linux-kernel - [PATCH v1 17/20] x86/resctrl: Move get_corrected_mbm_count() into resctrl_arch_rmid

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Date:   Thu, 29 Jul 2021 22:36:07 +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,
        Jamie Iles <jamie@...iainc.com>,
        D Scott Phillips OS <scott@...amperecomputing.com>,
        lcherian@...vell.com, bobo.shaobowang@...wei.com
Subject: [PATCH v1 17/20] x86/resctrl: Move get_corrected_mbm_count() into resctrl_arch_rmid_read()

resctrl_arch_rmid_read() is intended as the function that an
architecture agnostic resctrl filesystem driver can use to
read a value in bytes from a counter. Currently the function returns
the mbm values in chunks directly from hardware. When reading a bandwidth
counter, get_corrected_mbm_count() must be used to correct the
value read.

get_corrected_mbm_count() is architecture specific, this work should be
done in resctrl_arch_rmid_read().

Move the function calls. This allows the resctrl filesystems's chunks
value to be removed in favour of the architecture private version.

Signed-off-by: James Morse <james.morse@....com>
---
 arch/x86/kernel/cpu/resctrl/internal.h |  4 ++--
 arch/x86/kernel/cpu/resctrl/monitor.c  | 15 ++++++---------
 2 files changed, 8 insertions(+), 11 deletions(-)

diff --git a/arch/x86/kernel/cpu/resctrl/internal.h b/arch/x86/kernel/cpu/resctrl/internal.h
index 2d0a6bba4a01..65b472d6b146 100644
--- a/arch/x86/kernel/cpu/resctrl/internal.h
+++ b/arch/x86/kernel/cpu/resctrl/internal.h
@@ -279,14 +279,12 @@ struct rftype {
 
 /**
  * struct mbm_state - status for each MBM counter in each domain
- * @chunks:	Total data moved (multiply by rdt_group.mon_scale to get bytes)
  * @prev_bw_chunks: Previous chunks value read when for bandwidth calculation
  * @prev_bw:	The most recent bandwidth in MBps
  * @delta_bw:	Difference between the current and previous bandwidth
  * @delta_comp:	Indicates whether to compute the delta_bw
  */
 struct mbm_state {
-	u64	chunks;
 	u64	prev_bw_chunks;
 	u32	prev_bw;
 	u32	delta_bw;
@@ -296,9 +294,11 @@ struct mbm_state {
 /**
  * struct arch_mbm_state - values used to compute resctrl_arch_rmid_read()s
  *			   return value.
+ * @chunks:	Total data moved (multiply by rdt_group.mon_scale to get bytes)
  * @prev_msr	Value of IA32_QM_CTR for this RMID last time we read it
  */
 struct arch_mbm_state {
+	u64	chunks;
 	u64	prev_msr;
 };
 
diff --git a/arch/x86/kernel/cpu/resctrl/monitor.c b/arch/x86/kernel/cpu/resctrl/monitor.c
index 39f7e74a4236..9321c758752a 100644
--- a/arch/x86/kernel/cpu/resctrl/monitor.c
+++ b/arch/x86/kernel/cpu/resctrl/monitor.c
@@ -201,7 +201,9 @@ int resctrl_arch_rmid_read(struct rdt_resource	*r, struct rdt_domain *d,
 
 	m = get_arch_mbm_state(hw_dom, rmid, eventid);
 	if (m) {
-		*val = mbm_overflow_count(m->prev_msr, msr_val, hw_res->mbm_width);
+		m->chunks += mbm_overflow_count(m->prev_msr, msr_val,
+						hw_res->mbm_width);
+		*val = get_corrected_mbm_count(rmid, m->chunks);
 		m->prev_msr = msr_val;
 	} else {
 		*val = msr_val;
@@ -366,9 +368,7 @@ static int __mon_event_count(u32 rmid, struct rmid_read *rr)
 		return 0;
 	}
 
-	m->chunks += tval;
-
-	rr->val += get_corrected_mbm_count(rmid, m->chunks);
+	rr->val += tval;
 
 	return 0;
 }
@@ -381,14 +381,11 @@ static void mbm_bw_count(u32 rmid, struct rmid_read *rr)
 {
 	struct rdt_hw_resource *hw_res = resctrl_to_arch_res(rr->r);
 	struct mbm_state *m = &rr->d->mbm_local[rmid];
-	u64 tval = 0, cur_bw, bw_chunks;
+	u64 cur_bw, bw_chunks = 0;
 
-	if (resctrl_arch_rmid_read(rr->r, rr->d, rmid, rr->evtid, &tval))
+	if (resctrl_arch_rmid_read(rr->r, rr->d, rmid, rr->evtid, &bw_chunks))
 		return;
 
-	m->chunks += tval;
-	bw_chunks = get_corrected_mbm_count(rmid, m->chunks);
-
 	cur_bw = (bw_chunks - m->prev_bw_chunks) * hw_res->mon_scale;
 	cur_bw >>= 20;
 
-- 
2.30.2