[PATCH v6 18/21] x86/resctrl: Move get_corrected_mbm_count() into resctrl_arch_rmid_read()

James Morse
2022-09-02T15:58:02Z

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.

Reviewed-by: Jamie Iles <quic_jiles@quicinc.com>
Tested-by: Xin Hao <xhao@linux.alibaba.com>
Reviewed-by: Shaopeng Tan <tan.shaopeng@fujitsu.com>
Tested-by: Shaopeng Tan <tan.shaopeng@fujitsu.com>
Tested-by: Cristian Marussi <cristian.marussi@arm.com>
Reviewed-by: Reinette Chatre <reinette.chatre@intel.com>
Signed-off-by: James Morse <james.morse@arm.com>
---
arch/x86/kernel/cpu/resctrl/internal.h | 4 ++--
arch/x86/kernel/cpu/resctrl/monitor.c | 8 ++++----
2 files changed, 6 insertions(+), 6 deletions(-)

diff --git a/arch/x86/kernel/cpu/resctrl/internal.h b/arch/x86/kernel/cpu/resctrl/internal.h
index 8039e8aba7de..bdb55c2fbdd3 100644
--- a/arch/x86/kernel/cpu/resctrl/internal.h
+++ b/arch/x86/kernel/cpu/resctrl/internal.h
@@ -280,14 +280,12 @@ 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 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;
@@ -297,10 +295,12 @@ 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 last time it was read for the RMID used to
* find this struct.
*/
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 862a4462ed60..27bb4947a176 100644
--- a/arch/x86/kernel/cpu/resctrl/monitor.c
+++ b/arch/x86/kernel/cpu/resctrl/monitor.c
@@ -204,7 +204,9 @@ int resctrl_arch_rmid_read(struct rdt_resource *r, struct rdt_domain *d,

am = get_arch_mbm_state(hw_dom, rmid, eventid);
if (am) {
- *val = mbm_overflow_count(am->prev_msr, msr_val, hw_res->mbm_width);
+ am->chunks += mbm_overflow_count(am->prev_msr, msr_val,
+ hw_res->mbm_width);
+ *val = get_corrected_mbm_count(rmid, am->chunks);
am->prev_msr = msr_val;
} else {
*val = msr_val;
@@ -374,9 +376,7 @@ 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;
}
--
2.30.2