Function report

Linux Kernel

v5.5.9

Brick Technologies Co., Ltd

Source Code:mm\swap_state.c Create Date:2022-07-28 15:14:28
Last Modify:2020-03-17 22:02:06 Copyright©Brick
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Name:add_to_swap_cache resembles add_to_page_cache_locked on swapper_space,* but sets SwapCache flag and private instead of mapping and index.

Proto:int add_to_swap_cache(struct page *page, swp_entry_t entry, gfp_t gfp)

Type:int

Parameter:

TypeParameterName
struct page *page
swp_entry_tentry
gfp_tgfp
116  address_space = swap_address_space(entry)
117  idx = Extract the `offset' field from a swp_entry_t. The swp_entry_t is in* arch-independent format
118  XA_STATE_ORDER() - Declare an XArray operation state.*@name: Name of this operation state (usually xas).*@array: Array to operate on.*@index: Initial index of interest.*@order: Order of entry.* Declare and initialise an xa_state on the stack(xas, & i_pages, idx, compound_order(page))
119  nr = Returns the number of pages in this potentially compound page.
121  VM_BUG_ON_PAGE(!PageLocked(page), page)
122  VM_BUG_ON_PAGE(PageSwapCache(page), page)
123  VM_BUG_ON_PAGE(!PageSwapBacked(page), page)
125  page_ref_add(page, nr)
126  SetPageSwapCache(page)
128  Do
129  xas_lock_irq( & xas)
130  xas_create_range() - Ensure that stores to this range will succeed*@xas: XArray operation state.* Creates all of the slots in the range covered by @xas. Sets @xas to* create single-index entries and positions it at the beginning of the* range
131  If xas_error() - Return an errno stored in the xa_state.*@xas: XArray operation state.* Return: 0 if no error has been noted. A negative errno if one has. Then Go to unlock
133  When i < nr cycle
134  VM_BUG_ON_PAGE(xa_index != idx + i, page)
135  set_page_private(page + i, val + i)
136  xas_store() - Store this entry in the XArray
137  xas_next() - Move state to next index.*@xas: XArray operation state.* If the @xas was in an error state, it will remain in an error state* and this function will return %NULL. If the @xas has never been walked,
139  nrpages += nr
140  __mod_node_page_state(page_pgdat(page), NR_FILE_PAGES, nr)
141  ADD_CACHE_INFO(add_total, nr)
142  unlock :
143  xas_unlock_irq( & xas)
144  When xas_nomem() - Allocate memory if needed.*@xas: XArray operation state.*@gfp: Memory allocation flags.* If we need to add new nodes to the XArray, we try to allocate memory* with GFP_NOWAIT while holding the lock, which will usually succeed. cycle
146  If Not xas_error() - Return an errno stored in the xa_state.*@xas: XArray operation state.* Return: 0 if no error has been noted. A negative errno if one has. Then Return 0
149  ClearPageSwapCache(page)
150  page_ref_sub(page, nr)
151  Return xas_error() - Return an errno stored in the xa_state.*@xas: XArray operation state.* Return: 0 if no error has been noted. A negative errno if one has.
Caller
NameDescribe
add_to_swapadd_to_swap - allocate swap space for a page*@page: page we want to move to swap* Allocate swap space for the page and add the page to the* swap cache. Caller needs to hold the page lock.
__read_swap_cache_async