linux-kernel - Re: [RFC V2 PATCH 05/11] cxl/mem: Trace General Media Event Record

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Message-ID: <20221011135702.00006f74@huawei.com>
Date:   Tue, 11 Oct 2022 13:57:02 +0100
From:   Jonathan Cameron <Jonathan.Cameron@...wei.com>
To:     <ira.weiny@...el.com>
CC:     Dan Williams <dan.j.williams@...el.com>,
        Alison Schofield <alison.schofield@...el.com>,
        Vishal Verma <vishal.l.verma@...el.com>,
        "Ben Widawsky" <bwidawsk@...nel.org>,
        Steven Rostedt <rostedt@...dmis.org>,
        Davidlohr Bueso <dave@...olabs.net>,
        <linux-kernel@...r.kernel.org>, <linux-cxl@...r.kernel.org>
Subject: Re: [RFC V2 PATCH 05/11] cxl/mem: Trace General Media Event Record

On Mon, 10 Oct 2022 15:41:25 -0700
ira.weiny@...el.com wrote:

> From: Ira Weiny <ira.weiny@...el.com>
> 
> CXL rev 3.0 section 8.2.9.2.1.1 defines the General Media Event Record.
> 
> Determine if the event read is a general media record and if so trace
> the record.
> 
> Signed-off-by: Ira Weiny <ira.weiny@...el.com>

I'll review the rest of these with the assumption that the question
of reserved bytes in tracepoints will get resolved before these go in.

One minor comment on a comment inline.  Other than those lgtm

Reviewed-by: Jonathan Cameron <Jonathan.Cameron@...wei.com>

> 
> ---
> Changes from RFC:
> 	Add reserved byte array
> 	Use common CXL event header record macros
> 	Jonathan
> 		Use unaligned_le{24,16} for unaligned fields
> 		Don't use the inverse of phy addr mask
> 	Dave Jiang
> 		s/cxl_gen_media_event/general_media
> 		s/cxl_evt_gen_media/cxl_event_gen_media
> ---
>  drivers/cxl/core/mbox.c    |  30 ++++++++++-
>  drivers/cxl/cxlmem.h       |  20 +++++++
>  include/trace/events/cxl.h | 108 +++++++++++++++++++++++++++++++++++++
>  3 files changed, 156 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/cxl/core/mbox.c b/drivers/cxl/core/mbox.c
> index bc4e42b3e01b..1097250c115a 100644
> --- a/drivers/cxl/core/mbox.c
> +++ b/drivers/cxl/core/mbox.c
> @@ -712,6 +712,32 @@ int cxl_enumerate_cmds(struct cxl_dev_state *cxlds)
>  }
>  EXPORT_SYMBOL_NS_GPL(cxl_enumerate_cmds, CXL);
>  
> +/*
> + * General Media Event Record
> + * CXL rev 3.0 Section 8.2.9.2.1.1; Table 8-43
> + */
> +static const uuid_t gen_media_event_uuid =
> +	UUID_INIT(0xfbcd0a77, 0xc260, 0x417f,
> +		  0x85, 0xa9, 0x08, 0x8b, 0x16, 0x21, 0xeb, 0xa6);
> +
> +static void cxl_trace_event_record(const char *dev_name,
> +				   enum cxl_event_log_type type,
> +				   struct cxl_get_event_payload *payload)
> +{
> +	uuid_t *id = &payload->record.hdr.id;
> +
> +	if (uuid_equal(id, &gen_media_event_uuid)) {
> +		struct cxl_event_gen_media *rec =
> +				(struct cxl_event_gen_media *)&payload->record;
> +
> +		trace_general_media(dev_name, type, rec);
> +		return;
> +	}
> +
> +	/* For unknown record types print just the header */
> +	trace_generic_event(dev_name, type, &payload->record);

Looks like it prints the whole thing now...


> +}
> +


> diff --git a/include/trace/events/cxl.h b/include/trace/events/cxl.h
> index 318ba5fe046e..82a8d3b750a2 100644
> --- a/include/trace/events/cxl.h
> +++ b/include/trace/events/cxl.h
> @@ -122,6 +122,114 @@ TRACE_EVENT(generic_event,


> +#define CXL_GMER_VALID_CHANNEL				BIT(0)
> +#define CXL_GMER_VALID_RANK				BIT(1)
> +#define CXL_GMER_VALID_DEVICE				BIT(2)
> +#define CXL_GMER_VALID_COMPONENT			BIT(3)
> +#define show_valid_flags(flags)	__print_flags(flags, "|",		   \
> +	{ CXL_GMER_VALID_CHANNEL,			"CHANNEL"	}, \
> +	{ CXL_GMER_VALID_RANK,				"RANK"		}, \
> +	{ CXL_GMER_VALID_DEVICE,			"DEVICE"	}, \
> +	{ CXL_GMER_VALID_COMPONENT,			"COMPONENT"	}  \
> +)

I'd still rather we only had the TP_printk only print those parts that are valid
rather than the mess of having to go check the validity bit before deciding whether
to take notice of the field.  But meh, not that important given thats
not the main intended way to consume this data.


> +
> +TRACE_EVENT(general_media,
> +
> +	TP_PROTO(const char *dev_name, enum cxl_event_log_type log,
> +		 struct cxl_event_gen_media *rec),
> +
> +	TP_ARGS(dev_name, log, rec),
> +
> +	TP_STRUCT__entry(
> +		CXL_EVT_TP_entry
> +		/* General Media */
> +		__field(u64, phys_addr)
> +		__field(u8, descriptor)
> +		__field(u8, type)
> +		__field(u8, transaction_type)
> +		__field(u8, channel)
> +		__field(u32, device)
> +		__array(u8, comp_id, CXL_EVENT_GEN_MED_COMP_ID_SIZE)
> +		__array(u8, reserved, CXL_EVENT_GEN_MED_RES_SIZE)
> +		__field(u16, validity_flags)
> +		__field(u8, rank) /* Out of order to pack trace record */
> +	),
> +
> +	TP_fast_assign(
> +		CXL_EVT_TP_fast_assign(dev_name, log, rec->hdr);
> +
> +		/* General Media */
> +		__entry->phys_addr = le64_to_cpu(rec->phys_addr);
> +		__entry->descriptor = rec->descriptor;
> +		__entry->type = rec->type;
> +		__entry->transaction_type = rec->transaction_type;
> +		__entry->channel = rec->channel;
> +		__entry->rank = rec->rank;
> +		__entry->device = get_unaligned_le24(rec->device);
> +		memcpy(__entry->comp_id, &rec->component_id,
> +			CXL_EVENT_GEN_MED_COMP_ID_SIZE);
> +		memcpy(__entry->reserved, &rec->reserved,
> +			CXL_EVENT_GEN_MED_RES_SIZE);
> +		__entry->validity_flags = get_unaligned_le16(&rec->validity_flags);
> +	),