linux-imx
Public
Source
committed c7cdff0e8643
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*4
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* Common interface for making balloon pages movable by compaction.5
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*6
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* Copyright (C) 2012, Red Hat, Inc. Rafael Aquini <aquini@redhat.com>7
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*/8
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#include <linux/mm.h>9
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#include <linux/slab.h>10
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#include <linux/export.h>11
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#include <linux/balloon_compaction.h>12
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/*14
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* balloon_page_alloc - allocates a new page for insertion into the balloon15
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* page list.16
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*17
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* Driver must call it to properly allocate a new enlisted balloon page.18
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* Driver must call balloon_page_enqueue before definitively removing it from19
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* the guest system. This function returns the page address for the recently20
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* allocated page or NULL in the case we fail to allocate a new page this turn.21
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*/22
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struct page *balloon_page_alloc(void)23
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{24
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struct page *page = alloc_page(balloon_mapping_gfp_mask() |25
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__GFP_NOMEMALLOC | __GFP_NORETRY);26
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return page;27
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}28
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EXPORT_SYMBOL_GPL(balloon_page_alloc);29
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/*14
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* balloon_page_enqueue - allocates a new page and inserts it into the balloon15
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* page list.16
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* @b_dev_info: balloon device descriptor where we will insert a new page to34
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* @page: new page to enqueue - allocated using balloon_page_alloc.17
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*18
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* Driver must call it to properly allocate a new enlisted balloon page36
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* Driver must call it to properly enqueue a new allocated balloon page19
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* before definitively removing it from the guest system.20
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* This function returns the page address for the recently enqueued page or21
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* NULL in the case we fail to allocate a new page this turn.22
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*/23
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struct page *balloon_page_enqueue(struct balloon_dev_info *b_dev_info)41
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void balloon_page_enqueue(struct balloon_dev_info *b_dev_info,42
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struct page *page)24
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{25
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unsigned long flags;26
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struct page *page = alloc_page(balloon_mapping_gfp_mask() |27
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__GFP_NOMEMALLOC | __GFP_NORETRY);28
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if (!page)29
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return NULL;30
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/*32
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* Block others from accessing the 'page' when we get around to33
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* establishing additional references. We should be the only one34
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* holding a reference to the 'page' at this point.35
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*/36
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BUG_ON(!trylock_page(page));37
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spin_lock_irqsave(&b_dev_info->pages_lock, flags);38
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balloon_page_insert(b_dev_info, page);39
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__count_vm_event(BALLOON_INFLATE);40
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spin_unlock_irqrestore(&b_dev_info->pages_lock, flags);41
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unlock_page(page);42
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return page;43
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}44
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EXPORT_SYMBOL_GPL(balloon_page_enqueue);45
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/*47
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* balloon_page_dequeue - removes a page from balloon's page list and returns48
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* the its address to allow the driver release the page.49
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* @b_dev_info: balloon device decriptor where we will grab a page from.50
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*51
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* Driver must call it to properly de-allocate a previous enlisted balloon page52
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* before definetively releasing it back to the guest system.