VM_IO,它指定设备的内存映射I/O VM_DONTCOPY,它告诉内核不要在fork上复制这个vma VM_DONTEXPAND,它阻止vma使用mremap(2)展开 VM_DONTDUMP,它阻止vma包含在核心转储中 你可能需要修改这个值,以便禁用缓存,如果使用这个I/O内存(vma->vm_page_prot = pgprot_noncached(vma->vm_page_prot);)。 使用io_remap_...
}if(!file->f_op->mmap)return-ENODEV;if(vm_flags & (VM_GROWSDOWN|VM_GROWSUP))return-EINVAL;break;default:return-EINVAL; } }else{switch(flags &MAP_TYPE) {caseMAP_SHARED:if(vm_flags & (VM_GROWSDOWN|VM_GROWSUP))return-EINVAL;/** Ignore pgoff.*/pgoff=0; vm_flags|= VM_SHARED |VM...
vma->vm_flags|=VM_IO|VM_PFNMAP|VM_DONTEXPAND|VM_DONTDUMP;//设置vm_flags,remap_pfn_range直接使用物理内存。Linux内核对物理页面分为两类:normalmapping,specialmapping。specialmapping就是内核不希望该页面参与到内核的页面回收等活动中。 BUG_ON(addr>=end); pfn-=addr>>PAGE_SHIFT; pgd=pgd_offset(mm...
VM_IO,它指定设备的内存映射I/O VM_DONTCOPY,它告诉内核不要在fork上复制这个vma VM_DONTEXPAND,它阻止vma使用mremap(2)展开 VM_DONTDUMP,它阻止vma包含在核心转储中 你可能需要修改这个值,以便禁用缓存,如果使用这个I/O内存(vma->vm_page_prot = pgprot_noncached(vma->vm_page_prot);)。 使用io_remap_...
大量的驱动程序使用remap_pfn_range()函数来实现映射内核页面到用户空间。这些用户程序使用的VMA通常设置了(VM_IO|VM_PFNMAP|VM_DONTEXPAND|VM_DONTDUMP) vm_insert_page()/vm_insert_pfn()映射内核页面到用户空间 vm_normal_page()函数把page页面分为两阵营,一个是normal page,另一个是special page。
unsigned long vm_end; /* The first byte after our end address within vm_mm. */ /* linked list of VM areas per task, sorted by address */ struct vm_area_struct *vm_next, *vm_prev; struct rb_node vm_rb; /* * Largest free memory gap in bytes to the left of this VMA. ...
VM_WIPEONFORK 0x02000000/* Wipe VMA contents in child. */#define VM_DONTDUMP 0x04000000/* Do not include in the core dump */#ifdef CONFIG_MEM_SOFT_DIRTY# define VM_SOFTDIRTY 0x08000000/* Not soft dirty clean area */#else# define VM_SOFTDIRTY 0#endif#define VM_MIXEDMAP 0x10000000/...
Now that `obj->funcs->mmap()` is no longer NULL we don't run the default code. It looks like the fact that the vm_flags got VM_IO / VM_DONTDUMP was important because we're now getting crashes on Chromebooks that use ARC++ while logging out. Specifically a crash that looks like ...
|g" /etc/sysctl.conf || echo "vm.max_map_count = 262144" >> /etc/sysctl.conf -a /etc/sysctl.conf <<'EOF' # 调整提升服务器负载能力,还能够防御小流量的DosCC和SYN攻击net.ipv4.tcp_syncookies = 1 net.ipv4.tcp_tw_reuse = 1 # net.ipv4tcp_tw_recycle = 1 net.ipv4tcp_...