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Date: Tue, 22 Nov 2022 16:19:48 -0800
From: Reinette Chatre <reinette.chatre@...el.com>
To: Babu Moger <babu.moger@....com>, <corbet@....net>,
<tglx@...utronix.de>, <mingo@...hat.com>, <bp@...en8.de>
CC: <fenghua.yu@...el.com>, <dave.hansen@...ux.intel.com>,
<x86@...nel.org>, <hpa@...or.com>, <paulmck@...nel.org>,
<akpm@...ux-foundation.org>, <quic_neeraju@...cinc.com>,
<rdunlap@...radead.org>, <damien.lemoal@...nsource.wdc.com>,
<songmuchun@...edance.com>, <peterz@...radead.org>,
<jpoimboe@...nel.org>, <pbonzini@...hat.com>,
<chang.seok.bae@...el.com>, <pawan.kumar.gupta@...ux.intel.com>,
<jmattson@...gle.com>, <daniel.sneddon@...ux.intel.com>,
<sandipan.das@....com>, <tony.luck@...el.com>,
<james.morse@....com>, <linux-doc@...r.kernel.org>,
<linux-kernel@...r.kernel.org>, <bagasdotme@...il.com>,
<eranian@...gle.com>
Subject: Re: [PATCH v8 08/13] x86/resctrl: Add sysfs interface to read
mbm_total_bytes_config
Hi Babu,
On 11/4/2022 1:00 PM, Babu Moger wrote:
> The current event configuration can be viewed by the user by reading
> the configuration file /sys/fs/resctrl/info/L3_MON/mbm_total_bytes_config.
> The event configuration settings are domain specific and will affect all
> the CPUs in the domain.
>
> Following are the types of events supported:
> ==== ===========================================================
> Bits Description
> ==== ===========================================================
> 6 Dirty Victims from the QOS domain to all types of memory
> 5 Reads to slow memory in the non-local NUMA domain
> 4 Reads to slow memory in the local NUMA domain
> 3 Non-temporal writes to non-local NUMA domain
> 2 Non-temporal writes to local NUMA domain
> 1 Reads to memory in the non-local NUMA domain
> 0 Reads to memory in the local NUMA domain
> ==== ===========================================================
>
> By default, the mbm_total_bytes_config is set to 0x7f to count all the
> event types.
>
> For example:
> $cat /sys/fs/resctrl/info/L3_MON/mbm_total_bytes_config
> 0=0x7f;1=0x7f;2=0x7f;3=0x7f
>
> In this case, the event mbm_total_bytes is currently configured
> with 0x7f on domains 0 to 3.
>
> Signed-off-by: Babu Moger <babu.moger@....com>
> ---
> arch/x86/kernel/cpu/resctrl/internal.h | 28 ++++++++++
> arch/x86/kernel/cpu/resctrl/monitor.c | 1
> arch/x86/kernel/cpu/resctrl/rdtgroup.c | 87 ++++++++++++++++++++++++++++++++
> 3 files changed, 116 insertions(+)
>
> diff --git a/arch/x86/kernel/cpu/resctrl/internal.h b/arch/x86/kernel/cpu/resctrl/internal.h
> index 5459b5022760..c74285fd0f6e 100644
> --- a/arch/x86/kernel/cpu/resctrl/internal.h
> +++ b/arch/x86/kernel/cpu/resctrl/internal.h
> @@ -15,6 +15,7 @@
> #define MSR_IA32_MBA_THRTL_BASE 0xd50
> #define MSR_IA32_MBA_BW_BASE 0xc0000200
> #define MSR_IA32_SMBA_BW_BASE 0xc0000280
> +#define MSR_IA32_EVT_CFG_BASE 0xc0000400
>
> #define MSR_IA32_QM_CTR 0x0c8e
> #define MSR_IA32_QM_EVTSEL 0x0c8d
> @@ -41,6 +42,32 @@
> */
> #define MBM_CNTR_WIDTH_OFFSET_MAX (62 - MBM_CNTR_WIDTH_BASE)
>
> +/* Reads to Local DRAM Memory */
> +#define READS_TO_LOCAL_MEM BIT(0)
> +
> +/* Reads to Remote DRAM Memory */
> +#define READS_TO_REMOTE_MEM BIT(1)
> +
> +/* Non-Temporal Writes to Local Memory */
> +#define NON_TEMP_WRITE_TO_LOCAL_MEM BIT(2)
> +
> +/* Non-Temporal Writes to Remote Memory */
> +#define NON_TEMP_WRITE_TO_REMOTE_MEM BIT(3)
> +
> +/* Reads to Local Memory the system identifies as "Slow Memory" */
> +#define READS_TO_LOCAL_S_MEM BIT(4)
> +
> +/* Reads to Remote Memory the system identifies as "Slow Memory" */
> +#define READS_TO_REMOTE_S_MEM BIT(5)
> +
> +/* Dirty Victims to All Types of Memory */
> +#define DIRTY_VICTIMS_TO_ALL_MEM BIT(6)
> +
> +/* Max event bits supported */
> +#define MAX_EVT_CONFIG_BITS GENMASK(6, 0)
> +
> +/* Max configurable events */
> +#define MAX_CONFIG_EVENTS 2
>
This max being disconnected from what it is a max of looks like
a source of future confusion.
> struct rdt_fs_context {
> struct kernfs_fs_context kfc;
> @@ -542,5 +569,6 @@ bool has_busy_rmid(struct rdt_resource *r, struct rdt_domain *d);
> void __check_limbo(struct rdt_domain *d, bool force_free);
> void rdt_domain_reconfigure_cdp(struct rdt_resource *r);
> void __init thread_throttle_mode_init(void);
> +void mbm_config_rftype_init(void);
>
> #endif /* _ASM_X86_RESCTRL_INTERNAL_H */
> diff --git a/arch/x86/kernel/cpu/resctrl/monitor.c b/arch/x86/kernel/cpu/resctrl/monitor.c
> index 06c2dc980855..a188dacab6c8 100644
> --- a/arch/x86/kernel/cpu/resctrl/monitor.c
> +++ b/arch/x86/kernel/cpu/resctrl/monitor.c
> @@ -787,6 +787,7 @@ int rdt_get_mon_l3_config(struct rdt_resource *r)
> if (mon_configurable) {
> mbm_total_event.configurable = true;
> mbm_local_event.configurable = true;
> + mbm_config_rftype_init();
> }
>
> l3_mon_evt_init(r);
> diff --git a/arch/x86/kernel/cpu/resctrl/rdtgroup.c b/arch/x86/kernel/cpu/resctrl/rdtgroup.c
> index 8342feb54a7f..dea58b6b4aa4 100644
> --- a/arch/x86/kernel/cpu/resctrl/rdtgroup.c
> +++ b/arch/x86/kernel/cpu/resctrl/rdtgroup.c
> @@ -1423,6 +1423,78 @@ static int rdtgroup_size_show(struct kernfs_open_file *of,
> return ret;
> }
>
> +struct mon_config_info {
> + u32 evtid;
> + u32 mon_config;
> +};
> +
> +/**
> + * mon_event_config_index_get - get the index for the configurable event
> + * @evtid: event id.
> + *
> + * Return: 0 for evtid == QOS_L3_MBM_TOTAL_EVENT_ID
> + * 1 for evtid == QOS_L3_MBM_LOCAL_EVENT_ID
> + * > 1 otherwise
> + */
> +static inline unsigned int mon_event_config_index_get(u32 evtid)
> +{
> + return evtid - QOS_L3_MBM_TOTAL_EVENT_ID;
> +}
It seems strange that the validation of the index is split
from where the index is determined. I think it would be easier
to understand, and reduce code duplication, it if is done together.
How about:
#define INVALID_CONFIG_INDEX UINT_MAX
static inline unsigned int mon_event_config_index_get(u32 evtid)
{
switch (evtid) {
case QOS_L3_MBM_TOTAL_EVENT_ID:
return 0;
case QOS_L3_MBM_LOCAL_EVENT_ID:
return 1;
default:
/* WARN */
return INVALID_CONFIG_INDEX;
}
}
What do you think?
> +
> +static void mon_event_config_read(void *info)
> +{
> + struct mon_config_info *mon_info = info;
> + u32 h, index;
> +
> + index = mon_event_config_index_get(mon_info->evtid);
> + if (index >= MAX_CONFIG_EVENTS) {
> + pr_warn_once("Invalid event id %d\n", mon_info->evtid);
> + return;
> + }
> + rdmsr(MSR_IA32_EVT_CFG_BASE + index, mon_info->mon_config, h);
> +}
> +
> +static void mondata_config_read(struct rdt_domain *d, struct mon_config_info *mon_info)
> +{
> + smp_call_function_any(&d->cpu_mask, mon_event_config_read, mon_info, 1);
> +}
> +
> +static int mbm_config_show(struct seq_file *s, struct rdt_resource *r, u32 evtid)
> +{
> + struct mon_config_info mon_info = {0};
> + struct rdt_domain *dom;
> + bool sep = false;
> +
> + mutex_lock(&rdtgroup_mutex);
> +
> + list_for_each_entry(dom, &r->domains, list) {
> + if (sep)
> + seq_puts(s, ";");
> +
> + mon_info.evtid = evtid;
> + mondata_config_read(dom, &mon_info);
> +
> + seq_printf(s, "%d=0x%02lx", dom->id,
This is a u32 ... is just x sufficient?
> + mon_info.mon_config & MAX_EVT_CONFIG_BITS);
Please do this masking within mondata_config_read(). It should
not be required for every mon_config_read() caller to validate the
data because they may forget (re. patch 10).
> + sep = true;
> + }
> + seq_puts(s, "\n");
> +
> + mutex_unlock(&rdtgroup_mutex);
> +
> + return 0;
> +}
> +
> +static int mbm_total_bytes_config_show(struct kernfs_open_file *of,
> + struct seq_file *seq, void *v)
> +{
> + struct rdt_resource *r = of->kn->parent->priv;
> +
> + mbm_config_show(seq, r, QOS_L3_MBM_TOTAL_EVENT_ID);
> +
> + return 0;
> +}
> +
> /* rdtgroup information files for one cache resource. */
> static struct rftype res_common_files[] = {
> {
> @@ -1521,6 +1593,12 @@ static struct rftype res_common_files[] = {
> .seq_show = max_threshold_occ_show,
> .fflags = RF_MON_INFO | RFTYPE_RES_CACHE,
> },
> + {
> + .name = "mbm_total_bytes_config",
> + .mode = 0444,
> + .kf_ops = &rdtgroup_kf_single_ops,
> + .seq_show = mbm_total_bytes_config_show,
> + },
> {
> .name = "cpus",
> .mode = 0644,
> @@ -1627,6 +1705,15 @@ void __init thread_throttle_mode_init(void)
> rft->fflags = RF_CTRL_INFO | RFTYPE_RES_MB;
> }
>
> +void mbm_config_rftype_init(void)
Does this need __init?
> +{
> + struct rftype *rft;
> +
> + rft = rdtgroup_get_rftype_by_name("mbm_total_bytes_config");
> + if (rft)
> + rft->fflags = RF_MON_INFO | RFTYPE_RES_CACHE;
> +}
> +
> /**
> * rdtgroup_kn_mode_restrict - Restrict user access to named resctrl file
> * @r: The resource group with which the file is associated.
>
>
Reinette
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