From: Brian Gerst <brgerst@gmail.com>
Date: Wed, 27 Oct 2010 05:43:02 +0000 (-0400)
Subject: x86-32: Allocate irq stacks seperate from percpu area
X-Git-Url: http://drtracing.org/?a=commitdiff_plain;h=22d4cd4c4d;p=deliverable%2Flinux.git

x86-32: Allocate irq stacks seperate from percpu area

The percpu allocator cannot handle alignments larger than one
page. Allocate the irq stacks seperately, and only keep the
pointers as percpu data.

Signed-off-by: Brian Gerst <brgerst@gmail.com>
Acked-by: Linus Torvalds <torvalds@linux-foundation.org>
Cc: tj@kernel.org
LKML-Reference: <1288158182-1753-1-git-send-email-brgerst@gmail.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
---

diff --git a/arch/x86/include/asm/irq.h b/arch/x86/include/asm/irq.h
index 0bf5b0083650..13b0ebaa512f 100644
--- a/arch/x86/include/asm/irq.h
+++ b/arch/x86/include/asm/irq.h
@@ -21,10 +21,8 @@ static inline int irq_canonicalize(int irq)
 
 #ifdef CONFIG_X86_32
 extern void irq_ctx_init(int cpu);
-extern void irq_ctx_exit(int cpu);
 #else
 # define irq_ctx_init(cpu) do { } while (0)
-# define irq_ctx_exit(cpu) do { } while (0)
 #endif
 
 #define __ARCH_HAS_DO_SOFTIRQ
diff --git a/arch/x86/kernel/irq_32.c b/arch/x86/kernel/irq_32.c
index 50fbbe60e507..64668dbf00a4 100644
--- a/arch/x86/kernel/irq_32.c
+++ b/arch/x86/kernel/irq_32.c
@@ -60,9 +60,6 @@ union irq_ctx {
 static DEFINE_PER_CPU(union irq_ctx *, hardirq_ctx);
 static DEFINE_PER_CPU(union irq_ctx *, softirq_ctx);
 
-static DEFINE_PER_CPU_MULTIPAGE_ALIGNED(union irq_ctx, hardirq_stack, THREAD_SIZE);
-static DEFINE_PER_CPU_MULTIPAGE_ALIGNED(union irq_ctx, softirq_stack, THREAD_SIZE);
-
 static void call_on_stack(void *func, void *stack)
 {
 	asm volatile("xchgl	%%ebx,%%esp	\n"
@@ -128,7 +125,7 @@ void __cpuinit irq_ctx_init(int cpu)
 	if (per_cpu(hardirq_ctx, cpu))
 		return;
 
-	irqctx = &per_cpu(hardirq_stack, cpu);
+	irqctx = (union irq_ctx *)__get_free_pages(THREAD_FLAGS, THREAD_ORDER);
 	irqctx->tinfo.task		= NULL;
 	irqctx->tinfo.exec_domain	= NULL;
 	irqctx->tinfo.cpu		= cpu;
@@ -137,7 +134,7 @@ void __cpuinit irq_ctx_init(int cpu)
 
 	per_cpu(hardirq_ctx, cpu) = irqctx;
 
-	irqctx = &per_cpu(softirq_stack, cpu);
+	irqctx = (union irq_ctx *)__get_free_pages(THREAD_FLAGS, THREAD_ORDER);
 	irqctx->tinfo.task		= NULL;
 	irqctx->tinfo.exec_domain	= NULL;
 	irqctx->tinfo.cpu		= cpu;
@@ -150,11 +147,6 @@ void __cpuinit irq_ctx_init(int cpu)
 	       cpu, per_cpu(hardirq_ctx, cpu),  per_cpu(softirq_ctx, cpu));
 }
 
-void irq_ctx_exit(int cpu)
-{
-	per_cpu(hardirq_ctx, cpu) = NULL;
-}
-
 asmlinkage void do_softirq(void)
 {
 	unsigned long flags;
diff --git a/arch/x86/kernel/smpboot.c b/arch/x86/kernel/smpboot.c
index 6af118511b4a..90baf567bbf7 100644
--- a/arch/x86/kernel/smpboot.c
+++ b/arch/x86/kernel/smpboot.c
@@ -1373,7 +1373,6 @@ void play_dead_common(void)
 {
 	idle_task_exit();
 	reset_lazy_tlbstate();
-	irq_ctx_exit(raw_smp_processor_id());
 	c1e_remove_cpu(raw_smp_processor_id());
 
 	mb();