On 15/02/17 15:49, Linus Walleij wrote: > On Fri, Feb 10, 2017 at 1:55 PM, Adrian Hunter <adrian.hunter@xxxxxxxxx> wrote: > >> Enhance mmc_blk_data_prep() to support CQE requests. >> >> Signed-off-by: Adrian Hunter <adrian.hunter@xxxxxxxxx> > > Hey: > >> +#include <linux/ioprio.h> > (...) >> + if (IOPRIO_PRIO_CLASS(req_get_ioprio(req)) == IOPRIO_CLASS_RT) >> + brq->data.flags |= MMC_DATA_PRIO; > > What is this? It is the command queue priority. The command queue supports 2 priorities: "high" (1) and "simple" (0). The eMMC will give "high" priority tasks priority over "simple" priority tasks. So here we give priority to IOPRIO_CLASS_RT which seems appropriate. > > Why are we not already doing this and why is it not a separate patch? I think adding a comment is better since it is a command queue feature. > >> /* >> * Data tag is used only during writing meta data to speed >> * up write and any subsequent read of this meta data >> */ > > Is this comment still true? AFAIK > >> - *do_data_tag = card->ext_csd.data_tag_unit_size && >> - (req->cmd_flags & REQ_META) && >> - (rq_data_dir(req) == WRITE) && >> - ((brq->data.blocks * brq->data.blksz) >= >> - card->ext_csd.data_tag_unit_size); >> + do_data_tag = card->ext_csd.data_tag_unit_size && >> + (req->cmd_flags & REQ_META) && >> + (rq_data_dir(req) == WRITE) && >> + ((brq->data.blocks * brq->data.blksz) >= >> + card->ext_csd.data_tag_unit_size); >> + >> + if (do_data_tag) >> + brq->data.flags |= MMC_DATA_DAT_TAG; > > Because it seems to be more unconditionally used now. The key ingredient is (req->cmd_flags & REQ_META) i.e. meta-data gets tagged. -- To unsubscribe from this list: send the line "unsubscribe linux-mmc" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
