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Fri, 3 Sep 2021 15:25:11 +0000 (UTC) Received: from virtlab512.virt.lab.eng.bos.redhat.com (virtlab512.virt.lab.eng.bos.redhat.com [10.19.152.206]) by smtp.corp.redhat.com (Postfix) with ESMTP id D7E3F69CBB; Fri, 3 Sep 2021 15:25:05 +0000 (UTC) From: Nitesh Narayan Lal To: linux-kernel@vger.kernel.org, linux-pci@vger.kernel.org, linux-scsi@vger.kernel.org, netdev@vger.kernel.org, davem@davemloft.net, ajit.khaparde@broadcom.com, sriharsha.basavapatna@broadcom.com, somnath.kotur@broadcom.com, huangguangbin2@huawei.com, huangdaode@huawei.com, mtosatti@redhat.com, juri.lelli@redhat.com, frederic@kernel.org, abelits@marvell.com, bhelgaas@google.com, rostedt@goodmis.org, peterz@infradead.org Cc: nilal@redhat.com, jesse.brandeburg@intel.com, robin.murphy@arm.com, mingo@kernel.org, jbrandeb@kernel.org, akpm@linuxfoundation.org, sfr@canb.auug.org.au, stephen@networkplumber.org, rppt@linux.vnet.ibm.com, chris.friesen@windriver.com, maz@kernel.org, nhorman@tuxdriver.com, pjwaskiewicz@gmail.com, sassmann@redhat.com, thenzl@redhat.com, james.smart@broadcom.com, dick.kennedy@broadcom.com, jkc@redhat.com, faisal.latif@intel.com, shiraz.saleem@intel.com, tariqt@nvidia.com, ahleihel@redhat.com, kheib@redhat.com, borisp@nvidia.com, saeedm@nvidia.com, tatyana.e.nikolova@intel.com, mustafa.ismail@intel.com, ahs3@redhat.com, leonro@nvidia.com, chandrakanth.patil@broadcom.com, bjorn.andersson@linaro.org, chunkuang.hu@kernel.org, yongqiang.niu@mediatek.com, baolin.wang7@gmail.com, poros@redhat.com, minlei@redhat.com, emilne@redhat.com, jejb@linux.ibm.com, martin.petersen@oracle.com, kabel@kernel.org, viresh.kumar@linaro.org, kuba@kernel.org, kashyap.desai@broadcom.com, sumit.saxena@broadcom.com, shivasharan.srikanteshwara@broadcom.com, sathya.prakash@broadcom.com, sreekanth.reddy@broadcom.com, suganath-prabu.subramani@broadcom.com, tglx@linutronix.de, ley.foon.tan@intel.com, jbrunet@baylibre.com, johannes@sipsolutions.net, snelson@pensando.io, lewis.hanly@microchip.com, benve@cisco.com, _govind@gmx.com, jassisinghbrar@gmail.com Subject: [PATCH v6 01/14] genirq: Provide new interfaces for affinity hints Date: Fri, 3 Sep 2021 11:24:17 -0400 Message-Id: <20210903152430.244937-2-nitesh@redhat.com> In-Reply-To: <20210903152430.244937-1-nitesh@redhat.com> References: <20210903152430.244937-1-nitesh@redhat.com> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Scanned-By: MIMEDefang 2.79 on 10.5.11.11 Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Thomas Gleixner The discussion about removing the side effect of irq_set_affinity_hint() of actually applying the cpumask (if not NULL) as affinity to the interrupt, unearthed a few unpleasantries: 1) The modular perf drivers rely on the current behaviour for the very wrong reasons. 2) While none of the other drivers prevents user space from changing the affinity, a cursorily inspection shows that there are at least expectations in some drivers. #1 needs to be cleaned up anyway, so that's not a problem #2 might result in subtle regressions especially when irqbalanced (which nowadays ignores the affinity hint) is disabled. Provide new interfaces: irq_update_affinity_hint() - Only sets the affinity hint pointer irq_set_affinity_and_hint() - Set the pointer and apply the affinity to the interrupt Make irq_set_affinity_hint() a wrapper around irq_apply_affinity_hint() and document it to be phased out. Signed-off-by: Thomas Gleixner Signed-off-by: Nitesh Narayan Lal Link: https://lore.kernel.org/r/20210501021832.743094-1-jesse.brandeburg@intel.com Reviewed-by: Ming Lei --- include/linux/interrupt.h | 53 ++++++++++++++++++++++++++++++++++++++- kernel/irq/manage.c | 8 +++--- 2 files changed, 56 insertions(+), 5 deletions(-) diff --git a/include/linux/interrupt.h b/include/linux/interrupt.h index 1f22a30c0963..9367f1cb2e3c 100644 --- a/include/linux/interrupt.h +++ b/include/linux/interrupt.h @@ -329,7 +329,46 @@ extern int irq_force_affinity(unsigned int irq, const struct cpumask *cpumask); extern int irq_can_set_affinity(unsigned int irq); extern int irq_select_affinity(unsigned int irq); -extern int irq_set_affinity_hint(unsigned int irq, const struct cpumask *m); +extern int __irq_apply_affinity_hint(unsigned int irq, const struct cpumask *m, + bool setaffinity); + +/** + * irq_update_affinity_hint - Update the affinity hint + * @irq: Interrupt to update + * @m: cpumask pointer (NULL to clear the hint) + * + * Updates the affinity hint, but does not change the affinity of the interrupt. + */ +static inline int +irq_update_affinity_hint(unsigned int irq, const struct cpumask *m) +{ + return __irq_apply_affinity_hint(irq, m, false); +} + +/** + * irq_set_affinity_and_hint - Update the affinity hint and apply the provided + * cpumask to the interrupt + * @irq: Interrupt to update + * @m: cpumask pointer (NULL to clear the hint) + * + * Updates the affinity hint and if @m is not NULL it applies it as the + * affinity of that interrupt. + */ +static inline int +irq_set_affinity_and_hint(unsigned int irq, const struct cpumask *m) +{ + return __irq_apply_affinity_hint(irq, m, true); +} + +/* + * Deprecated. Use irq_update_affinity_hint() or irq_set_affinity_and_hint() + * instead. + */ +static inline int irq_set_affinity_hint(unsigned int irq, const struct cpumask *m) +{ + return irq_set_affinity_and_hint(irq, m); +} + extern int irq_update_affinity_desc(unsigned int irq, struct irq_affinity_desc *affinity); @@ -361,6 +400,18 @@ static inline int irq_can_set_affinity(unsigned int irq) static inline int irq_select_affinity(unsigned int irq) { return 0; } +static inline int irq_update_affinity_hint(unsigned int irq, + const struct cpumask *m) +{ + return -EINVAL; +} + +static inline int irq_set_affinity_and_hint(unsigned int irq, + const struct cpumask *m) +{ + return -EINVAL; +} + static inline int irq_set_affinity_hint(unsigned int irq, const struct cpumask *m) { diff --git a/kernel/irq/manage.c b/kernel/irq/manage.c index 27667e82ecc9..707ad7be3378 100644 --- a/kernel/irq/manage.c +++ b/kernel/irq/manage.c @@ -486,7 +486,8 @@ int irq_force_affinity(unsigned int irq, const struct cpumask *cpumask) } EXPORT_SYMBOL_GPL(irq_force_affinity); -int irq_set_affinity_hint(unsigned int irq, const struct cpumask *m) +int __irq_apply_affinity_hint(unsigned int irq, const struct cpumask *m, + bool setaffinity) { unsigned long flags; struct irq_desc *desc = irq_get_desc_lock(irq, &flags, IRQ_GET_DESC_CHECK_GLOBAL); @@ -495,12 +496,11 @@ int irq_set_affinity_hint(unsigned int irq, const struct cpumask *m) return -EINVAL; desc->affinity_hint = m; irq_put_desc_unlock(desc, flags); - /* set the initial affinity to prevent every interrupt being on CPU0 */ - if (m) + if (m && setaffinity) __irq_set_affinity(irq, m, false); return 0; } -EXPORT_SYMBOL_GPL(irq_set_affinity_hint); +EXPORT_SYMBOL_GPL(__irq_apply_affinity_hint); static void irq_affinity_notify(struct work_struct *work) { -- 2.27.0