memcg: change page_cgroup_zoneinfo signature

Instead of passing a whole struct page_cgroup to this function, let it
take only what it really needs from it: the struct mem_cgroup and the
page.

This has the advantage that reading pc->mem_cgroup is now done at the same
place where the ordering rules for this pointer are enforced and
explained.

It is also in preparation for removing the pc->page backpointer.

Signed-off-by: Johannes Weiner <hannes@cmpxchg.org>
Acked-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp>
Cc: Balbir Singh <balbir@linux.vnet.ibm.com>
Cc: Minchan Kim <minchan.kim@gmail.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 6d6cb7a57bb3af7129baa644d7f3de0c24a58eab..363bbc8b0f49cf17576bbe4a700ce195fd547d1d 100644 (file)
--- a/include/linux/page_cgroup.h
+++ b/include/linux/page_cgroup.h
@@ -85,16 +85,6 @@ SETPCGFLAG(Migration, MIGRATION)
 CLEARPCGFLAG(Migration, MIGRATION)
 TESTPCGFLAG(Migration, MIGRATION)
 
-static inline int page_cgroup_nid(struct page_cgroup *pc)
-{
-       return page_to_nid(pc->page);
-}
-
-static inline enum zone_type page_cgroup_zid(struct page_cgroup *pc)
-{
-       return page_zonenum(pc->page);
-}
-
 static inline void lock_page_cgroup(struct page_cgroup *pc)
 {
        /*

diff --git a/mm/memcontrol.c b/mm/memcontrol.c
index 5f7b0e1d789cd89c12517e0cb1c4204f5aed4780..2881c9ef969a7131f510ec5add64c14724dbe819 100644 (file)
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -364,11 +364,10 @@ struct cgroup_subsys_state *mem_cgroup_css(struct mem_cgroup *mem)
 }
 
 static struct mem_cgroup_per_zone *
-page_cgroup_zoneinfo(struct page_cgroup *pc)
+page_cgroup_zoneinfo(struct mem_cgroup *mem, struct page *page)
 {
-       struct mem_cgroup *mem = pc->mem_cgroup;
-       int nid = page_cgroup_nid(pc);
-       int zid = page_cgroup_zid(pc);
+       int nid = page_to_nid(page);
+       int zid = page_zonenum(page);
 
        return mem_cgroup_zoneinfo(mem, nid, zid);
 }
@@ -800,7 +799,7 @@ void mem_cgroup_del_lru_list(struct page *page, enum lru_list lru)
         * We don't check PCG_USED bit. It's cleared when the "page" is finally
         * removed from global LRU.
         */
-       mz = page_cgroup_zoneinfo(pc);
+       mz = page_cgroup_zoneinfo(pc->mem_cgroup, page);
        /* huge page split is done under lru_lock. so, we have no races. */
        MEM_CGROUP_ZSTAT(mz, lru) -= 1 << compound_order(page);
        if (mem_cgroup_is_root(pc->mem_cgroup))
@@ -836,7 +835,7 @@ void mem_cgroup_rotate_reclaimable_page(struct page *page)
        smp_rmb();
        if (mem_cgroup_is_root(pc->mem_cgroup))
                return;
-       mz = page_cgroup_zoneinfo(pc);
+       mz = page_cgroup_zoneinfo(pc->mem_cgroup, page);
        list_move_tail(&pc->lru, &mz->lists[lru]);
 }
 
@@ -856,7 +855,7 @@ void mem_cgroup_rotate_lru_list(struct page *page, enum lru_list lru)
        smp_rmb();
        if (mem_cgroup_is_root(pc->mem_cgroup))
                return;
-       mz = page_cgroup_zoneinfo(pc);
+       mz = page_cgroup_zoneinfo(pc->mem_cgroup, page);
        list_move(&pc->lru, &mz->lists[lru]);
 }
 
@@ -873,7 +872,7 @@ void mem_cgroup_add_lru_list(struct page *page, enum lru_list lru)
                return;
        /* Ensure pc->mem_cgroup is visible after reading PCG_USED. */
        smp_rmb();
-       mz = page_cgroup_zoneinfo(pc);
+       mz = page_cgroup_zoneinfo(pc->mem_cgroup, page);
        /* huge page split is done under lru_lock. so, we have no races. */
        MEM_CGROUP_ZSTAT(mz, lru) += 1 << compound_order(page);
        SetPageCgroupAcctLRU(pc);
@@ -1043,7 +1042,7 @@ mem_cgroup_get_reclaim_stat_from_page(struct page *page)
                return NULL;
        /* Ensure pc->mem_cgroup is visible after reading PCG_USED. */
        smp_rmb();
-       mz = page_cgroup_zoneinfo(pc);
+       mz = page_cgroup_zoneinfo(pc->mem_cgroup, page);
        if (!mz)
                return NULL;
 
@@ -2192,7 +2191,7 @@ void mem_cgroup_split_huge_fixup(struct page *head, struct page *tail)
                 * We hold lru_lock, then, reduce counter directly.
                 */
                lru = page_lru(head);
-               mz = page_cgroup_zoneinfo(head_pc);
+               mz = page_cgroup_zoneinfo(head_pc->mem_cgroup, head);
                MEM_CGROUP_ZSTAT(mz, lru) -= 1;
        }
        tail_pc->flags = head_pc->flags & ~PCGF_NOCOPY_AT_SPLIT;