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Message-ID: <d52bee12-5c6c-04da-3044-7121a2c15f12@intel.com>
Date: Wed, 1 Sep 2021 14:26:38 -0700
From: Reinette Chatre <reinette.chatre@...el.com>
To: James Morse <james.morse@....com>, <x86@...nel.org>,
<linux-kernel@...r.kernel.org>
CC: Fenghua Yu <fenghua.yu@...el.com>,
Thomas Gleixner <tglx@...utronix.de>,
Ingo Molnar <mingo@...hat.com>, Borislav Petkov <bp@...en8.de>,
H Peter Anvin <hpa@...or.com>,
Babu Moger <Babu.Moger@....com>,
<shameerali.kolothum.thodi@...wei.com>,
Jamie Iles <jamie@...iainc.com>,
"D Scott Phillips OS" <scott@...amperecomputing.com>,
<lcherian@...vell.com>, <bobo.shaobowang@...wei.com>
Subject: Re: [PATCH v1 07/20] x86/resctrl: Remove architecture copy of
mbps_val
Hi James,
On 7/29/2021 3:35 PM, James Morse wrote:
> The resctrl arch code provides a second configuration array mbps_val[]
> for the mba socftware controller.
"mba socftware" -> "MBA software"
>
> Since resctrl switched over to allocating and freeing its own array
> when needed, nothing uses the arch code version.
>
> Remove it.
>
> Signed-off-by: James Morse <james.morse@....com>
> ---
> arch/x86/kernel/cpu/resctrl/core.c | 20 ++++----------------
> arch/x86/kernel/cpu/resctrl/internal.h | 4 +---
> arch/x86/kernel/cpu/resctrl/rdtgroup.c | 2 +-
> 3 files changed, 6 insertions(+), 20 deletions(-)
>
> diff --git a/arch/x86/kernel/cpu/resctrl/core.c b/arch/x86/kernel/cpu/resctrl/core.c
> index 56b3541617b5..e864dbc6fe3d 100644
> --- a/arch/x86/kernel/cpu/resctrl/core.c
> +++ b/arch/x86/kernel/cpu/resctrl/core.c
> @@ -397,7 +397,7 @@ struct rdt_domain *rdt_find_domain(struct rdt_resource *r, int id,
> return NULL;
> }
>
> -void setup_default_ctrlval(struct rdt_resource *r, u32 *dc, u32 *dm)
> +void setup_default_ctrlval(struct rdt_resource *r, u32 *dc)
> {
> struct rdt_hw_resource *hw_res = resctrl_to_arch_res(r);
> int i;
> @@ -406,12 +406,9 @@ void setup_default_ctrlval(struct rdt_resource *r, u32 *dc, u32 *dm)
> * Initialize the Control MSRs to having no control.
> * For Cache Allocation: Set all bits in cbm
> * For Memory Allocation: Set b/w requested to 100%
> - * and the bandwidth in MBps to U32_MAX
> */
> - for (i = 0; i < hw_res->num_closid; i++, dc++, dm++) {
> + for (i = 0; i < hw_res->num_closid; i++, dc++)
> *dc = r->default_ctrl;
> - *dm = MBA_MAX_MBPS;
> - }
Since this function used to reset the array to default I was expecting
its callers to now reset the new array (more below).
> }
>
> static int domain_setup_ctrlval(struct rdt_resource *r, struct rdt_domain *d)
> @@ -419,23 +416,15 @@ static int domain_setup_ctrlval(struct rdt_resource *r, struct rdt_domain *d)
> struct rdt_hw_resource *hw_res = resctrl_to_arch_res(r);
> struct rdt_hw_domain *hw_dom = resctrl_to_arch_dom(d);
> struct msr_param m;
> - u32 *dc, *dm;
> + u32 *dc;
>
> dc = kmalloc_array(hw_res->num_closid, sizeof(*hw_dom->ctrl_val),
> GFP_KERNEL);
> if (!dc)
> return -ENOMEM;
>
> - dm = kmalloc_array(hw_res->num_closid, sizeof(*hw_dom->mbps_val),
> - GFP_KERNEL);
> - if (!dm) {
> - kfree(dc);
> - return -ENOMEM;
> - }
> -
> hw_dom->ctrl_val = dc;
> - hw_dom->mbps_val = dm;
> - setup_default_ctrlval(r, dc, dm);
> + setup_default_ctrlval(r, dc);
>
> m.low = 0;
> m.high = hw_res->num_closid;
> @@ -527,7 +516,6 @@ static void domain_remove_cpu(int cpu, struct rdt_resource *r)
> d->plr->d = NULL;
>
> kfree(hw_dom->ctrl_val);
> - kfree(hw_dom->mbps_val);
> kfree(hw_dom);
> return;
> }
> diff --git a/arch/x86/kernel/cpu/resctrl/internal.h b/arch/x86/kernel/cpu/resctrl/internal.h
> index a7e2cbce29d5..796e13a0e8dc 100644
> --- a/arch/x86/kernel/cpu/resctrl/internal.h
> +++ b/arch/x86/kernel/cpu/resctrl/internal.h
> @@ -308,14 +308,12 @@ struct mbm_state {
> * a resource
> * @d_resctrl: Properties exposed to the resctrl file system
> * @ctrl_val: array of cache or mem ctrl values (indexed by CLOSID)
> - * @mbps_val: When mba_sc is enabled, this holds the bandwidth in MBps
> *
> * Members of this structure are accessed via helpers that provide abstraction.
> */
> struct rdt_hw_domain {
> struct rdt_domain d_resctrl;
> u32 *ctrl_val;
> - u32 *mbps_val;
> };
>
> static inline struct rdt_hw_domain *resctrl_to_arch_dom(struct rdt_domain *r)
> @@ -529,7 +527,7 @@ void mbm_setup_overflow_handler(struct rdt_domain *dom,
> void mbm_handle_overflow(struct work_struct *work);
> void __init intel_rdt_mbm_apply_quirk(void);
> bool is_mba_sc(struct rdt_resource *r);
> -void setup_default_ctrlval(struct rdt_resource *r, u32 *dc, u32 *dm);
> +void setup_default_ctrlval(struct rdt_resource *r, u32 *dc);
> u32 delay_bw_map(unsigned long bw, struct rdt_resource *r);
> void cqm_setup_limbo_handler(struct rdt_domain *dom, unsigned long delay_ms);
> void cqm_handle_limbo(struct work_struct *work);
> diff --git a/arch/x86/kernel/cpu/resctrl/rdtgroup.c b/arch/x86/kernel/cpu/resctrl/rdtgroup.c
> index 185f9bb992d1..297c20491549 100644
> --- a/arch/x86/kernel/cpu/resctrl/rdtgroup.c
> +++ b/arch/x86/kernel/cpu/resctrl/rdtgroup.c
> @@ -1906,7 +1906,7 @@ static int set_mba_sc(bool mba_sc)
> r->membw.mba_sc = mba_sc;
> list_for_each_entry(d, &r->domains, list) {
> hw_dom = resctrl_to_arch_dom(d);
> - setup_default_ctrlval(r, hw_dom->ctrl_val, hw_dom->mbps_val);
> + setup_default_ctrlval(r, hw_dom->ctrl_val);
> }
>
I am wondering why new array is not reset instead of original at this
call site? oh ... I see it is removed in following patch BUT it mentions
that it is ok because reset_all_ctrls() does similar reset ... but it
does not seem to do so for mbps_val.
Reinette
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