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author | Linus Torvalds <torvalds@linux-foundation.org> | 2018-12-26 12:17:43 -0800 |
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committer | Linus Torvalds <torvalds@linux-foundation.org> | 2018-12-26 12:17:43 -0800 |
commit | a52fb43a5faa40507cb164a793a7fa08da863ac7 (patch) | |
tree | 437f0c5dbdbbd81b38783f9f034971af525ddcfa /arch/x86/include/asm/resctrl_sched.h | |
parent | 42b00f122cfbfed79fc29b0b3610f3abbb1e3864 (diff) | |
parent | 52eb74339a6233c69f4e3794b69ea7c98eeeae1b (diff) |
Merge branch 'x86-cache-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull x86 cache control updates from Borislav Petkov:
- The generalization of the RDT code to accommodate the addition of
AMD's very similar implementation of the cache monitoring feature.
This entails a subsystem move into a separate and generic
arch/x86/kernel/cpu/resctrl/ directory along with adding
vendor-specific initialization and feature detection helpers.
Ontop of that is the unification of user-visible strings, both in the
resctrl filesystem error handling and Kconfig.
Provided by Babu Moger and Sherry Hurwitz.
- Code simplifications and error handling improvements by Reinette
Chatre.
* 'x86-cache-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
x86/resctrl: Fix rdt_find_domain() return value and checks
x86/resctrl: Remove unnecessary check for cbm_validate()
x86/resctrl: Use rdt_last_cmd_puts() where possible
MAINTAINERS: Update resctrl filename patterns
Documentation: Rename and update intel_rdt_ui.txt to resctrl_ui.txt
x86/resctrl: Introduce AMD QOS feature
x86/resctrl: Fixup the user-visible strings
x86/resctrl: Add AMD's X86_FEATURE_MBA to the scattered CPUID features
x86/resctrl: Rename the config option INTEL_RDT to RESCTRL
x86/resctrl: Add vendor check for the MBA software controller
x86/resctrl: Bring cbm_validate() into the resource structure
x86/resctrl: Initialize the vendor-specific resource functions
x86/resctrl: Move all the macros to resctrl/internal.h
x86/resctrl: Re-arrange the RDT init code
x86/resctrl: Rename the RDT functions and definitions
x86/resctrl: Rename and move rdt files to a separate directory
Diffstat (limited to 'arch/x86/include/asm/resctrl_sched.h')
-rw-r--r-- | arch/x86/include/asm/resctrl_sched.h | 93 |
1 files changed, 93 insertions, 0 deletions
diff --git a/arch/x86/include/asm/resctrl_sched.h b/arch/x86/include/asm/resctrl_sched.h new file mode 100644 index 000000000000..54990fe2a3ae --- /dev/null +++ b/arch/x86/include/asm/resctrl_sched.h @@ -0,0 +1,93 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +#ifndef _ASM_X86_RESCTRL_SCHED_H +#define _ASM_X86_RESCTRL_SCHED_H + +#ifdef CONFIG_RESCTRL + +#include <linux/sched.h> +#include <linux/jump_label.h> + +#define IA32_PQR_ASSOC 0x0c8f + +/** + * struct resctrl_pqr_state - State cache for the PQR MSR + * @cur_rmid: The cached Resource Monitoring ID + * @cur_closid: The cached Class Of Service ID + * @default_rmid: The user assigned Resource Monitoring ID + * @default_closid: The user assigned cached Class Of Service ID + * + * The upper 32 bits of IA32_PQR_ASSOC contain closid and the + * lower 10 bits rmid. The update to IA32_PQR_ASSOC always + * contains both parts, so we need to cache them. This also + * stores the user configured per cpu CLOSID and RMID. + * + * The cache also helps to avoid pointless updates if the value does + * not change. + */ +struct resctrl_pqr_state { + u32 cur_rmid; + u32 cur_closid; + u32 default_rmid; + u32 default_closid; +}; + +DECLARE_PER_CPU(struct resctrl_pqr_state, pqr_state); + +DECLARE_STATIC_KEY_FALSE(rdt_enable_key); +DECLARE_STATIC_KEY_FALSE(rdt_alloc_enable_key); +DECLARE_STATIC_KEY_FALSE(rdt_mon_enable_key); + +/* + * __resctrl_sched_in() - Writes the task's CLOSid/RMID to IA32_PQR_MSR + * + * Following considerations are made so that this has minimal impact + * on scheduler hot path: + * - This will stay as no-op unless we are running on an Intel SKU + * which supports resource control or monitoring and we enable by + * mounting the resctrl file system. + * - Caches the per cpu CLOSid/RMID values and does the MSR write only + * when a task with a different CLOSid/RMID is scheduled in. + * - We allocate RMIDs/CLOSids globally in order to keep this as + * simple as possible. + * Must be called with preemption disabled. + */ +static void __resctrl_sched_in(void) +{ + struct resctrl_pqr_state *state = this_cpu_ptr(&pqr_state); + u32 closid = state->default_closid; + u32 rmid = state->default_rmid; + + /* + * If this task has a closid/rmid assigned, use it. + * Else use the closid/rmid assigned to this cpu. + */ + if (static_branch_likely(&rdt_alloc_enable_key)) { + if (current->closid) + closid = current->closid; + } + + if (static_branch_likely(&rdt_mon_enable_key)) { + if (current->rmid) + rmid = current->rmid; + } + + if (closid != state->cur_closid || rmid != state->cur_rmid) { + state->cur_closid = closid; + state->cur_rmid = rmid; + wrmsr(IA32_PQR_ASSOC, rmid, closid); + } +} + +static inline void resctrl_sched_in(void) +{ + if (static_branch_likely(&rdt_enable_key)) + __resctrl_sched_in(); +} + +#else + +static inline void resctrl_sched_in(void) {} + +#endif /* CONFIG_RESCTRL */ + +#endif /* _ASM_X86_RESCTRL_SCHED_H */ |