[v12] x86/resctrl: Move the resctrl filesystem code to /fs/resctrl

[PATCH v12 19/25] x86/resctrl: Move pseudo lock prototypes to include/linux/resctrl.h

Posted by James Morse 7 months ago

The resctrl pseudo-lock feature allows an architecture to allocate data
into particular cache portions, which are then treated as reserved to
avoid that data ever being evicted. Setting this up is deeply architecture
specific as it involves disabling prefetchers etc. It is not possible
to support this kind of feature on arm64. Risc-V is assumed to be the
same.

The prototypes for the architecture code were added to x86's asm/resctrl.h,
with other architectures able to provide stubs for their architecture. This
forces other architectures to provide identical stubs.

Move the prototypes and stubs to linux/resctrl.h, and switch between them
using the existing Kconfig symbol.

Signed-off-by: James Morse <james.morse@arm.com>
Tested-by: Babu Moger <babu.moger@amd.com>
Tested-by: Shaopeng Tan <tan.shaopeng@jp.fujitsu.com>
Tested-by: Tony Luck <tony.luck@intel.com>
Reviewed-by: Reinette Chatre <reinette.chatre@intel.com>
Reviewed-by: Fenghua Yu <fenghuay@nvidia.com>
---
I'm assuming risc-v's hardware prefetcher controls are restricted to the
higehst privilege level, and that this isn't where linux runs.

Changes since v9:
 * Typo fix in commit message.

Changse since v8:
 * This patch is new.
---
 arch/x86/include/asm/resctrl.h |  5 -----
 include/linux/resctrl.h        | 13 +++++++++++++
 2 files changed, 13 insertions(+), 5 deletions(-)

diff --git a/arch/x86/include/asm/resctrl.h b/arch/x86/include/asm/resctrl.h
index a2e20fe90a2c..ad497ab196d1 100644
--- a/arch/x86/include/asm/resctrl.h
+++ b/arch/x86/include/asm/resctrl.h
@@ -205,11 +205,6 @@ static inline void resctrl_arch_mon_ctx_free(struct rdt_resource *r,
 					     enum resctrl_event_id evtid,
 					     void *ctx) { }
 
-u64 resctrl_arch_get_prefetch_disable_bits(void);
-int resctrl_arch_pseudo_lock_fn(void *_plr);
-int resctrl_arch_measure_cycles_lat_fn(void *_plr);
-int resctrl_arch_measure_l2_residency(void *_plr);
-int resctrl_arch_measure_l3_residency(void *_plr);
 void resctrl_cpu_detect(struct cpuinfo_x86 *c);
 
 #else
diff --git a/include/linux/resctrl.h b/include/linux/resctrl.h
index 5ef972cbf56b..9ba771f2ddea 100644
--- a/include/linux/resctrl.h
+++ b/include/linux/resctrl.h
@@ -534,4 +534,17 @@ extern unsigned int resctrl_rmid_realloc_limit;
 int resctrl_init(void);
 void resctrl_exit(void);
 
+#ifdef CONFIG_RESCTRL_FS_PSEUDO_LOCK
+u64 resctrl_arch_get_prefetch_disable_bits(void);
+int resctrl_arch_pseudo_lock_fn(void *_plr);
+int resctrl_arch_measure_cycles_lat_fn(void *_plr);
+int resctrl_arch_measure_l2_residency(void *_plr);
+int resctrl_arch_measure_l3_residency(void *_plr);
+#else
+static inline u64 resctrl_arch_get_prefetch_disable_bits(void) { return 0; }
+static inline int resctrl_arch_pseudo_lock_fn(void *_plr) { return 0; }
+static inline int resctrl_arch_measure_cycles_lat_fn(void *_plr) { return 0; }
+static inline int resctrl_arch_measure_l2_residency(void *_plr) { return 0; }
+static inline int resctrl_arch_measure_l3_residency(void *_plr) { return 0; }
+#endif /* CONFIG_RESCTRL_FS_PSEUDO_LOCK */
 #endif /* _RESCTRL_H */
-- 
2.39.5

[tip: x86/cache] x86/resctrl: Move pseudo lock prototypes to include/linux/resctrl.h

Posted by tip-bot2 for James Morse 7 months ago

The following commit has been merged into the x86/cache branch of tip:

Commit-ID:     279f225951e3c77a1708d77f557b4cc7bdbd76ed
Gitweb:        https://git.kernel.org/tip/279f225951e3c77a1708d77f557b4cc7bdbd76ed
Author:        James Morse <james.morse@arm.com>
AuthorDate:    Thu, 15 May 2025 16:58:49 
Committer:     Borislav Petkov (AMD) <bp@alien8.de>
CommitterDate: Fri, 16 May 2025 12:21:00 +02:00

x86/resctrl: Move pseudo lock prototypes to include/linux/resctrl.h

The resctrl pseudo-lock feature allows an architecture to allocate data
into particular cache portions, which are then treated as reserved to
avoid that data ever being evicted. Setting this up is deeply architecture
specific as it involves disabling prefetchers etc. It is not possible
to support this kind of feature on arm64. Risc-V is assumed to be the
same.

The prototypes for the architecture code were added to x86's asm/resctrl.h,
with other architectures able to provide stubs for their architecture. This
forces other architectures to provide identical stubs.

Move the prototypes and stubs to linux/resctrl.h, and switch between them
using the existing Kconfig symbol.

Signed-off-by: James Morse <james.morse@arm.com>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Reviewed-by: Reinette Chatre <reinette.chatre@intel.com>
Reviewed-by: Fenghua Yu <fenghuay@nvidia.com>
Tested-by: Fenghua Yu <fenghuay@nvidia.com>
Tested-by: Babu Moger <babu.moger@amd.com>
Tested-by: Shaopeng Tan <tan.shaopeng@jp.fujitsu.com>
Tested-by: Tony Luck <tony.luck@intel.com>
Link: https://lore.kernel.org/20250515165855.31452-20-james.morse@arm.com
---
 arch/x86/include/asm/resctrl.h |  5 -----
 include/linux/resctrl.h        | 13 +++++++++++++
 2 files changed, 13 insertions(+), 5 deletions(-)

diff --git a/arch/x86/include/asm/resctrl.h b/arch/x86/include/asm/resctrl.h
index a2e20fe..ad497ab 100644
--- a/arch/x86/include/asm/resctrl.h
+++ b/arch/x86/include/asm/resctrl.h
@@ -205,11 +205,6 @@ static inline void resctrl_arch_mon_ctx_free(struct rdt_resource *r,
 					     enum resctrl_event_id evtid,
 					     void *ctx) { }
 
-u64 resctrl_arch_get_prefetch_disable_bits(void);
-int resctrl_arch_pseudo_lock_fn(void *_plr);
-int resctrl_arch_measure_cycles_lat_fn(void *_plr);
-int resctrl_arch_measure_l2_residency(void *_plr);
-int resctrl_arch_measure_l3_residency(void *_plr);
 void resctrl_cpu_detect(struct cpuinfo_x86 *c);
 
 #else
diff --git a/include/linux/resctrl.h b/include/linux/resctrl.h
index 5ef972c..9ba771f 100644
--- a/include/linux/resctrl.h
+++ b/include/linux/resctrl.h
@@ -534,4 +534,17 @@ extern unsigned int resctrl_rmid_realloc_limit;
 int resctrl_init(void);
 void resctrl_exit(void);
 
+#ifdef CONFIG_RESCTRL_FS_PSEUDO_LOCK
+u64 resctrl_arch_get_prefetch_disable_bits(void);
+int resctrl_arch_pseudo_lock_fn(void *_plr);
+int resctrl_arch_measure_cycles_lat_fn(void *_plr);
+int resctrl_arch_measure_l2_residency(void *_plr);
+int resctrl_arch_measure_l3_residency(void *_plr);
+#else
+static inline u64 resctrl_arch_get_prefetch_disable_bits(void) { return 0; }
+static inline int resctrl_arch_pseudo_lock_fn(void *_plr) { return 0; }
+static inline int resctrl_arch_measure_cycles_lat_fn(void *_plr) { return 0; }
+static inline int resctrl_arch_measure_l2_residency(void *_plr) { return 0; }
+static inline int resctrl_arch_measure_l3_residency(void *_plr) { return 0; }
+#endif /* CONFIG_RESCTRL_FS_PSEUDO_LOCK */
 #endif /* _RESCTRL_H */