[PATCH 09/10] x86: make x86_32 use tlb_64.c

Tejun Heo
2009-01-21T08:51:21Z

Impact: less contention when issuing invalidate IPI, cleanup

Make x86_32 use the same tlb code as 64bit. The 64bit code uses
multiple IPI vectors for tlb shootdown to reduce contention. This
patch makes x86_32 allocate the same 8 IPIs as x86_64 and share the
code paths.

Note that the usage of asmlinkage is inconsistent for x86_32 and 64
and calls for further cleanup. This has been noted with a FIXME
comment in tlb_64.c.

Signed-off-by: Tejun Heo <tj@kernel.org>
---
arch/x86/include/asm/irq_vectors.h | 7 +-
arch/x86/include/asm/mach-default/entry_arch.h | 18 ++-
arch/x86/kernel/Makefile | 2 +-
arch/x86/kernel/entry_32.S | 6 +-
arch/x86/kernel/irqinit_32.c | 11 +-
arch/x86/kernel/tlb_32.c | 239 ------------------------
arch/x86/kernel/tlb_64.c | 12 +-
7 files changed, 47 insertions(+), 248 deletions(-)
delete mode 100644 arch/x86/kernel/tlb_32.c

diff --git a/arch/x86/include/asm/irq_vectors.h b/arch/x86/include/asm/irq_vectors.h
index 4ee8f80..9a83a10 100644
--- a/arch/x86/include/asm/irq_vectors.h
+++ b/arch/x86/include/asm/irq_vectors.h
@@ -58,8 +58,11 @@
# define CALL_FUNCTION_VECTOR 0xfc
# define CALL_FUNCTION_SINGLE_VECTOR 0xfb
# define THERMAL_APIC_VECTOR 0xfa
-/* 0xf1 - 0xf9 : free */
-# define INVALIDATE_TLB_VECTOR 0xf0
+/* 0xf8 - 0xf9 : free */
+# define INVALIDATE_TLB_VECTOR_END 0xf7
+# define INVALIDATE_TLB_VECTOR_START 0xf0 /* f0-f7 used for TLB flush */
+
+# define NUM_INVALIDATE_TLB_VECTORS 8

#else

diff --git a/arch/x86/include/asm/mach-default/entry_arch.h b/arch/x86/include/asm/mach-default/entry_arch.h
index 6b1add8..6fa399a 100644
--- a/arch/x86/include/asm/mach-default/entry_arch.h
+++ b/arch/x86/include/asm/mach-default/entry_arch.h
@@ -11,10 +11,26 @@
*/
#ifdef CONFIG_X86_SMP
BUILD_INTERRUPT(reschedule_interrupt,RESCHEDULE_VECTOR)
-BUILD_INTERRUPT(invalidate_interrupt,INVALIDATE_TLB_VECTOR)
BUILD_INTERRUPT(call_function_interrupt,CALL_FUNCTION_VECTOR)
BUILD_INTERRUPT(call_function_single_interrupt,CALL_FUNCTION_SINGLE_VECTOR)
BUILD_INTERRUPT(irq_move_cleanup_interrupt,IRQ_MOVE_CLEANUP_VECTOR)
+
+BUILD_INTERRUPT3(invalidate_interrupt0,INVALIDATE_TLB_VECTOR_START+0,
+ smp_invalidate_interrupt)
+BUILD_INTERRUPT3(invalidate_interrupt1,INVALIDATE_TLB_VECTOR_START+1,
+ smp_invalidate_interrupt)
+BUILD_INTERRUPT3(invalidate_interrupt2,INVALIDATE_TLB_VECTOR_START+2,
+ smp_invalidate_interrupt)
+BUILD_INTERRUPT3(invalidate_interrupt3,INVALIDATE_TLB_VECTOR_START+3,
+ smp_invalidate_interrupt)
+BUILD_INTERRUPT3(invalidate_interrupt4,INVALIDATE_TLB_VECTOR_START+4,
+ smp_invalidate_interrupt)
+BUILD_INTERRUPT3(invalidate_interrupt5,INVALIDATE_TLB_VECTOR_START+5,
+ smp_invalidate_interrupt)
+BUILD_INTERRUPT3(invalidate_interrupt6,INVALIDATE_TLB_VECTOR_START+6,
+ smp_invalidate_interrupt)
+BUILD_INTERRUPT3(invalidate_interrupt7,INVALIDATE_TLB_VECTOR_START+7,
+ smp_invalidate_interrupt)
#endif

/*
diff --git a/arch/x86/kernel/Makefile b/arch/x86/kernel/Makefile
index eb07453..a62a15c 100644
--- a/arch/x86/kernel/Makefile
+++ b/arch/x86/kernel/Makefile
@@ -58,7 +58,7 @@ obj-$(CONFIG_PCI) += early-quirks.o
apm-y := apm_32.o
obj-$(CONFIG_APM) += apm.o
obj-$(CONFIG_X86_SMP) += smp.o
-obj-$(CONFIG_X86_SMP) += smpboot.o tsc_sync.o ipi.o tlb_$(BITS).o
+obj-$(CONFIG_X86_SMP) += smpboot.o tsc_sync.o ipi.o tlb_64.o
obj-$(CONFIG_X86_32_SMP) += smpcommon.o
obj-$(CONFIG_X86_64_SMP) += tsc_sync.o smpcommon.o
obj-$(CONFIG_X86_TRAMPOLINE) += trampoline_$(BITS).o
diff --git a/arch/x86/kernel/entry_32.S b/arch/x86/kernel/entry_32.S
index 4646902..a0b91aa 100644
--- a/arch/x86/kernel/entry_32.S
+++ b/arch/x86/kernel/entry_32.S
@@ -672,7 +672,7 @@ common_interrupt:
ENDPROC(common_interrupt)
CFI_ENDPROC

-#define BUILD_INTERRUPT(name, nr) \
+#define BUILD_INTERRUPT3(name, nr, fn) \
ENTRY(name) \
RING0_INT_FRAME; \
pushl $~(nr); \
@@ -680,11 +680,13 @@ ENTRY(name) \
SAVE_ALL; \
TRACE_IRQS_OFF \
movl %esp,%eax; \
- call smp_##name; \
+ call fn; \
jmp ret_from_intr; \
CFI_ENDPROC; \
ENDPROC(name)

+#define BUILD_INTERRUPT(name, nr) BUILD_INTERRUPT3(name, nr, smp_##name)
+
/* The include is where all of the SMP etc. interrupts come from */
#include "entry_arch.h"

diff --git a/arch/x86/kernel/irqinit_32.c b/arch/x86/kernel/irqinit_32.c
index 1507ad4..bf629ca 100644
--- a/arch/x86/kernel/irqinit_32.c
+++ b/arch/x86/kernel/irqinit_32.c
@@ -149,8 +149,15 @@ void __init native_init_IRQ(void)
*/
alloc_intr_gate(RESCHEDULE_VECTOR, reschedule_interrupt);

- /* IPI for invalidation */
- alloc_intr_gate(INVALIDATE_TLB_VECTOR, invalidate_interrupt);
+ /* IPIs for invalidation */
+ alloc_intr_gate(INVALIDATE_TLB_VECTOR_START+0, invalidate_interrupt0);
+ alloc_intr_gate(INVALIDATE_TLB_VECTOR_START+1, invalidate_interrupt1);
+ alloc_intr_gate(INVALIDATE_TLB_VECTOR_START+2, invalidate_interrupt2);
+ alloc_intr_gate(INVALIDATE_TLB_VECTOR_START+3, invalidate_interrupt3);
+ alloc_intr_gate(INVALIDATE_TLB_VECTOR_START+4, invalidate_interrupt4);
+ alloc_intr_gate(INVALIDATE_TLB_VECTOR_START+5, invalidate_interrupt5);
+ alloc_intr_gate(INVALIDATE_TLB_VECTOR_START+6, invalidate_interrupt6);
+ alloc_intr_gate(INVALIDATE_TLB_VECTOR_START+7, invalidate_interrupt7);

/* IPI for generic function call */
alloc_intr_gate(CALL_FUNCTION_VECTOR, call_function_interrupt);
diff --git a/arch/x86/kernel/tlb_32.c b/arch/x86/kernel/tlb_32.c
deleted file mode 100644
index 93fcb05..0000000
--- a/arch/x86/kernel/tlb_32.c
+++ /dev/null
@@ -1,239 +0,0 @@
-#include <linux/spinlock.h>
-#include <linux/cpu.h>
-#include <linux/interrupt.h>
-
-#include <asm/tlbflush.h>
-
-DEFINE_PER_CPU_SHARED_ALIGNED(struct tlb_state, cpu_tlbstate)
- = { &init_mm, 0, };
-
-/* must come after the send_IPI functions above for inlining */
-#include <mach_ipi.h>
-
-/*
- * Smarter SMP flushing macros.
- * c/o Linus Torvalds.
- *
- * These mean you can really definitely utterly forget about
- * writing to user space from interrupts. (Its not allowed anyway).
- *
- * Optimizations Manfred Spraul <manfred@colorfullife.com>
- */
-
-static cpumask_var_t flush_cpumask;
-static struct mm_struct *flush_mm;
-static unsigned long flush_va;
-static DEFINE_SPINLOCK(tlbstate_lock);
-
-/*
- * We cannot call mmdrop() because we are in interrupt context,
- * instead update mm->cpu_vm_mask.
- *
- * We need to reload %cr3 since the page tables may be going
- * away from under us..
- */
-void leave_mm(int cpu)
-{
- BUG_ON(percpu_read(cpu_tlbstate.state) == TLBSTATE_OK);
- cpu_clear(cpu, percpu_read(cpu_tlbstate.active_mm)->cpu_vm_mask);
- load_cr3(swapper_pg_dir);
-}
-EXPORT_SYMBOL_GPL(leave_mm);
-
-/*
- *
- * The flush IPI assumes that a thread switch happens in this order:
- * [cpu0: the cpu that switches]
- * 1) switch_mm() either 1a) or 1b)
- * 1a) thread switch to a different mm
- * 1a1) cpu_clear(cpu, old_mm->cpu_vm_mask);
- * Stop ipi delivery for the old mm. This is not synchronized with
- * the other cpus, but smp_invalidate_interrupt ignore flush ipis
- * for the wrong mm, and in the worst case we perform a superfluous
- * tlb flush.
- * 1a2) set cpu_tlbstate to TLBSTATE_OK
- * Now the smp_invalidate_interrupt won't call leave_mm if cpu0
- * was in lazy tlb mode.
- * 1a3) update cpu_tlbstate[].active_mm
- * Now cpu0 accepts tlb flushes for the new mm.
- * 1a4) cpu_set(cpu, new_mm->cpu_vm_mask);
- * Now the other cpus will send tlb flush ipis.
- * 1a4) change cr3.
- * 1b) thread switch without mm change
- * cpu_tlbstate[].active_mm is correct, cpu0 already handles
- * flush ipis.
- * 1b1) set cpu_tlbstate to TLBSTATE_OK
- * 1b2) test_and_set the cpu bit in cpu_vm_mask.
- * Atomically set the bit [other cpus will start sending flush ipis],
- * and test the bit.
- * 1b3) if the bit was 0: leave_mm was called, flush the tlb.
- * 2) switch %%esp, ie current
- *
- * The interrupt must handle 2 special cases:
- * - cr3 is changed before %%esp, ie. it cannot use current->{active_,}mm.
- * - the cpu performs speculative tlb reads, i.e. even if the cpu only
- * runs in kernel space, the cpu could load tlb entries for user space
- * pages.
- *
- * The good news is that cpu_tlbstate is local to each cpu, no
- * write/read ordering problems.
- */
-
-/*
- * TLB flush IPI:
- *
- * 1) Flush the tlb entries if the cpu uses the mm that's being flushed.
- * 2) Leave the mm if we are in the lazy tlb mode.
- *
- * Interrupts are disabled.
- */
-
-void smp_invalidate_interrupt(struct pt_regs *regs)
-{
- unsigned int cpu;
-
- cpu = smp_processor_id();
-
- if (!cpumask_test_cpu(cpu, flush_cpumask))
- goto out;
- /*
- * This was a BUG() but until someone can quote me the
- * line from the intel manual that guarantees an IPI to
- * multiple CPUs is retried _only_ on the erroring CPUs
- * its staying as a return
- *
- * BUG();
- */
-
- if (flush_mm == percpu_read(cpu_tlbstate.active_mm)) {
- if (percpu_read(cpu_tlbstate.state) == TLBSTATE_OK) {
- if (flush_va == TLB_FLUSH_ALL)
- local_flush_tlb();
- else
- __flush_tlb_one(flush_va);
- } else
- leave_mm(cpu);
- }
-out:
- ack_APIC_irq();
- smp_mb__before_clear_bit();
- cpumask_clear_cpu(cpu, flush_cpumask);
- smp_mb__after_clear_bit();
- inc_irq_stat(irq_tlb_count);
-}
-
-void native_flush_tlb_others(const struct cpumask *cpumask,
- struct mm_struct *mm, unsigned long va)
-{
- /*
- * - mask must exist :)
- */
- BUG_ON(cpumask_empty(cpumask));
- BUG_ON(!mm);
-
- /*
- * i'm not happy about this global shared spinlock in the
- * MM hot path, but we'll see how contended it is.
- * AK: x86-64 has a faster method that could be ported.
- */
- spin_lock(&tlbstate_lock);
-
- cpumask_andnot(flush_cpumask, cpumask, cpumask_of(smp_processor_id()));
-#ifdef CONFIG_HOTPLUG_CPU
- /* If a CPU which we ran on has gone down, OK. */
- cpumask_and(flush_cpumask, flush_cpumask, cpu_online_mask);
- if (unlikely(cpumask_empty(flush_cpumask))) {
- spin_unlock(&tlbstate_lock);
- return;
- }
-#endif
- flush_mm = mm;
- flush_va = va;
-
- /*
- * Make the above memory operations globally visible before
- * sending the IPI.
- */
- smp_mb();
- /*
- * We have to send the IPI only to
- * CPUs affected.
- */
- send_IPI_mask(flush_cpumask, INVALIDATE_TLB_VECTOR);
-
- while (!cpumask_empty(flush_cpumask))
- /* nothing. lockup detection does not belong here */
- cpu_relax();
-
- flush_mm = NULL;
- flush_va = 0;
- spin_unlock(&tlbstate_lock);
-}
-
-void flush_tlb_current_task(void)
-{
- struct mm_struct *mm = current->mm;
-
- preempt_disable();
-
- local_flush_tlb();
- if (cpumask_any_but(&mm->cpu_vm_mask, smp_processor_id()) < nr_cpu_ids)
- flush_tlb_others(&mm->cpu_vm_mask, mm, TLB_FLUSH_ALL);
- preempt_enable();
-}
-
-void flush_tlb_mm(struct mm_struct *mm)
-{
-
- preempt_disable();
-
- if (current->active_mm == mm) {
- if (current->mm)
- local_flush_tlb();
- else
- leave_mm(smp_processor_id());
- }
- if (cpumask_any_but(&mm->cpu_vm_mask, smp_processor_id()) < nr_cpu_ids)
- flush_tlb_others(&mm->cpu_vm_mask, mm, TLB_FLUSH_ALL);
-
- preempt_enable();
-}
-
-void flush_tlb_page(struct vm_area_struct *vma, unsigned long va)
-{
- struct mm_struct *mm = vma->vm_mm;
-
- preempt_disable();
-
- if (current->active_mm == mm) {
- if (current->mm)
- __flush_tlb_one(va);
- else
- leave_mm(smp_processor_id());
- }
-
- if (cpumask_any_but(&mm->cpu_vm_mask, smp_processor_id()) < nr_cpu_ids)
- flush_tlb_others(&mm->cpu_vm_mask, mm, va);
- preempt_enable();
-}
-
-static void do_flush_tlb_all(void *info)
-{
- unsigned long cpu = smp_processor_id();
-
- __flush_tlb_all();
- if (percpu_read(cpu_tlbstate.state) == TLBSTATE_LAZY)
- leave_mm(cpu);
-}
-
-void flush_tlb_all(void)
-{
- on_each_cpu(do_flush_tlb_all, NULL, 1);
-}
-
-static int init_flush_cpumask(void)
-{
- alloc_cpumask_var(&flush_cpumask, GFP_KERNEL);
- return 0;
-}
-early_initcall(init_flush_cpumask);
diff --git a/arch/x86/kernel/tlb_64.c b/arch/x86/kernel/tlb_64.c
index 19ac661..b3ca1b9 100644
--- a/arch/x86/kernel/tlb_64.c
+++ b/arch/x86/kernel/tlb_64.c
@@ -113,7 +113,17 @@ EXPORT_SYMBOL_GPL(leave_mm);
* Interrupts are disabled.
*/

-asmlinkage void smp_invalidate_interrupt(struct pt_regs *regs)
+/*
+ * FIXME: use of asmlinkage is not consistent. On x86_64 it's noop
+ * but still used for documentation purpose but the usage is slightly
+ * inconsistent. On x86_32, asmlinkage is regparm(0) but interrupt
+ * entry calls in with the first parameter in %eax. Maybe define
+ * intrlinkage?
+ */
+#ifdef CONFIG_X86_64
+asmlinkage
+#endif
+void smp_invalidate_interrupt(struct pt_regs *regs)
{
unsigned int cpu;
unsigned int sender;
--
1.6.0.2