lkml.org 
[lkml]   [2019]   [Apr]   [3]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
    Patch in this message
    /
    From
    Subject[PATCH] mm:workingset use real time to judge activity of the file page
    Date
    From: Zhaoyang Huang <zhaoyang.huang@unisoc.com>

    In previous implementation, the number of refault pages is used
    for judging the refault period of each page, which is not precised as
    eviction of other files will be affect a lot on current cache.
    We introduce the timestamp into the workingset's entry and refault ratio
    to measure the file page's activity. It helps to decrease the affection
    of other files(average refault ratio can reflect the view of whole system
    's memory).
    The patch is tested on an Android system, which can be described as
    comparing the launch time of an application between a huge memory
    consumption. The result is launch time decrease 50% and the page fault
    during the test decrease 80%.

    Signed-off-by: Zhaoyang Huang <huangzhaoyang@gmail.com>
    ---
    include/linux/mmzone.h | 2 ++
    mm/workingset.c | 24 +++++++++++++++++-------
    2 files changed, 19 insertions(+), 7 deletions(-)

    diff --git a/include/linux/mmzone.h b/include/linux/mmzone.h
    index 32699b2..c38ba0a 100644
    --- a/include/linux/mmzone.h
    +++ b/include/linux/mmzone.h
    @@ -240,6 +240,8 @@ struct lruvec {
    atomic_long_t inactive_age;
    /* Refaults at the time of last reclaim cycle */
    unsigned long refaults;
    + atomic_long_t refaults_ratio;
    + atomic_long_t prev_fault;
    #ifdef CONFIG_MEMCG
    struct pglist_data *pgdat;
    #endif
    diff --git a/mm/workingset.c b/mm/workingset.c
    index 40ee02c..6361853 100644
    --- a/mm/workingset.c
    +++ b/mm/workingset.c
    @@ -159,7 +159,7 @@
    NODES_SHIFT + \
    MEM_CGROUP_ID_SHIFT)
    #define EVICTION_MASK (~0UL >> EVICTION_SHIFT)
    -
    +#define EVICTION_JIFFIES (BITS_PER_LONG >> 3)
    /*
    * Eviction timestamps need to be able to cover the full range of
    * actionable refaults. However, bits are tight in the radix tree
    @@ -175,18 +175,22 @@ static void *pack_shadow(int memcgid, pg_data_t *pgdat, unsigned long eviction)
    eviction >>= bucket_order;
    eviction = (eviction << MEM_CGROUP_ID_SHIFT) | memcgid;
    eviction = (eviction << NODES_SHIFT) | pgdat->node_id;
    + eviction = (eviction << EVICTION_JIFFIES) | (jiffies >> EVICTION_JIFFIES);
    eviction = (eviction << RADIX_TREE_EXCEPTIONAL_SHIFT);

    return (void *)(eviction | RADIX_TREE_EXCEPTIONAL_ENTRY);
    }

    static void unpack_shadow(void *shadow, int *memcgidp, pg_data_t **pgdat,
    - unsigned long *evictionp)
    + unsigned long *evictionp, unsigned long *prev_jiffp)
    {
    unsigned long entry = (unsigned long)shadow;
    int memcgid, nid;
    + unsigned long prev_jiff;

    entry >>= RADIX_TREE_EXCEPTIONAL_SHIFT;
    + entry >>= EVICTION_JIFFIES;
    + prev_jiff = (entry & ((1UL << EVICTION_JIFFIES) - 1)) << EVICTION_JIFFIES;
    nid = entry & ((1UL << NODES_SHIFT) - 1);
    entry >>= NODES_SHIFT;
    memcgid = entry & ((1UL << MEM_CGROUP_ID_SHIFT) - 1);
    @@ -195,6 +199,7 @@ static void unpack_shadow(void *shadow, int *memcgidp, pg_data_t **pgdat,
    *memcgidp = memcgid;
    *pgdat = NODE_DATA(nid);
    *evictionp = entry << bucket_order;
    + *prev_jiffp = prev_jiff;
    }

    /**
    @@ -242,8 +247,12 @@ bool workingset_refault(void *shadow)
    unsigned long refault;
    struct pglist_data *pgdat;
    int memcgid;
    + unsigned long refault_ratio;
    + unsigned long prev_jiff;
    + unsigned long avg_refault_time;
    + unsigned long refault_time;

    - unpack_shadow(shadow, &memcgid, &pgdat, &eviction);
    + unpack_shadow(shadow, &memcgid, &pgdat, &eviction, &prev_jiff);

    rcu_read_lock();
    /*
    @@ -288,10 +297,11 @@ bool workingset_refault(void *shadow)
    * list is not a problem.
    */
    refault_distance = (refault - eviction) & EVICTION_MASK;
    -
    inc_lruvec_state(lruvec, WORKINGSET_REFAULT);
    -
    - if (refault_distance <= active_file) {
    + lruvec->refaults_ratio = atomic_long_read(&lruvec->inactive_age) / jiffies;
    + refault_time = jiffies - prev_jiff;
    + avg_refault_time = refault_distance / lruvec->refaults_ratio;
    + if (refault_time <= avg_refault_time) {
    inc_lruvec_state(lruvec, WORKINGSET_ACTIVATE);
    rcu_read_unlock();
    return true;
    @@ -521,7 +531,7 @@ static int __init workingset_init(void)
    * some more pages at runtime, so keep working with up to
    * double the initial memory by using totalram_pages as-is.
    */
    - timestamp_bits = BITS_PER_LONG - EVICTION_SHIFT;
    + timestamp_bits = BITS_PER_LONG - EVICTION_SHIFT - EVICTION_JIFFIES;
    max_order = fls_long(totalram_pages - 1);
    if (max_order > timestamp_bits)
    bucket_order = max_order - timestamp_bits;
    --
    1.9.1
    \
     
     \ /
      Last update: 2019-04-04 05:31    [W:3.817 / U:1.500 seconds]
    ©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site