On 2016/3/11 15:30, Minchan Kim wrote:
For migration, we need to create sub-page chain of zspage dynamically so this patch factors it out from alloc_zspage. As a minor refactoring, it makes OBJ_ALLOCATED_TAG assign more clear in obj_malloc(it could be another patch but it's trivial so I want to put together in this patch). Signed-off-by: Minchan Kim <minchan@xxxxxxxxxx> --- mm/zsmalloc.c | 78 ++++++++++++++++++++++++++++++++++------------------------- 1 file changed, 45 insertions(+), 33 deletions(-) diff --git a/mm/zsmalloc.c b/mm/zsmalloc.c index bfc6a048afac..f86f8aaeb902 100644 --- a/mm/zsmalloc.c +++ b/mm/zsmalloc.c @@ -977,7 +977,9 @@ 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; + INIT_LIST_HEAD(&first_page->lru); + set_zspage_inuse(first_page, 0); while (page) { struct page *next_page; @@ -1022,13 +1024,44 @@ static void init_zspage(struct size_class *class, struct page *first_page) set_freeobj(first_page, 0); } +static void create_page_chain(struct page *pages[], int nr_pages) +{ + int i; + struct page *page; + struct page *prev_page = NULL; + struct page *first_page = NULL; + + for (i = 0; i < nr_pages; i++) { + page = pages[i]; + + INIT_LIST_HEAD(&page->lru); + if (i == 0) { + SetPagePrivate(page); + set_page_private(page, 0); + first_page = page; + } + + if (i == 1) + set_page_private(first_page, (unsigned long)page); + if (i >= 1) + set_page_private(page, (unsigned long)first_page); + if (i >= 2) + list_add(&page->lru, &prev_page->lru); + if (i == nr_pages - 1) + SetPagePrivate2(page); + + prev_page = page; + } +} + /* * Allocate a zspage for the given size class */ static struct page *alloc_zspage(struct size_class *class, gfp_t flags) { - int i, error; + int i; struct page *first_page = NULL, *uninitialized_var(prev_page); + struct page *pages[ZS_MAX_PAGES_PER_ZSPAGE]; /* * Allocate individual pages and link them together as: @@ -1041,43 +1074,23 @@ static struct page *alloc_zspage(struct size_class *class, gfp_t flags)
*uninitialized_var(prev_page) in alloc_zspage is not in use more.
* (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; - - INIT_LIST_HEAD(&page->lru); - if (i == 0) { /* first page */ - page->freelist = NULL; - SetPagePrivate(page); - set_page_private(page, 0); - first_page = page; - set_zspage_inuse(page, 0); + if (!page) { + while (--i >= 0) + __free_page(pages[i]); + return NULL; } - if (i == 1) - set_page_private(first_page, (unsigned long)page); - if (i >= 1) - 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 */ - SetPagePrivate2(page); - prev_page = page; + + pages[i] = page; } + create_page_chain(pages, class->pages_per_zspage); + first_page = pages[0]; init_zspage(class, first_page); - error = 0; /* Success */ - -cleanup: - if (unlikely(error) && first_page) { - free_zspage(first_page); - first_page = NULL; - } - return first_page; } @@ -1419,7 +1432,6 @@ static unsigned long obj_malloc(struct size_class *class, unsigned long m_offset; void *vaddr; - handle |= OBJ_ALLOCATED_TAG; obj = get_freeobj(first_page); objidx_to_page_and_ofs(class, first_page, obj, &m_page, &m_offset); @@ -1429,10 +1441,10 @@ static unsigned long obj_malloc(struct size_class *class, set_freeobj(first_page, link->next >> OBJ_ALLOCATED_TAG); if (!class->huge) /* record handle in the header of allocated chunk */ - link->handle = handle; + link->handle = handle | OBJ_ALLOCATED_TAG; else /* record handle in first_page->private */ - set_page_private(first_page, handle); + set_page_private(first_page, handle | OBJ_ALLOCATED_TAG); kunmap_atomic(vaddr); mod_zspage_inuse(first_page, 1); zs_stat_inc(class, OBJ_USED, 1);
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