| lists.openwall.net | lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC | |
|
Open Source and information security mailing list archives
| ||
|
Message-ID: <d92fbaab082180740baa7a1ade0edaaac51e005b.camel@intel.com>
Date: Mon, 4 Nov 2024 07:15:59 +0000
From: "Zhang, Rui" <rui.zhang@...el.com>
To: "Dhananjay.Ugwekar@....com" <Dhananjay.Ugwekar@....com>,
"gautham.shenoy@....com" <gautham.shenoy@....com>
CC: "alexander.shishkin@...ux.intel.com" <alexander.shishkin@...ux.intel.com>,
"ananth.narayan@....com" <ananth.narayan@....com>,
"dave.hansen@...ux.intel.com" <dave.hansen@...ux.intel.com>,
"ravi.bangoria@....com" <ravi.bangoria@....com>, "Hunter, Adrian"
<adrian.hunter@...el.com>, "linux-kernel@...r.kernel.org"
<linux-kernel@...r.kernel.org>, "mingo@...hat.com" <mingo@...hat.com>,
"irogers@...gle.com" <irogers@...gle.com>, "linux-perf-users@...r.kernel.org"
<linux-perf-users@...r.kernel.org>, "tglx@...utronix.de"
<tglx@...utronix.de>, "kan.liang@...ux.intel.com"
<kan.liang@...ux.intel.com>, "mark.rutland@....com" <mark.rutland@....com>,
"peterz@...radead.org" <peterz@...radead.org>, "bp@...en8.de" <bp@...en8.de>,
"acme@...nel.org" <acme@...nel.org>, "kprateek.nayak@....com"
<kprateek.nayak@....com>, "jolsa@...nel.org" <jolsa@...nel.org>,
"namhyung@...nel.org" <namhyung@...nel.org>, "x86@...nel.org"
<x86@...nel.org>
Subject: Re: [PATCH v6 03/10] perf/x86/rapl: Remove the cpu_to_rapl_pmu()
function
On Mon, 2024-11-04 at 08:45 +0530, Dhananjay Ugwekar wrote:
> Hello Rui,
>
> Thanks for reviewing and testing the series!,
>
> On 11/1/2024 1:36 PM, Zhang, Rui wrote:
> > On Mon, 2024-10-28 at 14:49 +0530, Dhananjay Ugwekar wrote:
> > > Hello Gautham,
> > >
> > > On 10/28/2024 2:23 PM, Gautham R. Shenoy wrote:
> > > > Hello Dhananjay,
> > > >
> > > > On Fri, Oct 25, 2024 at 11:13:41AM +0000, Dhananjay Ugwekar
> > > > wrote:
> > > > > Prepare for the addition of RAPL core energy counter support.
> > > > > Post which, one CPU might be mapped to more than one rapl_pmu
> > > > > (package/die one and a core one). So, remove the
> > > > > cpu_to_rapl_pmu()
> > > > > function.
> > > > >
> > > > > Signed-off-by: Dhananjay Ugwekar <Dhananjay.Ugwekar@....com>
> > > > > ---
> > > > > arch/x86/events/rapl.c | 19 ++++++-------------
> > > > > 1 file changed, 6 insertions(+), 13 deletions(-)
> > > > >
> > > > > diff --git a/arch/x86/events/rapl.c b/arch/x86/events/rapl.c
> > > > > index f70c49ca0ef3..d20c5b1dd0ad 100644
> > > > > --- a/arch/x86/events/rapl.c
> > > > > +++ b/arch/x86/events/rapl.c
> > > > > @@ -162,17 +162,6 @@ static inline unsigned int
> > > > > get_rapl_pmu_idx(int cpu)
> > > > >
> > > > > topology_logical_die_id(cpu);
> > > > > }
> > > > >
> > > > > -static inline struct rapl_pmu *cpu_to_rapl_pmu(unsigned int
> > > > > cpu)
> > > > > -{
> > > > > - unsigned int rapl_pmu_idx = get_rapl_pmu_idx(cpu);
> > > > > -
> > > > > - /*
> > > > > - * The unsigned check also catches the '-1' return
> > > > > value
> > > > > for non
> > > > > - * existent mappings in the topology map.
> > > > > - */
> > > >
> > > >
> > > > See the comment here why rapl_pmu_idx should be an "unsigned
> > > > int".
> > > >
> > > >
> > > > > - return rapl_pmu_idx < rapl_pmus->nr_rapl_pmu ?
> > > > > rapl_pmus-
> > > > > > pmus[rapl_pmu_idx] : NULL;
> > > > > -}
> > > > > -
> > > > > static inline u64 rapl_read_counter(struct perf_event
> > > > > *event)
> > > > > {
> > > > > u64 raw;
> > > > > @@ -348,7 +337,7 @@ static void rapl_pmu_event_del(struct
> > > > > perf_event *event, int flags)
> > > > > static int rapl_pmu_event_init(struct perf_event *event)
> > > > > {
> > > > > u64 cfg = event->attr.config & RAPL_EVENT_MASK;
> > > > > - int bit, ret = 0;
> > > > > + int bit, rapl_pmu_idx, ret = 0;
> > > >
> > > > Considering that, shouldn't rapl_pmu_idx be an "unsigned int"
> > > > no?
> > >
> > > Correct, with unsigned int we will be able to check for negative
> > > values as well with the
> > > "if (rapl_pmu_idx >= rapl_pmus->nr_rapl_pmu)" check. Will fix
> > > this in
> > > next version.
> > >
> > you can stick with unsigned int here, but in patch 10/10, IMO,
> > making
> > get_rapl_pmu_idx() return int instead of unsigned int is more
> > straightforward.
>
> But I have one doubt, there wont be any functional difference in
> returning
> "unsigned int" vs "int" right?
yes, this doesn't cause any issue.
> , we will still need to check the same condition
> for the return value i.e. "if (rapl_pmu_idx >= rapl_pmus-
> >nr_rapl_pmu)"
> (assuming we are still storing the return value in "unsigned int
> rapl_pmu_idx"),
> I think I didnt get your point.
With this patch, below comment is removed
/*
* The unsigned check also catches the '-1' return
value for non
* existent mappings in the topology map.
*/
And we still rely on the unsigned int -> int conversion for the error
check.
So IMO, we should either add back a similar comment, or convert
get_rapl_pmu_idx() to return int and modify the error check.
thanks,
rui
> Thanks,
> Dhananjay
>
> >
> > thanks,
> > rui
> >
> > > Thanks,
> > > Dhananjay
> > >
> > > >
> > > > --
> > > > Thanks and Regards
> > > > gautham.
> > > >
> > > >
> > > > > struct rapl_pmu *pmu;
> > > > >
> > > > > /* only look at RAPL events */
> > > > > @@ -376,8 +365,12 @@ static int rapl_pmu_event_init(struct
> > > > > perf_event *event)
> > > > > if (event->attr.sample_period) /* no sampling */
> > > > > return -EINVAL;
> > > > >
> > > > > + rapl_pmu_idx = get_rapl_pmu_idx(event->cpu);
> > > > > + if (rapl_pmu_idx >= rapl_pmus->nr_rapl_pmu)
> > > > > + return -EINVAL;
> > > > > +
> > > > > /* must be done before validate_group */
> > > > > - pmu = cpu_to_rapl_pmu(event->cpu);
> > > > > + pmu = rapl_pmus->pmus[rapl_pmu_idx];
> > > > > if (!pmu)
> > > > > return -EINVAL;
> > > > > event->pmu_private = pmu;
> > > > > --
> > > > > 2.34.1
> > > > >
> >
Powered by blists - more mailing lists