linux-kernel - [PATCH v4 17/39] x86/resctrl: Rewrite and move the for_each_*_rdt

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Message-Id: <20240802172853.22529-18-james.morse@arm.com>
Date: Fri,  2 Aug 2024 17:28:31 +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 17/39] x86/resctrl: Rewrite and move the for_each_*_rdt_resource() walkers

The for_each_*_rdt_resource() helpers walk the architecture's array
of structures, using the resctrl visible part as an iterator. These
became over-complex when the structures were split into a
filesystem and architecture-specific struct. This approach avoided
the need to touch every call site, and was done before there was a
helper to retrieve a resource by rid.

Once the filesystem parts of resctrl are moved to /fs/, both the
architecture's resource array, and the definition of those structures
is no longer accessible. To support resctrl, each architecture would
have to provide equally complex macros.

Rewrite the macro to make use of resctrl_arch_get_resource(), and
move these to the core header so existing x86 arch code continues
to use them.

Signed-off-by: James Morse <james.morse@....com>
---
Changes since v3:
 * Restructure the existing macros instead of open-coding the for loop.

Changes since v1:
 * [Whitespace only] Fix bogus whitespace introduced in
   rdtgroup_create_info_dir().

 * [Commit message only] Typo fix:
   s/architectures/architecture's/g
---
 arch/x86/kernel/cpu/resctrl/internal.h | 29 --------------------------
 include/linux/resctrl.h                | 18 ++++++++++++++++
 2 files changed, 18 insertions(+), 29 deletions(-)

diff --git a/arch/x86/kernel/cpu/resctrl/internal.h b/arch/x86/kernel/cpu/resctrl/internal.h
index 8e52e81a044b..84e0d019423d 100644
--- a/arch/x86/kernel/cpu/resctrl/internal.h
+++ b/arch/x86/kernel/cpu/resctrl/internal.h
@@ -472,14 +472,6 @@ extern struct rdt_hw_resource rdt_resources_all[];
 extern struct rdtgroup rdtgroup_default;
 extern struct dentry *debugfs_resctrl;
 
-static inline struct rdt_resource *resctrl_inc(struct rdt_resource *res)
-{
-	struct rdt_hw_resource *hw_res = resctrl_to_arch_res(res);
-
-	hw_res++;
-	return &hw_res->r_resctrl;
-}
-
 static inline bool resctrl_arch_get_cdp_enabled(enum resctrl_res_level l)
 {
 	return rdt_resources_all[l].cdp_enabled;
@@ -489,27 +481,6 @@ int resctrl_arch_set_cdp_enabled(enum resctrl_res_level l, bool enable);
 
 void arch_mon_domain_online(struct rdt_resource *r, struct rdt_mon_domain *d);
 
-/*
- * To return the common struct rdt_resource, which is contained in struct
- * rdt_hw_resource, walk the resctrl member of struct rdt_hw_resource.
- */
-#define for_each_rdt_resource(r)					      \
-	for (r = &rdt_resources_all[0].r_resctrl;			      \
-	     r <= &rdt_resources_all[RDT_NUM_RESOURCES - 1].r_resctrl;	      \
-	     r = resctrl_inc(r))
-
-#define for_each_capable_rdt_resource(r)				      \
-	for_each_rdt_resource(r)					      \
-		if (r->alloc_capable || r->mon_capable)
-
-#define for_each_alloc_capable_rdt_resource(r)				      \
-	for_each_rdt_resource(r)					      \
-		if (r->alloc_capable)
-
-#define for_each_mon_capable_rdt_resource(r)				      \
-	for_each_rdt_resource(r)					      \
-		if (r->mon_capable)
-
 /* CPUID.(EAX=10H, ECX=ResID=1).EAX */
 union cpuid_0x10_1_eax {
 	struct {
diff --git a/include/linux/resctrl.h b/include/linux/resctrl.h
index c8cd6dde91ed..04a410a5e739 100644
--- a/include/linux/resctrl.h
+++ b/include/linux/resctrl.h
@@ -26,6 +26,24 @@ int proc_resctrl_show(struct seq_file *m,
 /* max value for struct rdt_domain's mbps_val */
 #define MBA_MAX_MBPS   U32_MAX
 
+/* Walk all possible resources, with variants for only controls or monitors. */
+#define for_each_rdt_resource(_r)						\
+	for ((_r) = resctrl_arch_get_resource(0);				\
+	     (_r)->rid < RDT_NUM_RESOURCES - 1;					\
+	     (_r) = resctrl_arch_get_resource((_r)->rid + 1))
+
+#define for_each_capable_rdt_resource(r)				      \
+	for_each_rdt_resource((r))					      \
+		if ((r)->alloc_capable || (r)->mon_capable)
+
+#define for_each_alloc_capable_rdt_resource(r)				      \
+	for_each_rdt_resource((r))					      \
+		if ((r)->alloc_capable)
+
+#define for_each_mon_capable_rdt_resource(r)				      \
+	for_each_rdt_resource((r))					      \
+		if ((r)->mon_capable)
+
 /**
  * enum resctrl_conf_type - The type of configuration.
  * @CDP_NONE:	No prioritisation, both code and data are controlled or monitored.
-- 
2.39.2