diff options
Diffstat (limited to 'kernel/power/snapshot.c')
| -rw-r--r-- | kernel/power/snapshot.c | 141 |
1 files changed, 84 insertions, 57 deletions
diff --git a/kernel/power/snapshot.c b/kernel/power/snapshot.c index 513eef3..3d92841 100644 --- a/kernel/power/snapshot.c +++ b/kernel/power/snapshot.c @@ -401,62 +401,29 @@ static inline void create_pbe_list(struct pbe *pblist, unsigned int nr_pages) } } -/** - * On resume it is necessary to trace and eventually free the unsafe - * pages that have been allocated, because they are needed for I/O - * (on x86-64 we likely will "eat" these pages once again while - * creating the temporary page translation tables) - */ - -struct eaten_page { - struct eaten_page *next; - char padding[PAGE_SIZE - sizeof(void *)]; -}; - -static struct eaten_page *eaten_pages = NULL; - -static void release_eaten_pages(void) -{ - struct eaten_page *p, *q; - - p = eaten_pages; - while (p) { - q = p->next; - /* We don't want swsusp_free() to free this page again */ - ClearPageNosave(virt_to_page(p)); - free_page((unsigned long)p); - p = q; - } - eaten_pages = NULL; -} +static unsigned int unsafe_pages; /** * @safe_needed - on resume, for storing the PBE list and the image, * we can only use memory pages that do not conflict with the pages - * which had been used before suspend. + * used before suspend. * * The unsafe pages are marked with the PG_nosave_free flag - * - * Allocated but unusable (ie eaten) memory pages should be marked - * so that swsusp_free() can release them + * and we count them using unsafe_pages */ static inline void *alloc_image_page(gfp_t gfp_mask, int safe_needed) { void *res; + res = (void *)get_zeroed_page(gfp_mask); if (safe_needed) - do { + while (res && PageNosaveFree(virt_to_page(res))) { + /* The page is unsafe, mark it for swsusp_free() */ + SetPageNosave(virt_to_page(res)); + unsafe_pages++; res = (void *)get_zeroed_page(gfp_mask); - if (res && PageNosaveFree(virt_to_page(res))) { - /* This is for swsusp_free() */ - SetPageNosave(virt_to_page(res)); - ((struct eaten_page *)res)->next = eaten_pages; - eaten_pages = res; - } - } while (res && PageNosaveFree(virt_to_page(res))); - else - res = (void *)get_zeroed_page(gfp_mask); + } if (res) { SetPageNosave(virt_to_page(res)); SetPageNosaveFree(virt_to_page(res)); @@ -751,6 +718,8 @@ static int mark_unsafe_pages(struct pbe *pblist) return -EFAULT; } + unsafe_pages = 0; + return 0; } @@ -828,42 +797,99 @@ static inline struct pbe *unpack_orig_addresses(unsigned long *buf, } /** - * create_image - use metadata contained in the PBE list + * prepare_image - use metadata contained in the PBE list * pointed to by pagedir_nosave to mark the pages that will * be overwritten in the process of restoring the system - * memory state from the image and allocate memory for - * the image avoiding these pages + * memory state from the image ("unsafe" pages) and allocate + * memory for the image + * + * The idea is to allocate the PBE list first and then + * allocate as many pages as it's needed for the image data, + * but not to assign these pages to the PBEs initially. + * Instead, we just mark them as allocated and create a list + * of "safe" which will be used later */ -static int create_image(struct snapshot_handle *handle) +struct safe_page { + struct safe_page *next; + char padding[PAGE_SIZE - sizeof(void *)]; +}; + +static struct safe_page *safe_pages; + +static int prepare_image(struct snapshot_handle *handle) { int error = 0; - struct pbe *p, *pblist; + unsigned int nr_pages = nr_copy_pages; + struct pbe *p, *pblist = NULL; p = pagedir_nosave; error = mark_unsafe_pages(p); if (!error) { - pblist = alloc_pagedir(nr_copy_pages, GFP_ATOMIC, 1); + pblist = alloc_pagedir(nr_pages, GFP_ATOMIC, 1); if (pblist) copy_page_backup_list(pblist, p); free_pagedir(p, 0); if (!pblist) error = -ENOMEM; } - if (!error) - error = alloc_data_pages(pblist, GFP_ATOMIC, 1); + safe_pages = NULL; + if (!error && nr_pages > unsafe_pages) { + nr_pages -= unsafe_pages; + while (nr_pages--) { + struct safe_page *ptr; + + ptr = (struct safe_page *)get_zeroed_page(GFP_ATOMIC); + if (!ptr) { + error = -ENOMEM; + break; + } + if (!PageNosaveFree(virt_to_page(ptr))) { + /* The page is "safe", add it to the list */ + ptr->next = safe_pages; + safe_pages = ptr; + } + /* Mark the page as allocated */ + SetPageNosave(virt_to_page(ptr)); + SetPageNosaveFree(virt_to_page(ptr)); + } + } if (!error) { - release_eaten_pages(); pagedir_nosave = pblist; } else { - pagedir_nosave = NULL; handle->pbe = NULL; - nr_copy_pages = 0; - nr_meta_pages = 0; + swsusp_free(); } return error; } +static void *get_buffer(struct snapshot_handle *handle) +{ + struct pbe *pbe = handle->pbe, *last = handle->last_pbe; + struct page *page = virt_to_page(pbe->orig_address); + + if (PageNosave(page) && PageNosaveFree(page)) { + /* + * We have allocated the "original" page frame and we can + * use it directly to store the read page + */ + pbe->address = 0; + if (last && last->next) + last->next = NULL; + return (void *)pbe->orig_address; + } + /* + * The "original" page frame has not been allocated and we have to + * use a "safe" page frame to store the read page + */ + pbe->address = (unsigned long)safe_pages; + safe_pages = safe_pages->next; + if (last) + last->next = pbe; + handle->last_pbe = pbe; + return (void *)pbe->address; +} + /** * snapshot_write_next - used for writing the system memory snapshot. * @@ -908,15 +934,16 @@ int snapshot_write_next(struct snapshot_handle *handle, size_t count) } else if (handle->prev <= nr_meta_pages) { handle->pbe = unpack_orig_addresses(buffer, handle->pbe); if (!handle->pbe) { - error = create_image(handle); + error = prepare_image(handle); if (error) return error; handle->pbe = pagedir_nosave; - handle->buffer = (void *)handle->pbe->address; + handle->last_pbe = NULL; + handle->buffer = get_buffer(handle); } } else { handle->pbe = handle->pbe->next; - handle->buffer = (void *)handle->pbe->address; + handle->buffer = get_buffer(handle); } handle->prev = handle->page; } |
