mm: memcg: remove unused node/section info from pc->flags

To find the page corresponding to a certain page_cgroup, the pc->flags
encoded the node or section ID with the base array to compare the pc
pointer to.

Now that the per-memory cgroup LRU lists link page descriptors directly,
there is no longer any code that knows the struct page_cgroup of a PFN
but not the struct page.

[hughd@google.com: remove unused node/section info from pc->flags fix]
Signed-off-by: Johannes Weiner <jweiner@redhat.com>
Reviewed-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Reviewed-by: Michal Hocko <mhocko@suse.cz>
Reviewed-by: Kirill A. Shutemov <kirill@shutemov.name>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Michal Hocko <mhocko@suse.cz>
Cc: "Kirill A. Shutemov" <kirill@shutemov.name>
Cc: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp>
Cc: Balbir Singh <bsingharora@gmail.com>
Cc: Ying Han <yinghan@google.com>
Cc: Greg Thelen <gthelen@google.com>
Cc: Michel Lespinasse <walken@google.com>
Cc: Rik van Riel <riel@redhat.com>
Cc: Minchan Kim <minchan.kim@gmail.com>
Cc: Christoph Hellwig <hch@infradead.org>
Signed-off-by: Hugh Dickins <hughd@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

diff --git a/include/linux/page_cgroup.h b/include/linux/page_cgroup.h
index 5bae7535c2021fa8575e371b31c473e45da91f71..aaa60da8783c5f893a287734e2994d5fd675b48b 100644 (file)
--- a/include/linux/page_cgroup.h
+++ b/include/linux/page_cgroup.h
@@ -121,39 +121,6 @@ static inline void move_unlock_page_cgroup(struct page_cgroup *pc,
        local_irq_restore(*flags);
 }
 
-#ifdef CONFIG_SPARSEMEM
-#define PCG_ARRAYID_WIDTH      SECTIONS_SHIFT
-#else
-#define PCG_ARRAYID_WIDTH      NODES_SHIFT
-#endif
-
-#if (PCG_ARRAYID_WIDTH > BITS_PER_LONG - NR_PCG_FLAGS)
-#error Not enough space left in pc->flags to store page_cgroup array IDs
-#endif
-
-/* pc->flags: ARRAY-ID | FLAGS */
-
-#define PCG_ARRAYID_MASK       ((1UL << PCG_ARRAYID_WIDTH) - 1)
-
-#define PCG_ARRAYID_OFFSET     (BITS_PER_LONG - PCG_ARRAYID_WIDTH)
-/*
- * Zero the shift count for non-existent fields, to prevent compiler
- * warnings and ensure references are optimized away.
- */
-#define PCG_ARRAYID_SHIFT      (PCG_ARRAYID_OFFSET * (PCG_ARRAYID_WIDTH != 0))
-
-static inline void set_page_cgroup_array_id(struct page_cgroup *pc,
-                                           unsigned long id)
-{
-       pc->flags &= ~(PCG_ARRAYID_MASK << PCG_ARRAYID_SHIFT);
-       pc->flags |= (id & PCG_ARRAYID_MASK) << PCG_ARRAYID_SHIFT;
-}
-
-static inline unsigned long page_cgroup_array_id(struct page_cgroup *pc)
-{
-       return (pc->flags >> PCG_ARRAYID_SHIFT) & PCG_ARRAYID_MASK;
-}
-
 #else /* CONFIG_CGROUP_MEM_RES_CTLR */
 struct page_cgroup;
 

diff --git a/mm/page_cgroup.c b/mm/page_cgroup.c
index f59405a8d7523596559920f254223ad370ae10ba..f0559e049e002e48eda0160c41a71abc18a95460 100644 (file)
--- a/mm/page_cgroup.c
+++ b/mm/page_cgroup.c
@@ -11,12 +11,6 @@
 #include <linux/swapops.h>
 #include <linux/kmemleak.h>
 
-static void __meminit init_page_cgroup(struct page_cgroup *pc, unsigned long id)
-{
-       pc->flags = 0;
-       set_page_cgroup_array_id(pc, id);
-       pc->mem_cgroup = NULL;
-}
 static unsigned long total_usage;
 
 #if !defined(CONFIG_SPARSEMEM)
@@ -41,28 +35,13 @@ struct page_cgroup *lookup_page_cgroup(struct page *page)
        return base + offset;
 }
 
-struct page *lookup_cgroup_page(struct page_cgroup *pc)
-{
-       unsigned long pfn;
-       struct page *page;
-       pg_data_t *pgdat;
-
-       pgdat = NODE_DATA(page_cgroup_array_id(pc));
-       pfn = pc - pgdat->node_page_cgroup + pgdat->node_start_pfn;
-       page = pfn_to_page(pfn);
-       VM_BUG_ON(pc != lookup_page_cgroup(page));
-       return page;
-}
-
 static int __init alloc_node_page_cgroup(int nid)
 {
-       struct page_cgroup *base, *pc;
+       struct page_cgroup *base;
        unsigned long table_size;
-       unsigned long start_pfn, nr_pages, index;
+       unsigned long nr_pages;
 
-       start_pfn = NODE_DATA(nid)->node_start_pfn;
        nr_pages = NODE_DATA(nid)->node_spanned_pages;
-
        if (!nr_pages)
                return 0;
 
@@ -72,10 +51,6 @@ static int __init alloc_node_page_cgroup(int nid)
                        table_size, PAGE_SIZE, __pa(MAX_DMA_ADDRESS));
        if (!base)
                return -ENOMEM;
-       for (index = 0; index < nr_pages; index++) {
-               pc = base + index;
-               init_page_cgroup(pc, nid);
-       }
        NODE_DATA(nid)->node_page_cgroup = base;
        total_usage += table_size;
        return 0;
@@ -116,23 +91,10 @@ struct page_cgroup *lookup_page_cgroup(struct page *page)
        return section->page_cgroup + pfn;
 }
 
-struct page *lookup_cgroup_page(struct page_cgroup *pc)
-{
-       struct mem_section *section;
-       struct page *page;
-       unsigned long nr;
-
-       nr = page_cgroup_array_id(pc);
-       section = __nr_to_section(nr);
-       page = pfn_to_page(pc - section->page_cgroup);
-       VM_BUG_ON(pc != lookup_page_cgroup(page));
-       return page;
-}
-
 static void *__meminit alloc_page_cgroup(size_t size, int nid)
 {
+       gfp_t flags = GFP_KERNEL | __GFP_ZERO | __GFP_NOWARN;
        void *addr = NULL;
-       gfp_t flags = GFP_KERNEL | __GFP_NOWARN;
 
        addr = alloc_pages_exact_nid(nid, size, flags);
        if (addr) {
@@ -141,9 +103,9 @@ static void *__meminit alloc_page_cgroup(size_t size, int nid)
        }
 
        if (node_state(nid, N_HIGH_MEMORY))
-               addr = vmalloc_node(size, nid);
+               addr = vzalloc_node(size, nid);
        else
-               addr = vmalloc(size);
+               addr = vzalloc(size);
 
        return addr;
 }
@@ -166,14 +128,11 @@ static void free_page_cgroup(void *addr)
 
 static int __meminit init_section_page_cgroup(unsigned long pfn, int nid)
 {
-       struct page_cgroup *base, *pc;
        struct mem_section *section;
+       struct page_cgroup *base;
        unsigned long table_size;
-       unsigned long nr;
-       int index;
 
-       nr = pfn_to_section_nr(pfn);
-       section = __nr_to_section(nr);
+       section = __pfn_to_section(pfn);
 
        if (section->page_cgroup)
                return 0;
@@ -193,10 +152,6 @@ static int __meminit init_section_page_cgroup(unsigned long pfn, int nid)
                return -ENOMEM;
        }
 
-       for (index = 0; index < PAGES_PER_SECTION; index++) {
-               pc = base + index;
-               init_page_cgroup(pc, nr);
-       }
        /*
         * The passed "pfn" may not be aligned to SECTION.  For the calculation
         * we need to apply a mask.