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Use VM_FAULT_DIRTY to fault in pages for write access in

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proc_rwmen.
Otherwise copy on write may create an anonymous page that is
not marked as dirty. Since  writing data to these pages
in this function also does not dirty these pages they may be
later discarded by the pagedaemon.
This commit is contained in:
ups 2007-11-08 19:35:36 +00:00
parent a38a20f6dd
commit c6c6cc7efa
1 changed files with 3 additions and 2 deletions
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5
sys/kern/sys_process.c
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@ -216,7 +216,7 @@ proc_rwmem(struct proc *p, struct uio *uio)
vm_object_t backing_object, object = NULL;
vm_offset_t pageno = 0; /* page number */
vm_prot_t reqprot;
int error, writing;
int error, fault_flags, writing;
/*
* Assert that someone has locked this vmspace. (Should be
@ -234,6 +234,7 @@ proc_rwmem(struct proc *p, struct uio *uio)
writing = uio->uio_rw == UIO_WRITE;
reqprot = writing ? (VM_PROT_WRITE | VM_PROT_OVERRIDE_WRITE) :
VM_PROT_READ;
fault_flags = writing ? VM_FAULT_DIRTY : VM_FAULT_NORMAL;
/*
* Only map in one page at a time. We don't have to, but it
@ -268,7 +269,7 @@ proc_rwmem(struct proc *p, struct uio *uio)
/*
* Fault the page on behalf of the process
*/
error = vm_fault(map, pageno, reqprot, VM_FAULT_NORMAL);
error = vm_fault(map, pageno, reqprot, fault_flags);
if (error) {
error = EFAULT;
break;