From: Rusty Russell <rusty@rustcorp.com.au>
To: Andi Kleen <ak@muc.de>
Cc: virtualization <virtualization@lists.osdl.org>,
lkml - Kernel Mailing List <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH 6/7] (Optional) implement smp_processor_id() as a per-cpu var
Date: Mon, 25 Sep 2006 15:27:43 +1000 [thread overview]
Message-ID: <1159162065.26986.45.camel@localhost.localdomain> (raw)
In-Reply-To: <1158926451.26261.18.camel@localhost.localdomain>
On Fri, 2006-09-22 at 22:00 +1000, Rusty Russell wrote:
> This implements smp_processor_id() as a per-cpu variable.
Updated for revised 5/7: we no longer need to avoid using
smp_processor_id() in cpu_init.
This implements smp_processor_id() as a per-cpu variable. The generic
code expects it in thread_info still, so we can't remove it from
there, but reducing smp_processor_id() from 9 bytes/3 insns to 6
bytes/1 insn is a nice micro-optimization.
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Index: ak-fresh/arch/i386/kernel/smpboot.c
===================================================================
--- ak-fresh.orig/arch/i386/kernel/smpboot.c 2006-09-25 14:49:05.000000000 +1000
+++ ak-fresh/arch/i386/kernel/smpboot.c 2006-09-25 15:02:51.000000000 +1000
@@ -105,6 +105,9 @@
DEFINE_PER_CPU(unsigned long, this_cpu_off);
EXPORT_PER_CPU_SYMBOL(this_cpu_off);
+DEFINE_PER_CPU(u32, processor_id);
+EXPORT_PER_CPU_SYMBOL(processor_id);
+
/*
* Trampoline 80x86 program as an array.
*/
@@ -939,6 +942,7 @@
struct Xgt_desc_struct *cpu_gdt_descr = &per_cpu(cpu_gdt_descr, cpu);
per_cpu(this_cpu_off, cpu) = __per_cpu_offset[cpu];
+ per_cpu(processor_id, cpu) = cpu;
setup_percpu_descriptor(&gdt[GDT_ENTRY_PERCPU], __per_cpu_offset[cpu]);
cpu_gdt_descr->address = (unsigned long)gdt;
cpu_gdt_descr->size = GDT_SIZE - 1;
@@ -1361,6 +1365,7 @@
struct Xgt_desc_struct *cpu_gdt_descr = &per_cpu(cpu_gdt_descr, cpu);
per_cpu(this_cpu_off, cpu) = __per_cpu_offset[cpu];
+ per_cpu(processor_id, cpu) = cpu;
setup_percpu_descriptor(&gdt[GDT_ENTRY_PERCPU], __per_cpu_offset[cpu]);
cpu_gdt_descr->address = (unsigned long)gdt;
cpu_gdt_descr->size = GDT_SIZE - 1;
Index: ak-fresh/include/asm-i386/smp.h
===================================================================
--- ak-fresh.orig/include/asm-i386/smp.h 2006-09-25 14:49:05.000000000 +1000
+++ ak-fresh/include/asm-i386/smp.h 2006-09-25 14:52:05.000000000 +1000
@@ -8,6 +8,7 @@
#include <linux/kernel.h>
#include <linux/threads.h>
#include <linux/cpumask.h>
+#include <asm/percpu.h>
#endif
#ifdef CONFIG_X86_LOCAL_APIC
@@ -56,7 +57,8 @@
* from the initial startup. We map APIC_BASE very early in page_setup(),
* so this is correct in the x86 case.
*/
-#define raw_smp_processor_id() (current_thread_info()->cpu)
+DECLARE_PER_CPU(u32, processor_id);
+#define raw_smp_processor_id() x86_read_percpu(processor_id)
extern cpumask_t cpu_callout_map;
extern cpumask_t cpu_callin_map;
--
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next prev parent reply other threads:[~2006-09-25 5:27 UTC|newest]
Thread overview: 32+ messages / expand[flat|nested] mbox.gz Atom feed top
2006-09-22 11:51 [PATCH 0/7] Using %gs for per-cpu areas on x86 Rusty Russell
2006-09-22 11:53 ` [PATCH 1/7] Use per-cpu GDT tables from early in boot Rusty Russell
2006-09-22 11:55 ` [PATCH 2/7] Rusty Russell
2006-09-22 11:56 ` [PATCH 3/7] Update sys_vm86 to cope with changed pt_regs and %gs usage Rusty Russell
2006-09-22 11:58 ` [PATCH 4/7] Fix places where using %gs changes the usermode ABI Rusty Russell
2006-09-22 11:59 ` [PATCH 5/7] Use %gs for per-cpu sections in kernel Rusty Russell
2006-09-22 12:00 ` [PATCH 6/7] (Optional) implement smp_processor_id() as a per-cpu var Rusty Russell
2006-09-22 12:01 ` [PATCH 7/7] (Optional) implement current " Rusty Russell
2006-09-25 5:29 ` Rusty Russell
2006-09-25 5:27 ` Rusty Russell [this message]
2006-09-22 12:32 ` [PATCH 5/7] Use %gs for per-cpu sections in kernel Andi Kleen
2006-09-22 22:43 ` Jeremy Fitzhardinge
2006-09-22 23:52 ` Andi Kleen
2006-09-23 4:51 ` Rusty Russell
2006-09-23 8:17 ` Andi Kleen
2006-09-23 8:55 ` Rusty Russell
2006-09-22 22:39 ` Jeremy Fitzhardinge
2006-09-23 4:31 ` Rusty Russell
2006-09-25 1:03 ` Jeremy Fitzhardinge
2006-09-25 1:16 ` Rusty Russell
2006-09-25 1:36 ` Jeremy Fitzhardinge
2006-09-25 2:51 ` Rusty Russell
2006-09-25 5:25 ` Jeremy Fitzhardinge
2006-09-25 6:03 ` Rusty Russell
2006-09-25 6:25 ` Jeremy Fitzhardinge
2006-09-25 23:33 ` Rusty Russell
2006-09-23 8:13 ` Andi Kleen
2006-09-25 1:07 ` Jeremy Fitzhardinge
2006-09-25 1:20 ` Rusty Russell
2006-09-25 5:26 ` Rusty Russell
2006-09-22 22:24 ` [PATCH 2/7] Jeremy Fitzhardinge
2006-09-23 4:36 ` Rusty Russell
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