From: Christoph Lameter <cl@linux-foundation.org>
To: Tejun Heo <tj@kernel.org>
Cc: linux-kernel@vger.kernel.org
Cc: Mel Gorman <mel@csn.ul.ie>
Cc: Pekka Enberg <penberg@cs.helsinki.fi>
Cc: Mathieu Desnoyers <mathieu.desnoyers@polymtl.ca>
Subject: [this_cpu_xx V9 4/7] Generic inc / dec percpu instructions
Date: Mon, 04 Jan 2010 16:34:43 -0600 [thread overview]
Message-ID: <20100104223556.090044300@quilx.com> (raw)
In-Reply-To: 20100104223439.228028923@quilx.com
[-- Attachment #1: x86_inc_dec --]
[-- Type: text/plain, Size: 7073 bytes --]
Optimize code generated for percpu access by checking for increment and
decrements.
Signed-off-by: Christoph Lameter <cl@linux-foundation.org>
---
arch/x86/include/asm/percpu.h | 100 ++++++++++++++++++++++++++++++++++++------
1 file changed, 86 insertions(+), 14 deletions(-)
Index: linux-2.6/arch/x86/include/asm/percpu.h
===================================================================
--- linux-2.6.orig/arch/x86/include/asm/percpu.h 2010-01-04 15:33:02.000000000 -0600
+++ linux-2.6/arch/x86/include/asm/percpu.h 2010-01-04 16:11:29.000000000 -0600
@@ -104,6 +104,78 @@ do { \
} \
} while (0)
+/*
+ * Generate a percpu add to memory instruction and optimize code
+ * if a one is added or subtracted.
+ */
+#define percpu_add_op(var, val) \
+do { \
+ typedef typeof(var) pto_T__; \
+ if (0) { \
+ pto_T__ pto_tmp__; \
+ pto_tmp__ = (val); \
+ } \
+ switch (sizeof(var)) { \
+ case 1: \
+ if (__builtin_constant_p(val) == 1) \
+ asm("incb "__percpu_arg(0) \
+ : "+m" (var) \
+ : ); \
+ else if (__builtin_constant_p(val) == -1) \
+ asm("decb "__percpu_arg(0) \
+ : "+m" (var) \
+ : ); \
+ else \
+ asm("addb %1,"__percpu_arg(0) \
+ : "+m" (var) \
+ : "qi" ((pto_T__)(val))); \
+ break; \
+ case 2: \
+ if (__builtin_constant_p(val) == 1) \
+ asm("incw "__percpu_arg(0) \
+ : "+m" (var) \
+ : ); \
+ else if (__builtin_constant_p(val) == -1) \
+ asm("decw "__percpu_arg(0) \
+ : "+m" (var) \
+ : ); \
+ else \
+ asm("addw %1,"__percpu_arg(0) \
+ : "+m" (var) \
+ : "ri" ((pto_T__)(val))); \
+ break; \
+ case 4: \
+ if (__builtin_constant_p(val) == 1) \
+ asm("incl "__percpu_arg(0) \
+ : "+m" (var) \
+ : ); \
+ else if (__builtin_constant_p(val) == -1) \
+ asm("decl "__percpu_arg(0) \
+ : "+m" (var) \
+ : ); \
+ else \
+ asm("addl %1,"__percpu_arg(0) \
+ : "+m" (var) \
+ : "ri" ((pto_T__)(val))); \
+ break; \
+ case 8: \
+ if (__builtin_constant_p(val) == 1) \
+ asm("incq "__percpu_arg(0) \
+ : "+m" (var) \
+ : ); \
+ else if (__builtin_constant_p(val) == -1) \
+ asm("decq "__percpu_arg(0) \
+ : "+m" (var) \
+ : ); \
+ else \
+ asm("addq %1,"__percpu_arg(0) \
+ : "+m" (var) \
+ : "re" ((pto_T__)(val))); \
+ break; \
+ default: __bad_percpu_size(); \
+ } \
+} while (0)
+
#define percpu_from_op(op, var, constraint) \
({ \
typeof(var) pfo_ret__; \
@@ -147,8 +219,8 @@ do { \
#define percpu_read_stable(var) percpu_from_op("mov", per_cpu__##var, \
"p" (&per_cpu__##var))
#define percpu_write(var, val) percpu_to_op("mov", per_cpu__##var, val)
-#define percpu_add(var, val) percpu_to_op("add", per_cpu__##var, val)
-#define percpu_sub(var, val) percpu_to_op("sub", per_cpu__##var, val)
+#define percpu_add(var, val) percpu_add_op(per_cpu__##var, val)
+#define percpu_sub(var, val) percpu_add_op(per_cpu__##var, -(val))
#define percpu_and(var, val) percpu_to_op("and", per_cpu__##var, val)
#define percpu_or(var, val) percpu_to_op("or", per_cpu__##var, val)
#define percpu_xor(var, val) percpu_to_op("xor", per_cpu__##var, val)
@@ -160,9 +232,9 @@ do { \
#define __this_cpu_write_1(pcp, val) percpu_to_op("mov", (pcp), val)
#define __this_cpu_write_2(pcp, val) percpu_to_op("mov", (pcp), val)
#define __this_cpu_write_4(pcp, val) percpu_to_op("mov", (pcp), val)
-#define __this_cpu_add_1(pcp, val) percpu_to_op("add", (pcp), val)
-#define __this_cpu_add_2(pcp, val) percpu_to_op("add", (pcp), val)
-#define __this_cpu_add_4(pcp, val) percpu_to_op("add", (pcp), val)
+#define __this_cpu_add_1(pcp, val) percpu_add_op((pcp), val)
+#define __this_cpu_add_2(pcp, val) percpu_add_op((pcp), val)
+#define __this_cpu_add_4(pcp, val) percpu_add_op((pcp), val)
#define __this_cpu_and_1(pcp, val) percpu_to_op("and", (pcp), val)
#define __this_cpu_and_2(pcp, val) percpu_to_op("and", (pcp), val)
#define __this_cpu_and_4(pcp, val) percpu_to_op("and", (pcp), val)
@@ -179,9 +251,9 @@ do { \
#define this_cpu_write_1(pcp, val) percpu_to_op("mov", (pcp), val)
#define this_cpu_write_2(pcp, val) percpu_to_op("mov", (pcp), val)
#define this_cpu_write_4(pcp, val) percpu_to_op("mov", (pcp), val)
-#define this_cpu_add_1(pcp, val) percpu_to_op("add", (pcp), val)
-#define this_cpu_add_2(pcp, val) percpu_to_op("add", (pcp), val)
-#define this_cpu_add_4(pcp, val) percpu_to_op("add", (pcp), val)
+#define this_cpu_add_1(pcp, val) percpu_add_op((pcp), val)
+#define this_cpu_add_2(pcp, val) percpu_add_op((pcp), val)
+#define this_cpu_add_4(pcp, val) percpu_add_op((pcp), val)
#define this_cpu_and_1(pcp, val) percpu_to_op("and", (pcp), val)
#define this_cpu_and_2(pcp, val) percpu_to_op("and", (pcp), val)
#define this_cpu_and_4(pcp, val) percpu_to_op("and", (pcp), val)
@@ -192,9 +264,9 @@ do { \
#define this_cpu_xor_2(pcp, val) percpu_to_op("xor", (pcp), val)
#define this_cpu_xor_4(pcp, val) percpu_to_op("xor", (pcp), val)
-#define irqsafe_cpu_add_1(pcp, val) percpu_to_op("add", (pcp), val)
-#define irqsafe_cpu_add_2(pcp, val) percpu_to_op("add", (pcp), val)
-#define irqsafe_cpu_add_4(pcp, val) percpu_to_op("add", (pcp), val)
+#define irqsafe_cpu_add_1(pcp, val) percpu_add_op((pcp), val)
+#define irqsafe_cpu_add_2(pcp, val) percpu_add_op((pcp), val)
+#define irqsafe_cpu_add_4(pcp, val) percpu_add_op((pcp), val)
#define irqsafe_cpu_and_1(pcp, val) percpu_to_op("and", (pcp), val)
#define irqsafe_cpu_and_2(pcp, val) percpu_to_op("and", (pcp), val)
#define irqsafe_cpu_and_4(pcp, val) percpu_to_op("and", (pcp), val)
@@ -212,19 +284,19 @@ do { \
#ifdef CONFIG_X86_64
#define __this_cpu_read_8(pcp) percpu_from_op("mov", (pcp), "m"(pcp))
#define __this_cpu_write_8(pcp, val) percpu_to_op("mov", (pcp), val)
-#define __this_cpu_add_8(pcp, val) percpu_to_op("add", (pcp), val)
+#define __this_cpu_add_8(pcp, val) percpu_add_op((pcp), val)
#define __this_cpu_and_8(pcp, val) percpu_to_op("and", (pcp), val)
#define __this_cpu_or_8(pcp, val) percpu_to_op("or", (pcp), val)
#define __this_cpu_xor_8(pcp, val) percpu_to_op("xor", (pcp), val)
#define this_cpu_read_8(pcp) percpu_from_op("mov", (pcp), "m"(pcp))
#define this_cpu_write_8(pcp, val) percpu_to_op("mov", (pcp), val)
-#define this_cpu_add_8(pcp, val) percpu_to_op("add", (pcp), val)
+#define this_cpu_add_8(pcp, val) percpu_add_op((pcp), val)
#define this_cpu_and_8(pcp, val) percpu_to_op("and", (pcp), val)
#define this_cpu_or_8(pcp, val) percpu_to_op("or", (pcp), val)
#define this_cpu_xor_8(pcp, val) percpu_to_op("xor", (pcp), val)
-#define irqsafe_cpu_add_8(pcp, val) percpu_to_op("add", (pcp), val)
+#define irqsafe_cpu_add_8(pcp, val) percpu_add_op((pcp), val)
#define irqsafe_cpu_and_8(pcp, val) percpu_to_op("and", (pcp), val)
#define irqsafe_cpu_or_8(pcp, val) percpu_to_op("or", (pcp), val)
#define irqsafe_cpu_xor_8(pcp, val) percpu_to_op("xor", (pcp), val)
--
next prev parent reply other threads:[~2010-01-04 22:37 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-01-04 22:34 [this_cpu_xx V9 0/7] Per cpu atomics in page allocator, modules, cleanup and optimized inc/dec Christoph Lameter
2010-01-04 22:34 ` [this_cpu_xx V9 1/7] Remove cpu_local_xx macros Christoph Lameter
2010-01-04 22:34 ` [this_cpu_xx V9 2/7] Module handling: Use this_cpu_xx to dynamically allocate counters Christoph Lameter
2010-01-04 22:34 ` [this_cpu_xx V9 3/7] Move local.h include to ringbuffer.c and ring_buffer_benchmark.c Christoph Lameter
2010-01-04 22:34 ` Christoph Lameter [this message]
2010-01-05 1:19 ` [this_cpu_xx V9 4/7] Generic inc / dec percpu instructions Tejun Heo
2010-01-05 15:21 ` Christoph Lameter
2010-01-04 22:34 ` [this_cpu_xx V9 5/7] this_cpu_ops: page allocator conversion Christoph Lameter
2010-01-05 6:32 ` Tejun Heo
2010-01-05 15:22 ` Christoph Lameter
2010-01-05 23:44 ` Tejun Heo
2010-01-04 22:34 ` [this_cpu_xx V9 6/7] this_cpu ops: Remove pageset_notifier Christoph Lameter
2010-01-04 22:34 ` [this_cpu_xx V9 7/7] Remove leftover local.h Christoph Lameter
2010-01-05 6:37 ` [this_cpu_xx V9 0/7] Per cpu atomics in page allocator, modules, cleanup and optimized inc/dec Tejun Heo
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