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From: jeremy@goop.org
To: akpm@osdl.org
Cc: linux-kernel@vger.kernel.org,
	Chuck Ebbert <76306.1226@compuserve.com>,
	Zachary Amsden <zach@vmware.com>,
	Jan Beulich <jbeulich@novell.com>, Andi Kleen <ak@suse.de>
Subject: [PATCH 6/6] Implement "current" with the PDA.
Date: Mon, 25 Sep 2006 11:45:46 -0700	[thread overview]
Message-ID: <20060925184639.290985244@goop.org> (raw)
In-Reply-To: <20060925184540.601971833@goop.org>

[-- Attachment #1: pda/i386-pda-current.patch --]
[-- Type: text/plain, Size: 1040 bytes --]

Use the pcurrent field in the PDA to implement the "current" macro.
This ends up compiling down to a single instruction to get the current
task.

Signed-off-by: Jeremy Fitzhardinge <jeremy@xensource.com>
Cc: Chuck Ebbert <76306.1226@compuserve.com>
Cc: Zachary Amsden <zach@vmware.com>
Cc: Jan Beulich <jbeulich@novell.com>
Cc: Andi Kleen <ak@suse.de>

---
 include/asm-i386/current.h |    7 ++++---
 1 file changed, 4 insertions(+), 3 deletions(-)

diff -r 3752f3a5974a include/asm-i386/current.h
--- a/include/asm-i386/current.h	Mon Sep 25 01:48:09 2006 -0700
+++ b/include/asm-i386/current.h	Mon Sep 25 01:48:09 2006 -0700
@@ -1,13 +1,14 @@
 #ifndef _I386_CURRENT_H
 #define _I386_CURRENT_H
 
-#include <linux/thread_info.h>
+#include <asm/pda.h>
+#include <linux/compiler.h>
 
 struct task_struct;
 
-static __always_inline struct task_struct * get_current(void)
+static __always_inline struct task_struct *get_current(void)
 {
-	return current_thread_info()->task;
+	return read_pda(pcurrent);
 }
 
 #define current get_current()

--


  parent reply	other threads:[~2006-09-25 20:14 UTC|newest]

Thread overview: 15+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2006-09-25 18:45 [PATCH 0/6] Per-processor private data areas for i386 jeremy
2006-09-25 18:45 ` [PATCH 1/6] Initialize the per-CPU data area jeremy
2006-09-25 20:49   ` Andi Kleen
2006-09-25 20:59     ` Jeremy Fitzhardinge
2006-09-25 21:05       ` Andi Kleen
2006-09-25 21:33         ` Jeremy Fitzhardinge
2006-09-25 18:45 ` [PATCH 2/6] Use %gs as the PDA base-segment in the kernel jeremy
2006-09-25 18:45 ` [PATCH 3/6] Fix places where using %gs changes the usermode ABI jeremy
2006-09-25 18:45 ` [PATCH 4/6] Update sys_vm86 to cope with changed pt_regs and %gs usage jeremy
2006-09-25 18:45 ` [PATCH 5/6] Implement smp_processor_id() with the PDA jeremy
2006-09-25 18:45 ` jeremy [this message]
2006-09-27 19:46 ` [PATCH 0/6] Per-processor private data areas for i386 Pavel Machek
2006-09-27 20:28   ` Jeremy Fitzhardinge
2006-09-27 20:28   ` Jeremy Fitzhardinge
2006-09-29  0:22     ` Rusty Russell

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