From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mx0b-001b2d01.pphosted.com ([148.163.158.5]:59036 "EHLO mx0a-001b2d01.pphosted.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1726523AbfJOPYL (ORCPT ); Tue, 15 Oct 2019 11:24:11 -0400 Subject: Re: [RFC PATCH 3/4] vfio-ccw: Add a trace for asynchronous requests References: <20191014180855.19400-1-farman@linux.ibm.com> <20191014180855.19400-4-farman@linux.ibm.com> <2fd50890-2d94-37ae-8266-1b41b9bf9a74@linux.ibm.com> From: Eric Farman Message-ID: <7c52ae8f-c38d-206e-03fb-11e89a8f1dd7@linux.ibm.com> Date: Tue, 15 Oct 2019 11:24:05 -0400 MIME-Version: 1.0 In-Reply-To: <2fd50890-2d94-37ae-8266-1b41b9bf9a74@linux.ibm.com> Content-Type: text/plain; charset="utf-8" Content-Language: en-US Content-Transfer-Encoding: 8bit Sender: linux-s390-owner@vger.kernel.org List-ID: To: Steffen Maier , Cornelia Huck , Halil Pasic Cc: Jason Herne , Jared Rossi , linux-s390@vger.kernel.org, kvm@vger.kernel.org On 10/15/19 5:54 AM, Steffen Maier wrote: > On 10/14/19 8:08 PM, Eric Farman wrote: >> Since the asynchronous requests are typically associated with >> error recovery, let's add a simple trace when one of those is >> issued to a device. >> >> Signed-off-by: Eric Farman >> --- >>   drivers/s390/cio/vfio_ccw_fsm.c   |  4 ++++ >>   drivers/s390/cio/vfio_ccw_trace.c |  1 + >>   drivers/s390/cio/vfio_ccw_trace.h | 26 ++++++++++++++++++++++++++ >>   3 files changed, 31 insertions(+) >> >> diff --git a/drivers/s390/cio/vfio_ccw_fsm.c >> b/drivers/s390/cio/vfio_ccw_fsm.c >> index d4119e4c4a8c..23648a9aa721 100644 >> --- a/drivers/s390/cio/vfio_ccw_fsm.c >> +++ b/drivers/s390/cio/vfio_ccw_fsm.c >> @@ -341,6 +341,10 @@ static void fsm_async_request(struct >> vfio_ccw_private *private, >>           /* should not happen? */ >>           cmd_region->ret_code = -EINVAL; >>       } >> + >> +    trace_vfio_ccw_fsm_async_request(get_schid(private), >> +                     cmd_region->command, >> +                     cmd_region->ret_code); >>   } >> >>   /* >> diff --git a/drivers/s390/cio/vfio_ccw_trace.c >> b/drivers/s390/cio/vfio_ccw_trace.c >> index b37bc68e7f18..37ecbf8be805 100644 >> --- a/drivers/s390/cio/vfio_ccw_trace.c >> +++ b/drivers/s390/cio/vfio_ccw_trace.c >> @@ -9,5 +9,6 @@ >>   #define CREATE_TRACE_POINTS >>   #include "vfio_ccw_trace.h" >> >> +EXPORT_TRACEPOINT_SYMBOL(vfio_ccw_fsm_async_request); >>   EXPORT_TRACEPOINT_SYMBOL(vfio_ccw_fsm_event); >>   EXPORT_TRACEPOINT_SYMBOL(vfio_ccw_io_fctl); >> diff --git a/drivers/s390/cio/vfio_ccw_trace.h >> b/drivers/s390/cio/vfio_ccw_trace.h >> index 24a8152acfdf..4be2e36242e6 100644 >> --- a/drivers/s390/cio/vfio_ccw_trace.h >> +++ b/drivers/s390/cio/vfio_ccw_trace.h >> @@ -17,6 +17,32 @@ >> >>   #include >> >> +TRACE_EVENT(vfio_ccw_fsm_async_request, >> +    TP_PROTO(struct subchannel_id schid, >> +         int command, >> +         int errno), >> +    TP_ARGS(schid, command, errno), >> + >> +    TP_STRUCT__entry( >> +        __field_struct(struct subchannel_id, schid) > > Not sure: Does this allow the user to filter for fields of struct > subchannel_id or can the user express a filter on the entire combined > struct subchannel_id? Good question... I tried playing around with this a little bit, and while format says it's using "REC->schid.foo", trying any combination to get an element within schid just fails, citing some form of invalid argument (the exact reason depends on what I try). Harrumph. > In the preceding patch you have the 3 parts of schid as explicit > separate trace fields in the tracepoint. Yeah, I did. Why didn't I do that here? :) Well it seems that the one trace that exists (vfio_ccw_fsm_io_request (nee vfio_ccw_fsm_io_fctl)), uses this same field_struct, instead of the three-piece schid. So, I need to change this in both the I/O and asynchronous traces. Thanks for the suggestions! - Eric > >> +        __field(int, command) >> +        __field(int, errno) >> +    ), >> + >> +    TP_fast_assign( >> +        __entry->schid = schid; >> +        __entry->command = command; >> +        __entry->errno = errno; >> +    ), >> + >> +    TP_printk("schid=%x.%x.%04x command=%d errno=%d", >> +          __entry->schid.cssid, >> +          __entry->schid.ssid, >> +          __entry->schid.sch_no, >> +          __entry->command, >> +          __entry->errno) >> +); >> + >>   TRACE_EVENT(vfio_ccw_fsm_event, >>       TP_PROTO(struct subchannel_id schid, int state, int event), >>       TP_ARGS(schid, state, event), >> > >