forked from luck/tmp_suning_uos_patched
6e6fcbc27e
More and more drivers want to get batching requests queued from block layer, such as mmc, and tcp based storage drivers. Also current in-tree users have virtio-scsi, virtio-blk and nvme. For none, we already support batching dispatch. But for io scheduler, every time we just take one request from scheduler and pass the single request to blk_mq_dispatch_rq_list(). This way makes batching dispatch not possible when io scheduler is applied. One reason is that we don't want to hurt sequential IO performance, becasue IO merge chance is reduced if more requests are dequeued from scheduler queue. Try to support batching dispatch for io scheduler by starting with the following simple approach: 1) still make sure we can get budget before dequeueing request 2) use hctx->dispatch_busy to evaluate if queue is busy, if it is busy we fackback to non-batching dispatch, otherwise dequeue as many as possible requests from scheduler, and pass them to blk_mq_dispatch_rq_list(). Wrt. 2), we use similar policy for none, and turns out that SCSI SSD performance got improved much. In future, maybe we can develop more intelligent algorithem for batching dispatch. Baolin has tested this patch and found that MMC performance is improved[3]. [1] https://lore.kernel.org/linux-block/20200512075501.GF1531898@T590/#r [2] https://lore.kernel.org/linux-block/fe6bd8b9-6ed9-b225-f80c-314746133722@grimberg.me/ [3] https://lore.kernel.org/linux-block/CADBw62o9eTQDJ9RvNgEqSpXmg6Xcq=2TxH0Hfxhp29uF2W=TXA@mail.gmail.com/ Signed-off-by: Ming Lei <ming.lei@redhat.com> Tested-by: Baolin Wang <baolin.wang7@gmail.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Cc: Sagi Grimberg <sagi@grimberg.me> Cc: Baolin Wang <baolin.wang7@gmail.com> Cc: Christoph Hellwig <hch@infradead.org> Signed-off-by: Jens Axboe <axboe@kernel.dk> |
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| .. | ||
| partitions | ||
| badblocks.c | ||
| bfq-cgroup.c | ||
| bfq-iosched.c | ||
| bfq-iosched.h | ||
| bfq-wf2q.c | ||
| bio-integrity.c | ||
| bio.c | ||
| blk-cgroup-rwstat.c | ||
| blk-cgroup-rwstat.h | ||
| blk-cgroup.c | ||
| blk-core.c | ||
| blk-crypto-fallback.c | ||
| blk-crypto-internal.h | ||
| blk-crypto.c | ||
| blk-exec.c | ||
| blk-flush.c | ||
| blk-integrity.c | ||
| blk-ioc.c | ||
| blk-iocost.c | ||
| blk-iolatency.c | ||
| blk-lib.c | ||
| blk-map.c | ||
| blk-merge.c | ||
| blk-mq-cpumap.c | ||
| blk-mq-debugfs-zoned.c | ||
| blk-mq-debugfs.c | ||
| blk-mq-debugfs.h | ||
| blk-mq-pci.c | ||
| blk-mq-rdma.c | ||
| blk-mq-sched.c | ||
| blk-mq-sched.h | ||
| blk-mq-sysfs.c | ||
| blk-mq-tag.c | ||
| blk-mq-tag.h | ||
| blk-mq-virtio.c | ||
| blk-mq.c | ||
| blk-mq.h | ||
| blk-pm.c | ||
| blk-pm.h | ||
| blk-rq-qos.c | ||
| blk-rq-qos.h | ||
| blk-settings.c | ||
| blk-stat.c | ||
| blk-stat.h | ||
| blk-sysfs.c | ||
| blk-throttle.c | ||
| blk-timeout.c | ||
| blk-wbt.c | ||
| blk-wbt.h | ||
| blk-zoned.c | ||
| blk.h | ||
| bounce.c | ||
| bsg-lib.c | ||
| bsg.c | ||
| cmdline-parser.c | ||
| elevator.c | ||
| genhd.c | ||
| ioctl.c | ||
| ioprio.c | ||
| Kconfig | ||
| Kconfig.iosched | ||
| keyslot-manager.c | ||
| kyber-iosched.c | ||
| Makefile | ||
| mq-deadline.c | ||
| opal_proto.h | ||
| scsi_ioctl.c | ||
| sed-opal.c | ||
| t10-pi.c | ||