[lkml]   [2010]   [Nov]   [20]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
Messages in this thread
    SubjectRe: [PATCH][resend][SCSI] Reduce number of sequential pointer derefs in scsi_error.c and reduce size as well
    On Sat, Nov 20, 2010 at 12:30 PM, Jesper Juhl <> wrote:
    > Ok, I tried doing that (see patch below)

    Actually, you kind of chose exactly the reverse of the functions I'd
    have chosen.

    Try doing the added parameter to the small static helper functions.
    Those are the ones that tend to get inlined, and then the parameter
    should actually result in _fewer_ pointer reloads.

    So the ones like this:

    >  static int __scsi_try_to_abort_cmd(struct scsi_cmnd *scmd)
    >  {
    > -       if (!scmd->device->host->hostt->eh_abort_handler)
    > +       struct scsi_host_template *hostt = scmd->device->host->hostt;
    > +       if (!hostt->eh_abort_handler)
    >                return FAILED;
    > -
    > -       return scmd->device->host->hostt->eh_abort_handler(scmd);
    > +       return hostt->eh_abort_handler(scmd);
    >  }

    Where the function is trivial, and almost all it does is to just
    dereference those pointers.

    If that function got the "host" pointer as an argument, it should make
    it much smaller. Because half of that function is that
    "scmd->device->host" lookup.

    (ok, that's exaggerated, but not by much).

    To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
    the body of a message to
    More majordomo info at
    Please read the FAQ at

     \ /
      Last update: 2010-11-21 01:07    [W:0.022 / U:7.976 seconds]
    ©2003-2016 Jasper Spaans. hosted at Digital OceanAdvertise on this site