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SubjectRe: [tip:x86/cache] x86/resctrl: Initialize a new resource group with default MBA values
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Hi Boris,

I found a nitpick - an unnecessary newline at the end of the patch.
Please help double check. Thank you.

On 4/18/2019 6:14, tip-bot for Xiaochen Shen wrote:
> Commit-ID: 47820e73f5b3a1fdb8ebd1219191edc96e0c85c1
> Gitweb: https://git.kernel.org/tip/47820e73f5b3a1fdb8ebd1219191edc96e0c85c1
> Author: Xiaochen Shen <xiaochen.shen@intel.com>
> AuthorDate: Wed, 17 Apr 2019 19:08:49 +0800
> Committer: Borislav Petkov <bp@suse.de>
> CommitDate: Thu, 18 Apr 2019 00:06:31 +0200
>
> x86/resctrl: Initialize a new resource group with default MBA values
>
> Currently, when a new resource group is created, the allocation values
> of the MBA resource are not initialized and remain meaningless data.
>
> For example:
>
> mkdir /sys/fs/resctrl/p1
> cat /sys/fs/resctrl/p1/schemata
> MB:0=100;1=100
>
> echo "MB:0=10;1=20" > /sys/fs/resctrl/p1/schemata
> cat /sys/fs/resctrl/p1/schemata
> MB:0= 10;1= 20
>
> rmdir /sys/fs/resctrl/p1
> mkdir /sys/fs/resctrl/p2
> cat /sys/fs/resctrl/p2/schemata
> MB:0= 10;1= 20
>
> Therefore, when the new group is created, it is reasonable to initialize
> MBA resource with default values.
>
> Initialize the MBA resource and cache resources in separate functions.
>
> [ bp: Add newlines between code blocks for better readability. ]
>
> Signed-off-by: Xiaochen Shen <xiaochen.shen@intel.com>
> Signed-off-by: Borislav Petkov <bp@suse.de>
> Reviewed-by: Fenghua Yu <fenghua.yu@intel.com>
> Reviewed-by: Reinette Chatre <reinette.chatre@intel.com>
> Cc: "H. Peter Anvin" <hpa@zytor.com>
> Cc: Ingo Molnar <mingo@redhat.com>
> Cc: pei.p.jia@intel.com
> Cc: Thomas Gleixner <tglx@linutronix.de>
> Cc: Tony Luck <tony.luck@intel.com>
> Cc: x86-ml <x86@kernel.org>
> Link: https://lkml.kernel.org/r/1555499329-1170-3-git-send-email-xiaochen.shen@intel.com
> ---
> arch/x86/kernel/cpu/resctrl/ctrlmondata.c | 4 +--
> arch/x86/kernel/cpu/resctrl/rdtgroup.c | 52 ++++++++++++++++++++-----------
> 2 files changed, 35 insertions(+), 21 deletions(-)
>
> diff --git a/arch/x86/kernel/cpu/resctrl/ctrlmondata.c b/arch/x86/kernel/cpu/resctrl/ctrlmondata.c
> index 2dbd990a2eb7..89320c0396b1 100644
> --- a/arch/x86/kernel/cpu/resctrl/ctrlmondata.c
> +++ b/arch/x86/kernel/cpu/resctrl/ctrlmondata.c
> @@ -342,10 +342,10 @@ int update_domains(struct rdt_resource *r, int closid)
> if (cpumask_empty(cpu_mask) || mba_sc)
> goto done;
> cpu = get_cpu();
> - /* Update CBM on this cpu if it's in cpu_mask. */
> + /* Update resource control msr on this CPU if it's in cpu_mask. */
> if (cpumask_test_cpu(cpu, cpu_mask))
> rdt_ctrl_update(&msr_param);
> - /* Update CBM on other cpus. */
> + /* Update resource control msr on other CPUs. */
> smp_call_function_many(cpu_mask, rdt_ctrl_update, &msr_param, 1);
> put_cpu();
>
> diff --git a/arch/x86/kernel/cpu/resctrl/rdtgroup.c b/arch/x86/kernel/cpu/resctrl/rdtgroup.c
> index 36ace51ee705..333c177a2471 100644
> --- a/arch/x86/kernel/cpu/resctrl/rdtgroup.c
> +++ b/arch/x86/kernel/cpu/resctrl/rdtgroup.c
> @@ -2581,8 +2581,8 @@ static int __init_one_rdt_domain(struct rdt_domain *d, struct rdt_resource *r,
> return 0;
> }
>
> -/**
> - * rdtgroup_init_alloc - Initialize the new RDT group's allocations
> +/*
> + * Initialize cache resources with default values.
> *
> * A new RDT group is being created on an allocation capable (CAT)
> * supporting system. Set this group up to start off with all usable
> @@ -2591,38 +2591,52 @@ static int __init_one_rdt_domain(struct rdt_domain *d, struct rdt_resource *r,
> * If there are no more shareable bits available on any domain then
> * the entire allocation will fail.
> */
> +static int rdtgroup_init_cat(struct rdt_resource *r, u32 closid)
> +{
> + struct rdt_domain *d;
> + int ret;
> +
> + list_for_each_entry(d, &r->domains, list) {
> + ret = __init_one_rdt_domain(d, r, closid);
> + if (ret < 0)
> + return ret;
> + }
> +
> + return 0;
> +}
> +
> +/* Initialize MBA resource with default values. */
> +static void rdtgroup_init_mba(struct rdt_resource *r)
> +{
> + struct rdt_domain *d;
> +
> + list_for_each_entry(d, &r->domains, list) {
> + d->new_ctrl = is_mba_sc(r) ? MBA_MAX_MBPS : r->default_ctrl;
> + d->have_new_ctrl = true;
> + }
> +}
> +
> +/* Initialize the RDT group's allocations. */
> static int rdtgroup_init_alloc(struct rdtgroup *rdtgrp)
> {
> struct rdt_resource *r;
> - struct rdt_domain *d;
> int ret;
>
> for_each_alloc_enabled_rdt_resource(r) {
> - /*
> - * Only initialize default allocations for CBM cache
> - * resources
> - */
> - if (r->rid == RDT_RESOURCE_MBA)
> - continue;
> - list_for_each_entry(d, &r->domains, list) {
> - ret = __init_one_rdt_domain(d, r, rdtgrp->closid);
> + if (r->rid == RDT_RESOURCE_MBA) {
> + rdtgroup_init_mba(r);
> + } else {
> + ret = rdtgroup_init_cat(r, rdtgrp->closid);
> if (ret < 0)
> return ret;
> }
> - }
>
> - for_each_alloc_enabled_rdt_resource(r) {
> - /*
> - * Only initialize default allocations for CBM cache
> - * resources
> - */
> - if (r->rid == RDT_RESOURCE_MBA)
> - continue;
> ret = update_domains(r, rdtgrp->closid);
> if (ret < 0) {
> rdt_last_cmd_puts("Failed to initialize allocations\n");
> return ret;
> }
> +

In my opinion, this newline is unnecessary. Thank you.

> }
>
> rdtgrp->mode = RDT_MODE_SHAREABLE;
>

--
Best regards,
Xiaochen

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