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855 lines
22 KiB
855 lines
22 KiB
// SPDX-License-Identifier: GPL-2.0 |
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/* |
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* linux/mm/mlock.c |
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* |
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* (C) Copyright 1995 Linus Torvalds |
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* (C) Copyright 2002 Christoph Hellwig |
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*/ |
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|
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#include <linux/capability.h> |
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#include <linux/mman.h> |
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#include <linux/mm.h> |
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#include <linux/sched/user.h> |
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#include <linux/swap.h> |
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#include <linux/swapops.h> |
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#include <linux/pagemap.h> |
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#include <linux/pagevec.h> |
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#include <linux/mempolicy.h> |
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#include <linux/syscalls.h> |
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#include <linux/sched.h> |
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#include <linux/export.h> |
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#include <linux/rmap.h> |
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#include <linux/mmzone.h> |
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#include <linux/hugetlb.h> |
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#include <linux/memcontrol.h> |
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#include <linux/mm_inline.h> |
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#include <linux/secretmem.h> |
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#include "internal.h" |
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bool can_do_mlock(void) |
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{ |
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if (rlimit(RLIMIT_MEMLOCK) != 0) |
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return true; |
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if (capable(CAP_IPC_LOCK)) |
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return true; |
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return false; |
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} |
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EXPORT_SYMBOL(can_do_mlock); |
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/* |
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* Mlocked pages are marked with PageMlocked() flag for efficient testing |
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* in vmscan and, possibly, the fault path; and to support semi-accurate |
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* statistics. |
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* |
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* An mlocked page [PageMlocked(page)] is unevictable. As such, it will |
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* be placed on the LRU "unevictable" list, rather than the [in]active lists. |
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* The unevictable list is an LRU sibling list to the [in]active lists. |
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* PageUnevictable is set to indicate the unevictable state. |
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* |
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* When lazy mlocking via vmscan, it is important to ensure that the |
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* vma's VM_LOCKED status is not concurrently being modified, otherwise we |
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* may have mlocked a page that is being munlocked. So lazy mlock must take |
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* the mmap_lock for read, and verify that the vma really is locked |
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* (see mm/rmap.c). |
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*/ |
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/* |
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* LRU accounting for clear_page_mlock() |
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*/ |
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void clear_page_mlock(struct page *page) |
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{ |
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int nr_pages; |
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if (!TestClearPageMlocked(page)) |
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return; |
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nr_pages = thp_nr_pages(page); |
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mod_zone_page_state(page_zone(page), NR_MLOCK, -nr_pages); |
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count_vm_events(UNEVICTABLE_PGCLEARED, nr_pages); |
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/* |
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* The previous TestClearPageMlocked() corresponds to the smp_mb() |
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* in __pagevec_lru_add_fn(). |
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* |
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* See __pagevec_lru_add_fn for more explanation. |
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*/ |
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if (!isolate_lru_page(page)) { |
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putback_lru_page(page); |
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} else { |
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/* |
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* We lost the race. the page already moved to evictable list. |
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*/ |
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if (PageUnevictable(page)) |
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count_vm_events(UNEVICTABLE_PGSTRANDED, nr_pages); |
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} |
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} |
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/* |
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* Mark page as mlocked if not already. |
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* If page on LRU, isolate and putback to move to unevictable list. |
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*/ |
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void mlock_vma_page(struct page *page) |
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{ |
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/* Serialize with page migration */ |
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BUG_ON(!PageLocked(page)); |
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VM_BUG_ON_PAGE(PageTail(page), page); |
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VM_BUG_ON_PAGE(PageCompound(page) && PageDoubleMap(page), page); |
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if (!TestSetPageMlocked(page)) { |
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int nr_pages = thp_nr_pages(page); |
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mod_zone_page_state(page_zone(page), NR_MLOCK, nr_pages); |
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count_vm_events(UNEVICTABLE_PGMLOCKED, nr_pages); |
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if (!isolate_lru_page(page)) |
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putback_lru_page(page); |
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} |
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} |
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/* |
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* Finish munlock after successful page isolation |
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* |
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* Page must be locked. This is a wrapper for page_mlock() |
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* and putback_lru_page() with munlock accounting. |
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*/ |
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static void __munlock_isolated_page(struct page *page) |
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{ |
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/* |
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* Optimization: if the page was mapped just once, that's our mapping |
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* and we don't need to check all the other vmas. |
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*/ |
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if (page_mapcount(page) > 1) |
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page_mlock(page); |
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/* Did try_to_unlock() succeed or punt? */ |
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if (!PageMlocked(page)) |
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count_vm_events(UNEVICTABLE_PGMUNLOCKED, thp_nr_pages(page)); |
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putback_lru_page(page); |
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} |
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/* |
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* Accounting for page isolation fail during munlock |
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* |
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* Performs accounting when page isolation fails in munlock. There is nothing |
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* else to do because it means some other task has already removed the page |
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* from the LRU. putback_lru_page() will take care of removing the page from |
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* the unevictable list, if necessary. vmscan [page_referenced()] will move |
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* the page back to the unevictable list if some other vma has it mlocked. |
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*/ |
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static void __munlock_isolation_failed(struct page *page) |
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{ |
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int nr_pages = thp_nr_pages(page); |
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if (PageUnevictable(page)) |
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__count_vm_events(UNEVICTABLE_PGSTRANDED, nr_pages); |
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else |
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__count_vm_events(UNEVICTABLE_PGMUNLOCKED, nr_pages); |
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} |
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/** |
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* munlock_vma_page - munlock a vma page |
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* @page: page to be unlocked, either a normal page or THP page head |
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* |
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* returns the size of the page as a page mask (0 for normal page, |
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* HPAGE_PMD_NR - 1 for THP head page) |
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* |
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* called from munlock()/munmap() path with page supposedly on the LRU. |
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* When we munlock a page, because the vma where we found the page is being |
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* munlock()ed or munmap()ed, we want to check whether other vmas hold the |
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* page locked so that we can leave it on the unevictable lru list and not |
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* bother vmscan with it. However, to walk the page's rmap list in |
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* page_mlock() we must isolate the page from the LRU. If some other |
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* task has removed the page from the LRU, we won't be able to do that. |
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* So we clear the PageMlocked as we might not get another chance. If we |
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* can't isolate the page, we leave it for putback_lru_page() and vmscan |
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* [page_referenced()/try_to_unmap()] to deal with. |
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*/ |
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unsigned int munlock_vma_page(struct page *page) |
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{ |
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int nr_pages; |
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/* For page_mlock() and to serialize with page migration */ |
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BUG_ON(!PageLocked(page)); |
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VM_BUG_ON_PAGE(PageTail(page), page); |
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if (!TestClearPageMlocked(page)) { |
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/* Potentially, PTE-mapped THP: do not skip the rest PTEs */ |
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return 0; |
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} |
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nr_pages = thp_nr_pages(page); |
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mod_zone_page_state(page_zone(page), NR_MLOCK, -nr_pages); |
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if (!isolate_lru_page(page)) |
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__munlock_isolated_page(page); |
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else |
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__munlock_isolation_failed(page); |
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return nr_pages - 1; |
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} |
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/* |
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* convert get_user_pages() return value to posix mlock() error |
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*/ |
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static int __mlock_posix_error_return(long retval) |
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{ |
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if (retval == -EFAULT) |
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retval = -ENOMEM; |
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else if (retval == -ENOMEM) |
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retval = -EAGAIN; |
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return retval; |
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} |
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/* |
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* Prepare page for fast batched LRU putback via putback_lru_evictable_pagevec() |
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* |
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* The fast path is available only for evictable pages with single mapping. |
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* Then we can bypass the per-cpu pvec and get better performance. |
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* when mapcount > 1 we need page_mlock() which can fail. |
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* when !page_evictable(), we need the full redo logic of putback_lru_page to |
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* avoid leaving evictable page in unevictable list. |
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* |
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* In case of success, @page is added to @pvec and @pgrescued is incremented |
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* in case that the page was previously unevictable. @page is also unlocked. |
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*/ |
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static bool __putback_lru_fast_prepare(struct page *page, struct pagevec *pvec, |
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int *pgrescued) |
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{ |
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VM_BUG_ON_PAGE(PageLRU(page), page); |
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VM_BUG_ON_PAGE(!PageLocked(page), page); |
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if (page_mapcount(page) <= 1 && page_evictable(page)) { |
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pagevec_add(pvec, page); |
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if (TestClearPageUnevictable(page)) |
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(*pgrescued)++; |
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unlock_page(page); |
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return true; |
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} |
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return false; |
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} |
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/* |
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* Putback multiple evictable pages to the LRU |
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* |
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* Batched putback of evictable pages that bypasses the per-cpu pvec. Some of |
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* the pages might have meanwhile become unevictable but that is OK. |
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*/ |
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static void __putback_lru_fast(struct pagevec *pvec, int pgrescued) |
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{ |
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count_vm_events(UNEVICTABLE_PGMUNLOCKED, pagevec_count(pvec)); |
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/* |
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*__pagevec_lru_add() calls release_pages() so we don't call |
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* put_page() explicitly |
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*/ |
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__pagevec_lru_add(pvec); |
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count_vm_events(UNEVICTABLE_PGRESCUED, pgrescued); |
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} |
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/* |
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* Munlock a batch of pages from the same zone |
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* |
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* The work is split to two main phases. First phase clears the Mlocked flag |
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* and attempts to isolate the pages, all under a single zone lru lock. |
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* The second phase finishes the munlock only for pages where isolation |
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* succeeded. |
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* |
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* Note that the pagevec may be modified during the process. |
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*/ |
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static void __munlock_pagevec(struct pagevec *pvec, struct zone *zone) |
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{ |
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int i; |
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int nr = pagevec_count(pvec); |
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int delta_munlocked = -nr; |
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struct pagevec pvec_putback; |
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struct lruvec *lruvec = NULL; |
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int pgrescued = 0; |
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pagevec_init(&pvec_putback); |
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/* Phase 1: page isolation */ |
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for (i = 0; i < nr; i++) { |
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struct page *page = pvec->pages[i]; |
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if (TestClearPageMlocked(page)) { |
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/* |
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* We already have pin from follow_page_mask() |
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* so we can spare the get_page() here. |
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*/ |
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if (TestClearPageLRU(page)) { |
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lruvec = relock_page_lruvec_irq(page, lruvec); |
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del_page_from_lru_list(page, lruvec); |
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continue; |
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} else |
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__munlock_isolation_failed(page); |
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} else { |
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delta_munlocked++; |
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} |
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/* |
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* We won't be munlocking this page in the next phase |
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* but we still need to release the follow_page_mask() |
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* pin. We cannot do it under lru_lock however. If it's |
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* the last pin, __page_cache_release() would deadlock. |
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*/ |
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pagevec_add(&pvec_putback, pvec->pages[i]); |
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pvec->pages[i] = NULL; |
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} |
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if (lruvec) { |
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__mod_zone_page_state(zone, NR_MLOCK, delta_munlocked); |
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unlock_page_lruvec_irq(lruvec); |
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} else if (delta_munlocked) { |
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mod_zone_page_state(zone, NR_MLOCK, delta_munlocked); |
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} |
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/* Now we can release pins of pages that we are not munlocking */ |
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pagevec_release(&pvec_putback); |
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/* Phase 2: page munlock */ |
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for (i = 0; i < nr; i++) { |
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struct page *page = pvec->pages[i]; |
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if (page) { |
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lock_page(page); |
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if (!__putback_lru_fast_prepare(page, &pvec_putback, |
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&pgrescued)) { |
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/* |
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* Slow path. We don't want to lose the last |
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* pin before unlock_page() |
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*/ |
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get_page(page); /* for putback_lru_page() */ |
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__munlock_isolated_page(page); |
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unlock_page(page); |
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put_page(page); /* from follow_page_mask() */ |
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} |
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} |
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} |
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/* |
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* Phase 3: page putback for pages that qualified for the fast path |
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* This will also call put_page() to return pin from follow_page_mask() |
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*/ |
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if (pagevec_count(&pvec_putback)) |
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__putback_lru_fast(&pvec_putback, pgrescued); |
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} |
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/* |
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* Fill up pagevec for __munlock_pagevec using pte walk |
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* |
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* The function expects that the struct page corresponding to @start address is |
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* a non-TPH page already pinned and in the @pvec, and that it belongs to @zone. |
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* |
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* The rest of @pvec is filled by subsequent pages within the same pmd and same |
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* zone, as long as the pte's are present and vm_normal_page() succeeds. These |
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* pages also get pinned. |
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* |
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* Returns the address of the next page that should be scanned. This equals |
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* @start + PAGE_SIZE when no page could be added by the pte walk. |
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*/ |
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static unsigned long __munlock_pagevec_fill(struct pagevec *pvec, |
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struct vm_area_struct *vma, struct zone *zone, |
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unsigned long start, unsigned long end) |
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{ |
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pte_t *pte; |
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spinlock_t *ptl; |
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/* |
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* Initialize pte walk starting at the already pinned page where we |
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* are sure that there is a pte, as it was pinned under the same |
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* mmap_lock write op. |
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*/ |
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pte = get_locked_pte(vma->vm_mm, start, &ptl); |
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/* Make sure we do not cross the page table boundary */ |
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end = pgd_addr_end(start, end); |
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end = p4d_addr_end(start, end); |
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end = pud_addr_end(start, end); |
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end = pmd_addr_end(start, end); |
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/* The page next to the pinned page is the first we will try to get */ |
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start += PAGE_SIZE; |
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while (start < end) { |
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struct page *page = NULL; |
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pte++; |
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if (pte_present(*pte)) |
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page = vm_normal_page(vma, start, *pte); |
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/* |
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* Break if page could not be obtained or the page's node+zone does not |
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* match |
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*/ |
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if (!page || page_zone(page) != zone) |
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break; |
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/* |
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* Do not use pagevec for PTE-mapped THP, |
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* munlock_vma_pages_range() will handle them. |
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*/ |
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if (PageTransCompound(page)) |
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break; |
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get_page(page); |
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/* |
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* Increase the address that will be returned *before* the |
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* eventual break due to pvec becoming full by adding the page |
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*/ |
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start += PAGE_SIZE; |
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if (pagevec_add(pvec, page) == 0) |
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break; |
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} |
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pte_unmap_unlock(pte, ptl); |
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return start; |
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} |
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/* |
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* munlock_vma_pages_range() - munlock all pages in the vma range.' |
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* @vma - vma containing range to be munlock()ed. |
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* @start - start address in @vma of the range |
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* @end - end of range in @vma. |
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* |
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* For mremap(), munmap() and exit(). |
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* |
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* Called with @vma VM_LOCKED. |
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* |
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* Returns with VM_LOCKED cleared. Callers must be prepared to |
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* deal with this. |
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* |
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* We don't save and restore VM_LOCKED here because pages are |
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* still on lru. In unmap path, pages might be scanned by reclaim |
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* and re-mlocked by page_mlock/try_to_unmap before we unmap and |
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* free them. This will result in freeing mlocked pages. |
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*/ |
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void munlock_vma_pages_range(struct vm_area_struct *vma, |
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unsigned long start, unsigned long end) |
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{ |
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vma->vm_flags &= VM_LOCKED_CLEAR_MASK; |
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while (start < end) { |
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struct page *page; |
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unsigned int page_mask = 0; |
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unsigned long page_increm; |
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struct pagevec pvec; |
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struct zone *zone; |
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pagevec_init(&pvec); |
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/* |
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* Although FOLL_DUMP is intended for get_dump_page(), |
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* it just so happens that its special treatment of the |
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* ZERO_PAGE (returning an error instead of doing get_page) |
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* suits munlock very well (and if somehow an abnormal page |
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* has sneaked into the range, we won't oops here: great). |
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*/ |
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page = follow_page(vma, start, FOLL_GET | FOLL_DUMP); |
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if (page && !IS_ERR(page)) { |
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if (PageTransTail(page)) { |
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VM_BUG_ON_PAGE(PageMlocked(page), page); |
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put_page(page); /* follow_page_mask() */ |
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} else if (PageTransHuge(page)) { |
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lock_page(page); |
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/* |
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* Any THP page found by follow_page_mask() may |
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* have gotten split before reaching |
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* munlock_vma_page(), so we need to compute |
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* the page_mask here instead. |
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*/ |
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page_mask = munlock_vma_page(page); |
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unlock_page(page); |
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put_page(page); /* follow_page_mask() */ |
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} else { |
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/* |
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* Non-huge pages are handled in batches via |
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* pagevec. The pin from follow_page_mask() |
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* prevents them from collapsing by THP. |
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*/ |
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pagevec_add(&pvec, page); |
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zone = page_zone(page); |
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|
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/* |
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* Try to fill the rest of pagevec using fast |
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* pte walk. This will also update start to |
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* the next page to process. Then munlock the |
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* pagevec. |
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*/ |
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start = __munlock_pagevec_fill(&pvec, vma, |
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zone, start, end); |
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__munlock_pagevec(&pvec, zone); |
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goto next; |
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} |
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} |
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page_increm = 1 + page_mask; |
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start += page_increm * PAGE_SIZE; |
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next: |
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cond_resched(); |
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} |
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} |
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|
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/* |
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* mlock_fixup - handle mlock[all]/munlock[all] requests. |
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* |
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* Filters out "special" vmas -- VM_LOCKED never gets set for these, and |
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* munlock is a no-op. However, for some special vmas, we go ahead and |
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* populate the ptes. |
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* |
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* For vmas that pass the filters, merge/split as appropriate. |
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*/ |
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static int mlock_fixup(struct vm_area_struct *vma, struct vm_area_struct **prev, |
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unsigned long start, unsigned long end, vm_flags_t newflags) |
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{ |
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struct mm_struct *mm = vma->vm_mm; |
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pgoff_t pgoff; |
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int nr_pages; |
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int ret = 0; |
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int lock = !!(newflags & VM_LOCKED); |
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vm_flags_t old_flags = vma->vm_flags; |
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|
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if (newflags == vma->vm_flags || (vma->vm_flags & VM_SPECIAL) || |
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is_vm_hugetlb_page(vma) || vma == get_gate_vma(current->mm) || |
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vma_is_dax(vma) || vma_is_secretmem(vma)) |
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/* don't set VM_LOCKED or VM_LOCKONFAULT and don't count */ |
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goto out; |
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pgoff = vma->vm_pgoff + ((start - vma->vm_start) >> PAGE_SHIFT); |
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*prev = vma_merge(mm, *prev, start, end, newflags, vma->anon_vma, |
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vma->vm_file, pgoff, vma_policy(vma), |
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vma->vm_userfaultfd_ctx); |
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if (*prev) { |
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vma = *prev; |
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goto success; |
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} |
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|
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if (start != vma->vm_start) { |
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ret = split_vma(mm, vma, start, 1); |
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if (ret) |
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goto out; |
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} |
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|
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if (end != vma->vm_end) { |
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ret = split_vma(mm, vma, end, 0); |
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if (ret) |
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goto out; |
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} |
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success: |
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/* |
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* Keep track of amount of locked VM. |
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*/ |
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nr_pages = (end - start) >> PAGE_SHIFT; |
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if (!lock) |
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nr_pages = -nr_pages; |
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else if (old_flags & VM_LOCKED) |
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nr_pages = 0; |
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mm->locked_vm += nr_pages; |
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|
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/* |
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* vm_flags is protected by the mmap_lock held in write mode. |
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* It's okay if try_to_unmap_one unmaps a page just after we |
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* set VM_LOCKED, populate_vma_page_range will bring it back. |
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*/ |
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|
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if (lock) |
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vma->vm_flags = newflags; |
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else |
|
munlock_vma_pages_range(vma, start, end); |
|
|
|
out: |
|
*prev = vma; |
|
return ret; |
|
} |
|
|
|
static int apply_vma_lock_flags(unsigned long start, size_t len, |
|
vm_flags_t flags) |
|
{ |
|
unsigned long nstart, end, tmp; |
|
struct vm_area_struct *vma, *prev; |
|
int error; |
|
|
|
VM_BUG_ON(offset_in_page(start)); |
|
VM_BUG_ON(len != PAGE_ALIGN(len)); |
|
end = start + len; |
|
if (end < start) |
|
return -EINVAL; |
|
if (end == start) |
|
return 0; |
|
vma = find_vma(current->mm, start); |
|
if (!vma || vma->vm_start > start) |
|
return -ENOMEM; |
|
|
|
prev = vma->vm_prev; |
|
if (start > vma->vm_start) |
|
prev = vma; |
|
|
|
for (nstart = start ; ; ) { |
|
vm_flags_t newflags = vma->vm_flags & VM_LOCKED_CLEAR_MASK; |
|
|
|
newflags |= flags; |
|
|
|
/* Here we know that vma->vm_start <= nstart < vma->vm_end. */ |
|
tmp = vma->vm_end; |
|
if (tmp > end) |
|
tmp = end; |
|
error = mlock_fixup(vma, &prev, nstart, tmp, newflags); |
|
if (error) |
|
break; |
|
nstart = tmp; |
|
if (nstart < prev->vm_end) |
|
nstart = prev->vm_end; |
|
if (nstart >= end) |
|
break; |
|
|
|
vma = prev->vm_next; |
|
if (!vma || vma->vm_start != nstart) { |
|
error = -ENOMEM; |
|
break; |
|
} |
|
} |
|
return error; |
|
} |
|
|
|
/* |
|
* Go through vma areas and sum size of mlocked |
|
* vma pages, as return value. |
|
* Note deferred memory locking case(mlock2(,,MLOCK_ONFAULT) |
|
* is also counted. |
|
* Return value: previously mlocked page counts |
|
*/ |
|
static unsigned long count_mm_mlocked_page_nr(struct mm_struct *mm, |
|
unsigned long start, size_t len) |
|
{ |
|
struct vm_area_struct *vma; |
|
unsigned long count = 0; |
|
|
|
if (mm == NULL) |
|
mm = current->mm; |
|
|
|
vma = find_vma(mm, start); |
|
if (vma == NULL) |
|
return 0; |
|
|
|
for (; vma ; vma = vma->vm_next) { |
|
if (start >= vma->vm_end) |
|
continue; |
|
if (start + len <= vma->vm_start) |
|
break; |
|
if (vma->vm_flags & VM_LOCKED) { |
|
if (start > vma->vm_start) |
|
count -= (start - vma->vm_start); |
|
if (start + len < vma->vm_end) { |
|
count += start + len - vma->vm_start; |
|
break; |
|
} |
|
count += vma->vm_end - vma->vm_start; |
|
} |
|
} |
|
|
|
return count >> PAGE_SHIFT; |
|
} |
|
|
|
static __must_check int do_mlock(unsigned long start, size_t len, vm_flags_t flags) |
|
{ |
|
unsigned long locked; |
|
unsigned long lock_limit; |
|
int error = -ENOMEM; |
|
|
|
start = untagged_addr(start); |
|
|
|
if (!can_do_mlock()) |
|
return -EPERM; |
|
|
|
len = PAGE_ALIGN(len + (offset_in_page(start))); |
|
start &= PAGE_MASK; |
|
|
|
lock_limit = rlimit(RLIMIT_MEMLOCK); |
|
lock_limit >>= PAGE_SHIFT; |
|
locked = len >> PAGE_SHIFT; |
|
|
|
if (mmap_write_lock_killable(current->mm)) |
|
return -EINTR; |
|
|
|
locked += current->mm->locked_vm; |
|
if ((locked > lock_limit) && (!capable(CAP_IPC_LOCK))) { |
|
/* |
|
* It is possible that the regions requested intersect with |
|
* previously mlocked areas, that part area in "mm->locked_vm" |
|
* should not be counted to new mlock increment count. So check |
|
* and adjust locked count if necessary. |
|
*/ |
|
locked -= count_mm_mlocked_page_nr(current->mm, |
|
start, len); |
|
} |
|
|
|
/* check against resource limits */ |
|
if ((locked <= lock_limit) || capable(CAP_IPC_LOCK)) |
|
error = apply_vma_lock_flags(start, len, flags); |
|
|
|
mmap_write_unlock(current->mm); |
|
if (error) |
|
return error; |
|
|
|
error = __mm_populate(start, len, 0); |
|
if (error) |
|
return __mlock_posix_error_return(error); |
|
return 0; |
|
} |
|
|
|
SYSCALL_DEFINE2(mlock, unsigned long, start, size_t, len) |
|
{ |
|
return do_mlock(start, len, VM_LOCKED); |
|
} |
|
|
|
SYSCALL_DEFINE3(mlock2, unsigned long, start, size_t, len, int, flags) |
|
{ |
|
vm_flags_t vm_flags = VM_LOCKED; |
|
|
|
if (flags & ~MLOCK_ONFAULT) |
|
return -EINVAL; |
|
|
|
if (flags & MLOCK_ONFAULT) |
|
vm_flags |= VM_LOCKONFAULT; |
|
|
|
return do_mlock(start, len, vm_flags); |
|
} |
|
|
|
SYSCALL_DEFINE2(munlock, unsigned long, start, size_t, len) |
|
{ |
|
int ret; |
|
|
|
start = untagged_addr(start); |
|
|
|
len = PAGE_ALIGN(len + (offset_in_page(start))); |
|
start &= PAGE_MASK; |
|
|
|
if (mmap_write_lock_killable(current->mm)) |
|
return -EINTR; |
|
ret = apply_vma_lock_flags(start, len, 0); |
|
mmap_write_unlock(current->mm); |
|
|
|
return ret; |
|
} |
|
|
|
/* |
|
* Take the MCL_* flags passed into mlockall (or 0 if called from munlockall) |
|
* and translate into the appropriate modifications to mm->def_flags and/or the |
|
* flags for all current VMAs. |
|
* |
|
* There are a couple of subtleties with this. If mlockall() is called multiple |
|
* times with different flags, the values do not necessarily stack. If mlockall |
|
* is called once including the MCL_FUTURE flag and then a second time without |
|
* it, VM_LOCKED and VM_LOCKONFAULT will be cleared from mm->def_flags. |
|
*/ |
|
static int apply_mlockall_flags(int flags) |
|
{ |
|
struct vm_area_struct *vma, *prev = NULL; |
|
vm_flags_t to_add = 0; |
|
|
|
current->mm->def_flags &= VM_LOCKED_CLEAR_MASK; |
|
if (flags & MCL_FUTURE) { |
|
current->mm->def_flags |= VM_LOCKED; |
|
|
|
if (flags & MCL_ONFAULT) |
|
current->mm->def_flags |= VM_LOCKONFAULT; |
|
|
|
if (!(flags & MCL_CURRENT)) |
|
goto out; |
|
} |
|
|
|
if (flags & MCL_CURRENT) { |
|
to_add |= VM_LOCKED; |
|
if (flags & MCL_ONFAULT) |
|
to_add |= VM_LOCKONFAULT; |
|
} |
|
|
|
for (vma = current->mm->mmap; vma ; vma = prev->vm_next) { |
|
vm_flags_t newflags; |
|
|
|
newflags = vma->vm_flags & VM_LOCKED_CLEAR_MASK; |
|
newflags |= to_add; |
|
|
|
/* Ignore errors */ |
|
mlock_fixup(vma, &prev, vma->vm_start, vma->vm_end, newflags); |
|
cond_resched(); |
|
} |
|
out: |
|
return 0; |
|
} |
|
|
|
SYSCALL_DEFINE1(mlockall, int, flags) |
|
{ |
|
unsigned long lock_limit; |
|
int ret; |
|
|
|
if (!flags || (flags & ~(MCL_CURRENT | MCL_FUTURE | MCL_ONFAULT)) || |
|
flags == MCL_ONFAULT) |
|
return -EINVAL; |
|
|
|
if (!can_do_mlock()) |
|
return -EPERM; |
|
|
|
lock_limit = rlimit(RLIMIT_MEMLOCK); |
|
lock_limit >>= PAGE_SHIFT; |
|
|
|
if (mmap_write_lock_killable(current->mm)) |
|
return -EINTR; |
|
|
|
ret = -ENOMEM; |
|
if (!(flags & MCL_CURRENT) || (current->mm->total_vm <= lock_limit) || |
|
capable(CAP_IPC_LOCK)) |
|
ret = apply_mlockall_flags(flags); |
|
mmap_write_unlock(current->mm); |
|
if (!ret && (flags & MCL_CURRENT)) |
|
mm_populate(0, TASK_SIZE); |
|
|
|
return ret; |
|
} |
|
|
|
SYSCALL_DEFINE0(munlockall) |
|
{ |
|
int ret; |
|
|
|
if (mmap_write_lock_killable(current->mm)) |
|
return -EINTR; |
|
ret = apply_mlockall_flags(0); |
|
mmap_write_unlock(current->mm); |
|
return ret; |
|
} |
|
|
|
/* |
|
* Objects with different lifetime than processes (SHM_LOCK and SHM_HUGETLB |
|
* shm segments) get accounted against the user_struct instead. |
|
*/ |
|
static DEFINE_SPINLOCK(shmlock_user_lock); |
|
|
|
int user_shm_lock(size_t size, struct ucounts *ucounts) |
|
{ |
|
unsigned long lock_limit, locked; |
|
long memlock; |
|
int allowed = 0; |
|
|
|
locked = (size + PAGE_SIZE - 1) >> PAGE_SHIFT; |
|
lock_limit = rlimit(RLIMIT_MEMLOCK); |
|
if (lock_limit == RLIM_INFINITY) |
|
allowed = 1; |
|
lock_limit >>= PAGE_SHIFT; |
|
spin_lock(&shmlock_user_lock); |
|
memlock = inc_rlimit_ucounts(ucounts, UCOUNT_RLIMIT_MEMLOCK, locked); |
|
|
|
if (!allowed && (memlock == LONG_MAX || memlock > lock_limit) && !capable(CAP_IPC_LOCK)) { |
|
dec_rlimit_ucounts(ucounts, UCOUNT_RLIMIT_MEMLOCK, locked); |
|
goto out; |
|
} |
|
if (!get_ucounts(ucounts)) { |
|
dec_rlimit_ucounts(ucounts, UCOUNT_RLIMIT_MEMLOCK, locked); |
|
goto out; |
|
} |
|
allowed = 1; |
|
out: |
|
spin_unlock(&shmlock_user_lock); |
|
return allowed; |
|
} |
|
|
|
void user_shm_unlock(size_t size, struct ucounts *ucounts) |
|
{ |
|
spin_lock(&shmlock_user_lock); |
|
dec_rlimit_ucounts(ucounts, UCOUNT_RLIMIT_MEMLOCK, (size + PAGE_SIZE - 1) >> PAGE_SHIFT); |
|
spin_unlock(&shmlock_user_lock); |
|
put_ucounts(ucounts); |
|
}
|
|
|