From: "Verma, Vishal L" <vishal.l.verma@intel.com>
To: "Jiang, Dave" <dave.jiang@intel.com>,
"linux-cxl@vger.kernel.org" <linux-cxl@vger.kernel.org>,
"nvdimm@lists.linux.dev" <nvdimm@lists.linux.dev>
Cc: "Schofield, Alison" <alison.schofield@intel.com>
Subject: Re: [NDCTL PATCH v6 3/4] ndctl: cxl: add QoS class check for CXL region creation
Date: Wed, 7 Feb 2024 21:02:51 +0000 [thread overview]
Message-ID: <51b7c1c3f354b2fe0f0ac7fca9a35de07c5b7f23.camel@intel.com> (raw)
In-Reply-To: <20240207172055.1882900-4-dave.jiang@intel.com>
On Wed, 2024-02-07 at 10:19 -0700, Dave Jiang wrote:
> The CFMWS provides a QTG ID. The kernel driver creates a root decoder that
> represents the CFMWS. A qos_class attribute is exported via sysfs for the root
> decoder.
>
> One or more QoS class tokens are retrieved via QTG ID _DSM from the ACPI0017
> device for a CXL memory device. The input for the _DSM is the read and write
> latency and bandwidth for the path between the device and the CPU. The
> numbers are constructed by the kernel driver for the _DSM input. When a
> device is probed, QoS class tokens are retrieved. This is useful for a
> hot-plugged CXL memory device that does not have regions created.
>
> Add a QoS check during region creation. Emit a warning if the qos_class
> token from the root decoder is different than the mem device qos_class
> token. User parameter options are provided to fail instead of just
> warning.
>
> Reviewed-by: Alison Schofield <alison.schofield@intel.com>
> Signed-off-by: Dave Jiang <dave.jiang@intel.com>
> ---
> v6:
> - Check return value of create_region_validate_qos_class() (Wonjae)
> ---
> Documentation/cxl/cxl-create-region.txt | 9 ++++
> cxl/region.c | 58 ++++++++++++++++++++++++-
> 2 files changed, 66 insertions(+), 1 deletion(-)
>
> diff --git a/Documentation/cxl/cxl-create-region.txt b/Documentation/cxl/cxl-create-region.txt
> index f11a412bddfe..d5e34cf38236 100644
> --- a/Documentation/cxl/cxl-create-region.txt
> +++ b/Documentation/cxl/cxl-create-region.txt
> @@ -105,6 +105,15 @@ include::bus-option.txt[]
> supplied, the first cross-host bridge (if available), decoder that
> supports the largest interleave will be chosen.
>
> +-e::
> +--strict::
> + Enforce strict execution where any potential error will force failure.
> + For example, if qos_class mismatches region creation will fail.
> +
> +-q::
> +--no-enforce-qos::
> + Parameter to bypass qos_class mismatch failure. Will only emit warning.
Hm, -q is usually synonymous with --quiet, it might be nice to reserve
it for that in case we ever need to add a quiet mode. Maybe use -Q?
next prev parent reply other threads:[~2024-02-07 21:03 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-02-07 17:19 [NDCTL PATCH v6 0/4] ndctl: Add support of qos_class for CXL CLI Dave Jiang
2024-02-07 17:19 ` [NDCTL PATCH v6 1/4] ndctl: cxl: Add QoS class retrieval for the root decoder Dave Jiang
2024-02-07 20:05 ` Alison Schofield
2024-02-07 20:13 ` Alison Schofield
2024-02-07 20:16 ` Dave Jiang
2024-02-07 20:24 ` Verma, Vishal L
2024-02-07 17:19 ` [NDCTL PATCH v6 2/4] ndctl: cxl: Add QoS class support for the memory device Dave Jiang
2024-02-07 17:19 ` [NDCTL PATCH v6 3/4] ndctl: cxl: add QoS class check for CXL region creation Dave Jiang
2024-02-07 21:02 ` Verma, Vishal L [this message]
2024-02-07 23:32 ` Dave Jiang
2024-02-07 17:19 ` [NDCTL PATCH v6 4/4] ndctl: add test for qos_class in CXL test suite Dave Jiang
2024-02-07 21:05 ` Verma, Vishal L
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