[PATCH 03/12] x86-64: Convert irqstacks to per-cpu
From: Tejun Heo
Date: Sun Jan 18 2009 - 11:41:27 EST
From: Brian Gerst <brgerst@xxxxxxxxx>
Move the irqstackptr variable from the PDA to per-cpu. Make the
stacks themselves per-cpu, removing some specific allocation code.
Add a seperate flag (is_boot_cpu) to simplify the per-cpu boot
adjustments.
tj: * sprinkle some underbars around.
* irq_stack_ptr is not used till traps_init(), no reason to
initialize it early. On SMP, just leaving it NULL till proper
initialization in setup_per_cpu_areas() works. Dropped
is_boot_cpu and early irq_stack_ptr initialization.
* do DECLARE/DEFINE_PER_CPU(char[IRQ_STACK_SIZE], irq_stack)
instead of (char, irq_stack[IRQ_STACK_SIZE]).
Signed-off-by: Brian Gerst <brgerst@xxxxxxxxx>
Signed-off-by: Tejun Heo <tj@xxxxxxxxxx>
---
arch/x86/include/asm/page_64.h | 4 ++--
arch/x86/include/asm/pda.h | 1 -
arch/x86/include/asm/processor.h | 3 +++
arch/x86/kernel/asm-offsets_64.c | 1 -
arch/x86/kernel/cpu/common.c | 19 +++++++------------
arch/x86/kernel/dumpstack_64.c | 33 +++++++++++++++++----------------
arch/x86/kernel/entry_64.S | 6 +++---
arch/x86/kernel/setup_percpu.c | 4 +++-
8 files changed, 35 insertions(+), 36 deletions(-)
diff --git a/arch/x86/include/asm/page_64.h b/arch/x86/include/asm/page_64.h
index 5ebca29..e27fdbe 100644
--- a/arch/x86/include/asm/page_64.h
+++ b/arch/x86/include/asm/page_64.h
@@ -13,8 +13,8 @@
#define DEBUG_STACK_ORDER (EXCEPTION_STACK_ORDER + 1)
#define DEBUG_STKSZ (PAGE_SIZE << DEBUG_STACK_ORDER)
-#define IRQSTACK_ORDER 2
-#define IRQSTACKSIZE (PAGE_SIZE << IRQSTACK_ORDER)
+#define IRQ_STACK_ORDER 2
+#define IRQ_STACK_SIZE (PAGE_SIZE << IRQ_STACK_ORDER)
#define STACKFAULT_STACK 1
#define DOUBLEFAULT_STACK 2
diff --git a/arch/x86/include/asm/pda.h b/arch/x86/include/asm/pda.h
index 8ee835e..09965f7 100644
--- a/arch/x86/include/asm/pda.h
+++ b/arch/x86/include/asm/pda.h
@@ -22,7 +22,6 @@ struct x8664_pda {
/* gcc-ABI: this canary MUST be at
offset 40!!! */
#endif
- char *irqstackptr;
short nodenumber; /* number of current node (32k max) */
short in_bootmem; /* pda lives in bootmem */
short isidle;
diff --git a/arch/x86/include/asm/processor.h b/arch/x86/include/asm/processor.h
index 091cd88..f511246 100644
--- a/arch/x86/include/asm/processor.h
+++ b/arch/x86/include/asm/processor.h
@@ -378,6 +378,9 @@ union thread_xstate {
#ifdef CONFIG_X86_64
DECLARE_PER_CPU(struct orig_ist, orig_ist);
+
+DECLARE_PER_CPU(char[IRQ_STACK_SIZE], irq_stack);
+DECLARE_PER_CPU(char *, irq_stack_ptr);
#endif
extern void print_cpu_info(struct cpuinfo_x86 *);
diff --git a/arch/x86/kernel/asm-offsets_64.c b/arch/x86/kernel/asm-offsets_64.c
index f4cc81b..5b821fb 100644
--- a/arch/x86/kernel/asm-offsets_64.c
+++ b/arch/x86/kernel/asm-offsets_64.c
@@ -54,7 +54,6 @@ int main(void)
ENTRY(pcurrent);
ENTRY(irqcount);
ENTRY(cpunumber);
- ENTRY(irqstackptr);
DEFINE(pda_size, sizeof(struct x8664_pda));
BLANK();
#undef ENTRY
diff --git a/arch/x86/kernel/cpu/common.c b/arch/x86/kernel/cpu/common.c
index 3d0cc6f..496f0a0 100644
--- a/arch/x86/kernel/cpu/common.c
+++ b/arch/x86/kernel/cpu/common.c
@@ -881,7 +881,13 @@ __setup("clearcpuid=", setup_disablecpuid);
#ifdef CONFIG_X86_64
struct desc_ptr idt_descr = { 256 * 16 - 1, (unsigned long) idt_table };
-static char boot_cpu_stack[IRQSTACKSIZE] __page_aligned_bss;
+DEFINE_PER_CPU_PAGE_ALIGNED(char[IRQ_STACK_SIZE], irq_stack);
+#ifdef CONFIG_SMP
+DEFINE_PER_CPU(char *, irq_stack_ptr); /* will be set during per cpu init */
+#else
+DEFINE_PER_CPU(char *, irq_stack_ptr) =
+ per_cpu_var(irq_stack) + IRQ_STACK_SIZE - 64;
+#endif
void __cpuinit pda_init(int cpu)
{
@@ -901,18 +907,7 @@ void __cpuinit pda_init(int cpu)
if (cpu == 0) {
/* others are initialized in smpboot.c */
pda->pcurrent = &init_task;
- pda->irqstackptr = boot_cpu_stack;
- pda->irqstackptr += IRQSTACKSIZE - 64;
} else {
- if (!pda->irqstackptr) {
- pda->irqstackptr = (char *)
- __get_free_pages(GFP_ATOMIC, IRQSTACK_ORDER);
- if (!pda->irqstackptr)
- panic("cannot allocate irqstack for cpu %d",
- cpu);
- pda->irqstackptr += IRQSTACKSIZE - 64;
- }
-
if (pda->nodenumber == 0 && cpu_to_node(cpu) != NUMA_NO_NODE)
pda->nodenumber = cpu_to_node(cpu);
}
diff --git a/arch/x86/kernel/dumpstack_64.c b/arch/x86/kernel/dumpstack_64.c
index c302d07..28e26a4 100644
--- a/arch/x86/kernel/dumpstack_64.c
+++ b/arch/x86/kernel/dumpstack_64.c
@@ -106,7 +106,8 @@ void dump_trace(struct task_struct *task, struct pt_regs *regs,
const struct stacktrace_ops *ops, void *data)
{
const unsigned cpu = get_cpu();
- unsigned long *irqstack_end = (unsigned long *)cpu_pda(cpu)->irqstackptr;
+ unsigned long *irq_stack_end =
+ (unsigned long *)per_cpu(irq_stack_ptr, cpu);
unsigned used = 0;
struct thread_info *tinfo;
int graph = 0;
@@ -160,23 +161,23 @@ void dump_trace(struct task_struct *task, struct pt_regs *regs,
stack = (unsigned long *) estack_end[-2];
continue;
}
- if (irqstack_end) {
- unsigned long *irqstack;
- irqstack = irqstack_end -
- (IRQSTACKSIZE - 64) / sizeof(*irqstack);
+ if (irq_stack_end) {
+ unsigned long *irq_stack;
+ irq_stack = irq_stack_end -
+ (IRQ_STACK_SIZE - 64) / sizeof(*irq_stack);
- if (stack >= irqstack && stack < irqstack_end) {
+ if (stack >= irq_stack && stack < irq_stack_end) {
if (ops->stack(data, "IRQ") < 0)
break;
bp = print_context_stack(tinfo, stack, bp,
- ops, data, irqstack_end, &graph);
+ ops, data, irq_stack_end, &graph);
/*
* We link to the next stack (which would be
* the process stack normally) the last
* pointer (index -1 to end) in the IRQ stack:
*/
- stack = (unsigned long *) (irqstack_end[-1]);
- irqstack_end = NULL;
+ stack = (unsigned long *) (irq_stack_end[-1]);
+ irq_stack_end = NULL;
ops->stack(data, "EOI");
continue;
}
@@ -199,10 +200,10 @@ show_stack_log_lvl(struct task_struct *task, struct pt_regs *regs,
unsigned long *stack;
int i;
const int cpu = smp_processor_id();
- unsigned long *irqstack_end =
- (unsigned long *) (cpu_pda(cpu)->irqstackptr);
- unsigned long *irqstack =
- (unsigned long *) (cpu_pda(cpu)->irqstackptr - IRQSTACKSIZE);
+ unsigned long *irq_stack_end =
+ (unsigned long *)(per_cpu(irq_stack_ptr, cpu));
+ unsigned long *irq_stack =
+ (unsigned long *)(per_cpu(irq_stack_ptr, cpu) - IRQ_STACK_SIZE);
/*
* debugging aid: "show_stack(NULL, NULL);" prints the
@@ -218,9 +219,9 @@ show_stack_log_lvl(struct task_struct *task, struct pt_regs *regs,
stack = sp;
for (i = 0; i < kstack_depth_to_print; i++) {
- if (stack >= irqstack && stack <= irqstack_end) {
- if (stack == irqstack_end) {
- stack = (unsigned long *) (irqstack_end[-1]);
+ if (stack >= irq_stack && stack <= irq_stack_end) {
+ if (stack == irq_stack_end) {
+ stack = (unsigned long *) (irq_stack_end[-1]);
printk(" <EOI> ");
}
} else {
diff --git a/arch/x86/kernel/entry_64.S b/arch/x86/kernel/entry_64.S
index 4833f3a..d22677a 100644
--- a/arch/x86/kernel/entry_64.S
+++ b/arch/x86/kernel/entry_64.S
@@ -345,7 +345,7 @@ ENTRY(save_args)
1: incl %gs:pda_irqcount
jne 2f
popq_cfi %rax /* move return address... */
- mov %gs:pda_irqstackptr,%rsp
+ mov PER_CPU_VAR(irq_stack_ptr),%rsp
EMPTY_FRAME 0
pushq_cfi %rax /* ... to the new stack */
/*
@@ -1261,7 +1261,7 @@ ENTRY(call_softirq)
mov %rsp,%rbp
CFI_DEF_CFA_REGISTER rbp
incl %gs:pda_irqcount
- cmove %gs:pda_irqstackptr,%rsp
+ cmove PER_CPU_VAR(irq_stack_ptr),%rsp
push %rbp # backlink for old unwinder
call __do_softirq
leaveq
@@ -1300,7 +1300,7 @@ ENTRY(xen_do_hypervisor_callback) # do_hypervisor_callback(struct *pt_regs)
11: incl %gs:pda_irqcount
movq %rsp,%rbp
CFI_DEF_CFA_REGISTER rbp
- cmovzq %gs:pda_irqstackptr,%rsp
+ cmovzq PER_CPU_VAR(irq_stack_ptr),%rsp
pushq %rbp # backlink for old unwinder
call xen_evtchn_do_upcall
popq %rsp
diff --git a/arch/x86/kernel/setup_percpu.c b/arch/x86/kernel/setup_percpu.c
index b5c35af..8b53ef8 100644
--- a/arch/x86/kernel/setup_percpu.c
+++ b/arch/x86/kernel/setup_percpu.c
@@ -192,7 +192,10 @@ void __init setup_per_cpu_areas(void)
memcpy(ptr, __per_cpu_load, __per_cpu_end - __per_cpu_start);
per_cpu_offset(cpu) = ptr - __per_cpu_start;
+ per_cpu(this_cpu_off, cpu) = per_cpu_offset(cpu);
#ifdef CONFIG_X86_64
+ per_cpu(irq_stack_ptr, cpu) =
+ (char *)per_cpu(irq_stack, cpu) + IRQ_STACK_SIZE - 64;
/*
* CPU0 modified pda in the init data area, reload pda
* offset for CPU0 and clear the area for others.
@@ -202,7 +205,6 @@ void __init setup_per_cpu_areas(void)
else
memset(cpu_pda(cpu), 0, sizeof(*cpu_pda(cpu)));
#endif
- per_cpu(this_cpu_off, cpu) = per_cpu_offset(cpu);
DBG("PERCPU: cpu %4d %p\n", cpu, ptr);
}
--
1.6.0.2
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/