce tracing to swiotbl-xen Date: Thu, 22 Aug 2013 22:47:28 +0100 Message-ID: <1377208048-8963-1-git-send-email-zoltan.kiss@citrix.com> X-Mailer: git-send-email 1.7.9.5 MIME-Version: 1.0 Content-Type: text/plain X-Originating-IP: [10.80.2.133] X-DLP: MIA1 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 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-xen: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 (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 --- drivers/xen/swiotlb-xen.c | 7 ++++++ include/trace/events/swiotlb-xen.h | 46 ++++++++++++++++++++++++++++++++++++ 2 files changed, 53 insertions(+) create mode 100644 include/trace/events/swiotlb-xen.h diff --git a/drivers/xen/swiotlb-xen.c b/drivers/xen/swiotlb-xen.c index aadffcf..f08440d 100644 --- a/drivers/xen/swiotlb-xen.c +++ b/drivers/xen/swiotlb-xen.c @@ -42,6 +42,10 @@ #include #include #include + +#define CREATE_TRACE_POINTS +#include + /* * Used to do a quick range check in swiotlb_tbl_unmap_single and * swiotlb_tbl_sync_single_*, to see if the memory was in fact allocated by this @@ -358,6 +362,9 @@ dma_addr_t xen_swiotlb_map_page(struct device *dev, struct page *page, /* * Oh well, have to allocate and map a bounce buffer. */ + + trace_bounced(dev, dev_addr, size, swiotlb_force); + map = swiotlb_tbl_map_single(dev, start_dma_addr, phys, size, dir); if (map == SWIOTLB_MAP_ERROR) return DMA_ERROR_CODE; diff --git a/include/trace/events/swiotlb-xen.h b/include/trace/events/swiotlb-xen.h new file mode 100644 index 0000000..cbe2dca --- /dev/null +++ b/include/trace/events/swiotlb-xen.h @@ -0,0 +1,46 @@ +#undef TRACE_SYSTEM +#define TRACE_SYSTEM swiotlb-xen + +#if !defined(_TRACE_SWIOTLBXEN_H) || defined(TRACE_HEADER_MULTI_READ) +#define _TRACE_SWIOTLBXEN_H + +#include + +TRACE_EVENT(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 swiotlb_force=%x", + __get_str(dev_name), + __entry->dma_mask, + (unsigned long long)__entry->dev_addr, + __entry->size, + __entry->swiotlb_force ) +); + +#endif /* _TRACE_IRQ_H */ + +/* This part must be outside protection */ +#include -- 1.7.9.5