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Violators will be prosecuted; (version=TLSv1/SSLv3 cipher=AES256-GCM-SHA384 bits=256/256) Thu, 12 Mar 2020 00:15:26 -0000 Received: from d06av21.portsmouth.uk.ibm.com (d06av21.portsmouth.uk.ibm.com [9.149.105.232]) by b06cxnps4075.portsmouth.uk.ibm.com (8.14.9/8.14.9/NCO v10.0) with ESMTP id 02C0FQlS42860610 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Thu, 12 Mar 2020 00:15:26 GMT Received: from d06av21.portsmouth.uk.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id F109552057; Thu, 12 Mar 2020 00:15:25 +0000 (GMT) Received: from ozlabs.au.ibm.com (unknown [9.192.253.14]) by d06av21.portsmouth.uk.ibm.com (Postfix) with ESMTP id 5372C5204F; Thu, 12 Mar 2020 00:15:25 +0000 (GMT) Received: from adsilva.ozlabs.ibm.com (haven.au.ibm.com [9.192.254.114]) (using TLSv1.2 with cipher AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ozlabs.au.ibm.com (Postfix) with ESMTPSA id 370EBA024B; Thu, 12 Mar 2020 11:15:20 +1100 (AEDT) Subject: Re: [PATCH v3 19/27] powerpc/powernv/pmem: Add an IOCTL to report controller statistics From: "Alastair D'Silva" To: Frederic Barrat Cc: "Aneesh Kumar K . V" , "Oliver O'Halloran" , Benjamin Herrenschmidt , Paul Mackerras , Michael Ellerman , Andrew Donnellan , Arnd Bergmann , Greg Kroah-Hartman , Dan Williams , Vishal Verma , Dave Jiang , Ira Weiny , Andrew Morton , Mauro Carvalho Chehab , "David S. Miller" , Rob Herring , Anton Blanchard , Krzysztof Kozlowski , Mahesh Salgaonkar , Madhavan Srinivasan , =?ISO-8859-1?Q?C=E9dric?= Le Goater , Anju T Sudhakar , Hari Bathini , Thomas Gleixner , Greg Kurz , Nicholas Piggin , Masahiro Yamada , Alexey Kardashevskiy , linux-kernel@vger.kernel.org, linuxppc-dev@lists.ozlabs.org, linux-nvdimm@lists.01.org, linux-mm@kvack.org Date: Thu, 12 Mar 2020 11:15:24 +1100 In-Reply-To: <6ee036c7-f4ea-4e42-faad-66a1921553ce@linux.ibm.com> References: <20200221032720.33893-1-alastair@au1.ibm.com> <20200221032720.33893-20-alastair@au1.ibm.com> <6ee036c7-f4ea-4e42-faad-66a1921553ce@linux.ibm.com> Organization: IBM Australia Content-Type: text/plain; charset="UTF-8" User-Agent: Evolution 3.34.4 (3.34.4-1.fc31) MIME-Version: 1.0 X-TM-AS-GCONF: 00 x-cbid: 20031200-0012-0000-0000-0000038F9C2F X-IBM-AV-DETECTION: SAVI=unused REMOTE=unused XFE=unused x-cbparentid: 20031200-0013-0000-0000-000021CC6C53 Message-Id: X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10434:6.0.138,18.0.572 definitions=2020-03-11_15:2020-03-11,2020-03-11 signatures=0 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 suspectscore=0 adultscore=0 lowpriorityscore=0 mlxlogscore=999 phishscore=0 clxscore=1015 mlxscore=0 bulkscore=0 spamscore=0 malwarescore=0 impostorscore=0 priorityscore=1501 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2001150001 definitions=main-2003110137 Content-Transfer-Encoding: quoted-printable X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: On Wed, 2020-03-04 at 10:25 +0100, Frederic Barrat wrote: >=20 > Le 21/02/2020 =C3=A0 04:27, Alastair D'Silva a =C3=A9crit : > > From: Alastair D'Silva > >=20 > > The controller can report a number of statistics that are useful > > in evaluating the performance and reliability of the card. > >=20 > > This patch exposes this information via an IOCTL. > >=20 > > Signed-off-by: Alastair D'Silva > > --- > > arch/powerpc/platforms/powernv/pmem/ocxl.c | 185 > > +++++++++++++++++++++ > > include/uapi/nvdimm/ocxl-pmem.h | 17 ++ > > 2 files changed, 202 insertions(+) > >=20 > > diff --git a/arch/powerpc/platforms/powernv/pmem/ocxl.c > > b/arch/powerpc/platforms/powernv/pmem/ocxl.c > > index 2cabafe1fc58..009d4fd29e7d 100644 > > --- a/arch/powerpc/platforms/powernv/pmem/ocxl.c > > +++ b/arch/powerpc/platforms/powernv/pmem/ocxl.c > > @@ -758,6 +758,186 @@ static int > > ioctl_controller_dump_complete(struct ocxlpmem *ocxlpmem) > > GLOBAL_MMIO_HCI_CONTROLLER_DUMP_COL > > LECTED); > > } > > =20 > > +/** > > + * controller_stats_header_parse() - Parse the first 64 bits of > > the controller stats admin command response > > + * @ocxlpmem: the device metadata > > + * @length: out, returns the number of bytes in the response > > (excluding the 64 bit header) > > + */ > > +static int controller_stats_header_parse(struct ocxlpmem > > *ocxlpmem, > > + u32 *length) > > +{ > > + int rc; > > + u64 val; > > + >=20 > unexpected empty line >=20 Ok >=20 > > + u16 data_identifier; > > + u32 data_length; > > + > > + rc =3D ocxl_global_mmio_read64(ocxlpmem->ocxl_afu, > > + ocxlpmem- > > >admin_command.data_offset, > > + OCXL_LITTLE_ENDIAN, &val); > > + if (rc) > > + return rc; > > + > > + data_identifier =3D val >> 48; > > + data_length =3D val & 0xFFFFFFFF; > > + > > + if (data_identifier !=3D 0x4353) { // 'CS' > > + dev_err(&ocxlpmem->dev, > > + "Bad data identifier for controller stats, > > expected 'CS', got '%-.*s'\n", > > + 2, (char *)&data_identifier); >=20 >=20 > Wow, I'm clueless what that string format looks like :-) > 2 arguments? Did you check the kernel string formatter does what you > want? > You may consider unifying the format though, the error log patch uses > a=20 > simpler (better?) format for a similar message. >=20 Sorry, force of habit from my old job where we dealt with a lot of variable length, non-NULL terminated buffers. FYI - it takes the string length from the first argument. I'll change it to a fixed length string like the others :) >=20 >=20 > > + return -EINVAL; > > + } > > + > > + *length =3D data_length; > > + return 0; > > +} > > + > > +static int ioctl_controller_stats(struct ocxlpmem *ocxlpmem, > > + struct > > ioctl_ocxl_pmem_controller_stats __user *uarg) > > +{ > > + struct ioctl_ocxl_pmem_controller_stats args; > > + u32 length; > > + int rc; > > + u64 val; > > + > > + memset(&args, '\0', sizeof(args)); > > + > > + mutex_lock(&ocxlpmem->admin_command.lock); > > + > > + rc =3D admin_command_request(ocxlpmem, > > ADMIN_COMMAND_CONTROLLER_STATS); > > + if (rc) > > + goto out; > > + > > + rc =3D ocxl_global_mmio_write64(ocxlpmem->ocxl_afu, > > + ocxlpmem- > > >admin_command.request_offset + 0x08, > > + OCXL_LITTLE_ENDIAN, 0); > > + if (rc) > > + goto out; > > + > > + rc =3D admin_command_execute(ocxlpmem); > > + if (rc) > > + goto out; > > + > > + > > + rc =3D admin_command_complete_timeout(ocxlpmem, > > + ADMIN_COMMAND_CONTROLLER_ST > > ATS); > > + if (rc < 0) { > > + dev_warn(&ocxlpmem->dev, "Controller stats timed > > out\n"); > > + goto out; > > + } > > + > > + rc =3D admin_response(ocxlpmem); > > + if (rc < 0) > > + goto out; > > + if (rc !=3D STATUS_SUCCESS) { > > + warn_status(ocxlpmem, > > + "Unexpected status from controller stats", > > rc); > > + goto out; > > + } >=20 > All those ioctls commands follow the same pattern: > 1. admin_command_request() > 2. optionnaly, set some mmio registers specific to the command > 3. admin_command_execute() > 4. admin_command_complete_timeout() > 5. admin_response() >=20 > By swapping 1 and 2, we could then factorize steps 1, 3, 4 and 5 in > a=20 > function and simplify/shorten the code each time a command is called. >=20 > Regarding step 2 (and that's true for all similar patches), a > comment=20 > about what the mmio tuning does would help and avoid looking up the=20 > spec. Looking up the spec during the review is expected, but it will=20 > ease reading the code 6 months from now. >=20 >=20 I'll rework this and add a wrapper in the Admin Commands patch. >=20 > > + > > + rc =3D controller_stats_header_parse(ocxlpmem, &length); > > + if (rc) > > + goto out; > > + > > + if (length !=3D 0x140) > > + warn_status(ocxlpmem, > > + "Unexpected length for controller stats > > data, expected 0x140, got 0x%x", > > + length); > > + > > + rc =3D ocxl_global_mmio_read64(ocxlpmem->ocxl_afu, > > + ocxlpmem- > > >admin_command.data_offset + 0x08 + 0x08, > > + OCXL_LITTLE_ENDIAN, &val); > > + if (rc) > > + goto out; > > + > > + args.reset_count =3D val >> 32; > > + args.reset_uptime =3D val & 0xFFFFFFFF; > > + > > + rc =3D ocxl_global_mmio_read64(ocxlpmem->ocxl_afu, > > + ocxlpmem- > > >admin_command.data_offset + 0x08 + 0x10, > > + OCXL_LITTLE_ENDIAN, &val); > > + if (rc) > > + goto out; > > + > > + args.power_on_uptime =3D val >> 32; > > + > > + rc =3D ocxl_global_mmio_read64(ocxlpmem->ocxl_afu, > > + ocxlpmem- > > >admin_command.data_offset + 0x08 + 0x40 + 0x08, > > + OCXL_LITTLE_ENDIAN, > &args.host_load_count); >=20 >=20 > Those offsets are hard to understand, even with the spec next to me. > And=20 > it seems that we could harden things a bit: > each block as a "statistics parameter ID" and the length of the data > for=20 > that block. We should check that and make sure we're reading what we > expect. > For example, from the spec I'm looking (110d), I would expect the > host=20 > load count to be at offset 0x10. It's entirely possible I'm > misreading=20 > it though. >=20 I'll rework this too. >=20 >=20 > > + if (rc) > > + goto out; > > + > > + rc =3D ocxl_global_mmio_read64(ocxlpmem->ocxl_afu, > > + ocxlpmem- > > >admin_command.data_offset + 0x08 + 0x40 + 0x10, > > + OCXL_LITTLE_ENDIAN, > > &args.host_store_count); > > + if (rc) > > + goto out; > > + > > + rc =3D ocxl_global_mmio_read64(ocxlpmem->ocxl_afu, > > + ocxlpmem- > > >admin_command.data_offset + 0x08 + 0x40 + 0x18, > > + OCXL_LITTLE_ENDIAN, > > &args.media_read_count); > > + if (rc) > > + goto out; > > + > > + rc =3D ocxl_global_mmio_read64(ocxlpmem->ocxl_afu, > > + ocxlpmem- > > >admin_command.data_offset + 0x08 + 0x40 + 0x20, > > + OCXL_LITTLE_ENDIAN, > > &args.media_write_count); > > + if (rc) > > + goto out; > > + > > + rc =3D ocxl_global_mmio_read64(ocxlpmem->ocxl_afu, > > + ocxlpmem- > > >admin_command.data_offset + 0x08 + 0x40 + 0x28, > > + OCXL_LITTLE_ENDIAN, > > &args.cache_hit_count); > > + if (rc) > > + goto out; > > + > > + rc =3D ocxl_global_mmio_read64(ocxlpmem->ocxl_afu, > > + ocxlpmem- > > >admin_command.data_offset + 0x08 + 0x40 + 0x30, > > + OCXL_LITTLE_ENDIAN, > > &args.cache_miss_count); > > + if (rc) > > + goto out; > > + > > + rc =3D ocxl_global_mmio_read64(ocxlpmem->ocxl_afu, > > + ocxlpmem- > > >admin_command.data_offset + 0x08 + 0x40 + 0x38, > > + OCXL_LITTLE_ENDIAN, > > &args.media_read_latency); > > + if (rc) > > + goto out; > > + > > + rc =3D ocxl_global_mmio_read64(ocxlpmem->ocxl_afu, > > + ocxlpmem- > > >admin_command.data_offset + 0x08 + 0x40 + 0x40, > > + OCXL_LITTLE_ENDIAN, > > &args.media_write_latency); > > + if (rc) > > + goto out; > > + > > + rc =3D ocxl_global_mmio_read64(ocxlpmem->ocxl_afu, > > + ocxlpmem- > > >admin_command.data_offset + 0x08 + 0x40 + 0x48, > > + OCXL_LITTLE_ENDIAN, > > &args.cache_read_latency); > > + if (rc) > > + goto out; > > + > > + rc =3D ocxl_global_mmio_read64(ocxlpmem->ocxl_afu, > > + ocxlpmem- > > >admin_command.data_offset + 0x08 + 0x40 + 0x50, > > + OCXL_LITTLE_ENDIAN, > > &args.cache_write_latency); > > + if (rc) > > + goto out; > > + > > + if (copy_to_user(uarg, &args, sizeof(args))) { > > + rc =3D -EFAULT; > > + goto out; > > + } > > + > > + rc =3D admin_response_handled(ocxlpmem); > > + if (rc) > > + goto out; > > + > > + rc =3D 0; > > + goto out; >=20 > That may be more of a personal habit, but that final goto disrupts > the=20 > "good case" flow. And I think it's pretty unusual within the kernel. >=20 Ok >=20 > > + > > +out: > > + mutex_unlock(&ocxlpmem->admin_command.lock); > > + return rc; > > +} > > + > > static long file_ioctl(struct file *file, unsigned int cmd, > > unsigned long args) > > { > > struct ocxlpmem *ocxlpmem =3D file->private_data; > > @@ -781,6 +961,11 @@ static long file_ioctl(struct file *file, > > unsigned int cmd, unsigned long args) > > case IOCTL_OCXL_PMEM_CONTROLLER_DUMP_COMPLETE: > > rc =3D ioctl_controller_dump_complete(ocxlpmem); > > break; > > + > > + case IOCTL_OCXL_PMEM_CONTROLLER_STATS: > > + rc =3D ioctl_controller_stats(ocxlpmem, > > + (struct > > ioctl_ocxl_pmem_controller_stats __user *)args); > > + break; > > } > > =20 > > return rc; > > diff --git a/include/uapi/nvdimm/ocxl-pmem.h > > b/include/uapi/nvdimm/ocxl-pmem.h > > index d4d8512d03f7..add223aa2fdb 100644 > > --- a/include/uapi/nvdimm/ocxl-pmem.h > > +++ b/include/uapi/nvdimm/ocxl-pmem.h > > @@ -50,6 +50,22 @@ struct ioctl_ocxl_pmem_controller_dump_data { > > __u64 reserved[8]; > > }; > > =20 > > +struct ioctl_ocxl_pmem_controller_stats { > > + __u32 reset_count; > > + __u32 reset_uptime; /* seconds */ > > + __u32 power_on_uptime; /* seconds */ >=20 > Same as before, we're going to have some padding here. >=20 > Fred >=20 Ok >=20 > > + __u64 host_load_count; > > + __u64 host_store_count; > > + __u64 media_read_count; > > + __u64 media_write_count; > > + __u64 cache_hit_count; > > + __u64 cache_miss_count; > > + __u64 media_read_latency; /* nanoseconds */ > > + __u64 media_write_latency; /* nanoseconds */ > > + __u64 cache_read_latency; /* nanoseconds */ > > + __u64 cache_write_latency; /* nanoseconds */ > > +}; > > + > > /* ioctl numbers */ > > #define OCXL_PMEM_MAGIC 0x5C > > /* SCM devices */ > > @@ -57,5 +73,6 @@ struct ioctl_ocxl_pmem_controller_dump_data { > > #define IOCTL_OCXL_PMEM_CONTROLLER_DUMP _IO(OCX > > L_PMEM_MAGIC, 0x02) > > #define IOCTL_OCXL_PMEM_CONTROLLER_DUMP_DATA _IOWR(O > > CXL_PMEM_MAGIC, 0x03, struct ioctl_ocxl_pmem_controller_dump_data) > > #define IOCTL_OCXL_PMEM_CONTROLLER_DUMP_COMPLETE _IO(OCXL_PMEM_M > > AGIC, 0x04) > > +#define IOCTL_OCXL_PMEM_CONTROLLER_STATS _IO(OCXL_PMEM_M > > AGIC, 0x05) > > =20 > > #endif /* _UAPI_OCXL_SCM_H */ > >=20 --=20 Alastair D'Silva Open Source Developer Linux Technology Centre, IBM Australia mob: 0423 762 819