lkml.org 
[lkml]   [2011]   [May]   [26]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
    Patch in this message
    /
    Date
    From
    Subject[PATCH v2] dm: pass up non-rotational flag
    Allow QUEUE_FLAG_NONROT to propagate up the device stack if all
    underlying devices are non-rotational. Tools like ureadahead will
    schedule IOs differently based on the rotational flag.

    With this patch, I see boot time go from 7.75 s to 7.46 s on my device.

    Suggested-by: J. Richard Barnette <jrbarnette@chromium.org>
    Signed-off-by: Mandeep Singh Baines <msb@chromium.org>
    Signed-off-by: Mike Snitzer <snitzer@redhat.com>
    Cc: Neil Brown <neilb@suse.de>
    Cc: Jens Axboe <jaxboe@fusionio.com>
    Cc: Martin K. Petersen <martin.petersen@oracle.com>
    Cc: Alasdair G Kergon <agk@redhat.com>
    Cc: dm-devel@redhat.com
    ---
    drivers/md/dm-table.c | 30 ++++++++++++++++++++++++++++++
    1 files changed, 30 insertions(+), 0 deletions(-)

    v2: last minute edit was to avoid double-negative in
    dm_table_set_restrictions's dm_table_is_nonrot conditional

    diff --git a/drivers/md/dm-table.c b/drivers/md/dm-table.c
    index cb8380c..a173828 100644
    --- a/drivers/md/dm-table.c
    +++ b/drivers/md/dm-table.c
    @@ -1177,6 +1177,31 @@ static void dm_table_set_integrity(struct dm_table *t)
    blk_get_integrity(template_disk));
    }

    +static int device_is_nonrot(struct dm_target *ti, struct dm_dev *dev,
    + sector_t start, sector_t len, void *data)
    +{
    + struct request_queue *q = bdev_get_queue(dev->bdev);
    +
    + return q && blk_queue_nonrot(q);
    +}
    +
    +static bool dm_table_is_nonrot(struct dm_table *t)
    +{
    + struct dm_target *ti;
    + unsigned i = 0;
    +
    + /* Ensure that all underlying device are non-rotational. */
    + while (i < dm_table_get_num_targets(t)) {
    + ti = dm_table_get_target(t, i++);
    +
    + if (!ti->type->iterate_devices ||
    + !ti->type->iterate_devices(ti, device_is_nonrot, NULL))
    + return 0;
    + }
    +
    + return 1;
    +}
    +
    void dm_table_set_restrictions(struct dm_table *t, struct request_queue *q,
    struct queue_limits *limits)
    {
    @@ -1190,6 +1215,11 @@ void dm_table_set_restrictions(struct dm_table *t, struct request_queue *q,
    else
    queue_flag_set_unlocked(QUEUE_FLAG_DISCARD, q);

    + if (dm_table_is_nonrot(t))
    + queue_flag_set_unlocked(QUEUE_FLAG_NONROT, q);
    + else
    + queue_flag_clear_unlocked(QUEUE_FLAG_NONROT, q);
    +
    dm_table_set_integrity(t);

    /*

    \
     
     \ /
      Last update: 2011-05-26 20:37    [W:0.043 / U:29.652 seconds]
    ©2003-2016 Jasper Spaans. hosted at Digital OceanAdvertise on this site