linux-kernel - RE: [PATCH V2 04/11] cxl/mem: Clear events on driver load

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Message-ID: <6389676c60d39_3cbe029487@dwillia2-xfh.jf.intel.com.notmuch>
Date:   Thu, 1 Dec 2022 18:48:12 -0800
From:   Dan Williams <dan.j.williams@...el.com>
To:     <ira.weiny@...el.com>, Dan Williams <dan.j.williams@...el.com>
CC:     Ira Weiny <ira.weiny@...el.com>,
        Jonathan Cameron <Jonathan.Cameron@...wei.com>,
        Dave Jiang <dave.jiang@...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: [PATCH V2 04/11] cxl/mem: Clear events on driver load

cxl/mem is cxl_mem.ko, This is cxl/pci.

ira.weiny@ wrote:
> From: Ira Weiny <ira.weiny@...el.com>
> 
> The information contained in the events prior to the driver loading can
> be queried at any time through other mailbox commands.
> 
> Ensure a clean slate of events by reading and clearing the events.  The
> events are sent to the trace buffer but it is not anticipated to have
> anyone listening to it at driver load time.

This is easy to guarantee with modprobe policy, so I am not sure it is
worth stating.

This breakdown feels odd. I would split the trace event definitions into
its own lead in patch since that is a pile of definitions that can be
merged on their own. Then squash get, clear, and this patch into one
patch as they don't have much reason to go in separately.

> Reviewed-by: Jonathan Cameron <Jonathan.Cameron@...wei.com>
> Reviewed-by: Dave Jiang <dave.jiang@...el.com>
> Signed-off-by: Ira Weiny <ira.weiny@...el.com>
> ---
>  drivers/cxl/pci.c            | 2 ++
>  tools/testing/cxl/test/mem.c | 2 ++
>  2 files changed, 4 insertions(+)
> 
> diff --git a/drivers/cxl/pci.c b/drivers/cxl/pci.c
> index 8f86f85d89c7..11e95a95195a 100644
> --- a/drivers/cxl/pci.c
> +++ b/drivers/cxl/pci.c
> @@ -521,6 +521,8 @@ static int cxl_pci_probe(struct pci_dev *pdev, const struct pci_device_id *id)
>  	if (IS_ERR(cxlmd))
>  		return PTR_ERR(cxlmd);
>  
> +	cxl_mem_get_event_records(cxlds);
> +
>  	if (resource_size(&cxlds->pmem_res) && IS_ENABLED(CONFIG_CXL_PMEM))
>  		rc = devm_cxl_add_nvdimm(&pdev->dev, cxlmd);
>  
> diff --git a/tools/testing/cxl/test/mem.c b/tools/testing/cxl/test/mem.c
> index aa2df3a15051..e2f5445d24ff 100644
> --- a/tools/testing/cxl/test/mem.c
> +++ b/tools/testing/cxl/test/mem.c
> @@ -285,6 +285,8 @@ static int cxl_mock_mem_probe(struct platform_device *pdev)
>  	if (IS_ERR(cxlmd))
>  		return PTR_ERR(cxlmd);
>  
> +	cxl_mem_get_event_records(cxlds);
> +

This hunk likely goes with the first patch that actually implements some
mocked events.

>  	if (resource_size(&cxlds->pmem_res) && IS_ENABLED(CONFIG_CXL_PMEM))
>  		rc = devm_cxl_add_nvdimm(dev, cxlmd);
>  
> -- 
> 2.37.2
>