From: Mark Rutland <mark.rutland@arm.com>
To: Thomas Gleixner <tglx@linutronix.de>
Cc: LKML <linux-kernel@vger.kernel.org>,
Peter Zijlstra <peterz@infradead.org>,
Robin Murphy <robin.murphy@arm.com>,
Nitesh Lal <nilal@redhat.com>,
Jesse Brandeburg <jesse.brandeburg@intel.com>,
Marc Zyngier <maz@kernel.org>, Will Deacon <will@kernel.org>,
linux-arm-kernel@lists.infradead.org, Frank Li <Frank.li@nxp.com>,
Shawn Guo <shawnguo@kernel.org>,
Sascha Hauer <s.hauer@pengutronix.de>,
Pengutronix Kernel Team <kernel@pengutronix.de>,
Fabio Estevam <festevam@gmail.com>,
NXP Linux Team <linux-imx@nxp.com>,
Shaokun Zhang <zhangshaokun@hisilicon.com>
Subject: Re: [patch 0/8] genirq, perf: Cleanup the abuse of irq_set_affinity_hint()
Date: Tue, 18 May 2021 11:11:17 +0100 [thread overview]
Message-ID: <20210518101117.GC82842@C02TD0UTHF1T.local> (raw)
In-Reply-To: <20210518091725.046774792@linutronix.de>
Hi Thomas,
On Tue, May 18, 2021 at 11:17:25AM +0200, Thomas Gleixner wrote:
> The modular PMU drivers use irq_set_affinity_hint() to set the affinity
> for the PMU interrupts, which relies on the undocumented side effect that
> this function actually sets the affinity under the hood.
>
> Setting an hint is clearly not a guarantee and for these PMU interrupts an
> affinity hint, which is supposed to guide userspace for setting affinity,
> is beyond pointless, because the affinity of these interrupts cannot be
> modified from user space.
>
> Aside of that the error checks are bogus because the only error which is
> returned from irq_set_affinity_hint() is when there is no irq descriptor
> for the interrupt number, but not when the affinity set fails. That's on
> purpose because the hint can point to an offline CPU.
>
> Sigh, if people would at least talk if something is missing...
>
> Clean up the mess by exposing irq_set_affinity() and converting the drivers
> over to that.
Sorry about this, and thanks for cleaning this up.
For the series:
Acked-by: Mark Rutland <mark.rutland@arm.com>
Mark.
>
> Thanks,
>
> tglx
> ---
> drivers/perf/arm-ccn.c | 6 +---
> drivers/perf/arm-cmn.c | 9 +-----
> drivers/perf/arm_dmc620_pmu.c | 5 +--
> drivers/perf/arm_dsu_pmu.c | 8 +----
> drivers/perf/arm_smmuv3_pmu.c | 10 ++-----
> drivers/perf/fsl_imx8_ddr_perf.c | 5 +--
> drivers/perf/hisilicon/hisi_uncore_ddrc_pmu.c | 3 --
> drivers/perf/hisilicon/hisi_uncore_hha_pmu.c | 3 --
> drivers/perf/hisilicon/hisi_uncore_l3c_pmu.c | 3 --
> drivers/perf/hisilicon/hisi_uncore_pa_pmu.c | 3 --
> drivers/perf/hisilicon/hisi_uncore_pmu.c | 4 +-
> drivers/perf/hisilicon/hisi_uncore_sllc_pmu.c | 3 --
> include/linux/interrupt.h | 35 +-------------------------
> kernel/irq/manage.c | 33 +++++++++++++++++++++++-
> 14 files changed, 49 insertions(+), 81 deletions(-)
>
>
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next prev parent reply other threads:[~2021-05-18 10:19 UTC|newest]
Thread overview: 16+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-05-18 9:17 [patch 0/8] genirq, perf: Cleanup the abuse of irq_set_affinity_hint() Thomas Gleixner
2021-05-18 9:17 ` [patch 1/8] genirq: Export affinity setter for modules Thomas Gleixner
2021-05-18 9:17 ` [patch 2/8] perf/arm-ccn: Use irq_set_affinity() Thomas Gleixner
2021-05-18 9:17 ` [patch 3/8] perf/arm-cmn: " Thomas Gleixner
2021-05-18 9:17 ` [patch 4/8] perf/arm-dmc620: " Thomas Gleixner
2021-05-18 9:17 ` [patch 5/8] perf/arm-dsu: " Thomas Gleixner
2021-05-18 11:31 ` John Garry
2021-05-18 15:50 ` Thomas Gleixner
2021-05-18 9:17 ` [patch 6/8] perf/arm-smmuv3: " Thomas Gleixner
2021-05-18 9:17 ` [patch 7/8] perf/imx_ddr: " Thomas Gleixner
2021-05-18 9:17 ` [patch 8/8] perf/hisi: " Thomas Gleixner
2021-05-18 10:11 ` Mark Rutland [this message]
2021-05-18 10:48 ` [patch 0/8] genirq, perf: Cleanup the abuse of irq_set_affinity_hint() Will Deacon
2021-05-18 15:51 ` Thomas Gleixner
2021-05-19 9:08 ` Thomas Gleixner
2021-05-24 20:20 ` Will Deacon
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