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    Subject[PATCH] slub - Use local_t protection
    slub - Use local_t protection

    Use local_enter/local_exit for protection in the fast path.

    Depends on the cmpxchg_local slub patch.

    Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@polymtl.ca>
    CC: Christoph Lameter <clameter@sgi.com>
    ---
    mm/slub.c | 18 ++++++++++--------
    1 file changed, 10 insertions(+), 8 deletions(-)

    Index: linux-2.6-lttng/mm/slub.c
    ===================================================================
    --- linux-2.6-lttng.orig/mm/slub.c 2007-09-04 15:47:20.000000000 -0400
    +++ linux-2.6-lttng/mm/slub.c 2007-09-04 15:52:07.000000000 -0400
    @@ -1456,7 +1456,6 @@ static void *__slab_alloc(struct kmem_ca
    unsigned long flags;

    local_irq_save(flags);
    - put_cpu_no_resched();
    if (!c->page)
    /* Slab was flushed */
    goto new_slab;
    @@ -1480,7 +1479,6 @@ load_freelist:
    out:
    slab_unlock(c->page);
    local_irq_restore(flags);
    - preempt_check_resched();
    if (unlikely((gfpflags & __GFP_ZERO)))
    memset(object, 0, c->objsize);
    return object;
    @@ -1524,7 +1522,6 @@ new_slab:
    goto load_freelist;
    }
    local_irq_restore(flags);
    - preempt_check_resched();
    return NULL;
    debug:
    object = c->page->freelist;
    @@ -1552,8 +1549,10 @@ static void __always_inline *slab_alloc(
    {
    void **object;
    struct kmem_cache_cpu *c;
    + unsigned long flags;

    - c = get_cpu_slab(s, get_cpu());
    + local_enter(flags);
    + c = get_cpu_slab(s, smp_processor_id());
    redo:
    object = c->freelist;
    if (unlikely(!object))
    @@ -1566,12 +1565,13 @@ redo:
    object[c->offset]) != object))
    goto redo;

    - put_cpu();
    + local_exit(flags);
    if (unlikely((gfpflags & __GFP_ZERO)))
    memset(object, 0, c->objsize);

    return object;
    slow:
    + local_exit(flags);
    return __slab_alloc(s, gfpflags, node, addr, c);

    }
    @@ -1605,7 +1605,6 @@ static void __slab_free(struct kmem_cach
    void **object = (void *)x;
    unsigned long flags;

    - put_cpu();
    local_irq_save(flags);
    slab_lock(page);

    @@ -1670,10 +1669,12 @@ static void __always_inline slab_free(st
    void **object = (void *)x;
    void **freelist;
    struct kmem_cache_cpu *c;
    + unsigned long flags;

    debug_check_no_locks_freed(object, s->objsize);

    - c = get_cpu_slab(s, get_cpu());
    + local_enter(flags);
    + c = get_cpu_slab(s, smp_processor_id());
    if (unlikely(c->node < 0))
    goto slow;
    redo:
    @@ -1687,9 +1688,10 @@ redo:
    != freelist))
    goto redo;

    - put_cpu();
    + local_exit(flags);
    return;
    slow:
    + local_exit(flags);
    __slab_free(s, page, x, addr, c->offset);
    }

    --
    Mathieu Desnoyers
    Computer Engineering Ph.D. Student, Ecole Polytechnique de Montreal
    OpenPGP key fingerprint: 8CD5 52C3 8E3C 4140 715F BA06 3F25 A8FE 3BAE 9A68
    -
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