Messages in this thread Patch in this message | | | From | James Morse <> | Subject | [PATCH v1 16/20] x86/resctrl: Move mbm_overflow_count() into resctrl_arch_rmid_read() | Date | Thu, 29 Jul 2021 22:36:06 +0000 |
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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, mbm_overflow_count() must be used to correct for any possible overflow.
mbm_overflow_count() is architecture specific, its behaviour should be part of resctrl_arch_rmid_read().
Move the mbm_overflow_count() calls into resctrl_arch_rmid_read(). This allows the resctrl filesystems's prev_msr to be removed in favour of the architecture private version.
Signed-off-by: James Morse <james.morse@arm.com> --- arch/x86/kernel/cpu/resctrl/internal.h | 2 -- arch/x86/kernel/cpu/resctrl/monitor.c | 42 ++++++++++++++------------ 2 files changed, 23 insertions(+), 21 deletions(-)
diff --git a/arch/x86/kernel/cpu/resctrl/internal.h b/arch/x86/kernel/cpu/resctrl/internal.h index eca7793d3342..2d0a6bba4a01 100644 --- a/arch/x86/kernel/cpu/resctrl/internal.h +++ b/arch/x86/kernel/cpu/resctrl/internal.h @@ -280,7 +280,6 @@ 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_msr: Value of IA32_QM_CTR for this RMID last time we read it * @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 @@ -288,7 +287,6 @@ struct rftype { */ struct mbm_state { u64 chunks; - u64 prev_msr; u64 prev_bw_chunks; u32 prev_bw; u32 delta_bw; diff --git a/arch/x86/kernel/cpu/resctrl/monitor.c b/arch/x86/kernel/cpu/resctrl/monitor.c index aa85cfd95904..39f7e74a4236 100644 --- a/arch/x86/kernel/cpu/resctrl/monitor.c +++ b/arch/x86/kernel/cpu/resctrl/monitor.c @@ -164,9 +164,20 @@ void resctrl_arch_reset_rmid(struct rdt_resource *r, struct rdt_domain *d, memset(m, 0, sizeof(*m)); } +static u64 mbm_overflow_count(u64 prev_msr, u64 cur_msr, unsigned int width) +{ + u64 shift = 64 - width, chunks; + + chunks = (cur_msr << shift) - (prev_msr << shift); + return chunks >>= shift; +} + int resctrl_arch_rmid_read(struct rdt_resource *r, struct rdt_domain *d, u32 rmid, enum resctrl_event_id eventid, u64 *val) { + struct rdt_hw_resource *hw_res = resctrl_to_arch_res(r); + struct rdt_hw_domain *hw_dom = resctrl_to_arch_dom(d); + struct arch_mbm_state *m; u64 msr_val; if (!cpumask_test_cpu(smp_processor_id(), &d->cpu_mask)) @@ -188,7 +199,13 @@ int resctrl_arch_rmid_read(struct rdt_resource *r, struct rdt_domain *d, if (msr_val & RMID_VAL_UNAVAIL) return -EINVAL; - *val = msr_val; + 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->prev_msr = msr_val; + } else { + *val = msr_val; + } return 0; } @@ -319,19 +336,10 @@ void free_rmid(u32 rmid) list_add_tail(&entry->list, &rmid_free_lru); } -static u64 mbm_overflow_count(u64 prev_msr, u64 cur_msr, unsigned int width) -{ - u64 shift = 64 - width, chunks; - - chunks = (cur_msr << shift) - (prev_msr << shift); - return chunks >>= shift; -} - static int __mon_event_count(u32 rmid, struct rmid_read *rr) { - struct rdt_hw_resource *hw_res = resctrl_to_arch_res(rr->r); struct mbm_state *m; - u64 chunks, tval = 0; + u64 tval = 0; if (rr->first) resctrl_arch_reset_rmid(rr->r, rr->d, rmid, rr->evtid); @@ -354,13 +362,11 @@ static int __mon_event_count(u32 rmid, struct rmid_read *rr) if (rr->first) { memset(m, 0, sizeof(struct mbm_state)); - m->prev_bw_chunks = m->prev_msr = tval; + m->prev_bw_chunks = tval; return 0; } - chunks = mbm_overflow_count(m->prev_msr, tval, hw_res->mbm_width); - m->chunks += chunks; - m->prev_msr = tval; + m->chunks += tval; rr->val += get_corrected_mbm_count(rmid, m->chunks); @@ -375,14 +381,12 @@ 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, chunks, bw_chunks; + u64 tval = 0, cur_bw, bw_chunks; if (resctrl_arch_rmid_read(rr->r, rr->d, rmid, rr->evtid, &tval)) return; - chunks = mbm_overflow_count(m->prev_msr, tval, hw_res->mbm_width); - m->chunks += chunks; - m->prev_msr = tval; + m->chunks += tval; bw_chunks = get_corrected_mbm_count(rmid, m->chunks); cur_bw = (bw_chunks - m->prev_bw_chunks) * hw_res->mon_scale; -- 2.30.2
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