Messages in this thread | | | Date | Fri, 4 Mar 2022 16:26:14 -0800 | Subject | Re: [PATCH v3 07/21] x86/resctrl: Create mba_sc configuration in the rdt_domain | From | Reinette Chatre <> |
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Hi James,
On 2/17/2022 10:20 AM, James Morse wrote: > To support resctrl's MBA software controller, the architecture must provide > a second configuration array to hold the mbps_val[] from user-space. > > This complicates the interface between the architecture specific code and > the filesystem portions of resctrl that will move to /fs/, to allow > multiple architectures to support resctrl. > > Make the filesystem parts of resctrl create an array for the mba_sc > values when is_mba_sc() is set to true. The software controller > can be changed to use this, allowing the architecture code to only > consider the values configured in hardware. > > Signed-off-by: James Morse <james.morse@arm.com> > --- > Changes since v2: > * Split patch in two, the liftime parts are a separate patch. > * Added reset in set_mba_sc() now that we can't depend on the lifetime. > * Initialise ret in mba_sc_allocate(), > * Made mbps_val allocation/freeing symmetric for cpuhp calls. > * Removed reference to squashed-out struct. > * Preserved kerneldoc for mbps_val. > > Changes since v1: > * Added missing error handling to mba_sc_domain_allocate() in > domain_setup_mon_state() > * Added comment about mba_sc_domain_allocate() races > * Squashed out struct resctrl_mba_sc > * Moved mount time alloc/free calls to set_mba_sc(). > * Removed mount check in resctrl_offline_domain() > * Reword commit message > --- > arch/x86/kernel/cpu/resctrl/internal.h | 1 - > arch/x86/kernel/cpu/resctrl/rdtgroup.c | 41 ++++++++++++++++++++++++++ > include/linux/resctrl.h | 7 +++++ > 3 files changed, 48 insertions(+), 1 deletion(-) > > diff --git a/arch/x86/kernel/cpu/resctrl/internal.h b/arch/x86/kernel/cpu/resctrl/internal.h > index e12b55f815bf..a7e2cbce29d5 100644 > --- a/arch/x86/kernel/cpu/resctrl/internal.h > +++ b/arch/x86/kernel/cpu/resctrl/internal.h > @@ -36,7 +36,6 @@ > #define MBM_OVERFLOW_INTERVAL 1000 > #define MAX_MBA_BW 100u > #define MBA_IS_LINEAR 0x4 > -#define MBA_MAX_MBPS U32_MAX > #define MAX_MBA_BW_AMD 0x800 > #define MBM_CNTR_WIDTH_OFFSET_AMD 20 > > diff --git a/arch/x86/kernel/cpu/resctrl/rdtgroup.c b/arch/x86/kernel/cpu/resctrl/rdtgroup.c > index 794a84ba9097..e4313f907eb6 100644 > --- a/arch/x86/kernel/cpu/resctrl/rdtgroup.c > +++ b/arch/x86/kernel/cpu/resctrl/rdtgroup.c > @@ -1889,6 +1889,30 @@ void rdt_domain_reconfigure_cdp(struct rdt_resource *r) > l3_qos_cfg_update(&hw_res->cdp_enabled); > } > > +static int mba_sc_domain_allocate(struct rdt_resource *r, struct rdt_domain *d) > +{ > + u32 num_closid = resctrl_arch_get_num_closid(r); > + int cpu = cpumask_any(&d->cpu_mask); > + int i; > + > + d->mbps_val = kcalloc_node(num_closid, sizeof(*d->mbps_val), > + GFP_KERNEL, cpu_to_node(cpu)); > + if (!d->mbps_val) > + return -ENOMEM; > + > + for (i = 0; i < num_closid; i++) > + d->mbps_val[i] = MBA_MAX_MBPS; > + > + return 0; > +} > + > +static void mba_sc_domain_destroy(struct rdt_resource *r, > + struct rdt_domain *d) > +{ > + kfree(d->mbps_val); > + d->mbps_val = NULL; > +} > +
...
> @@ -3263,6 +3295,9 @@ void resctrl_offline_domain(struct rdt_resource *r, struct rdt_domain *d) > cancel_delayed_work(&d->cqm_limbo); > } > > + if (is_mba_sc(r)) > + mba_sc_domain_destroy(r, d); > + > domain_destroy_mon_state(d); > } > > @@ -3309,6 +3344,12 @@ int resctrl_online_domain(struct rdt_resource *r, struct rdt_domain *d) > if (err) > return err; > > + err = mba_sc_domain_allocate(r, d); > + if (err) { > + domain_destroy_mon_state(d); > + return err; > + } > +
Thank you for making this all symmetrical. It seems as though the new array is always created but only destroyed when is_mba_sc() is true. Is this correct?
Reinette
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