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[PATCH] i386: PARAVIRT: add flush_tlb_others paravirt_op

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This patch adds a pv_op for flush_tlb_others.  Linux running on native
hardware uses cross-CPU IPIs to flush the TLB on any CPU which may
have a particular mm's pagetable entries cached in its TLB.  This is
inefficient in a paravirtualized environment, since the hypervisor
knows which real CPUs actually contain cached mappings, which may be a
small subset of a guest's VCPUs.

Signed-off-by: Jeremy Fitzhardinge <jeremy@xensource.com>
Signed-off-by: Andi Kleen <ak@suse.de>
This commit is contained in:
Jeremy Fitzhardinge 2007-05-02 19:27:15 +02:00 committed by Andi Kleen
parent 63f70270cc
commit d4c104771a
4 changed files with 34 additions and 8 deletions
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1
arch/i386/kernel/paravirt.c
View File

@ -300,6 +300,7 @@ struct paravirt_ops paravirt_ops = {
.flush_tlb_user = native_flush_tlb,
.flush_tlb_kernel = native_flush_tlb_global,
.flush_tlb_single = native_flush_tlb_single,
.flush_tlb_others = native_flush_tlb_others,
.map_pt_hook = paravirt_nop,

13
arch/i386/kernel/smp.c
View File

@ -256,7 +256,6 @@ static cpumask_t flush_cpumask;
static struct mm_struct * flush_mm;
static unsigned long flush_va;
static DEFINE_SPINLOCK(tlbstate_lock);
#define FLUSH_ALL 0xffffffff
/*
* We cannot call mmdrop() because we are in interrupt context,
@ -338,7 +337,7 @@ fastcall void smp_invalidate_interrupt(struct pt_regs *regs)
if (flush_mm == per_cpu(cpu_tlbstate, cpu).active_mm) {
if (per_cpu(cpu_tlbstate, cpu).state == TLBSTATE_OK) {
if (flush_va == FLUSH_ALL)
if (flush_va == TLB_FLUSH_ALL)
local_flush_tlb();
else
__flush_tlb_one(flush_va);
@ -353,9 +352,11 @@ out:
put_cpu_no_resched();
}
static void flush_tlb_others(cpumask_t cpumask, struct mm_struct *mm,
unsigned long va)
void native_flush_tlb_others(const cpumask_t *cpumaskp, struct mm_struct *mm,
unsigned long va)
{
cpumask_t cpumask = *cpumaskp;
/*
* A couple of (to be removed) sanity checks:
*
@ -417,7 +418,7 @@ void flush_tlb_current_task(void)
local_flush_tlb();
if (!cpus_empty(cpu_mask))
flush_tlb_others(cpu_mask, mm, FLUSH_ALL);
flush_tlb_others(cpu_mask, mm, TLB_FLUSH_ALL);
preempt_enable();
}
@ -436,7 +437,7 @@ void flush_tlb_mm (struct mm_struct * mm)
leave_mm(smp_processor_id());
}
if (!cpus_empty(cpu_mask))
flush_tlb_others(cpu_mask, mm, FLUSH_ALL);
flush_tlb_others(cpu_mask, mm, TLB_FLUSH_ALL);
preempt_enable();
}

9
include/asm-i386/paravirt.h
View File

@ -15,6 +15,7 @@
#ifndef __ASSEMBLY__
#include <linux/types.h>
#include <linux/cpumask.h>
struct thread_struct;
struct Xgt_desc_struct;
@ -165,6 +166,8 @@ struct paravirt_ops
void (*flush_tlb_user)(void);
void (*flush_tlb_kernel)(void);
void (*flush_tlb_single)(unsigned long addr);
void (*flush_tlb_others)(const cpumask_t *cpus, struct mm_struct *mm,
unsigned long va);
void (*map_pt_hook)(int type, pte_t *va, u32 pfn);
@ -853,6 +856,12 @@ static inline void __flush_tlb_single(unsigned long addr)
PVOP_VCALL1(flush_tlb_single, addr);
}
static inline void flush_tlb_others(cpumask_t cpumask, struct mm_struct *mm,
unsigned long va)
{
PVOP_VCALL3(flush_tlb_others, &cpumask, mm, va);
}
static inline void paravirt_map_pt_hook(int type, pte_t *va, u32 pfn)
{
PVOP_VCALL3(map_pt_hook, type, va, pfn);

19
include/asm-i386/tlbflush.h
View File

@ -79,11 +79,15 @@
* - flush_tlb_range(vma, start, end) flushes a range of pages
* - flush_tlb_kernel_range(start, end) flushes a range of kernel pages
* - flush_tlb_pgtables(mm, start, end) flushes a range of page tables
* - flush_tlb_others(cpumask, mm, va) flushes a TLBs on other cpus
*
* ..but the i386 has somewhat limited tlb flushing capabilities,
* and page-granular flushes are available only on i486 and up.
*/
#define TLB_FLUSH_ALL 0xffffffff
#ifndef CONFIG_SMP
#define flush_tlb() __flush_tlb()
@ -110,7 +114,12 @@ static inline void flush_tlb_range(struct vm_area_struct *vma,
__flush_tlb();
}
#else
static inline void native_flush_tlb_others(const cpumask_t *cpumask,
struct mm_struct *mm, unsigned long va)
{
}
#else /* SMP */
#include <asm/smp.h>
@ -129,6 +138,9 @@ static inline void flush_tlb_range(struct vm_area_struct * vma, unsigned long st
flush_tlb_mm(vma->vm_mm);
}
void native_flush_tlb_others(const cpumask_t *cpumask, struct mm_struct *mm,
unsigned long va);
#define TLBSTATE_OK 1
#define TLBSTATE_LAZY 2
@ -139,8 +151,11 @@ struct tlb_state
char __cacheline_padding[L1_CACHE_BYTES-8];
};
DECLARE_PER_CPU(struct tlb_state, cpu_tlbstate);
#endif /* SMP */
#ifndef CONFIG_PARAVIRT
#define flush_tlb_others(mask, mm, va) \
native_flush_tlb_others(&mask, mm, va)
#endif
#define flush_tlb_kernel_range(start, end) flush_tlb_all()