Messages in this thread | | | Subject | Re: [PATCH v2 15/23] x86/recstrl: Add per-rmid arch private storage for overflow and chunks | From | Reinette Chatre <> | Date | Fri, 15 Oct 2021 15:29:20 -0700 |
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Hi James,
On 10/1/2021 9:02 AM, James Morse wrote: > 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
resctrl_arch_rmid_read() does not exist at this point and is also not introduced in this patch.
> the mbm values in chunks directly from hardware. For bandwidth
Could you please replace mbm with MBM throughout the series?
> counters the resctrl filesystem uses this to calculate the number of > bytes ever seen. > > 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 an array 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 without assistance > from the filesystem. The values are moved in later patches when > the overflow and correction calls are moved into > resctrl_arch_rmid_read(). > > Signed-off-by: James Morse <james.morse@arm.com> > --- > arch/x86/kernel/cpu/resctrl/core.c | 34 ++++++++++++++++++++++++++ > arch/x86/kernel/cpu/resctrl/internal.h | 13 ++++++++++ > 2 files changed, 47 insertions(+) > > diff --git a/arch/x86/kernel/cpu/resctrl/core.c b/arch/x86/kernel/cpu/resctrl/core.c > index 583fb41db06d..f527489a607a 100644 > --- a/arch/x86/kernel/cpu/resctrl/core.c > +++ b/arch/x86/kernel/cpu/resctrl/core.c > @@ -413,6 +413,8 @@ void setup_default_ctrlval(struct rdt_resource *r, u32 *dc) > > void domain_free(struct rdt_hw_domain *hw_dom) > { > + kfree(hw_dom->arch_mbm_total); > + kfree(hw_dom->arch_mbm_local); > kfree(hw_dom->ctrl_val); > kfree(hw_dom); > } > @@ -438,6 +440,33 @@ static int domain_setup_ctrlval(struct rdt_resource *r, struct rdt_domain *d) > return 0; > } > > +/** > + * arch_domain_mbm_alloc() - Allocate arch private storage for the mbm counters
mbm -> MBM in comments also please .
> + * @num_rmid: The size of the mbm counter array > + * @hw_dom: The domain that owns the allocated the arrays
the allocated the -> the allocated
> + * > + * On error, call domain_free()
When following kerneldoc please use "Return:" to indicate the return section. It will help to run scripts/kernel-doc on these changes to make sure no new kernel-doc issues are introduced.
> + */ > +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) > + return -ENOMEM; > + } > +
Proper cleanup on error should be done in this function. Please do not use domain_free() as cleanup for what can be done in this function. I see domain_free() as the higher level error control ... like when a wrapper function calls arch_domain_mbm_alloc() and then something else fails after that ... then domain_free() would be that higher level error handling.
> + return 0; > +} > + > /* > * domain_add_cpu - Add a cpu to a resource's domain list. > * > @@ -487,6 +516,11 @@ 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)) { > + domain_free(hw_dom); > + return; > + } > + > list_add_tail(&d->list, add_pos); > > err = resctrl_online_domain(r, d); > 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
Missing a ":"? Please do not use "we".
This is a description of a struct ... can the doc elaborate on what "this RMID" means?
> + */ > +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) >
Reinette
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