From 415ccd9811da38aed04f54051c8ae87699c4e6c2 Mon Sep 17 00:00:00 2001 From: Mike Christie Date: Sat, 27 Feb 2021 11:00:03 -0600 Subject: [PATCH] scsi: target: iblock: Add backend plug/unplug callouts This patch adds plug/unplug callouts for iblock. For an initiator driver like iSCSI which wants to pass multiple cmds to its xmit thread instead of one cmd at a time, this increases IOPS by around 10% with vhost-scsi (combined with the last patches we can see a total 40-50% increase). For driver combos like tcm_loop and faster drivers like the iSER initiator, we can still see IOPS increase by 20-30% when tcm_loop's nr_hw_queues setting is also increased. Link: https://lore.kernel.org/r/20210227170006.5077-23-michael.christie@oracle.com Signed-off-by: Mike Christie Signed-off-by: Martin K. Petersen --- drivers/target/target_core_iblock.c | 44 ++++++++++++++++++++++++++++++++++++- drivers/target/target_core_iblock.h | 10 +++++++++ 2 files changed, 53 insertions(+), 1 deletion(-) diff --git a/drivers/target/target_core_iblock.c b/drivers/target/target_core_iblock.c index ee3d520..90e1c65 100644 --- a/drivers/target/target_core_iblock.c +++ b/drivers/target/target_core_iblock.c @@ -61,9 +61,18 @@ static struct se_device *iblock_alloc_device(struct se_hba *hba, const char *nam return NULL; } + ib_dev->ibd_plug = kcalloc(nr_cpu_ids, sizeof(*ib_dev->ibd_plug), + GFP_KERNEL); + if (!ib_dev->ibd_plug) + goto free_dev; + pr_debug( "IBLOCK: Allocated ib_dev for %s\n", name); return &ib_dev->dev; + +free_dev: + kfree(ib_dev); + return NULL; } static int iblock_configure_device(struct se_device *dev) @@ -171,6 +180,7 @@ static void iblock_dev_call_rcu(struct rcu_head *p) struct se_device *dev = container_of(p, struct se_device, rcu_head); struct iblock_dev *ib_dev = IBLOCK_DEV(dev); + kfree(ib_dev->ibd_plug); kfree(ib_dev); } @@ -188,6 +198,33 @@ static void iblock_destroy_device(struct se_device *dev) bioset_exit(&ib_dev->ibd_bio_set); } +static struct se_dev_plug *iblock_plug_device(struct se_device *se_dev) +{ + struct iblock_dev *ib_dev = IBLOCK_DEV(se_dev); + struct iblock_dev_plug *ib_dev_plug; + + /* + * Each se_device has a per cpu work this can be run from. Wwe + * shouldn't have multiple threads on the same cpu calling this + * at the same time. + */ + ib_dev_plug = &ib_dev->ibd_plug[smp_processor_id()]; + if (test_and_set_bit(IBD_PLUGF_PLUGGED, &ib_dev_plug->flags)) + return NULL; + + blk_start_plug(&ib_dev_plug->blk_plug); + return &ib_dev_plug->se_plug; +} + +static void iblock_unplug_device(struct se_dev_plug *se_plug) +{ + struct iblock_dev_plug *ib_dev_plug = container_of(se_plug, + struct iblock_dev_plug, se_plug); + + blk_finish_plug(&ib_dev_plug->blk_plug); + clear_bit(IBD_PLUGF_PLUGGED, &ib_dev_plug->flags); +} + static unsigned long long iblock_emulate_read_cap_with_block_size( struct se_device *dev, struct block_device *bd, @@ -335,7 +372,10 @@ static void iblock_submit_bios(struct bio_list *list) { struct blk_plug plug; struct bio *bio; - + /* + * The block layer handles nested plugs, so just plug/unplug to handle + * fabric drivers that didn't support batching and multi bio cmds. + */ blk_start_plug(&plug); while ((bio = bio_list_pop(list))) submit_bio(bio); @@ -867,6 +907,8 @@ static const struct target_backend_ops iblock_ops = { .configure_device = iblock_configure_device, .destroy_device = iblock_destroy_device, .free_device = iblock_free_device, + .plug_device = iblock_plug_device, + .unplug_device = iblock_unplug_device, .parse_cdb = iblock_parse_cdb, .set_configfs_dev_params = iblock_set_configfs_dev_params, .show_configfs_dev_params = iblock_show_configfs_dev_params, diff --git a/drivers/target/target_core_iblock.h b/drivers/target/target_core_iblock.h index cefc641..8c55375 100644 --- a/drivers/target/target_core_iblock.h +++ b/drivers/target/target_core_iblock.h @@ -4,6 +4,7 @@ #include #include +#include #include #define IBLOCK_VERSION "4.0" @@ -17,6 +18,14 @@ struct iblock_req { #define IBDF_HAS_UDEV_PATH 0x01 +#define IBD_PLUGF_PLUGGED 0x01 + +struct iblock_dev_plug { + struct se_dev_plug se_plug; + struct blk_plug blk_plug; + unsigned long flags; +}; + struct iblock_dev { struct se_device dev; unsigned char ibd_udev_path[SE_UDEV_PATH_LEN]; @@ -24,6 +33,7 @@ struct iblock_dev { struct bio_set ibd_bio_set; struct block_device *ibd_bd; bool ibd_readonly; + struct iblock_dev_plug *ibd_plug; } ____cacheline_aligned; #endif /* TARGET_CORE_IBLOCK_H */ -- 2.7.4