lkml.org 
[lkml]   [2004]   [Oct]   [14]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
    Patch in this message
    /
    Subject[PATCH] General purpose zeroed page slab
    From
    Date

    A while back Bill Irwin converted the page table code on ppc64 to use
    a zeroed page slab. I recently did the same on ia64 and got a
    significant performance improvement in terms of fault time (4 usec ->
    700 nsec).

    This cache needs to be initialized fairly early on and so far we've
    called it from pgtable_cache_init() on both archs. However, Tony Luck
    thought it might be useful to have a general purpose slab cache with
    zeroed pages. And other architectures might decide to use it for
    their page tables too.

    Consequently here's a patch that puts this functionality in slab.c.

    Signed-off-by: Martin K. Petersen <mkp@wildopensource.com>

    --
    Martin K. Petersen Wild Open Source, Inc.
    mkp@wildopensource.com http://www.wildopensource.com/

    diff -urN -X /usr/people/mkp/bin/dontdiff linux-pristine/include/linux/slab.h zero-slab/include/linux/slab.h
    --- linux-pristine/include/linux/slab.h 2004-10-11 14:57:20.000000000 -0700
    +++ zero-slab/include/linux/slab.h 2004-10-13 17:49:29.000000000 -0700
    @@ -115,6 +115,7 @@
    extern kmem_cache_t *signal_cachep;
    extern kmem_cache_t *sighand_cachep;
    extern kmem_cache_t *bio_cachep;
    +extern kmem_cache_t *zero_page_cachep;

    extern atomic_t slab_reclaim_pages;

    diff -urN -X /usr/people/mkp/bin/dontdiff linux-pristine/mm/slab.c zero-slab/mm/slab.c
    --- linux-pristine/mm/slab.c 2004-10-11 14:57:20.000000000 -0700
    +++ zero-slab/mm/slab.c 2004-10-13 17:49:57.000000000 -0700
    @@ -716,6 +716,13 @@

    static struct notifier_block cpucache_notifier = { &cpuup_callback, NULL, 0 };

    +kmem_cache_t *zero_page_cachep;
    +
    +static void zero_page_ctor(void *pte, kmem_cache_t *cache, unsigned long flags)
    +{
    + memset(pte, 0, PAGE_SIZE);
    +}
    +
    /* Initialisation.
    * Called after the gfp() functions have been enabled, and before smp_init().
    */
    @@ -837,6 +844,16 @@
    /* The reap timers are started later, with a module init call:
    * That part of the kernel is not yet operational.
    */
    +
    + /* General purpose cache of zeroed pages */
    + zero_page_cachep = kmem_cache_create("zero_page_cache",
    + PAGE_SIZE, 0,
    + SLAB_HWCACHE_ALIGN |
    + SLAB_MUST_HWCACHE_ALIGN,
    + zero_page_ctor,
    + NULL);
    + if (!zero_page_cachep)
    + panic("could not create zero_page_cache!\n");
    }

    static int __init cpucache_init(void)
    -
    To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
    the body of a message to majordomo@vger.kernel.org
    More majordomo info at http://vger.kernel.org/majordomo-info.html
    Please read the FAQ at http://www.tux.org/lkml/

    \
     
     \ /
      Last update: 2005-03-22 14:07    [W:0.020 / U:0.352 seconds]
    ©2003-2016 Jasper Spaans. hosted at Digital OceanAdvertise on this site