linux-kernel - [PATCH v20 09/18] x86/resctrl: Add a new field to struct rmid

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Message-ID: <20240610183528.349198-10-tony.luck@intel.com>
Date: Mon, 10 Jun 2024 11:35:19 -0700
From: Tony Luck <tony.luck@...el.com>
To: Fenghua Yu <fenghua.yu@...el.com>,
	Reinette Chatre <reinette.chatre@...el.com>,
	Maciej Wieczor-Retman <maciej.wieczor-retman@...el.com>,
	Peter Newman <peternewman@...gle.com>,
	James Morse <james.morse@....com>,
	Babu Moger <babu.moger@....com>,
	Drew Fustini <dfustini@...libre.com>,
	Dave Martin <Dave.Martin@....com>
Cc: x86@...nel.org,
	linux-kernel@...r.kernel.org,
	patches@...ts.linux.dev,
	Tony Luck <tony.luck@...el.com>
Subject: [PATCH v20 09/18] x86/resctrl: Add a new field to struct rmid_read for summation of domains

When a user reads a monitor file rdtgroup_mondata_show() calls
mon_event_read() to package up all the required details into an rmid_read
structure which is passed across the smp_call*() infrastructure to code
that will read data from hardware and return the value (or error status)
in the rmid_read structure.

Sub-NUMA Cluster (SNC) mode adds files with new semantics. These require
the smp_call-ed code to sum event data from all domains that share an
L3 cache.

Add a pointer to the L3 "cacheinfo" structure to struct rmid_read
for the data collection routines to use to pick the domains to be
summed.

Reinette suggested that the rmid_read structure has become complex
enough to warrant documentation of each of its fields. Add the kerneldoc
documentation for struct rmid_read.

Signed-off-by: Tony Luck <tony.luck@...el.com>
---
 arch/x86/kernel/cpu/resctrl/internal.h | 13 +++++++++++++
 1 file changed, 13 insertions(+)

diff --git a/arch/x86/kernel/cpu/resctrl/internal.h b/arch/x86/kernel/cpu/resctrl/internal.h
index 99f601d05f3b..d29c7b58c151 100644
--- a/arch/x86/kernel/cpu/resctrl/internal.h
+++ b/arch/x86/kernel/cpu/resctrl/internal.h
@@ -145,12 +145,25 @@ union mon_data_bits {
 	} u;
 };
 
+/**
+ * struct rmid_read - Data passed across smp_call*() to read event count
+ * @rgrp:	Resctrl group
+ * @r:		Resource
+ * @d:		Domain. If NULL then sum all domains in @r sharing L3 @ci.id
+ * @evtid:	Which monitor event to read
+ * @first:	Initializes MBM counter when true
+ * @ci:		Cacheinfo for L3. Used when summing domains
+ * @err:	Return error indication
+ * @val:	Return value of event counter
+ * @arch_mon_ctx: Hardware monitor allocated for this read request (MPAM only)
+ */
 struct rmid_read {
 	struct rdtgroup		*rgrp;
 	struct rdt_resource	*r;
 	struct rdt_mon_domain	*d;
 	enum resctrl_event_id	evtid;
 	bool			first;
+	struct cacheinfo	*ci;
 	int			err;
 	u64			val;
 	void			*arch_mon_ctx;
-- 
2.45.0