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    SubjectRe: [rfc PATCH]slub: per cpu partial statistics change
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    > Well the term releasing is unfortunate. per cpu partial pages can migrate
    > to and from the per node partial list and become per cpu slabs under
    > allocation.

    Yes, The word is really not good here. How about of CPU_PARTIAL_UNFREEZE
    since a unfreeze_cpu_partial() just called before ?
    >
    > > >> @@ -2465,9 +2466,10 @@ static void __slab_free(struct kmem_cache *s, struct page *page,
    > > >> * If we just froze the page then put it onto the
    > > >> * per cpu partial list.
    > > >> */
    > > >> - if (new.frozen && !was_frozen)
    > > >> + if (new.frozen && !was_frozen) {
    > > >> put_cpu_partial(s, page, 1);
    > > >> -
    > > >> + stat(s, CPU_PARTIAL_FREE);
    > > >
    > > > cpu partial list filled with a partial page created from a fully allocated
    > > > slab (which therefore was not on any list before).
    > >
    > >
    > > Yes, but the counting is not new here. It just moved out of
    > > put_cpu_partial().
    >
    > Ok but then you also added different accounting in put_cpu_partial.

    Yes, I want to account the unfreeze_partials() actions in
    put_cpu_partial(). The unfreezing accounting isn't conflict or repeat
    with the cpu_partial_free accounting, since they are different actions
    for the PCP.

    According your above comments, how about the new patch with new
    accounting name?
    ------------
    >From bd2b79297b4550035b0b0ec16dd0f3008a3a76dc Mon Sep 17 00:00:00 2001
    From: Alex Shi <alex.shi@intel.com>
    Date: Fri, 3 Feb 2012 23:34:56 +0800
    Subject: [PATCH] slub: per cpu partial statistics change

    This patch split the cpu_partial_free into 2 parts: cpu_partial_node, PCP refilling
    times from node partial; and same name cpu_partial_free, PCP refilling times in
    slab_free slow path. A new statistic 'cpu_partial_unfreeze' is added to get PCP
    unfreeze times. These info are useful when do PCP tunning.

    The slabinfo.c code is unchanged, since cpu_partial_node is not on slow path.

    Signed-off-by: Alex Shi <alex.shi@intel.com>
    ---
    include/linux/slub_def.h | 6 ++++--
    mm/slub.c | 12 +++++++++---
    2 files changed, 13 insertions(+), 5 deletions(-)

    diff --git a/include/linux/slub_def.h b/include/linux/slub_def.h
    index a32bcfd..2549483 100644
    --- a/include/linux/slub_def.h
    +++ b/include/linux/slub_def.h
    @@ -21,7 +21,7 @@ enum stat_item {
    FREE_FROZEN, /* Freeing to frozen slab */
    FREE_ADD_PARTIAL, /* Freeing moves slab to partial list */
    FREE_REMOVE_PARTIAL, /* Freeing removes last object */
    - ALLOC_FROM_PARTIAL, /* Cpu slab acquired from partial list */
    + ALLOC_FROM_PARTIAL, /* Cpu slab acquired from node partial list */
    ALLOC_SLAB, /* Cpu slab acquired from page allocator */
    ALLOC_REFILL, /* Refill cpu slab from slab freelist */
    ALLOC_NODE_MISMATCH, /* Switching cpu slab */
    @@ -37,7 +37,9 @@ enum stat_item {
    CMPXCHG_DOUBLE_CPU_FAIL,/* Failure of this_cpu_cmpxchg_double */
    CMPXCHG_DOUBLE_FAIL, /* Number of times that cmpxchg double did not match */
    CPU_PARTIAL_ALLOC, /* Used cpu partial on alloc */
    - CPU_PARTIAL_FREE, /* USed cpu partial on free */
    + CPU_PARTIAL_FREE, /* Refill cpu partial on free */
    + CPU_PARTIAL_NODE, /* Refill cpu partial from node partial */
    + CPU_PARTIAL_UNFREEZE, /* Unfreeze cpu partial */
    NR_SLUB_STAT_ITEMS };

    struct kmem_cache_cpu {
    diff --git a/mm/slub.c b/mm/slub.c
    index 4907563..6ededd7 100644
    --- a/mm/slub.c
    +++ b/mm/slub.c
    @@ -1560,6 +1560,7 @@ static void *get_partial_node(struct kmem_cache *s,
    } else {
    page->freelist = t;
    available = put_cpu_partial(s, page, 0);
    + stat(s, CPU_PARTIAL_NODE);
    }
    if (kmem_cache_debug(s) || available > s->cpu_partial / 2)
    break;
    @@ -1973,6 +1974,7 @@ int put_cpu_partial(struct kmem_cache *s, struct page *page, int drain)
    local_irq_restore(flags);
    pobjects = 0;
    pages = 0;
    + stat(s, CPU_PARTIAL_UNFREEZE);
    }
    }

    @@ -1984,7 +1986,6 @@ int put_cpu_partial(struct kmem_cache *s, struct page *page, int drain)
    page->next = oldpage;

    } while (this_cpu_cmpxchg(s->cpu_slab->partial, oldpage, page) != oldpage);
    - stat(s, CPU_PARTIAL_FREE);
    return pobjects;
    }

    @@ -2465,9 +2466,10 @@ static void __slab_free(struct kmem_cache *s, struct page *page,
    * If we just froze the page then put it onto the
    * per cpu partial list.
    */
    - if (new.frozen && !was_frozen)
    + if (new.frozen && !was_frozen) {
    put_cpu_partial(s, page, 1);
    -
    + stat(s, CPU_PARTIAL_FREE);
    + }
    /*
    * The list lock was not taken therefore no list
    * activity can be necessary.
    @@ -5059,6 +5061,8 @@ STAT_ATTR(CMPXCHG_DOUBLE_CPU_FAIL, cmpxchg_double_cpu_fail);
    STAT_ATTR(CMPXCHG_DOUBLE_FAIL, cmpxchg_double_fail);
    STAT_ATTR(CPU_PARTIAL_ALLOC, cpu_partial_alloc);
    STAT_ATTR(CPU_PARTIAL_FREE, cpu_partial_free);
    +STAT_ATTR(CPU_PARTIAL_NODE, cpu_partial_node);
    +STAT_ATTR(CPU_PARTIAL_UNFREEZE, cpu_partial_unfreeze);
    #endif

    static struct attribute *slab_attrs[] = {
    @@ -5124,6 +5128,8 @@ static struct attribute *slab_attrs[] = {
    &cmpxchg_double_cpu_fail_attr.attr,
    &cpu_partial_alloc_attr.attr,
    &cpu_partial_free_attr.attr,
    + &cpu_partial_node_attr.attr,
    + &cpu_partial_unfreeze_attr.attr,
    #endif
    #ifdef CONFIG_FAILSLAB
    &failslab_attr.attr,
    --
    1.6.3.3



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