[PATCH v6 28/42] x86/resctrl: Handle throttle_mode for SMBA resources

[James Morse]

Now that the visibility of throttle_mode is being managed by resctrl, it
should consider resources other than MBA that may have a throttle_mode.
SMBA is one such resource.

Extend resctrl_file_fflags_init() to check SMBA for a throttle_mode.

Adding support for multiple resources means it is possible for a platform
with both MBA and SMBA, but an undefined throttle_mode on one of them
to make the file visible.

Add the 'undefined' case to rdt_thread_throttle_mode_show().

Signed-off-by: James Morse <james.morse@xxxxxxx>
---
 Changes since v5:
  * This change split out of the previous patch.
---
 arch/x86/kernel/cpu/resctrl/rdtgroup.c | 33 +++++++++++++++++++++-----
 1 file changed, 27 insertions(+), 6 deletions(-)

diff --git a/arch/x86/kernel/cpu/resctrl/rdtgroup.c b/arch/x86/kernel/cpu/resctrl/rdtgroup.c
index 58feba3feefd..5fc60c9ce28f 100644
--- a/arch/x86/kernel/cpu/resctrl/rdtgroup.c
+++ b/arch/x86/kernel/cpu/resctrl/rdtgroup.c
@@ -1188,10 +1188,19 @@ static int rdt_thread_throttle_mode_show(struct kernfs_open_file *of,
 	struct resctrl_schema *s = of->kn->parent->priv;
 	struct rdt_resource *r = s->res;
 
-	if (r->membw.throttle_mode == THREAD_THROTTLE_PER_THREAD)
+	switch (r->membw.throttle_mode) {
+	case THREAD_THROTTLE_PER_THREAD:
 		seq_puts(seq, "per-thread\n");
-	else
+		return 0;
+	case THREAD_THROTTLE_MAX:
 		seq_puts(seq, "max\n");
+		return 0;
+	case THREAD_THROTTLE_UNDEFINED:
+		seq_puts(seq, "undefined\n");
+		return 0;
+	}
+
+	WARN_ON_ONCE(1);
 
 	return 0;
 }
@@ -2066,12 +2075,24 @@ static struct rftype *rdtgroup_get_rftype_by_name(const char *name)
 
 static void thread_throttle_mode_init(void)
 {
-	struct rdt_resource *r_mba;
+	enum membw_throttle_mode throttle_mode = THREAD_THROTTLE_UNDEFINED;
+	struct rdt_resource *r_mba, *r_smba;
 
 	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);
+	if (r_mba->alloc_capable &&
+	    r_mba->membw.throttle_mode != THREAD_THROTTLE_UNDEFINED)
+		throttle_mode = r_mba->membw.throttle_mode;
+
+	r_smba = resctrl_arch_get_resource(RDT_RESOURCE_SMBA);
+	if (r_smba->alloc_capable &&
+	    r_smba->membw.throttle_mode != THREAD_THROTTLE_UNDEFINED)
+		throttle_mode = r_smba->membw.throttle_mode;
+
+	if (throttle_mode == THREAD_THROTTLE_UNDEFINED)
+		return;
+
+	resctrl_file_fflags_init("thread_throttle_mode",
+				 RFTYPE_CTRL_INFO | RFTYPE_RES_MB);
 }
 
 void resctrl_file_fflags_init(const char *config, unsigned long fflags)
-- 
2.39.2