linux-kernel - [PATCH v4 26/39] x86/resctrl: Move thread_throttle_mode

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Message-Id: <20240802172853.22529-27-james.morse@arm.com>
Date: Fri,  2 Aug 2024 17:28:40 +0000
From: James Morse <james.morse@....com>
To: x86@...nel.org,
	linux-kernel@...r.kernel.org
Cc: Fenghua Yu <fenghua.yu@...el.com>,
	Reinette Chatre <reinette.chatre@...el.com>,
	Thomas Gleixner <tglx@...utronix.de>,
	Ingo Molnar <mingo@...hat.com>,
	Borislav Petkov <bp@...en8.de>,
	H Peter Anvin <hpa@...or.com>,
	Babu Moger <Babu.Moger@....com>,
	James Morse <james.morse@....com>,
	shameerali.kolothum.thodi@...wei.com,
	D Scott Phillips OS <scott@...amperecomputing.com>,
	carl@...amperecomputing.com,
	lcherian@...vell.com,
	bobo.shaobowang@...wei.com,
	tan.shaopeng@...itsu.com,
	baolin.wang@...ux.alibaba.com,
	Jamie Iles <quic_jiles@...cinc.com>,
	Xin Hao <xhao@...ux.alibaba.com>,
	peternewman@...gle.com,
	dfustini@...libre.com,
	amitsinght@...vell.com,
	David Hildenbrand <david@...hat.com>,
	Rex Nie <rex.nie@...uarmicro.com>,
	Dave Martin <dave.martin@....com>
Subject: [PATCH v4 26/39] x86/resctrl: Move thread_throttle_mode_init() to be managed by resctrl

thread_throttle_mode_init() is called from the architecture specific code
to make the 'thread_throttle_mode' file visible. The architecture specific
code has already set the membw.throttle_mode in the rdt_resource.

This doesn't need to be specific to the architecture, the throttle_mode
can be used by resctrl to determine if the 'thread_throttle_mode' file
should be visible.

Call thread_throttle_mode_init() from resctrl_setup(), check the
membw.throttle_mode on the MBA resource. This avoids publishing an
extra function between the architecture and filesystem code.

Signed-off-by: James Morse <james.morse@....com>
Tested-by: Carl Worth <carl@...amperecomputing.com> # arm64
---
 arch/x86/kernel/cpu/resctrl/core.c     | 1 -
 arch/x86/kernel/cpu/resctrl/internal.h | 1 -
 arch/x86/kernel/cpu/resctrl/rdtgroup.c | 9 ++++++++-
 3 files changed, 8 insertions(+), 3 deletions(-)

diff --git a/arch/x86/kernel/cpu/resctrl/core.c b/arch/x86/kernel/cpu/resctrl/core.c
index bfdd49695c37..b36d8e8afc1a 100644
--- a/arch/x86/kernel/cpu/resctrl/core.c
+++ b/arch/x86/kernel/cpu/resctrl/core.c
@@ -224,7 +224,6 @@ static bool __get_mem_config_intel(struct rdt_resource *r)
 		r->membw.throttle_mode = THREAD_THROTTLE_PER_THREAD;
 	else
 		r->membw.throttle_mode = THREAD_THROTTLE_MAX;
-	thread_throttle_mode_init();
 
 	r->alloc_capable = true;
 
diff --git a/arch/x86/kernel/cpu/resctrl/internal.h b/arch/x86/kernel/cpu/resctrl/internal.h
index a0e11260235f..66ff26a121ed 100644
--- a/arch/x86/kernel/cpu/resctrl/internal.h
+++ b/arch/x86/kernel/cpu/resctrl/internal.h
@@ -495,7 +495,6 @@ void cqm_handle_limbo(struct work_struct *work);
 bool has_busy_rmid(struct rdt_mon_domain *d);
 void __check_limbo(struct rdt_mon_domain *d, bool force_free);
 void rdt_domain_reconfigure_cdp(struct rdt_resource *r);
-void __init thread_throttle_mode_init(void);
 void mbm_config_rftype_init(const char *config);
 void rdt_staged_configs_clear(void);
 bool closid_allocated(unsigned int closid);
diff --git a/arch/x86/kernel/cpu/resctrl/rdtgroup.c b/arch/x86/kernel/cpu/resctrl/rdtgroup.c
index 68947e0f69d9..b35f9659e536 100644
--- a/arch/x86/kernel/cpu/resctrl/rdtgroup.c
+++ b/arch/x86/kernel/cpu/resctrl/rdtgroup.c
@@ -2048,10 +2048,15 @@ static struct rftype *rdtgroup_get_rftype_by_name(const char *name)
 	return NULL;
 }
 
-void __init thread_throttle_mode_init(void)
+static void __init thread_throttle_mode_init(void)
 {
+	struct rdt_resource *r = resctrl_arch_get_resource(RDT_RESOURCE_MBA);
 	struct rftype *rft;
 
+	if (!r->alloc_capable ||
+	    r->membw.throttle_mode == THREAD_THROTTLE_UNDEFINED)
+		return;
+
 	rft = rdtgroup_get_rftype_by_name("thread_throttle_mode");
 	if (!rft)
 		return;
@@ -4272,6 +4277,8 @@ int __init resctrl_init(void)
 
 	rdtgroup_setup_default();
 
+	thread_throttle_mode_init();
+
 	ret = resctrl_mon_resource_init();
 	if (ret)
 		return ret;
-- 
2.39.2