nvdimm.lists.linux.dev archive mirror
 help / color / mirror / Atom feed
From: Dan Williams <dan.j.williams@intel.com>
To: kajoljain <kjain@linux.ibm.com>
Cc: Michael Ellerman <mpe@ellerman.id.au>,
	linuxppc-dev <linuxppc-dev@lists.ozlabs.org>,
	 Linux NVDIMM <nvdimm@lists.linux.dev>,
	 Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
	Peter Zijlstra <peterz@infradead.org>,
	 "Weiny, Ira" <ira.weiny@intel.com>,
	Vishal L Verma <vishal.l.verma@intel.com>,
	maddy@linux.ibm.com,  Santosh Sivaraj <santosh@fossix.org>,
	"Aneesh Kumar K.V" <aneesh.kumar@linux.ibm.com>,
	 Vaibhav Jain <vaibhav@linux.ibm.com>,
	atrajeev@linux.vnet.ibm.com,
	 Thomas Gleixner <tglx@linutronix.de>,
	rnsastry@linux.ibm.com
Subject: Re: [RESEND PATCH v4 1/4] drivers/nvdimm: Add nvdimm pmu structure
Date: Tue, 14 Sep 2021 21:08:10 -0700	[thread overview]
Message-ID: <CAPcyv4hE4rh5R+8zy3X4gDJeuPzQ0oQHmHbe_pppgWB2_RjfAg@mail.gmail.com> (raw)
In-Reply-To: <d7f8bf51-059f-4496-37c4-6516a703e209@linux.ibm.com>

On Thu, Sep 9, 2021 at 12:56 AM kajoljain <kjain@linux.ibm.com> wrote:
>
>
>
> On 9/8/21 3:29 AM, Dan Williams wrote:
> > Hi Kajol,
> >
> > Apologies for the delay in responding to this series, some comments below:
>
> Hi Dan,
>     No issues, thanks for reviewing the patches.
>
> >
> > On Thu, Sep 2, 2021 at 10:10 PM Kajol Jain <kjain@linux.ibm.com> wrote:
> >>
> >> A structure is added, called nvdimm_pmu, for performance
> >> stats reporting support of nvdimm devices. It can be used to add
> >> nvdimm pmu data such as supported events and pmu event functions
> >> like event_init/add/read/del with cpu hotplug support.
> >>
> >> Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
> >> Reviewed-by: Madhavan Srinivasan <maddy@linux.ibm.com>
> >> Tested-by: Nageswara R Sastry <rnsastry@linux.ibm.com>
> >> Signed-off-by: Kajol Jain <kjain@linux.ibm.com>
> >> ---
> >>  include/linux/nd.h | 43 +++++++++++++++++++++++++++++++++++++++++++
> >>  1 file changed, 43 insertions(+)
> >>
> >> diff --git a/include/linux/nd.h b/include/linux/nd.h
> >> index ee9ad76afbba..712499cf7335 100644
> >> --- a/include/linux/nd.h
> >> +++ b/include/linux/nd.h
> >> @@ -8,6 +8,8 @@
> >>  #include <linux/ndctl.h>
> >>  #include <linux/device.h>
> >>  #include <linux/badblocks.h>
> >> +#include <linux/platform_device.h>
> >> +#include <linux/perf_event.h>
> >>
> >>  enum nvdimm_event {
> >>         NVDIMM_REVALIDATE_POISON,
> >> @@ -23,6 +25,47 @@ enum nvdimm_claim_class {
> >>         NVDIMM_CCLASS_UNKNOWN,
> >>  };
> >>
> >> +/* Event attribute array index */
> >> +#define NVDIMM_PMU_FORMAT_ATTR         0
> >> +#define NVDIMM_PMU_EVENT_ATTR          1
> >> +#define NVDIMM_PMU_CPUMASK_ATTR                2
> >> +#define NVDIMM_PMU_NULL_ATTR           3
> >> +
> >> +/**
> >> + * struct nvdimm_pmu - data structure for nvdimm perf driver
> >> + *
> >> + * @name: name of the nvdimm pmu device.
> >> + * @pmu: pmu data structure for nvdimm performance stats.
> >> + * @dev: nvdimm device pointer.
> >> + * @functions(event_init/add/del/read): platform specific pmu functions.
> >
> > This is not valid kernel-doc:
> >
> > include/linux/nd.h:67: warning: Function parameter or member
> > 'event_init' not described in 'nvdimm_pmu'
> > include/linux/nd.h:67: warning: Function parameter or member 'add' not
> > described in 'nvdimm_pmu'
> > include/linux/nd.h:67: warning: Function parameter or member 'del' not
> > described in 'nvdimm_pmu'
> > include/linux/nd.h:67: warning: Function parameter or member 'read'
> > not described in 'nvdimm_pmu'
> >
> > ...but I think rather than fixing those up 'struct nvdimm_pmu' should be pruned.
> >
> > It's not clear to me that it is worth the effort to describe these
> > details to the nvdimm core which is just going to turn around and call
> > the pmu core. I'd just as soon have the driver call the pmu core
> > directly, optionally passing in attributes and callbacks that come
> > from the nvdimm core and/or the nvdimm provider.
>
> The intend for adding these callbacks(event_init/add/del/read) is to give
> flexibility to the nvdimm core to add some common checks/routines if required
> in the future. Those checks can be common for all architecture with still having the
> ability to call arch/platform specific driver code to use its own routines.
>
> But as you said, currently we don't have any common checks and it directly
> calling platform specific code, so we can get rid of it.
> Should we remove this part for now?

Yes, lets go direct to the perf api for now and await the need for a
common core wrapper to present itself.

>
>
> >
> > Otherwise it's also not clear which of these structure members are
> > used at runtime vs purely used as temporary storage to pass parameters
> > to the pmu core.
> >
> >> + * @attr_groups: data structure for events, formats and cpumask
> >> + * @cpu: designated cpu for counter access.
> >> + * @node: node for cpu hotplug notifier link.
> >> + * @cpuhp_state: state for cpu hotplug notification.
> >> + * @arch_cpumask: cpumask to get designated cpu for counter access.
> >> + */
> >> +struct nvdimm_pmu {
> >> +       const char *name;
> >> +       struct pmu pmu;
> >> +       struct device *dev;
> >> +       int (*event_init)(struct perf_event *event);
> >> +       int  (*add)(struct perf_event *event, int flags);
> >> +       void (*del)(struct perf_event *event, int flags);
> >> +       void (*read)(struct perf_event *event);
> >> +       /*
> >> +        * Attribute groups for the nvdimm pmu. Index 0 used for
> >> +        * format attribute, index 1 used for event attribute,
> >> +        * index 2 used for cpusmask attribute and index 3 kept as NULL.
> >> +        */
> >> +       const struct attribute_group *attr_groups[4];
> >
> > Following from above, I'd rather this was organized as static
> > attributes with an is_visible() helper for the groups for any dynamic
> > aspects. That mirrors the behavior of nvdimm_create() and allows for
> > device drivers to compose the attribute groups from a core set and /
> > or a provider specific set.
>
> Since we don't have any common events right now, Can I use papr
> attributes directly or should we create dummy events for common thing and
> then merged it with papr event list.

Just use papr events directly.

  reply	other threads:[~2021-09-15  4:08 UTC|newest]

Thread overview: 16+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-09-03  5:09 [RESEND PATCH v4 0/4] Add perf interface to expose nvdimm Kajol Jain
2021-09-03  5:09 ` [RESEND PATCH v4 1/4] drivers/nvdimm: Add nvdimm pmu structure Kajol Jain
2021-09-07 21:59   ` Dan Williams
2021-09-09  7:55     ` kajoljain
2021-09-15  4:08       ` Dan Williams [this message]
2021-09-15  4:11         ` Dan Williams
2021-09-03  5:09 ` [RESEND PATCH v4 2/4] drivers/nvdimm: Add perf interface to expose nvdimm performance stats Kajol Jain
2021-09-03 12:32   ` kernel test robot
2021-09-03 15:19   ` kernel test robot
2021-09-04  6:38     ` kajoljain
2021-09-03 15:19   ` [RFC PATCH] drivers/nvdimm: nvdimm_pmu_free_hotplug_memory() can be static kernel test robot
2021-09-04  6:39     ` kajoljain
2021-09-03  5:09 ` [RESEND PATCH v4 3/4] powerpc/papr_scm: Add perf interface support Kajol Jain
2021-09-03  5:09 ` [RESEND PATCH v4 4/4] powerpc/papr_scm: Document papr_scm sysfs event format entries Kajol Jain
2021-09-08  1:03   ` Dan Williams
2021-09-09  8:03     ` kajoljain

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=CAPcyv4hE4rh5R+8zy3X4gDJeuPzQ0oQHmHbe_pppgWB2_RjfAg@mail.gmail.com \
    --to=dan.j.williams@intel.com \
    --cc=aneesh.kumar@linux.ibm.com \
    --cc=atrajeev@linux.vnet.ibm.com \
    --cc=ira.weiny@intel.com \
    --cc=kjain@linux.ibm.com \
    --cc=linux-kernel@vger.kernel.org \
    --cc=linuxppc-dev@lists.ozlabs.org \
    --cc=maddy@linux.ibm.com \
    --cc=mpe@ellerman.id.au \
    --cc=nvdimm@lists.linux.dev \
    --cc=peterz@infradead.org \
    --cc=rnsastry@linux.ibm.com \
    --cc=santosh@fossix.org \
    --cc=tglx@linutronix.de \
    --cc=vaibhav@linux.ibm.com \
    --cc=vishal.l.verma@intel.com \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).