Messages in this thread Patch in this message | | | From | James Morse <> | Subject | [PATCH v1 12/20] x86/recstrl: Add per-rmid arch private storage for overflow and chunks | Date | Thu, 29 Jul 2021 22:36:02 +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. For bandwidth counters the resctrl filesystem provides the number of bytes ever seen. Internally mba_sc uses a second prev_bw_msr to calculate the bytes read since the last mba_sc invocation.
MPAM's scaling of counters can be changed at runtime, reducing the resolution but increasing the range. When this is changed the prev_msr values need to be converted by the architecture code.
Add storage for per-rmid private storage. The prev_msr and chunks values will move here to allow resctrl_arch_rmid_read() to always return the number of bytes read by this counter.
Signed-off-by: James Morse <james.morse@arm.com> --- arch/x86/kernel/cpu/resctrl/core.c | 29 ++++++++++++++++++++++++++ arch/x86/kernel/cpu/resctrl/internal.h | 13 ++++++++++++ 2 files changed, 42 insertions(+)
diff --git a/arch/x86/kernel/cpu/resctrl/core.c b/arch/x86/kernel/cpu/resctrl/core.c index 8a3c13c6c19f..27c93d12ca27 100644 --- a/arch/x86/kernel/cpu/resctrl/core.c +++ b/arch/x86/kernel/cpu/resctrl/core.c @@ -432,6 +432,28 @@ static int domain_setup_ctrlval(struct rdt_resource *r, struct rdt_domain *d) return 0; } +static int arch_domain_mbm_alloc(u32 num_rmid, struct rdt_hw_domain *hw_dom) +{ + size_t tsize; + + if (is_mbm_total_enabled()) { + tsize = sizeof(*hw_dom->arch_mbm_total); + hw_dom->arch_mbm_total = kcalloc(num_rmid, tsize, GFP_KERNEL); + if (!hw_dom->arch_mbm_total) + return -ENOMEM; + } + if (is_mbm_local_enabled()) { + tsize = sizeof(*hw_dom->arch_mbm_local); + hw_dom->arch_mbm_local = kcalloc(num_rmid, tsize, GFP_KERNEL); + if (!hw_dom->arch_mbm_local) { + kfree(hw_dom->arch_mbm_total); + return -ENOMEM; + } + } + + return 0; +} + /* * domain_add_cpu - Add a cpu to a resource's domain list. * @@ -481,6 +503,11 @@ static void domain_add_cpu(int cpu, struct rdt_resource *r) return; } + if (r->mon_capable && arch_domain_mbm_alloc(r->num_rmid, hw_dom)) { + kfree(d); + return; + } + list_add_tail(&d->list, add_pos); err = resctrl_online_domain(r, d); @@ -516,6 +543,8 @@ static void domain_remove_cpu(int cpu, struct rdt_resource *r) d->plr->d = NULL; kfree(hw_dom->ctrl_val); + kfree(hw_dom->arch_mbm_total); + kfree(hw_dom->arch_mbm_local); kfree(hw_dom); return; } diff --git a/arch/x86/kernel/cpu/resctrl/internal.h b/arch/x86/kernel/cpu/resctrl/internal.h index 0a5721e1cc07..aaae900a8ef3 100644 --- a/arch/x86/kernel/cpu/resctrl/internal.h +++ b/arch/x86/kernel/cpu/resctrl/internal.h @@ -303,17 +303,30 @@ struct mbm_state { bool delta_comp; }; +/** + * struct arch_mbm_state - values used to compute resctrl_arch_rmid_read()s + * return value. + * @prev_msr Value of IA32_QM_CTR for this RMID last time we read it + */ +struct arch_mbm_state { + u64 prev_msr; +}; + /** * struct rdt_hw_domain - Arch private attributes of a set of CPUs that share * a resource * @d_resctrl: Properties exposed to the resctrl file system * @ctrl_val: array of cache or mem ctrl values (indexed by CLOSID) + * @arch_mbm_total: arch private state for MBM total bandwidth + * @arch_mbm_local: arch private state for MBM local bandwidth * * Members of this structure are accessed via helpers that provide abstraction. */ struct rdt_hw_domain { struct rdt_domain d_resctrl; u32 *ctrl_val; + struct arch_mbm_state *arch_mbm_total; + struct arch_mbm_state *arch_mbm_local; }; static inline struct rdt_hw_domain *resctrl_to_arch_dom(struct rdt_domain *r) -- 2.30.2
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