linux-kernel - [PATCH v6 27/42] x86/resctrl: Move RFTYPE flags to be managed by resctrl

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Message-Id: <20250207181823.6378-28-james.morse@arm.com>
Date: Fri,  7 Feb 2025 18:18:08 +0000
From: James Morse <james.morse@....com>
To: x86@...nel.org,
	linux-kernel@...r.kernel.org
Cc: 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>,
	Koba Ko <kobak@...dia.com>,
	Shanker Donthineni <sdonthineni@...dia.com>
Subject: [PATCH v6 27/42] x86/resctrl: Move RFTYPE flags to be managed by resctrl

resctrl_file_fflags_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 forces the RFTYPE flags used by resctrl to be exposed to the
architecture specific code.

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. This allows the RFTYPE flags to be private to resctrl.

Add thread_throttle_mode_init(), and use it to call
resctrl_file_fflags_init()  from resctrl_setup(). This avoids
publishing an extra function between the architecture and filesystem
code.

Signed-off-by: James Morse <james.morse@....com>
---
Changes since v5:
 * Added checking for SMBA.
 * Added printing of undefined to rdt_thread_throttle_mode_show().
 * Major juggling around commit 2937f9c361f7 ("x86/resctrl: Introduce resctrl_file_fflags_init() to initialize fflags")
 * Dropped tags, split patch
---
 arch/x86/kernel/cpu/resctrl/core.c     |  3 ---
 arch/x86/kernel/cpu/resctrl/rdtgroup.c | 12 ++++++++++++
 2 files changed, 12 insertions(+), 3 deletions(-)

diff --git a/arch/x86/kernel/cpu/resctrl/core.c b/arch/x86/kernel/cpu/resctrl/core.c
index 1fb4eb4e0ea9..e4b676879227 100644
--- a/arch/x86/kernel/cpu/resctrl/core.c
+++ b/arch/x86/kernel/cpu/resctrl/core.c
@@ -229,9 +229,6 @@ static __init bool __get_mem_config_intel(struct rdt_resource *r)
 	else
 		r->membw.throttle_mode = THREAD_THROTTLE_MAX;
 
-	resctrl_file_fflags_init("thread_throttle_mode",
-				 RFTYPE_CTRL_INFO | RFTYPE_RES_MB);
-
 	r->alloc_capable = true;
 
 	return true;
diff --git a/arch/x86/kernel/cpu/resctrl/rdtgroup.c b/arch/x86/kernel/cpu/resctrl/rdtgroup.c
index e59271515a46..58feba3feefd 100644
--- a/arch/x86/kernel/cpu/resctrl/rdtgroup.c
+++ b/arch/x86/kernel/cpu/resctrl/rdtgroup.c
@@ -2064,6 +2064,16 @@ static struct rftype *rdtgroup_get_rftype_by_name(const char *name)
 	return NULL;
 }
 
+static void thread_throttle_mode_init(void)
+{
+	struct rdt_resource *r_mba;
+
+	r_mba = resctrl_arch_get_resource(RDT_RESOURCE_MBA);
+	if (r_mba->membw.throttle_mode != THREAD_THROTTLE_UNDEFINED)
+		resctrl_file_fflags_init("thread_throttle_mode",
+					 RFTYPE_CTRL_INFO | RFTYPE_RES_MB);
+}
+
 void resctrl_file_fflags_init(const char *config, unsigned long fflags)
 {
 	struct rftype *rft;
@@ -4277,6 +4287,8 @@ int __init resctrl_init(void)
 
 	rdtgroup_setup_default();
 
+	thread_throttle_mode_init();
+
 	ret = resctrl_mon_resource_init();
 	if (ret)
 		return ret;
-- 
2.39.2