lkml.org 
[lkml]   [2019]   [Dec]   [25]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
    Patch in this message
    /
    From
    Subject[PATCH v7 02/10] mm/memcg: fold lru_lock in lock_page_lru
    Date
    From the commit_charge's explanations and mem_cgroup_commit_charge
    comments, as well as call path when lrucare is ture, The lru_lock is
    just to guard the task migration(which would be lead to move_account)
    So it isn't needed when !PageLRU, and better be fold into PageLRU to
    reduce lock contentions.

    Signed-off-by: Alex Shi <alex.shi@linux.alibaba.com>
    Cc: Johannes Weiner <hannes@cmpxchg.org>
    Cc: Michal Hocko <mhocko@kernel.org>
    Cc: Matthew Wilcox <willy@infradead.org>
    Cc: Vladimir Davydov <vdavydov.dev@gmail.com>
    Cc: Andrew Morton <akpm@linux-foundation.org>
    Cc: cgroups@vger.kernel.org
    Cc: linux-mm@kvack.org
    Cc: linux-kernel@vger.kernel.org
    ---
    mm/memcontrol.c | 9 ++++-----
    1 file changed, 4 insertions(+), 5 deletions(-)

    diff --git a/mm/memcontrol.c b/mm/memcontrol.c
    index c5b5f74cfd4d..0ad10caabc3d 100644
    --- a/mm/memcontrol.c
    +++ b/mm/memcontrol.c
    @@ -2572,12 +2572,11 @@ static void cancel_charge(struct mem_cgroup *memcg, unsigned int nr_pages)

    static void lock_page_lru(struct page *page, int *isolated)
    {
    - pg_data_t *pgdat = page_pgdat(page);
    -
    - spin_lock_irq(&pgdat->lru_lock);
    if (PageLRU(page)) {
    + pg_data_t *pgdat = page_pgdat(page);
    struct lruvec *lruvec;

    + spin_lock_irq(&pgdat->lru_lock);
    lruvec = mem_cgroup_page_lruvec(page, pgdat);
    ClearPageLRU(page);
    del_page_from_lru_list(page, lruvec, page_lru(page));
    @@ -2588,17 +2587,17 @@ static void lock_page_lru(struct page *page, int *isolated)

    static void unlock_page_lru(struct page *page, int isolated)
    {
    - pg_data_t *pgdat = page_pgdat(page);

    if (isolated) {
    + pg_data_t *pgdat = page_pgdat(page);
    struct lruvec *lruvec;

    lruvec = mem_cgroup_page_lruvec(page, pgdat);
    VM_BUG_ON_PAGE(PageLRU(page), page);
    SetPageLRU(page);
    add_page_to_lru_list(page, lruvec, page_lru(page));
    + spin_unlock_irq(&pgdat->lru_lock);
    }
    - spin_unlock_irq(&pgdat->lru_lock);
    }

    static void commit_charge(struct page *page, struct mem_cgroup *memcg,
    --
    1.8.3.1
    \
     
     \ /
      Last update: 2019-12-25 10:05    [W:4.565 / U:0.008 seconds]
    ©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site