From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from foss.arm.com (foss.arm.com [217.140.110.172]) by smtp.subspace.kernel.org (Postfix) with ESMTP id A0AE1626A9 for ; Tue, 13 Feb 2024 18:46:12 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=217.140.110.172 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1707849974; cv=none; b=D9a7NZYqKU+uCbzx35KFhxh9M8OCQbZhNpSYJIknPgRb5nZ/hhZd+60F8Qc4EF9vYUWuZbzgjbmhiRp/jCSZMMDNhv4KqlQgz+/+l/OhhHYecWYvFMIvuB2IOItc/KP8rbx+vXG849K0WEJ4YhBCqtPjHAc6CNrT2uUjKtm3RQU= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1707849974; c=relaxed/simple; bh=ZuU+KSA4ulzLmwkUHi/QZtXEigOgOSRtK0hCV6hjL3Y=; h=From:To:Cc:Subject:Date:Message-Id:In-Reply-To:References: MIME-Version; b=d12AItPXRe/rkt68E78jR2LSWmGT/JfZocOBx+r9od+VJfqL/QW7wJPxPBF2o9Vvt7lpmuUkaSOA6kIQ+NGdaXkdGkftAYuYAFRSlH84/sMV5dbjwe4LliMmqsYpKICIJxKbIt4VEgBaXB/CN2C/37Uva3il37XVLmoEZWRHmdQ= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=arm.com; spf=pass smtp.mailfrom=arm.com; arc=none smtp.client-ip=217.140.110.172 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=arm.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=arm.com Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id 6B7D01596; Tue, 13 Feb 2024 10:46:53 -0800 (PST) Received: from merodach.members.linode.com (unknown [172.31.20.19]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 120403F766; Tue, 13 Feb 2024 10:46:08 -0800 (PST) From: James Morse To: x86@kernel.org, linux-kernel@vger.kernel.org Cc: Fenghua Yu , Reinette Chatre , Thomas Gleixner , Ingo Molnar , Borislav Petkov , H Peter Anvin , Babu Moger , James Morse , shameerali.kolothum.thodi@huawei.com, D Scott Phillips OS , carl@os.amperecomputing.com, lcherian@marvell.com, bobo.shaobowang@huawei.com, tan.shaopeng@fujitsu.com, baolin.wang@linux.alibaba.com, Jamie Iles , Xin Hao , peternewman@google.com, dfustini@baylibre.com, amitsinght@marvell.com, David Hildenbrand , Babu Moger Subject: [PATCH v9 21/24] x86/resctrl: Allow overflow/limbo handlers to be scheduled on any-but cpu Date: Tue, 13 Feb 2024 18:44:35 +0000 Message-Id: <20240213184438.16675-22-james.morse@arm.com> X-Mailer: git-send-email 2.20.1 In-Reply-To: <20240213184438.16675-1-james.morse@arm.com> References: <20240213184438.16675-1-james.morse@arm.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit When a CPU is taken offline resctrl may need to move the overflow or limbo handlers to run on a different CPU. Once the offline callbacks have been split, cqm_setup_limbo_handler() will be called while the CPU that is going offline is still present in the cpu_mask. Pass the CPU to exclude to cqm_setup_limbo_handler() and mbm_setup_overflow_handler(). These functions can use a variant of cpumask_any_but() when selecting the CPU. -1 is used to indicate no CPUs need excluding. Signed-off-by: James Morse Tested-by: Shaopeng Tan Tested-by: Peter Newman Tested-by: Babu Moger Tested-by: Carl Worth # arm64 Reviewed-by: Shaopeng Tan Reviewed-by: Babu Moger Reviewed-by: Reinette Chatre --- Changes since v2: * Rephrased a comment to avoid a two letter bad-word. (we) * Avoid assigning mbm_work_cpu if the domain is going to be free()d * Added cpumask_any_housekeeping_but(), I dislike the name Changes since v3: * Marked an explanatory comment as temporary as the subsequent patch is no longer adjacent. Changes since v4: * Check against RESCTRL_PICK_ANY_CPU instead of -1. * Leave cqm_work_cpu as nr_cpu_ids when no CPU is available. * Made cpumask_any_housekeeping_but() more readable. Changes since v5: * Changes in captialisation, and a typo. * Merged cpumask helpers. Changes since v6: * Added the missing dom parameter to some kernel doc. * Re-added use of cpumask_any_but(), * Expanded comment above cpumask_any_housekeeping(), * Added some more comments for good measure. * Added explicit IS_ENABLED() check as gcc-12 doesn't seem to work this out. Changes since v7: * Removed the paragraph with the badword 'subsequent'. * Reworded a comment with the badword 'we'. * Fixed a bounds checking bug in cpumask_any_housekeeping(). --- arch/x86/kernel/cpu/resctrl/core.c | 8 +++-- arch/x86/kernel/cpu/resctrl/ctrlmondata.c | 2 +- arch/x86/kernel/cpu/resctrl/internal.h | 33 ++++++++++++++---- arch/x86/kernel/cpu/resctrl/monitor.c | 42 ++++++++++++++++++----- arch/x86/kernel/cpu/resctrl/rdtgroup.c | 6 ++-- include/linux/resctrl.h | 2 ++ 6 files changed, 72 insertions(+), 21 deletions(-) diff --git a/arch/x86/kernel/cpu/resctrl/core.c b/arch/x86/kernel/cpu/resctrl/core.c index 4627d447bc3d..55322ba629da 100644 --- a/arch/x86/kernel/cpu/resctrl/core.c +++ b/arch/x86/kernel/cpu/resctrl/core.c @@ -584,12 +584,16 @@ static void domain_remove_cpu(int cpu, struct rdt_resource *r) if (r == &rdt_resources_all[RDT_RESOURCE_L3].r_resctrl) { if (is_mbm_enabled() && cpu == d->mbm_work_cpu) { cancel_delayed_work(&d->mbm_over); - mbm_setup_overflow_handler(d, 0); + /* + * temporary: exclude_cpu=-1 as this CPU has already + * been removed by cpumask_clear_cpu()d + */ + mbm_setup_overflow_handler(d, 0, RESCTRL_PICK_ANY_CPU); } if (is_llc_occupancy_enabled() && cpu == d->cqm_work_cpu && has_busy_rmid(d)) { cancel_delayed_work(&d->cqm_limbo); - cqm_setup_limbo_handler(d, 0); + cqm_setup_limbo_handler(d, 0, RESCTRL_PICK_ANY_CPU); } } } diff --git a/arch/x86/kernel/cpu/resctrl/ctrlmondata.c b/arch/x86/kernel/cpu/resctrl/ctrlmondata.c index a033e8e32108..64db51455df3 100644 --- a/arch/x86/kernel/cpu/resctrl/ctrlmondata.c +++ b/arch/x86/kernel/cpu/resctrl/ctrlmondata.c @@ -552,7 +552,7 @@ void mon_event_read(struct rmid_read *rr, struct rdt_resource *r, return; } - cpu = cpumask_any_housekeeping(&d->cpu_mask); + cpu = cpumask_any_housekeeping(&d->cpu_mask, RESCTRL_PICK_ANY_CPU); /* * cpumask_any_housekeeping() prefers housekeeping CPUs, but diff --git a/arch/x86/kernel/cpu/resctrl/internal.h b/arch/x86/kernel/cpu/resctrl/internal.h index 3ee855c37447..c99f26ebe7a6 100644 --- a/arch/x86/kernel/cpu/resctrl/internal.h +++ b/arch/x86/kernel/cpu/resctrl/internal.h @@ -60,19 +60,36 @@ * cpumask_any_housekeeping() - Choose any CPU in @mask, preferring those that * aren't marked nohz_full * @mask: The mask to pick a CPU from. + * @exclude_cpu:The CPU to avoid picking. * - * Returns a CPU in @mask. If there are housekeeping CPUs that don't use - * nohz_full, these are preferred. + * Returns a CPU from @mask, but not @exclude_cpu. If there are housekeeping + * CPUs that don't use nohz_full, these are preferred. Pass + * RESCTRL_PICK_ANY_CPU to avoid excluding any CPUs. + * + * When a CPU is excluded, returns >= nr_cpu_ids if no CPUs are available. */ -static inline unsigned int cpumask_any_housekeeping(const struct cpumask *mask) +static inline unsigned int +cpumask_any_housekeeping(const struct cpumask *mask, int exclude_cpu) { unsigned int cpu, hk_cpu; - cpu = cpumask_any(mask); - if (!tick_nohz_full_cpu(cpu)) + if (exclude_cpu == RESCTRL_PICK_ANY_CPU) + cpu = cpumask_any(mask); + else + cpu = cpumask_any_but(mask, exclude_cpu); + + if (!IS_ENABLED(CONFIG_NO_HZ_FULL)) + return cpu; + + /* If the CPU picked isn't marked nohz_full nothing more needs doing. */ + if (cpu < nr_cpu_ids && !tick_nohz_full_cpu(cpu)) return cpu; + /* Try to find a CPU that isn't nohz_full to use in preference */ hk_cpu = cpumask_nth_andnot(0, mask, tick_nohz_full_mask); + if (hk_cpu == exclude_cpu) + hk_cpu = cpumask_nth_andnot(1, mask, tick_nohz_full_mask); + if (hk_cpu < nr_cpu_ids) cpu = hk_cpu; @@ -573,11 +590,13 @@ void mon_event_read(struct rmid_read *rr, struct rdt_resource *r, struct rdt_domain *d, struct rdtgroup *rdtgrp, int evtid, int first); void mbm_setup_overflow_handler(struct rdt_domain *dom, - unsigned long delay_ms); + unsigned long delay_ms, + int exclude_cpu); void mbm_handle_overflow(struct work_struct *work); void __init intel_rdt_mbm_apply_quirk(void); bool is_mba_sc(struct rdt_resource *r); -void cqm_setup_limbo_handler(struct rdt_domain *dom, unsigned long delay_ms); +void cqm_setup_limbo_handler(struct rdt_domain *dom, unsigned long delay_ms, + int exclude_cpu); void cqm_handle_limbo(struct work_struct *work); bool has_busy_rmid(struct rdt_domain *d); void __check_limbo(struct rdt_domain *d, bool force_free); diff --git a/arch/x86/kernel/cpu/resctrl/monitor.c b/arch/x86/kernel/cpu/resctrl/monitor.c index 92d7ba674003..67edd4c440f0 100644 --- a/arch/x86/kernel/cpu/resctrl/monitor.c +++ b/arch/x86/kernel/cpu/resctrl/monitor.c @@ -481,7 +481,8 @@ static void add_rmid_to_limbo(struct rmid_entry *entry) * setup up the limbo worker. */ if (!has_busy_rmid(d)) - cqm_setup_limbo_handler(d, CQM_LIMBOCHECK_INTERVAL); + cqm_setup_limbo_handler(d, CQM_LIMBOCHECK_INTERVAL, + RESCTRL_PICK_ANY_CPU); set_bit(idx, d->rmid_busy_llc); entry->busy++; } @@ -784,7 +785,8 @@ void cqm_handle_limbo(struct work_struct *work) __check_limbo(d, false); if (has_busy_rmid(d)) { - d->cqm_work_cpu = cpumask_any_housekeeping(&d->cpu_mask); + d->cqm_work_cpu = cpumask_any_housekeeping(&d->cpu_mask, + RESCTRL_PICK_ANY_CPU); schedule_delayed_work_on(d->cqm_work_cpu, &d->cqm_limbo, delay); } @@ -792,15 +794,25 @@ void cqm_handle_limbo(struct work_struct *work) mutex_unlock(&rdtgroup_mutex); } -void cqm_setup_limbo_handler(struct rdt_domain *dom, unsigned long delay_ms) +/** + * cqm_setup_limbo_handler() - Schedule the limbo handler to run for this + * domain. + * @dom: The domain the limbo handler should run for. + * @delay_ms: How far in the future the handler should run. + * @exclude_cpu: Which CPU the handler should not run on, + * RESCTRL_PICK_ANY_CPU to pick any CPU. + */ +void cqm_setup_limbo_handler(struct rdt_domain *dom, unsigned long delay_ms, + int exclude_cpu) { unsigned long delay = msecs_to_jiffies(delay_ms); int cpu; - cpu = cpumask_any_housekeeping(&dom->cpu_mask); + cpu = cpumask_any_housekeeping(&dom->cpu_mask, exclude_cpu); dom->cqm_work_cpu = cpu; - schedule_delayed_work_on(cpu, &dom->cqm_limbo, delay); + if (cpu < nr_cpu_ids) + schedule_delayed_work_on(cpu, &dom->cqm_limbo, delay); } void mbm_handle_overflow(struct work_struct *work) @@ -838,14 +850,24 @@ void mbm_handle_overflow(struct work_struct *work) * Re-check for housekeeping CPUs. This allows the overflow handler to * move off a nohz_full CPU quickly. */ - d->mbm_work_cpu = cpumask_any_housekeeping(&d->cpu_mask); + d->mbm_work_cpu = cpumask_any_housekeeping(&d->cpu_mask, + RESCTRL_PICK_ANY_CPU); schedule_delayed_work_on(d->mbm_work_cpu, &d->mbm_over, delay); out_unlock: mutex_unlock(&rdtgroup_mutex); } -void mbm_setup_overflow_handler(struct rdt_domain *dom, unsigned long delay_ms) +/** + * mbm_setup_overflow_handler() - Schedule the overflow handler to run for this + * domain. + * @dom: The domain the overflow handler should run for. + * @delay_ms: How far in the future the handler should run. + * @exclude_cpu: Which CPU the handler should not run on, + * RESCTRL_PICK_ANY_CPU to pick any CPU. + */ +void mbm_setup_overflow_handler(struct rdt_domain *dom, unsigned long delay_ms, + int exclude_cpu) { unsigned long delay = msecs_to_jiffies(delay_ms); int cpu; @@ -856,9 +878,11 @@ void mbm_setup_overflow_handler(struct rdt_domain *dom, unsigned long delay_ms) */ if (!resctrl_mounted || !resctrl_arch_mon_capable()) return; - cpu = cpumask_any_housekeeping(&dom->cpu_mask); + cpu = cpumask_any_housekeeping(&dom->cpu_mask, exclude_cpu); dom->mbm_work_cpu = cpu; - schedule_delayed_work_on(cpu, &dom->mbm_over, delay); + + if (cpu < nr_cpu_ids) + schedule_delayed_work_on(cpu, &dom->mbm_over, delay); } static int dom_data_init(struct rdt_resource *r) diff --git a/arch/x86/kernel/cpu/resctrl/rdtgroup.c b/arch/x86/kernel/cpu/resctrl/rdtgroup.c index 38d3b19a3aca..f5688c79d94f 100644 --- a/arch/x86/kernel/cpu/resctrl/rdtgroup.c +++ b/arch/x86/kernel/cpu/resctrl/rdtgroup.c @@ -2678,7 +2678,8 @@ static int rdt_get_tree(struct fs_context *fc) if (is_mbm_enabled()) { r = &rdt_resources_all[RDT_RESOURCE_L3].r_resctrl; list_for_each_entry(dom, &r->domains, list) - mbm_setup_overflow_handler(dom, MBM_OVERFLOW_INTERVAL); + mbm_setup_overflow_handler(dom, MBM_OVERFLOW_INTERVAL, + RESCTRL_PICK_ANY_CPU); } goto out; @@ -3989,7 +3990,8 @@ int resctrl_online_domain(struct rdt_resource *r, struct rdt_domain *d) if (is_mbm_enabled()) { INIT_DELAYED_WORK(&d->mbm_over, mbm_handle_overflow); - mbm_setup_overflow_handler(d, MBM_OVERFLOW_INTERVAL); + mbm_setup_overflow_handler(d, MBM_OVERFLOW_INTERVAL, + RESCTRL_PICK_ANY_CPU); } if (is_llc_occupancy_enabled()) diff --git a/include/linux/resctrl.h b/include/linux/resctrl.h index 4c4bad3c34e4..ccbbbe5d18d3 100644 --- a/include/linux/resctrl.h +++ b/include/linux/resctrl.h @@ -10,6 +10,8 @@ #define RESCTRL_RESERVED_CLOSID 0 #define RESCTRL_RESERVED_RMID 0 +#define RESCTRL_PICK_ANY_CPU -1 + #ifdef CONFIG_PROC_CPU_RESCTRL int proc_resctrl_show(struct seq_file *m, -- 2.39.2