lkml.org 
[lkml]   [2012]   [Feb]   [20]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
    Patch in this message
    /
    Subject[PATCH v2 19/22] mm: handle lruvec relock in memory controller
    From
    Date
    Carefully relock lruvec lru lock at page memory cgroup change.

    * Stabilize PageLRU() sign with __wait_lruvec_unlock(old_lruvec)
    It must be called between each pc->mem_cgroup change and
    page putback into new lruvec, otherwise someone else can lock old lruvec and
    see PageLRU(), while page already moved into other lruvec.
    * In free_pn_rcu() wait for lruvec lock release.
    Locking primitives keep lruvec pointer after successful lock held.

    Signed-off-by: Konstantin Khlebnikov <khlebnikov@openvz.org>
    ---
    mm/memcontrol.c | 36 ++++++++++++++++++++++++++++--------
    1 files changed, 28 insertions(+), 8 deletions(-)

    diff --git a/mm/memcontrol.c b/mm/memcontrol.c
    index 40e1a66..69763da 100644
    --- a/mm/memcontrol.c
    +++ b/mm/memcontrol.c
    @@ -2368,6 +2368,7 @@ static int mem_cgroup_move_account(struct page *page,
    unsigned long flags;
    int ret;
    bool anon = PageAnon(page);
    + struct lruvec *old_lruvec;

    VM_BUG_ON(from == to);
    VM_BUG_ON(PageLRU(page));
    @@ -2397,12 +2398,24 @@ static int mem_cgroup_move_account(struct page *page,
    preempt_enable();
    }
    mem_cgroup_charge_statistics(from, anon, -nr_pages);
    +
    + /* charge keep old lruvec alive */
    + old_lruvec = page_lruvec(page);
    +
    + /* caller should have done css_get */
    + pc->mem_cgroup = to;
    +
    + /*
    + * Stabilize PageLRU() sing for old_lruvec lock holder.
    + * Do not putback page while someone hold old_lruvec lock,
    + * otherwise it can think it catched page in old_lruvec lru.
    + */
    + __wait_lruvec_unlock(old_lruvec);
    +
    if (uncharge)
    /* This is not "cancel", but cancel_charge does all we need. */
    __mem_cgroup_cancel_charge(from, nr_pages);

    - /* caller should have done css_get */
    - pc->mem_cgroup = to;
    mem_cgroup_charge_statistics(to, anon, nr_pages);
    /*
    * We charges against "to" which may not have any tasks. Then, "to"
    @@ -2528,7 +2541,6 @@ __mem_cgroup_commit_charge_lrucare(struct page *page, struct mem_cgroup *memcg,
    enum charge_type ctype)
    {
    struct page_cgroup *pc = lookup_page_cgroup(page);
    - struct zone *zone = page_zone(page);
    struct lruvec *lruvec;
    unsigned long flags;
    bool removed = false;
    @@ -2538,20 +2550,19 @@ __mem_cgroup_commit_charge_lrucare(struct page *page, struct mem_cgroup *memcg,
    * is already on LRU. It means the page may on some other page_cgroup's
    * LRU. Take care of it.
    */
    - spin_lock_irqsave(&zone->lru_lock, flags);
    + lruvec = lock_page_lruvec(page, &flags);
    if (PageLRU(page)) {
    - lruvec = page_lruvec(page);
    del_page_from_lru_list(lruvec, page, page_lru(page));
    ClearPageLRU(page);
    removed = true;
    }
    __mem_cgroup_commit_charge(memcg, page, 1, pc, ctype);
    if (removed) {
    - lruvec = page_lruvec(page);
    + lruvec = __relock_page_lruvec(lruvec, page);
    add_page_to_lru_list(lruvec, page, page_lru(page));
    SetPageLRU(page);
    }
    - spin_unlock_irqrestore(&zone->lru_lock, flags);
    + unlock_lruvec(lruvec, &flags);
    }

    int mem_cgroup_cache_charge(struct page *page, struct mm_struct *mm,
    @@ -4648,7 +4659,16 @@ static int alloc_mem_cgroup_per_zone_info(struct mem_cgroup *memcg, int node)

    static void free_mem_cgroup_per_zone_info(struct mem_cgroup *memcg, int node)
    {
    - kfree(memcg->info.nodeinfo[node]);
    + struct mem_cgroup_per_node *pn = memcg->info.nodeinfo[node];
    + int zone;
    +
    + if (!pn)
    + return;
    +
    + for (zone = 0; zone < MAX_NR_ZONES; zone++)
    + wait_lruvec_unlock(&pn->zoneinfo[zone].lruvec);
    +
    + kfree(pn);
    }

    static struct mem_cgroup *mem_cgroup_alloc(void)


    \
     
     \ /
      Last update: 2012-02-20 18:37    [W:0.045 / U:0.608 seconds]
    ©2003-2016 Jasper Spaans. hosted at Digital OceanAdvertise on this site