zsmalloc: factor page chain functionality out

For page migration, we need to create page chain of zspage dynamically
so this patch factors it out from alloc_zspage.

Link: http://lkml.kernel.org/r/1464736881-24886-8-git-send-email-minchan@kernel.org
Signed-off-by: Minchan Kim <minchan@kernel.org>
Reviewed-by: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Minchan Kim 2016-07-26 15:23:20 -07:00 committed by Linus Torvalds
parent 4f42047bbd
commit bdb0af7ca8

View File

@ -960,7 +960,8 @@ static void init_zspage(struct size_class *class, struct page *first_page)
unsigned long off = 0;
struct page *page = first_page;
VM_BUG_ON_PAGE(!is_first_page(first_page), first_page);
first_page->freelist = NULL;
set_zspage_inuse(first_page, 0);
while (page) {
struct page *next_page;
@ -996,15 +997,16 @@ static void init_zspage(struct size_class *class, struct page *first_page)
page = next_page;
off %= PAGE_SIZE;
}
set_freeobj(first_page, (unsigned long)location_to_obj(first_page, 0));
}
/*
* Allocate a zspage for the given size class
*/
static struct page *alloc_zspage(struct size_class *class, gfp_t flags)
static void create_page_chain(struct page *pages[], int nr_pages)
{
int i, error;
struct page *first_page = NULL, *uninitialized_var(prev_page);
int i;
struct page *page;
struct page *prev_page = NULL;
struct page *first_page = NULL;
/*
* Allocate individual pages and link them together as:
@ -1017,20 +1019,14 @@ static struct page *alloc_zspage(struct size_class *class, gfp_t flags)
* (i.e. no other sub-page has this flag set) and PG_private_2 to
* identify the last page.
*/
error = -ENOMEM;
for (i = 0; i < class->pages_per_zspage; i++) {
struct page *page;
page = alloc_page(flags);
if (!page)
goto cleanup;
for (i = 0; i < nr_pages; i++) {
page = pages[i];
INIT_LIST_HEAD(&page->lru);
if (i == 0) { /* first page */
if (i == 0) {
SetPagePrivate(page);
set_page_private(page, 0);
first_page = page;
set_zspage_inuse(first_page, 0);
}
if (i == 1)
set_page_private(first_page, (unsigned long)page);
@ -1038,22 +1034,37 @@ static struct page *alloc_zspage(struct size_class *class, gfp_t flags)
set_page_private(page, (unsigned long)first_page);
if (i >= 2)
list_add(&page->lru, &prev_page->lru);
if (i == class->pages_per_zspage - 1) /* last page */
if (i == nr_pages - 1)
SetPagePrivate2(page);
prev_page = page;
}
init_zspage(class, first_page);
set_freeobj(first_page, (unsigned long)location_to_obj(first_page, 0));
error = 0; /* Success */
cleanup:
if (unlikely(error) && first_page) {
free_zspage(first_page);
first_page = NULL;
}
/*
* Allocate a zspage for the given size class
*/
static struct page *alloc_zspage(struct size_class *class, gfp_t flags)
{
int i;
struct page *first_page = NULL;
struct page *pages[ZS_MAX_PAGES_PER_ZSPAGE];
for (i = 0; i < class->pages_per_zspage; i++) {
struct page *page;
page = alloc_page(flags);
if (!page) {
while (--i >= 0)
__free_page(pages[i]);
return NULL;
}
pages[i] = page;
}
create_page_chain(pages, class->pages_per_zspage);
first_page = pages[0];
init_zspage(class, first_page);
return first_page;
}