函数逻辑报告

Linux Kernel

v5.5.9

Brick Technologies Co., Ltd

Source Code:mm\memory.c Create Date:2022-07-27 16:09:24
Last Modify:2020-03-12 14:18:49 Copyright©Brick
首页 函数Tree
注解内核,赢得工具下载SCCTEnglish

函数名称：This routine handles present pages, when users try to write* to a shared page. It is done by copying the page to a new address* and decrementing the shared-page counter for the old page.* Note that this routine assumes that the protection checks have been

函数原型：static vm_fault_t do_wp_page(struct vm_fault *vmf)__releases(vmf->ptl)

返回类型：vm_fault_t

参数：

类型参数名称
struct vm_fault *vmf
2717  vma等于Target VMA
2719  ->fault handlers should return a* page here, unless VM_FAULT_NOPAGE* is set (which is also implied by* VM_FAULT_ERROR).等于vm_normal_page -- This function gets the "struct page" associated with a pte.* "Special" mappings do not wish to be associated with a "struct page" (either* it doesn't exist, or it exists but they don't want to touch it). In this
2720  如果非->fault handlers should return a* page here, unless VM_FAULT_NOPAGE* is set (which is also implied by* VM_FAULT_ERROR).则
2728  如果Flags, see mm.h. 按位与VM_WRITE按位或VM_SHARED的值的值恒等于VM_WRITE按位或VM_SHARED的值则返回:Handle write page faults for VM_MIXEDMAP or VM_PFNMAP for a VM_SHARED* mapping
2732  pte_unmap_unlock(Pointer to pte entry matching* the 'address'. NULL if the page* table hasn't been allocated., Page table lock.* Protects pte page table if 'pte'* is not NULL, otherwise pmd.)
2733  返回:Handle the case of a page which we actually need to copy to a new page.* Called with mmap_sem locked and the old page referenced, but* without the ptl held.* High level logic flow:* - Allocate a page, copy the content of the old page to the new one.
2740  如果PageAnon(->fault handlers should return a* page here, unless VM_FAULT_NOPAGE* is set (which is also implied by* VM_FAULT_ERROR).)则
2742  如果A KSM page is one of those write-protected "shared pages" or "merged pages"* which KSM maps into multiple mms, wherever identical anonymous page content* is found in VM_MERGEABLE vmas. It's a PageAnon page, pointing not to any且PageSwapCache(->fault handlers should return a* page here, unless VM_FAULT_NOPAGE* is set (which is also implied by* VM_FAULT_ERROR).)或page_count(->fault handlers should return a* page here, unless VM_FAULT_NOPAGE* is set (which is also implied by* VM_FAULT_ERROR).)不等于1的值则转到:copy
2745  如果非Return true if the page was successfully locked则
2746  get_page(->fault handlers should return a* page here, unless VM_FAULT_NOPAGE* is set (which is also implied by* VM_FAULT_ERROR).)
2747  pte_unmap_unlock(Pointer to pte entry matching* the 'address'. NULL if the page* table hasn't been allocated., Page table lock.* Protects pte page table if 'pte'* is not NULL, otherwise pmd.)
2748  lock_page may only be called if we have the page's inode pinned.
2749  Pointer to pte entry matching* the 'address'. NULL if the page* table hasn't been allocated.等于pte_offset_map_lock(The address space we belong to. , Pointer to pmd entry matching* the 'address' , Faulting virtual address , & Page table lock.* Protects pte page table if 'pte'* is not NULL, otherwise pmd.)
2751  如果非pte_same( * Pointer to pte entry matching* the 'address'. NULL if the page* table hasn't been allocated., Value of PTE at the time of fault )则
2757  put_page(->fault handlers should return a* page here, unless VM_FAULT_NOPAGE* is set (which is also implied by* VM_FAULT_ERROR).)
2759  如果A KSM page is one of those write-protected "shared pages" or "merged pages"* which KSM maps into multiple mms, wherever identical anonymous page content* is found in VM_MERGEABLE vmas. It's a PageAnon page, pointing not to any则
2760  reused等于reuse_ksm_page(->fault handlers should return a* page here, unless VM_FAULT_NOPAGE* is set (which is also implied by* VM_FAULT_ERROR)., Target VMA , Faulting virtual address )
2762  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.
2763  如果非reused则转到:copy
2765  Handle write page faults for pages that can be reused in the current vma* This can happen either due to the mapping being with the VM_SHARED flag,* or due to us being the last reference standing to the page
2766  返回:VM_FAULT_WRITE
2768  如果reuse_swap_page(->fault handlers should return a* page here, unless VM_FAULT_NOPAGE* is set (which is also implied by* VM_FAULT_ERROR)., & total_map_swapcount)则
2769  如果total_map_swapcount恒等于1则
2779  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.
2780  Handle write page faults for pages that can be reused in the current vma* This can happen either due to the mapping being with the VM_SHARED flag,* or due to us being the last reference standing to the page
2781  返回:VM_FAULT_WRITE
2783  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.
2784  否则如果此条件成立可能性小(为编译器优化)((Flags, see mm.h. & (VM_WRITE | VM_SHARED)) == (VM_WRITE | VM_SHARED))则
2786  返回:wp_page_shared(vmf)
2788  copy :
2792  get_page(->fault handlers should return a* page here, unless VM_FAULT_NOPAGE* is set (which is also implied by* VM_FAULT_ERROR).)
2794  pte_unmap_unlock(Pointer to pte entry matching* the 'address'. NULL if the page* table hasn't been allocated., Page table lock.* Protects pte page table if 'pte'* is not NULL, otherwise pmd.)
2795  返回:Handle the case of a page which we actually need to copy to a new page.* Called with mmap_sem locked and the old page referenced, but* without the ptl held.* High level logic flow:* - Allocate a page, copy the content of the old page to the new one.
调用者
名称描述
do_swap_pageWe enter with non-exclusive mmap_sem (to exclude vma changes,* but allow concurrent faults), and pte mapped but not yet locked.* We return with pte unmapped and unlocked.* We return with the mmap_sem locked or unlocked in the same cases
handle_pte_faultThese routines also need to handle stuff like marking pages dirty* and/or accessed for architectures that don't do it in hardware (most* RISC architectures)