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Code Issues Releases Wiki Activity

Combine vma (#42)

Browse Source 
* 合并vma

* 调整vma映射，修复bug

* 删除注释

Co-authored-by: fslongjin <longjin@RinGoTek.cn>
Co-authored-by: houmkh <100781004+houmkh@users.noreply.github.com>
This commit is contained in:
houmkh
2022-09-22 00:31:17 +08:00
committed by GitHub
parent cbbf79b2cf
commit be9ac3d58b
7 changed files with 113 additions and 42 deletions
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28
kernel/mm/vma.c
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@ -122,21 +122,35 @@ int vma_insert(struct mm_struct *mm, struct vm_area_struct *vma)
{
struct vm_area_struct *prev;
prev = vma_find(mm, vma->vm_start);
if (prev && prev->vm_start <= vma->vm_start && prev->vm_end >= vma->vm_end)
{
// 已经存在了相同的vma
return -EEXIST;
}
else if (prev && (prev->vm_start == vma->vm_start || prev->vm_end == vma->vm_end)) // 暂时不支持扩展vma
// todo: bugfix: 这里的第二种情况貌似从来不会满足
else if (prev && ((vma->vm_start >= prev->vm_start && vma->vm_start <= prev->vm_end) || (prev->vm_start <= vma->vm_end && prev->vm_start >= vma->vm_start)))
{
kwarn("Not support: expand vma");
return -ENOTSUP;
//部分重叠
if ((!CROSS_2M_BOUND(vma->vm_start, prev->vm_start)) && (!CROSS_2M_BOUND(vma->vm_end, prev->vm_end))&& vma->vm_end)
{
//合并vma 并改变链表vma的范围
kdebug("before combining vma:vm_start = %#018lx, vm_end = %#018lx\n", vma->vm_start, vma->vm_end);
prev->vm_start = (vma->vm_start < prev->vm_start )? vma->vm_start : prev->vm_start;
prev->vm_end = (vma->vm_end > prev->vm_end) ? vma->vm_end : prev->vm_end;
// 计算page_offset
prev->page_offset = prev->vm_start - (prev->vm_start & PAGE_2M_MASK);
kdebug("combined vma:vm_start = %#018lx, vm_end = %#018lx\nprev:vm_start = %018lx, vm_end = %018lx\n", vma->vm_start, vma->vm_end, prev->vm_start, prev->vm_end);
kinfo("vma has same part\n");
return __VMA_MERGED;
}
}
prev = vma_find(mm, vma->vm_end);
if (prev)
prev = prev->vm_prev;
// prev = vma_find(mm, vma->vm_start);
if (prev == NULL) // 要将当前vma插入到链表的尾部
{
struct vm_area_struct *ptr = mm->vmas;
@ -151,6 +165,8 @@ int vma_insert(struct mm_struct *mm, struct vm_area_struct *vma)
}
}
}
else
prev = prev->vm_prev;
__vma_link_list(mm, vma, prev);
return 0;
}