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Message-ID: <20240822190212.1848788-1-peternewman@google.com>
Date: Thu, 22 Aug 2024 12:02:11 -0700
From: Peter Newman <peternewman@...gle.com>
To: reinette.chatre@...el.com
Cc: babu.moger@....com, bp@...en8.de, dave.hansen@...ux.intel.com,
eranian@...gle.com, fenghua.yu@...el.com, hpa@...or.com, irogers@...gle.com,
james.morse@....com, linux-kernel@...r.kernel.org,
maciej.wieczor-retman@...el.com, mingo@...hat.com, namhyung@...gle.com,
tan.shaopeng@...itsu.com, tglx@...utronix.de, tony.luck@...el.com,
x86@...nel.org, Peter Newman <peternewman@...gle.com>
Subject: [PATCH v2] x86/resctrl: Fix arch_mbm_* array overrun on SNC
When using resctrl on systems with Sub-NUMA Clustering enabled,
monitoring groups may be allocated RMID values which would overrun the
arch_mbm_{local,total} arrays.
This is due to inconsistencies in whether the SNC-adjusted num_rmid
value or the unadjusted value in resctrl_arch_system_num_rmid_idx() is
used. The num_rmid value for the L3 resource is currently:
resctrl_arch_system_num_rmid_idx() / snc_nodes_per_l3_cache
As a simple fix, make resctrl_arch_system_num_rmid_idx() return the
SNC-adjusted, L3 num_rmid value on x86.
Fixes: e13db55b5a0d ("x86/resctrl: Introduce snc_nodes_per_l3_cache")
Signed-off-by: Peter Newman <peternewman@...gle.com>
Reviewed-by: Reinette Chatre <reinette.chatre@...el.com>
---
v1->v2:
- Squashed blank lines added to linux/resctrl.h
- Reviewed-by Reinette
v1: https://lore.kernel.org/lkml/20240722204611.3549213-1-peternewman@google.com/
arch/x86/include/asm/resctrl.h | 6 ------
arch/x86/kernel/cpu/resctrl/core.c | 8 ++++++++
include/linux/resctrl.h | 1 +
3 files changed, 9 insertions(+), 6 deletions(-)
diff --git a/arch/x86/include/asm/resctrl.h b/arch/x86/include/asm/resctrl.h
index 12dbd2588ca7..8b1b6ce1e51b 100644
--- a/arch/x86/include/asm/resctrl.h
+++ b/arch/x86/include/asm/resctrl.h
@@ -156,12 +156,6 @@ static inline void resctrl_sched_in(struct task_struct *tsk)
__resctrl_sched_in(tsk);
}
-static inline u32 resctrl_arch_system_num_rmid_idx(void)
-{
- /* RMID are independent numbers for x86. num_rmid_idx == num_rmid */
- return boot_cpu_data.x86_cache_max_rmid + 1;
-}
-
static inline void resctrl_arch_rmid_idx_decode(u32 idx, u32 *closid, u32 *rmid)
{
*rmid = idx;
diff --git a/arch/x86/kernel/cpu/resctrl/core.c b/arch/x86/kernel/cpu/resctrl/core.c
index 1930fce9dfe9..8591d53c144b 100644
--- a/arch/x86/kernel/cpu/resctrl/core.c
+++ b/arch/x86/kernel/cpu/resctrl/core.c
@@ -119,6 +119,14 @@ struct rdt_hw_resource rdt_resources_all[] = {
},
};
+u32 resctrl_arch_system_num_rmid_idx(void)
+{
+ struct rdt_resource *r = &rdt_resources_all[RDT_RESOURCE_L3].r_resctrl;
+
+ /* RMID are independent numbers for x86. num_rmid_idx == num_rmid */
+ return r->num_rmid;
+}
+
/*
* cache_alloc_hsw_probe() - Have to probe for Intel haswell server CPUs
* as they do not have CPUID enumeration support for Cache allocation.
diff --git a/include/linux/resctrl.h b/include/linux/resctrl.h
index b0875b99e811..d94abba1c716 100644
--- a/include/linux/resctrl.h
+++ b/include/linux/resctrl.h
@@ -248,6 +248,7 @@ struct resctrl_schema {
/* The number of closid supported by this resource regardless of CDP */
u32 resctrl_arch_get_num_closid(struct rdt_resource *r);
+u32 resctrl_arch_system_num_rmid_idx(void);
int resctrl_arch_update_domains(struct rdt_resource *r, u32 closid);
/*
base-commit: 47ac09b91befbb6a235ab620c32af719f8208399
--
2.46.0.295.g3b9ea8a38a-goog
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