lkml.org 
[lkml]   [2002]   [Jan]   [15]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
    Patch in this message
    /
    Date
    From
    SubjectRe: [PATCH] O_DIRECT with hardware blocksize alignment
    On Tue, Jan 15 2002, Jens Axboe wrote:
    > On Tue, Jan 15 2002, Andrea Arcangeli wrote:
    > > actually we could also forbid merging at the ll_rw_block layer if b_size
    > > is not equal, maybe that's the simpler solution to that problem after
    > > all, merging between kiovec I/O and buffered I/O probably doesn't
    > > matter.
    >
    > Agreed, this is also what I suggested.

    Here's the right version, sorry. This still potentially decrements
    elevator sequence wrongly for a missed front merge, but that's an issue
    I can definitely live with :-)

    --- /opt/kernel/linux-2.4.18-pre3/drivers/block/ll_rw_blk.c Tue Jan 15 14:06:13 2002
    +++ drivers/block/ll_rw_blk.c Tue Jan 15 14:54:20 2002
    @@ -694,10 +694,11 @@
    switch (el_ret) {

    case ELEVATOR_BACK_MERGE:
    - if (!q->back_merge_fn(q, req, bh, max_segments)) {
    - insert_here = &req->queue;
    + insert_here = &req->queue;
    + if (req->current_nr_sectors != count)
    + break;
    + if (!q->back_merge_fn(q, req, bh, max_segments))
    break;
    - }
    elevator->elevator_merge_cleanup_fn(q, req, count);
    req->bhtail->b_reqnext = bh;
    req->bhtail = bh;
    @@ -708,10 +709,11 @@
    goto out;

    case ELEVATOR_FRONT_MERGE:
    - if (!q->front_merge_fn(q, req, bh, max_segments)) {
    - insert_here = req->queue.prev;
    + insert_here = req->queue.prev;
    + if (req->current_nr_sectors != count)
    + break;
    + if (!q->front_merge_fn(q, req, bh, max_segments))
    break;
    - }
    elevator->elevator_merge_cleanup_fn(q, req, count);
    bh->b_reqnext = req->bh;
    req->bh = bh;
    --
    Jens Axboe

    -
    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 13:23    [W:0.023 / U:2.864 seconds]
    ©2003-2017 Jasper Spaans. hosted at Digital OceanAdvertise on this site