c56004901f
This adds VM op batching to skas0. Rather than having a context switch to and from the userspace stub for each address space change, we write a number of operations to the stub data page and invoke a different stub which loops over them and executes them all in one go. The operations are stored as [ system call number, arg1, arg2, ... ] tuples. The set is terminated by a system call number of 0. Single operations, i.e. page faults, are handled in the old way, since that is slightly more efficient. For a kernel build, a minority (~1/4) of the operations are part of a set. These sets averaged ~100 in length, so for this quarter, the context switching overhead is greatly reduced. Signed-off-by: Jeff Dike <jdike@addtoit.com> Cc: Paolo Giarrusso <blaisorblade@yahoo.it> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
153 lines
3.6 KiB
C
153 lines
3.6 KiB
C
/*
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* Copyright (C) 2002 Jeff Dike (jdike@karaya.com)
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* Copyright 2003 PathScale, Inc.
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* Licensed under the GPL
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*/
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#include "linux/stddef.h"
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#include "linux/kernel.h"
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#include "linux/sched.h"
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#include "linux/mm.h"
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#include "asm/page.h"
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#include "asm/pgtable.h"
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#include "asm/uaccess.h"
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#include "asm/tlbflush.h"
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#include "user_util.h"
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#include "mem_user.h"
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#include "os.h"
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#include "tlb.h"
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static void *do_ops(union mm_context *mmu, struct host_vm_op *ops, int last,
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int finished, void *flush)
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{
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struct host_vm_op *op;
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int i;
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for(i = 0; i <= last; i++){
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op = &ops[i];
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switch(op->type){
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case MMAP:
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os_map_memory((void *) op->u.mmap.addr, op->u.mmap.fd,
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op->u.mmap.offset, op->u.mmap.len,
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op->u.mmap.r, op->u.mmap.w,
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op->u.mmap.x);
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break;
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case MUNMAP:
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os_unmap_memory((void *) op->u.munmap.addr,
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op->u.munmap.len);
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break;
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case MPROTECT:
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protect_memory(op->u.mprotect.addr, op->u.munmap.len,
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op->u.mprotect.r, op->u.mprotect.w,
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op->u.mprotect.x, 1);
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break;
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default:
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printk("Unknown op type %d in do_ops\n", op->type);
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break;
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}
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}
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return NULL;
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}
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static void fix_range(struct mm_struct *mm, unsigned long start_addr,
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unsigned long end_addr, int force)
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{
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if((current->thread.mode.tt.extern_pid != -1) &&
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(current->thread.mode.tt.extern_pid != os_getpid()))
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panic("fix_range fixing wrong address space, current = 0x%p",
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current);
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fix_range_common(mm, start_addr, end_addr, force, do_ops);
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}
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atomic_t vmchange_seq = ATOMIC_INIT(1);
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void flush_tlb_kernel_range_tt(unsigned long start, unsigned long end)
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{
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if(flush_tlb_kernel_range_common(start, end))
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atomic_inc(&vmchange_seq);
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}
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static void protect_vm_page(unsigned long addr, int w, int must_succeed)
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{
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int err;
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err = protect_memory(addr, PAGE_SIZE, 1, w, 1, must_succeed);
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if(err == 0) return;
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else if((err == -EFAULT) || (err == -ENOMEM)){
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flush_tlb_kernel_range(addr, addr + PAGE_SIZE);
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protect_vm_page(addr, w, 1);
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}
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else panic("protect_vm_page : protect failed, errno = %d\n", err);
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}
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void mprotect_kernel_vm(int w)
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{
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struct mm_struct *mm;
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pgd_t *pgd;
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pud_t *pud;
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pmd_t *pmd;
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pte_t *pte;
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unsigned long addr;
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mm = &init_mm;
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for(addr = start_vm; addr < end_vm;){
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pgd = pgd_offset(mm, addr);
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pud = pud_offset(pgd, addr);
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pmd = pmd_offset(pud, addr);
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if(pmd_present(*pmd)){
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pte = pte_offset_kernel(pmd, addr);
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if(pte_present(*pte)) protect_vm_page(addr, w, 0);
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addr += PAGE_SIZE;
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}
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else addr += PMD_SIZE;
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}
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}
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void flush_tlb_kernel_vm_tt(void)
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{
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flush_tlb_kernel_range(start_vm, end_vm);
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}
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void __flush_tlb_one_tt(unsigned long addr)
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{
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flush_tlb_kernel_range(addr, addr + PAGE_SIZE);
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}
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void flush_tlb_range_tt(struct vm_area_struct *vma, unsigned long start,
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unsigned long end)
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{
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if(vma->vm_mm != current->mm) return;
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/* Assumes that the range start ... end is entirely within
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* either process memory or kernel vm
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*/
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if((start >= start_vm) && (start < end_vm)){
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if(flush_tlb_kernel_range_common(start, end))
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atomic_inc(&vmchange_seq);
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}
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else fix_range(vma->vm_mm, start, end, 0);
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}
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void flush_tlb_mm_tt(struct mm_struct *mm)
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{
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unsigned long seq;
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if(mm != current->mm) return;
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fix_range(mm, 0, STACK_TOP, 0);
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seq = atomic_read(&vmchange_seq);
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if(current->thread.mode.tt.vm_seq == seq)
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return;
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current->thread.mode.tt.vm_seq = seq;
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flush_tlb_kernel_range_common(start_vm, end_vm);
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}
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void force_flush_all_tt(void)
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{
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fix_range(current->mm, 0, STACK_TOP, 1);
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flush_tlb_kernel_range_common(start_vm, end_vm);
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}
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