Function report

Linux Kernel

v5.5.9

Brick Technologies Co., Ltd

Source Code:mm\swapfile.c Create Date:2022-07-28 15:18:18
Last Modify:2020-03-17 22:19:49 Copyright©Brick
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Name:unuse_pte_range

Proto:static int unuse_pte_range(struct vm_area_struct *vma, pmd_t *pmd, unsigned long addr, unsigned long end, unsigned int type, bool frontswap, unsigned long *fs_pages_to_unuse)

Type:int

Parameter:

TypeParameterName
struct vm_area_struct *vma
pmd_t *pmd
unsigned longaddr
unsigned longend
unsigned inttype
boolfrontswap
unsigned long *fs_pages_to_unuse
1919  ret = 0
1922  si = swap_info[type]
1923  pte = pte_offset_map(pmd, addr)
1924  Do
1927  If Not heck whether a pte points to a swap entry Then Continue
1930  entry = Convert the arch-dependent pte representation of a swp_entry_t into an* arch-independent swp_entry_t.
1931  If Extract the `type' field from a swp_entry_t. The swp_entry_t is in* arch-independent format != type Then Continue
1934  offset = Extract the `offset' field from a swp_entry_t. The swp_entry_t is in* arch-independent format
1935  If frontswap && Not frontswap_test(si, offset) Then Continue
1938  pte_unmap(pte)
1939  swap_map = vmalloc'ed array of usage counts [offset]
1940  Target VMA = vma
1941  Faulting virtual address = addr
1942  Pointer to pmd entry matching* the 'address' = pmd
1943  page = swapin_readahead - swap in pages in hope we need them soon*@entry: swap entry of this memory*@gfp_mask: memory allocation flags*@vmf: fault information* Returns the struct page for entry and addr, after queueing swapin.
1944  If Not page Then
1945  If swap_map == 0 || swap_map == Note pageblock is bad, in first swap_map Then Go to try_next
1947  Return -ENOMEM
1950  lock_page may only be called if we have the page's inode pinned.
1951  Wait for a page to complete writeback
1952  ret = No need to decide whether this PTE shares the swap entry with others,* just let do_wp_page work it out if a write is requested later - to* force COW, vm_page_prot omits write permission from any private vma.
1953  If ret < 0 Then
1954  lock_page - unlock a locked page*@page: the page* Unlocks the page and wakes up sleepers in ___wait_on_page_locked().* Also wakes sleepers in wait_on_page_writeback() because the wakeup* mechanism between PageLocked pages and PageWriteback pages is shared.
1955  Perform a free_page(), also freeing any swap cache associated with* this page if it is the last user of the page.
1956  Go to out
1959  If swap is getting full, or if there are no more mappings of this page,* then try_to_free_swap is called to free its swap space.
1960  lock_page - unlock a locked page*@page: the page* Unlocks the page and wakes up sleepers in ___wait_on_page_locked().* Also wakes sleepers in wait_on_page_writeback() because the wakeup* mechanism between PageLocked pages and PageWriteback pages is shared.
1961  Perform a free_page(), also freeing any swap cache associated with* this page if it is the last user of the page.
1963  If fs_pages_to_unuse && Not --fs_pages_to_unuse Then
1964  ret = Return code to denote that requested number of* frontswap pages are unused(moved to page cache).* Used in in shmem_unuse and try_to_unuse.
1965  Go to out
1967  try_next :
1968  pte = pte_offset_map(pmd, addr)
1969  When pte++, addr += PAGE_SIZE , addr != end cycle
1970  pte_unmap(pte - 1)
1972  ret = 0
1973  out :
1974  Return ret
Caller
NameDescribe
unuse_pmd_range