From: "tip-bot2 for Thomas Gleixner" <tip-bot2@linutronix.de>
To: linux-tip-commits@vger.kernel.org
Cc: Thomas Gleixner <tglx@linutronix.de>,
"Peter Zijlstra (Intel)" <peterz@infradead.org>,
x86@kernel.org, linux-kernel@vger.kernel.org
Subject: [tip: x86/core] x86: Put hot per CPU variables into a struct
Date: Mon, 17 Oct 2022 14:54:09 -0000 [thread overview]
Message-ID: <166601844974.401.6529951474144185456.tip-bot2@tip-bot2> (raw)
In-Reply-To: <20220915111145.179707194@infradead.org>
The following commit has been merged into the x86/core branch of tip:
Commit-ID: e57ef2ed97c1d078973298658a8096644a1e9e09
Gitweb: https://git.kernel.org/tip/e57ef2ed97c1d078973298658a8096644a1e9e09
Author: Thomas Gleixner <tglx@linutronix.de>
AuthorDate: Thu, 15 Sep 2022 13:11:01 +02:00
Committer: Peter Zijlstra <peterz@infradead.org>
CommitterDate: Mon, 17 Oct 2022 16:41:03 +02:00
x86: Put hot per CPU variables into a struct
The layout of per-cpu variables is at the mercy of the compiler. This
can lead to random performance fluctuations from build to build.
Create a structure to hold some of the hottest per-cpu variables,
starting with current_task.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lore.kernel.org/r/20220915111145.179707194@infradead.org
---
arch/x86/include/asm/current.h | 19 ++++++++++++++++---
arch/x86/kernel/cpu/common.c | 14 +++++---------
arch/x86/kernel/process_32.c | 2 +-
arch/x86/kernel/process_64.c | 2 +-
arch/x86/kernel/smpboot.c | 2 +-
5 files changed, 24 insertions(+), 15 deletions(-)
diff --git a/arch/x86/include/asm/current.h b/arch/x86/include/asm/current.h
index 3e204e6..63c42ac 100644
--- a/arch/x86/include/asm/current.h
+++ b/arch/x86/include/asm/current.h
@@ -3,16 +3,29 @@
#define _ASM_X86_CURRENT_H
#include <linux/compiler.h>
-#include <asm/percpu.h>
#ifndef __ASSEMBLY__
+
+#include <linux/cache.h>
+#include <asm/percpu.h>
+
struct task_struct;
-DECLARE_PER_CPU(struct task_struct *, current_task);
+struct pcpu_hot {
+ union {
+ struct {
+ struct task_struct *current_task;
+ };
+ u8 pad[64];
+ };
+};
+static_assert(sizeof(struct pcpu_hot) == 64);
+
+DECLARE_PER_CPU_ALIGNED(struct pcpu_hot, pcpu_hot);
static __always_inline struct task_struct *get_current(void)
{
- return this_cpu_read_stable(current_task);
+ return this_cpu_read_stable(pcpu_hot.current_task);
}
#define current get_current()
diff --git a/arch/x86/kernel/cpu/common.c b/arch/x86/kernel/cpu/common.c
index 8e87318..5207153 100644
--- a/arch/x86/kernel/cpu/common.c
+++ b/arch/x86/kernel/cpu/common.c
@@ -2012,18 +2012,16 @@ static __init int setup_clearcpuid(char *arg)
}
__setup("clearcpuid=", setup_clearcpuid);
+DEFINE_PER_CPU_ALIGNED(struct pcpu_hot, pcpu_hot) = {
+ .current_task = &init_task,
+};
+EXPORT_PER_CPU_SYMBOL(pcpu_hot);
+
#ifdef CONFIG_X86_64
DEFINE_PER_CPU_FIRST(struct fixed_percpu_data,
fixed_percpu_data) __aligned(PAGE_SIZE) __visible;
EXPORT_PER_CPU_SYMBOL_GPL(fixed_percpu_data);
-/*
- * The following percpu variables are hot. Align current_task to
- * cacheline size such that they fall in the same cacheline.
- */
-DEFINE_PER_CPU(struct task_struct *, current_task) ____cacheline_aligned =
- &init_task;
-EXPORT_PER_CPU_SYMBOL(current_task);
DEFINE_PER_CPU(void *, hardirq_stack_ptr);
DEFINE_PER_CPU(bool, hardirq_stack_inuse);
@@ -2083,8 +2081,6 @@ void syscall_init(void)
#else /* CONFIG_X86_64 */
-DEFINE_PER_CPU(struct task_struct *, current_task) = &init_task;
-EXPORT_PER_CPU_SYMBOL(current_task);
DEFINE_PER_CPU(int, __preempt_count) = INIT_PREEMPT_COUNT;
EXPORT_PER_CPU_SYMBOL(__preempt_count);
diff --git a/arch/x86/kernel/process_32.c b/arch/x86/kernel/process_32.c
index 2f314b1..807da45 100644
--- a/arch/x86/kernel/process_32.c
+++ b/arch/x86/kernel/process_32.c
@@ -207,7 +207,7 @@ __switch_to(struct task_struct *prev_p, struct task_struct *next_p)
if (prev->gs | next->gs)
loadsegment(gs, next->gs);
- this_cpu_write(current_task, next_p);
+ raw_cpu_write(pcpu_hot.current_task, next_p);
switch_fpu_finish();
diff --git a/arch/x86/kernel/process_64.c b/arch/x86/kernel/process_64.c
index 6b3418b..c4f6cac 100644
--- a/arch/x86/kernel/process_64.c
+++ b/arch/x86/kernel/process_64.c
@@ -617,7 +617,7 @@ __switch_to(struct task_struct *prev_p, struct task_struct *next_p)
/*
* Switch the PDA and FPU contexts.
*/
- this_cpu_write(current_task, next_p);
+ raw_cpu_write(pcpu_hot.current_task, next_p);
this_cpu_write(cpu_current_top_of_stack, task_top_of_stack(next_p));
switch_fpu_finish();
diff --git a/arch/x86/kernel/smpboot.c b/arch/x86/kernel/smpboot.c
index ce8728d..05f3157 100644
--- a/arch/x86/kernel/smpboot.c
+++ b/arch/x86/kernel/smpboot.c
@@ -1046,7 +1046,7 @@ int common_cpu_up(unsigned int cpu, struct task_struct *idle)
/* Just in case we booted with a single CPU. */
alternatives_enable_smp();
- per_cpu(current_task, cpu) = idle;
+ per_cpu(pcpu_hot.current_task, cpu) = idle;
cpu_init_stack_canary(cpu, idle);
/* Initialize the interrupt stack(s) */
next prev parent reply other threads:[~2022-10-17 14:57 UTC|newest]
Thread overview: 138+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-09-15 11:10 [PATCH v3 00/59] x86/retbleed: Call depth tracking mitigation Peter Zijlstra
2022-09-15 11:10 ` [PATCH v3 01/59] x86/paravirt: Ensure proper alignment Peter Zijlstra
2022-09-21 11:08 ` [tip: x86/paravirt] " tip-bot2 for Thomas Gleixner
2022-09-15 11:10 ` [PATCH v3 02/59] x86/cpu: Remove segment load from switch_to_new_gdt() Peter Zijlstra
2022-10-17 14:54 ` [tip: x86/core] " tip-bot2 for Thomas Gleixner
2022-09-15 11:10 ` [PATCH v3 03/59] x86/cpu: Get rid of redundant switch_to_new_gdt() invocations Peter Zijlstra
2022-10-17 14:54 ` [tip: x86/core] " tip-bot2 for Thomas Gleixner
2022-09-15 11:10 ` [PATCH v3 04/59] x86/cpu: Re-enable stackprotector Peter Zijlstra
2022-10-17 14:54 ` [tip: x86/core] " tip-bot2 for Thomas Gleixner
2022-09-15 11:10 ` [PATCH v3 05/59] x86/modules: Set VM_FLUSH_RESET_PERMS in module_alloc() Peter Zijlstra
2022-10-17 14:54 ` [tip: x86/core] " tip-bot2 for Thomas Gleixner
2022-09-15 11:10 ` [PATCH v3 06/59] x86/vdso: Ensure all kernel code is seen by objtool Peter Zijlstra
2022-10-17 14:54 ` [tip: x86/core] " tip-bot2 for Thomas Gleixner
2022-09-15 11:10 ` [PATCH v3 07/59] x86: Sanitize linker script Peter Zijlstra
2022-10-07 16:03 ` Borislav Petkov
2022-10-17 14:54 ` [tip: x86/core] " tip-bot2 for Thomas Gleixner
2022-09-15 11:10 ` [PATCH v3 08/59] arch: Introduce CONFIG_FUNCTION_ALIGNMENT Peter Zijlstra
2022-10-17 14:54 ` [tip: x86/core] " tip-bot2 for Peter Zijlstra
2022-09-15 11:10 ` [PATCH v3 09/59] x86/asm: Differentiate between code and function alignment Peter Zijlstra
2022-10-17 14:54 ` [tip: x86/core] " tip-bot2 for Thomas Gleixner
2022-09-15 11:10 ` [PATCH v3 10/59] x86/error_inject: Align function properly Peter Zijlstra
2022-10-17 14:54 ` [tip: x86/core] " tip-bot2 for Peter Zijlstra
2022-09-15 11:10 ` [PATCH v3 11/59] x86/paravirt: Properly align PV functions Peter Zijlstra
2022-09-15 14:34 ` Juergen Gross
2022-10-17 14:54 ` [tip: x86/core] " tip-bot2 for Thomas Gleixner
2022-09-15 11:10 ` [PATCH v3 12/59] x86/entry: Align SYM_CODE_START() variants Peter Zijlstra
2022-10-17 14:54 ` [tip: x86/core] " tip-bot2 for Thomas Gleixner
2022-09-15 11:10 ` [PATCH v3 13/59] crypto: x86/camellia: Remove redundant alignments Peter Zijlstra
2022-10-17 14:54 ` [tip: x86/core] " tip-bot2 for Thomas Gleixner
2022-09-15 11:10 ` [PATCH v3 14/59] crypto: x86/cast5: " Peter Zijlstra
2022-10-17 14:54 ` [tip: x86/core] " tip-bot2 for Thomas Gleixner
2022-09-15 11:10 ` [PATCH v3 15/59] crypto: x86/crct10dif-pcl: " Peter Zijlstra
2022-10-17 14:54 ` [tip: x86/core] " tip-bot2 for Thomas Gleixner
2022-09-15 11:10 ` [PATCH v3 16/59] crypto: x86/serpent: " Peter Zijlstra
2022-10-17 14:54 ` [tip: x86/core] " tip-bot2 for Thomas Gleixner
2022-09-15 11:10 ` [PATCH v3 17/59] crypto: x86/sha1: Remove custom alignments Peter Zijlstra
2022-10-17 14:54 ` [tip: x86/core] " tip-bot2 for Thomas Gleixner
2022-09-15 11:10 ` [PATCH v3 18/59] crypto: x86/sha256: " Peter Zijlstra
2022-10-17 14:54 ` [tip: x86/core] " tip-bot2 for Thomas Gleixner
2022-09-15 11:10 ` [PATCH v3 19/59] crypto: x86/sm[34]: Remove redundant alignments Peter Zijlstra
2022-10-17 14:54 ` [tip: x86/core] " tip-bot2 for Thomas Gleixner
2022-09-15 11:10 ` [PATCH v3 20/59] crypto: twofish: " Peter Zijlstra
2022-10-17 14:54 ` [tip: x86/core] " tip-bot2 for Thomas Gleixner
2022-09-15 11:11 ` [PATCH v3 21/59] crypto: x86/poly1305: Remove custom function alignment Peter Zijlstra
2022-10-17 14:54 ` [tip: x86/core] " tip-bot2 for Thomas Gleixner
2022-09-15 11:11 ` [PATCH v3 22/59] x86: Put hot per CPU variables into a struct Peter Zijlstra
2022-10-17 14:54 ` tip-bot2 for Thomas Gleixner [this message]
2022-09-15 11:11 ` [PATCH v3 23/59] x86/percpu: Move preempt_count next to current_task Peter Zijlstra
2022-10-17 14:54 ` [tip: x86/core] " tip-bot2 for Thomas Gleixner
2022-09-15 11:11 ` [PATCH v3 24/59] x86/percpu: Move cpu_number " Peter Zijlstra
2022-10-17 14:54 ` [tip: x86/core] " tip-bot2 for Thomas Gleixner
2022-09-15 11:11 ` [PATCH v3 25/59] x86/percpu: Move current_top_of_stack " Peter Zijlstra
2022-10-17 14:54 ` [tip: x86/core] " tip-bot2 for Thomas Gleixner
2022-09-15 11:11 ` [PATCH v3 26/59] x86/percpu: Move irq_stack variables " Peter Zijlstra
2022-10-17 14:54 ` [tip: x86/core] " tip-bot2 for Thomas Gleixner
2022-09-15 11:11 ` [PATCH v3 27/59] x86/softirq: Move softirq pending next to current task Peter Zijlstra
2022-10-17 14:54 ` [tip: x86/core] " tip-bot2 for Thomas Gleixner
2022-09-15 11:11 ` [PATCH v3 28/59] objtool: Allow !PC relative relocations Peter Zijlstra
2022-10-17 14:54 ` [tip: x86/core] " tip-bot2 for Peter Zijlstra
2022-09-15 11:11 ` [PATCH v3 29/59] objtool: Track init section Peter Zijlstra
2022-10-17 14:54 ` [tip: x86/core] " tip-bot2 for Peter Zijlstra
2022-09-15 11:11 ` [PATCH v3 30/59] objtool: Add .call_sites section Peter Zijlstra
2022-10-17 14:54 ` [tip: x86/core] " tip-bot2 for Peter Zijlstra
2022-09-15 11:11 ` [PATCH v3 31/59] objtool: Add --hacks=skylake Peter Zijlstra
2022-10-17 14:53 ` [tip: x86/core] " tip-bot2 for Peter Zijlstra
2022-09-15 11:11 ` [PATCH v3 32/59] objtool: Allow STT_NOTYPE -> STT_FUNC+0 tail-calls Peter Zijlstra
2022-09-22 5:27 ` Pawan Gupta
2022-09-22 10:29 ` Peter Zijlstra
2022-09-22 10:47 ` Peter Zijlstra
2022-09-22 13:15 ` Peter Zijlstra
2022-09-23 14:35 ` Peter Zijlstra
2022-09-23 17:36 ` Pawan Gupta
2022-09-15 11:11 ` [PATCH v3 33/59] objtool: Fix find_{symbol,func}_containing() Peter Zijlstra
2022-10-17 14:53 ` [tip: x86/core] " tip-bot2 for Peter Zijlstra
2022-09-15 11:11 ` [PATCH v3 34/59] objtool: Allow symbol range comparisons for IBT/ENDBR Peter Zijlstra
2022-10-17 14:53 ` [tip: x86/core] " tip-bot2 for Peter Zijlstra
2022-09-15 11:11 ` [PATCH v3 35/59] x86/entry: Make sync_regs() invocation a tail call Peter Zijlstra
2022-10-17 14:53 ` [tip: x86/core] " tip-bot2 for Peter Zijlstra
2022-09-15 11:11 ` [PATCH v3 36/59] ftrace: Add HAVE_DYNAMIC_FTRACE_NO_PATCHABLE Peter Zijlstra
2022-09-15 11:11 ` [PATCH v3 37/59] x86/putuser: Provide room for padding Peter Zijlstra
2022-10-17 14:53 ` [tip: x86/core] " tip-bot2 for Thomas Gleixner
2022-09-15 11:11 ` [PATCH v3 38/59] x86/Kconfig: Add CONFIG_CALL_THUNKS Peter Zijlstra
2022-10-17 14:53 ` [tip: x86/core] " tip-bot2 for Thomas Gleixner
2022-09-15 11:11 ` [PATCH v3 39/59] x86/Kconfig: Introduce function padding Peter Zijlstra
2022-10-17 14:53 ` [tip: x86/core] " tip-bot2 for Thomas Gleixner
2022-09-15 11:11 ` [PATCH v3 40/59] x86/retbleed: Add X86_FEATURE_CALL_DEPTH Peter Zijlstra
2022-10-17 14:53 ` [tip: x86/core] " tip-bot2 for Thomas Gleixner
2022-09-15 11:11 ` [PATCH v3 41/59] x86/alternatives: Provide text_poke_copy_locked() Peter Zijlstra
2022-10-17 14:53 ` [tip: x86/core] " tip-bot2 for Thomas Gleixner
2022-09-15 11:11 ` [PATCH v3 42/59] x86/entry: Make some entry symbols global Peter Zijlstra
2022-10-17 14:53 ` [tip: x86/core] " tip-bot2 for Thomas Gleixner
2022-09-15 11:11 ` [PATCH v3 43/59] x86/paravirt: Make struct paravirt_call_site unconditionally available Peter Zijlstra
2022-10-17 14:53 ` [tip: x86/core] " tip-bot2 for Thomas Gleixner
2022-09-15 11:11 ` [PATCH v3 44/59] x86/callthunks: Add call patching for call depth tracking Peter Zijlstra
2022-10-17 14:53 ` [tip: x86/core] " tip-bot2 for Thomas Gleixner
2022-09-15 11:11 ` [PATCH v3 45/59] x86/modules: Add call patching Peter Zijlstra
2022-10-17 14:53 ` [tip: x86/core] " tip-bot2 for Thomas Gleixner
2022-09-15 11:11 ` [PATCH v3 46/59] x86/returnthunk: Allow different return thunks Peter Zijlstra
2022-10-17 14:53 ` [tip: x86/core] " tip-bot2 for Peter Zijlstra
2022-09-15 11:11 ` [PATCH v3 47/59] x86/asm: Provide ALTERNATIVE_3 Peter Zijlstra
2022-10-17 14:53 ` [tip: x86/core] " tip-bot2 for Peter Zijlstra
2022-09-15 11:11 ` [PATCH v3 48/59] x86/retbleed: Add SKL return thunk Peter Zijlstra
2022-10-17 14:53 ` [tip: x86/core] " tip-bot2 for Thomas Gleixner
2022-10-20 23:10 ` [PATCH v3 48/59] " Nathan Chancellor
2022-10-21 9:53 ` Peter Zijlstra
2022-10-21 15:21 ` Nathan Chancellor
2022-11-03 22:53 ` KVM vs AMD: " Andrew Cooper
2022-11-04 12:44 ` Peter Zijlstra
2022-11-04 15:29 ` Andrew Cooper
2022-11-04 15:32 ` Nathan Chancellor
2022-11-07 9:37 ` Paolo Bonzini
2022-09-15 11:11 ` [PATCH v3 49/59] x86/retpoline: Add SKL retthunk retpolines Peter Zijlstra
2022-10-17 14:53 ` [tip: x86/core] " tip-bot2 for Peter Zijlstra
2022-09-15 11:11 ` [PATCH v3 50/59] x86/retbleed: Add SKL call thunk Peter Zijlstra
2022-10-17 14:53 ` [tip: x86/core] " tip-bot2 for Thomas Gleixner
2022-09-15 11:11 ` [PATCH v3 51/59] x86/calldepth: Add ret/call counting for debug Peter Zijlstra
2022-10-17 14:53 ` [tip: x86/core] " tip-bot2 for Thomas Gleixner
2022-09-15 11:11 ` [PATCH v3 52/59] static_call: Add call depth tracking support Peter Zijlstra
2022-10-17 14:53 ` [tip: x86/core] " tip-bot2 for Peter Zijlstra
2022-09-15 11:11 ` [PATCH v3 53/59] kallsyms: Take callthunks into account Peter Zijlstra
2022-10-17 14:53 ` [tip: x86/core] " tip-bot2 for Peter Zijlstra
2022-09-15 11:11 ` [PATCH v3 54/59] x86/orc: Make it callthunk aware Peter Zijlstra
2022-10-17 14:53 ` [tip: x86/core] " tip-bot2 for Peter Zijlstra
2022-09-15 11:11 ` [PATCH v3 55/59] x86/bpf: Emit call depth accounting if required Peter Zijlstra
2022-10-17 14:53 ` [tip: x86/core] " tip-bot2 for Thomas Gleixner
2023-01-05 21:49 ` [PATCH v3 55/59] " Joan Bruguera
2022-09-15 11:11 ` [PATCH v3 56/59] x86/ftrace: Remove ftrace_epilogue() Peter Zijlstra
2022-10-17 14:53 ` [tip: x86/core] " tip-bot2 for Peter Zijlstra
2022-10-20 15:17 ` [tip: x86/urgent] " tip-bot2 for Peter Zijlstra
2022-12-09 15:41 ` [PATCH v3 56/59] " Steven Rostedt
2022-09-15 11:11 ` [PATCH v3 57/59] x86/ftrace: Rebalance RSB Peter Zijlstra
2022-10-17 14:53 ` [tip: x86/core] " tip-bot2 for Peter Zijlstra
2022-09-15 11:11 ` [PATCH v3 58/59] x86/ftrace: Make it call depth tracking aware Peter Zijlstra
2022-09-21 10:19 ` [PATCH v3.1 " Peter Zijlstra
2022-09-21 18:45 ` Pawan Gupta
2022-10-17 14:53 ` [tip: x86/core] " tip-bot2 for Peter Zijlstra
2022-09-15 11:11 ` [PATCH v3 59/59] x86/retbleed: Add call depth tracking mitigation Peter Zijlstra
2022-10-17 14:53 ` [tip: x86/core] " tip-bot2 for Thomas Gleixner
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