lkml.org 
[lkml]   [2013]   [Dec]   [2]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
    Patch in this message
    /
    From
    Subject[PATCH 3.12 089/212] dm: allocate buffer for messages with small number of arguments using GFP_NOIO
    Date
    3.12-stable review patch.  If anyone has any objections, please let me know.

    ------------------

    From: Mikulas Patocka <mpatocka@redhat.com>

    commit f36afb3957353d2529cb2b00f78fdccd14fc5e9c upstream.

    dm-mpath and dm-thin must process messages even if some device is
    suspended, so we allocate argv buffer with GFP_NOIO. These messages have
    a small fixed number of arguments.

    On the other hand, dm-switch needs to process bulk data using messages
    so excessive use of GFP_NOIO could cause trouble.

    The patch also lowers the default number of arguments from 64 to 8, so
    that there is smaller load on GFP_NOIO allocations.

    Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
    Acked-by: Alasdair G Kergon <agk@redhat.com>
    Signed-off-by: Mike Snitzer <snitzer@redhat.com>
    Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

    ---
    drivers/md/dm-table.c | 18 ++++++++++++++++--
    1 file changed, 16 insertions(+), 2 deletions(-)

    --- a/drivers/md/dm-table.c
    +++ b/drivers/md/dm-table.c
    @@ -545,14 +545,28 @@ static int adjoin(struct dm_table *table

    /*
    * Used to dynamically allocate the arg array.
    + *
    + * We do first allocation with GFP_NOIO because dm-mpath and dm-thin must
    + * process messages even if some device is suspended. These messages have a
    + * small fixed number of arguments.
    + *
    + * On the other hand, dm-switch needs to process bulk data using messages and
    + * excessive use of GFP_NOIO could cause trouble.
    */
    static char **realloc_argv(unsigned *array_size, char **old_argv)
    {
    char **argv;
    unsigned new_size;
    + gfp_t gfp;

    - new_size = *array_size ? *array_size * 2 : 64;
    - argv = kmalloc(new_size * sizeof(*argv), GFP_KERNEL);
    + if (*array_size) {
    + new_size = *array_size * 2;
    + gfp = GFP_KERNEL;
    + } else {
    + new_size = 8;
    + gfp = GFP_NOIO;
    + }
    + argv = kmalloc(new_size * sizeof(*argv), gfp);
    if (argv) {
    memcpy(argv, old_argv, *array_size * sizeof(*argv));
    *array_size = new_size;



    \
     
     \ /
      Last update: 2013-12-03 07:41    [W:4.023 / U:0.392 seconds]
    ©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site