| lists.openwall.net | lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC | |
|
Open Source and information security mailing list archives
| ||
|
Message-ID: <14b723c8-5d8e-45d4-9c25-ea1d8c6e69a4@intel.com>
Date: Tue, 24 Jun 2025 16:51:27 -0700
From: Reinette Chatre <reinette.chatre@...el.com>
To: Babu Moger <babu.moger@....com>, <corbet@....net>, <tony.luck@...el.com>,
<Dave.Martin@....com>, <james.morse@....com>, <tglx@...utronix.de>,
<mingo@...hat.com>, <bp@...en8.de>, <dave.hansen@...ux.intel.com>
CC: <x86@...nel.org>, <hpa@...or.com>, <akpm@...ux-foundation.org>,
<rostedt@...dmis.org>, <paulmck@...nel.org>, <thuth@...hat.com>,
<ardb@...nel.org>, <gregkh@...uxfoundation.org>, <seanjc@...gle.com>,
<thomas.lendacky@....com>, <pawan.kumar.gupta@...ux.intel.com>,
<manali.shukla@....com>, <perry.yuan@....com>, <kai.huang@...el.com>,
<peterz@...radead.org>, <xiaoyao.li@...el.com>, <kan.liang@...ux.intel.com>,
<mario.limonciello@....com>, <xin3.li@...el.com>, <gautham.shenoy@....com>,
<xin@...or.com>, <chang.seok.bae@...el.com>, <fenghuay@...dia.com>,
<peternewman@...gle.com>, <maciej.wieczor-retman@...el.com>,
<eranian@...gle.com>, <linux-doc@...r.kernel.org>,
<linux-kernel@...r.kernel.org>
Subject: Re: [PATCH v14 16/32] x86,fs/resctrl: Introduce event configuration
field in struct mon_evt
Hi Babu,
On 6/13/25 2:05 PM, Babu Moger wrote:
> When supported, mbm_assign_mode allows the user to configure events to
> track specific types of memory transactions.
Since there is also a "default" mbm_assign_mode this should be made specific
to mbm_event.
>
> Introduce the evt_cfg field in struct mon_evt to define the type of memory
> transactions tracked by a monitoring event. Also add helper functions to
> get and set the evt_cfg value.
hmmm ... this does not sound right (more below)
>
> Signed-off-by: Babu Moger <babu.moger@....com>
> ---
> v14: This is updated patch from previous patch.
> https://lore.kernel.org/lkml/95b7f4e9d72773e8fda327fc80b429646efc3a8a.1747349530.git.babu.moger@amd.com/
> Removed mbm_mode as it is not required anymore.
> Added resctrl_get_mon_evt_cfg() and resctrl_set_mon_evt_cfg().
>
> v13: New patch to handle different event configuration types with
> mbm_cntr_assign mode.
> ---
> arch/x86/kernel/cpu/resctrl/core.c | 4 ++++
> fs/resctrl/internal.h | 4 ++++
> fs/resctrl/monitor.c | 10 ++++++++++
> include/linux/resctrl.h | 3 +++
> 4 files changed, 21 insertions(+)
>
> diff --git a/arch/x86/kernel/cpu/resctrl/core.c b/arch/x86/kernel/cpu/resctrl/core.c
> index 01b210febc7d..1df171d04bea 100644
> --- a/arch/x86/kernel/cpu/resctrl/core.c
> +++ b/arch/x86/kernel/cpu/resctrl/core.c
> @@ -875,10 +875,14 @@ static __init bool get_rdt_mon_resources(void)
> }
> if (rdt_cpu_has(X86_FEATURE_CQM_MBM_TOTAL) || rdt_cpu_has(X86_FEATURE_ABMC)) {
> resctrl_enable_mon_event(QOS_L3_MBM_TOTAL_EVENT_ID);
> + resctrl_set_mon_evt_cfg(QOS_L3_MBM_TOTAL_EVENT_ID, MAX_EVT_CONFIG_BITS);
> ret = true;
> }
> if (rdt_cpu_has(X86_FEATURE_CQM_MBM_LOCAL) || rdt_cpu_has(X86_FEATURE_ABMC)) {
> resctrl_enable_mon_event(QOS_L3_MBM_LOCAL_EVENT_ID);
> + resctrl_set_mon_evt_cfg(QOS_L3_MBM_LOCAL_EVENT_ID,
> + READS_TO_LOCAL_MEM | READS_TO_LOCAL_S_MEM |
> + NON_TEMP_WRITE_TO_LOCAL_MEM);
> ret = true;
> }
The architecture should have no business setting the event configuration. This should
all be managed via resctrl fs, no? I think the resctrl_set_mon_evt_cfg() helper should
be dropped. The above initialization can be done as part of mon_event_all[] initialization
within resctrl.
>
> diff --git a/fs/resctrl/internal.h b/fs/resctrl/internal.h
> index 20e2c45cea64..71059c2cda16 100644
> --- a/fs/resctrl/internal.h
> +++ b/fs/resctrl/internal.h
> @@ -56,6 +56,9 @@ static inline struct rdt_fs_context *rdt_fc2context(struct fs_context *fc)
> * @evtid: event id
> * @rid: index of the resource for this event
> * @name: name of the event
> + * @@evt_cfg: Event configuration value that represents the
Extra @ in "@@evt_cfg"
> + * memory transactions (e.g., READS_TO_LOCAL_MEM,
> + * READS_TO_REMOTE_MEM) being tracked by @evtid.
Can append "Only valid if @evtid is an MBM event."
> * @configurable: true if the event is configurable
> * @enabled: true if the event is enabled
> */
> @@ -63,6 +66,7 @@ struct mon_evt {
> enum resctrl_event_id evtid;
> enum resctrl_res_level rid;
> char *name;
> + u32 evt_cfg;
> bool configurable;
> bool enabled;
> };
> diff --git a/fs/resctrl/monitor.c b/fs/resctrl/monitor.c
> index 2893da994f3c..3e1a8239b0d3 100644
> --- a/fs/resctrl/monitor.c
> +++ b/fs/resctrl/monitor.c
> @@ -884,6 +884,16 @@ bool resctrl_is_mon_event_enabled(enum resctrl_event_id eventid)
> mon_event_all[eventid].enabled;
> }
>
> +u32 resctrl_get_mon_evt_cfg(enum resctrl_event_id evtid)
> +{
> + return mon_event_all[evtid].evt_cfg;
> +}
> +
> +void resctrl_set_mon_evt_cfg(enum resctrl_event_id evtid, u32 evt_cfg)
> +{
> + mon_event_all[evtid].evt_cfg = evt_cfg;
> +}
> +
> /**
> * resctrl_mon_resource_init() - Initialise global monitoring structures.
> *
> diff --git a/include/linux/resctrl.h b/include/linux/resctrl.h
> index 468a4ebabc64..a58dd40b7246 100644
> --- a/include/linux/resctrl.h
> +++ b/include/linux/resctrl.h
> @@ -413,6 +413,9 @@ static inline bool resctrl_is_mbm_event(enum resctrl_event_id eventid)
> eventid <= QOS_L3_MBM_LOCAL_EVENT_ID);
> }
>
> +u32 resctrl_get_mon_evt_cfg(enum resctrl_event_id eventid);
> +void resctrl_set_mon_evt_cfg(enum resctrl_event_id eventid, u32 evt_cfg);
I think resctrl_set_mon_evt_cfg() should be dropped. Any changes to mon_evt:evt_cfg
should be via resctrl, either via initialization (all archs should use same default)
or when user writes to the event configuration's file.
> +
> #define for_each_mbm_event_id(eventid) \
> for (eventid = QOS_L3_MBM_TOTAL_EVENT_ID; \
> eventid <= QOS_L3_MBM_LOCAL_EVENT_ID; eventid++)
sidenote: This change looks to be a good foundation to bring back the BMEC optimization
you worked on earlier where it is no longer needed to read event configuration from
hardware.
Reinette
Powered by blists - more mailing lists