Function report

Linux Kernel

v5.5.9

Brick Technologies Co., Ltd

Source Code:mm\hugetlb.c Create Date:2022-07-28 15:29:22
Last Modify:2020-03-12 14:18:49 Copyright©Brick
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Name:follow_hugetlb_page

Proto:long follow_hugetlb_page(struct mm_struct *mm, struct vm_area_struct *vma, struct page **pages, struct vm_area_struct **vmas, unsigned long *position, unsigned long *nr_pages, long i, unsigned int flags, int *nonblocking)

Type:long

Parameter:

TypeParameterName
struct mm_struct *mm
struct vm_area_struct *vma
struct page **pages
struct vm_area_struct **vmas
unsigned long *position
unsigned long *nr_pages
longi
unsigned intflags
int *nonblocking
4272  vaddr = position
4273  remainder = nr_pages
4274  h = hstate_vma(vma)
4275  err = -EFAULT
4277  When vaddr < The first byte after our end addresswithin vm_mm. && remainder cycle
4279  spinlock_t * ptl = NULL
4287  If fatal_signal_pending(current process) Then
4288  remainder = 0
4289  Break
4299  pte = huge_pte_offset(mm, vaddr & huge_page_mask(h), huge_page_size(h))
4301  If pte Then ptl = huge_pte_lock(h, mm, pte)
4303  absent = Not pte || huge_pte_none(huge_ptep_get(pte))
4312  If absent && flags & give error on hole if it would be zero && Not Return whether there is a pagecache page to back given address within VMA.* Caller follow_hugetlb_page() holds page_table_lock so we cannot lock_page. Then
4314  If pte Then spin_unlock(ptl)
4316  remainder = 0
4317  Break
4330  If absent || heck whether a pte points to a swap entry || flags & check pte is writable && Not huge_pte_write(huge_ptep_get(pte)) Then
4334  fault_flags = 0
4336  If pte Then spin_unlock(ptl)
4338  If flags & check pte is writable Then fault_flags |= Fault was a write access
4340  If nonblocking Then fault_flags |= Retry fault if blocking
4342  If flags & a disk transfer is needed, start the IO* and return without waiting upon it Then fault_flags |= Retry fault if blocking | Don't drop mmap_sem and wait when retrying
4345  If flags & a retry, previous pass started an IO Then
4350  ret = hugetlb_fault(mm, vma, vaddr, fault_flags)
4351  If ret & VM_FAULT_ERROR Then
4356  If ret & VM_FAULT_RETRY Then
4357  If nonblocking && Not (fault_flags & Don't drop mmap_sem and wait when retrying ) Then nonblocking = 0
4360  nr_pages = 0
4370  Return i
4372  Continue
4375  pfn_offset = (vaddr & ~huge_page_mask(h)) >> PAGE_SHIFT determines the page size
4376  page = pte_page(huge_ptep_get(pte))
4382  If Value for the false possibility is greater at compile time(page_count(page) <= 0) Then
4383  If pages Then
4384  spin_unlock(ptl)
4385  remainder = 0
4386  err = -ENOMEM
4387  Break
4395  If Not pages && Not vmas && Not pfn_offset && vaddr + huge_page_size(h) < The first byte after our end addresswithin vm_mm. && remainder >= pages_per_huge_page(h) Then
4398  vaddr += huge_page_size(h)
4399  remainder -= pages_per_huge_page(h)
4400  i += pages_per_huge_page(h)
4401  spin_unlock(ptl)
4402  Continue
4405  same_page :
4406  If pages Then
4407  pages[i] = Return the mem_map entry representing the 'offset' subpage within* the maximally aligned gigantic page 'base'. Handle any discontiguity* in the mem_map at MAX_ORDER_NR_PAGES boundaries.
4408  get_page(pages[i])
4411  If vmas Then vmas[i] = vma
4414  vaddr += PAGE_SIZE
4415  ++pfn_offset
4416  --remainder
4417  ++i
4418  If vaddr < The first byte after our end addresswithin vm_mm. && remainder && pfn_offset < pages_per_huge_page(h) Then
4424  Go to same_page
4426  spin_unlock(ptl)
4428  nr_pages = remainder
4434  position = vaddr
4436  Return If i Then i Else err