[Devel] [PATCH] target/iscsi: add an ability to set io limits for iscsi targets
Vasily Averin
vvs at virtuozzo.com
Wed Mar 14 11:01:43 MSK 2018
See small comment below
On 2018-03-14 01:48, Andrei Vagin wrote:
> This patch add an ability to set a blkio cgroup for an iscsi target.
>
> When a new client is connected, the kernel creates two kernel threads and
> run all io requests from them, this means that we can set a blkio group
> for these threads and set io limits via this group.
>
> Here is an exampe how this works:
>
> $ TGT_PATH=/sys/kernel/config/target/iscsi/iqn.2014-06.com.vstorage\:test
> $ CG_PATH=/sys/fs/cgroup/blkio/system.slice/vstorage-iscsi/
>
> # create a group
> $ mkdir -p $CG_PATH
>
> # set cgroup for iscsi target
> $ bash -c 'echo $$ > $CG_PATH/tasks &&
> echo 1 > $TGT_PATH/tpgt_1/param/BlkioCgroup'
> $ cat $TGT_PATH/tpgt_1/param/BlkioCgroup
> /system.slice/vstorage-iscsi
>
> # attach iscsi target
> $ IQN=iqn.2014-06.com.vstorage:test
> $ iscsiadm -m node -T $IQN -l
> Logging in to [iface: default, target: iqn.2014-06.com.vstorage:test,
> portal: 10.94.120.187,3260] (multiple)
> Login to [iface: default, target: iqn.2014-06.com.vstorage:test, portal:
> 10.94.120.187,3260] successful.
>
> # check that iscsi threads in the required cgroup
> $ ps -C iscsi_ttx
> PID TTY TIME CMD
> 4097 ? 00:00:00 iscsi_ttx
> $ cat /proc/4097/cgroup | grep blkio
> 1:blkio:/system.slice/vstorage-iscsi
>
> # set io limits for a target backing store device
> $ ploop list
> ploop15810 /mnt/vstorage/vols/iscsi/iqn.2014-06.com.vstorage:test/lun1/ploop
> $ ls -l /dev/ploop15810
> brw-rw---- 1 root disk 182, 252960 Mar 14 00:59 /dev/ploop15810
> $ echo "182:252960 6291456" > $CG_PATH/blkio.throttle.read_bps_device
>
> # check that limits work as expected
> $ dd if=/dev/sda of=/dev/null bs=10M count=10
> 10+0 records in
> 10+0 records out
> 104857600 bytes (105 MB) copied, 17.3534 s, 6.0 MB/s
>
> Signed-off-by: Andrei Vagin <avagin at openvz.org>
> ---
> drivers/target/iscsi/iscsi_target_configfs.c | 46 ++++++++++++++++++++++++++++
> drivers/target/iscsi/iscsi_target_login.c | 34 +++++++++++++++++++-
> drivers/target/iscsi/iscsi_target_tpg.c | 36 ++++++++++++++++++++++
> drivers/target/iscsi/iscsi_target_tpg.h | 2 ++
> include/target/iscsi/iscsi_target_core.h | 2 ++
> kernel/cgroup.c | 1 +
> 6 files changed, 120 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/target/iscsi/iscsi_target_configfs.c b/drivers/target/iscsi/iscsi_target_configfs.c
> index e6631ab..6d754cf 100644
> --- a/drivers/target/iscsi/iscsi_target_configfs.c
> +++ b/drivers/target/iscsi/iscsi_target_configfs.c
> @@ -1412,6 +1412,51 @@ TPG_PARAM_ATTR(IFMarkInt, S_IRUGO | S_IWUSR);
> DEF_TPG_PARAM(OFMarkInt);
> TPG_PARAM_ATTR(OFMarkInt, S_IRUGO | S_IWUSR);
>
> +static ssize_t iscsi_tpg_param_show_BlkioCgroup(
> + struct se_portal_group *se_tpg,
> + char *page)
> +{
> + struct iscsi_portal_group *tpg = container_of(se_tpg,
> + struct iscsi_portal_group, tpg_se_tpg);
> + ssize_t rb;
> +
> + if (iscsit_get_tpg(tpg) < 0)
> + return -EINVAL;
> +
> + rb = iscsit_ta_tpg_show_blkcg(tpg, page);
> + iscsit_put_tpg(tpg);
> + return rb;
> +}
> +
> +static ssize_t iscsi_tpg_param_store_BlkioCgroup(
> + struct se_portal_group *se_tpg,
> + const char *page,
> + size_t count)
> +{
> + struct iscsi_portal_group *tpg = container_of(se_tpg,
> + struct iscsi_portal_group, tpg_se_tpg);
> + u32 val;
> + int ret;
> +
> + if (iscsit_get_tpg(tpg) < 0)
> + return -EINVAL;
> +
> + ret = kstrtou32(page, 0, &val);
> + if (ret)
> + goto out;
> + ret = iscsit_ta_tpg_set_blkcg(tpg, val);
> + if (ret < 0)
> + goto out;
> +
> + iscsit_put_tpg(tpg);
> + return count;
> +out:
> + iscsit_put_tpg(tpg);
> + return ret;
> +}
> +
> +TPG_PARAM_ATTR(BlkioCgroup, S_IRUGO | S_IWUSR);
> +
> static struct configfs_attribute *lio_target_tpg_param_attrs[] = {
> &iscsi_tpg_param_AuthMethod.attr,
> &iscsi_tpg_param_HeaderDigest.attr,
> @@ -1434,6 +1479,7 @@ static struct configfs_attribute *lio_target_tpg_param_attrs[] = {
> &iscsi_tpg_param_OFMarker.attr,
> &iscsi_tpg_param_IFMarkInt.attr,
> &iscsi_tpg_param_OFMarkInt.attr,
> + &iscsi_tpg_param_BlkioCgroup.attr,
> NULL,
> };
>
> diff --git a/drivers/target/iscsi/iscsi_target_login.c b/drivers/target/iscsi/iscsi_target_login.c
> index c20b561..4f59416 100644
> --- a/drivers/target/iscsi/iscsi_target_login.c
> +++ b/drivers/target/iscsi/iscsi_target_login.c
> @@ -20,6 +20,7 @@
> #include <linux/string.h>
> #include <linux/kthread.h>
> #include <linux/idr.h>
> +#include <linux/cgroup.h>
> #include <scsi/iscsi_proto.h>
> #include <target/target_core_base.h>
> #include <target/target_core_fabric.h>
> @@ -712,8 +713,18 @@ static void iscsi_post_login_start_timers(struct iscsi_conn *conn)
>
> int iscsit_start_kthreads(struct iscsi_conn *conn)
> {
> + struct iscsi_portal_group *tpg = conn->tpg;
> + struct cgroup_subsys_state *blk_css = NULL;
> int ret = 0;
>
> + if (iscsit_get_tpg(tpg) < 0)
> + return -EINVAL;
> + if (tpg->blk_css) {
> + blk_css = tpg->blk_css;
> + css_get(blk_css);
> + }
> + iscsit_put_tpg(tpg);
> +
> spin_lock(&iscsit_global->ts_bitmap_lock);
> conn->bitmap_id = bitmap_find_free_region(iscsit_global->ts_bitmap,
> ISCSIT_BITMAP_BITS, get_order(1));
> @@ -722,7 +733,8 @@ int iscsit_start_kthreads(struct iscsi_conn *conn)
> if (conn->bitmap_id < 0) {
> pr_err("bitmap_find_free_region() failed for"
> " iscsit_start_kthreads()\n");
> - return -ENOMEM;
> + ret = -ENOMEM;
> + goto put_blk_css;
> }
>
> conn->tx_thread = kthread_run(iscsi_target_tx_thread, conn,
> @@ -732,6 +744,11 @@ int iscsit_start_kthreads(struct iscsi_conn *conn)
> ret = PTR_ERR(conn->tx_thread);
> goto out_bitmap;
> }
> + if (blk_css) {
> + ret = cgroup_kernel_attach(blk_css->cgroup, conn->tx_thread);
> + if (ret < 0)
> + goto out_tx;
> + }
> conn->tx_thread_active = true;
>
> conn->rx_thread = kthread_run(iscsi_target_rx_thread, conn,
> @@ -741,9 +758,21 @@ int iscsit_start_kthreads(struct iscsi_conn *conn)
> ret = PTR_ERR(conn->rx_thread);
> goto out_tx;
> }
> + if (blk_css) {
> + ret = cgroup_kernel_attach(blk_css->cgroup, conn->rx_thread);
> + if (ret < 0)
> + goto out_rx;
> + }
> conn->rx_thread_active = true;
>
> + if (blk_css)
> + css_put(blk_css);
> +
> return 0;
> +out_rx:
> + send_sig(SIGINT, conn->rx_thread, 1);
> + kthread_stop(conn->rx_thread);
> + conn->rx_thread_active = false;
Seems rx_thread_active = false can be skipped here,
it is set to true in success case only,
after goto to this label.
> out_tx:
> send_sig(SIGINT, conn->tx_thread, 1);
> kthread_stop(conn->tx_thread);
> @@ -753,6 +782,9 @@ out_bitmap:
> bitmap_release_region(iscsit_global->ts_bitmap, conn->bitmap_id,
> get_order(1));
> spin_unlock(&iscsit_global->ts_bitmap_lock);
> +put_blk_css:
> + if (blk_css)
> + css_put(blk_css);
> return ret;
> }
>
> diff --git a/drivers/target/iscsi/iscsi_target_tpg.c b/drivers/target/iscsi/iscsi_target_tpg.c
> index 2426b0b..792d3ee 100644
> --- a/drivers/target/iscsi/iscsi_target_tpg.c
> +++ b/drivers/target/iscsi/iscsi_target_tpg.c
> @@ -16,6 +16,7 @@
> * GNU General Public License for more details.
> ******************************************************************************/
>
> +#include <linux/cgroup.h>
> #include <target/target_core_base.h>
> #include <target/target_core_fabric.h>
> #include <target/target_core_configfs.h>
> @@ -303,6 +304,9 @@ int iscsit_tpg_del_portal_group(
> list_del(&tpg->tpg_list);
> spin_unlock(&tiqn->tiqn_tpg_lock);
>
> + if (tpg->blk_css)
> + css_put(tpg->blk_css);
> +
> pr_debug("CORE[%s]_TPG[%hu] - Deleted iSCSI Target Portal Group\n",
> tiqn->tiqn, tpg->tpgt);
>
> @@ -896,3 +900,35 @@ int iscsit_ta_tpg_enabled_sendtargets(
>
> return 0;
> }
> +
> +int iscsit_ta_tpg_set_blkcg(struct iscsi_portal_group *tpg, u32 flag)
> +{
> + struct cgroup_subsys_state *css;
> +
> + if (flag != 1)
> + return -EINVAL;
> +
> + css = task_get_css(current, blkio_subsys_id);
> + if (tpg->blk_css)
> + css_put(tpg->blk_css);
> + tpg->blk_css = css;
> +
> + return 0;
> +}
> +
> +int iscsit_ta_tpg_show_blkcg(struct iscsi_portal_group *tpg, char *page)
> +{
> + int rb;
> +
> + if (tpg->blk_css) {
> + rb = cgroup_path(tpg->blk_css->cgroup, page, PAGE_SIZE - 1);
> + if (rb == 0)
> + rb = strlen(page);
> + page[rb] = '\n';
> + page[rb + 1] = 0;
> + rb++;
> + } else
> + rb = 0;
> +
> + return rb;
> +}
> diff --git a/drivers/target/iscsi/iscsi_target_tpg.h b/drivers/target/iscsi/iscsi_target_tpg.h
> index b2f49c0..416b929 100644
> --- a/drivers/target/iscsi/iscsi_target_tpg.h
> +++ b/drivers/target/iscsi/iscsi_target_tpg.h
> @@ -40,5 +40,7 @@ extern int iscsit_ta_demo_mode_discovery(struct iscsi_portal_group *, u32);
> extern int iscsit_ta_default_erl(struct iscsi_portal_group *, u32);
> extern int iscsit_ta_t10_pi(struct iscsi_portal_group *, u32);
> extern int iscsit_ta_tpg_enabled_sendtargets(struct iscsi_portal_group *, u32);
> +extern int iscsit_ta_tpg_set_blkcg(struct iscsi_portal_group *tpg, u32 flag);
> +extern int iscsit_ta_tpg_show_blkcg(struct iscsi_portal_group *tpg, char *page);
>
> #endif /* ISCSI_TARGET_TPG_H */
> diff --git a/include/target/iscsi/iscsi_target_core.h b/include/target/iscsi/iscsi_target_core.h
> index 3e3b2f9..83eb63b 100644
> --- a/include/target/iscsi/iscsi_target_core.h
> +++ b/include/target/iscsi/iscsi_target_core.h
> @@ -838,6 +838,8 @@ struct iscsi_portal_group {
> struct iscsi_tiqn *tpg_tiqn;
> struct list_head tpg_gnp_list;
> struct list_head tpg_list;
> +
> + struct cgroup_subsys_state *blk_css;
> } ____cacheline_aligned;
>
> struct iscsi_wwn_stat_grps {
> diff --git a/kernel/cgroup.c b/kernel/cgroup.c
> index 11c547f..0fbb37e 100644
> --- a/kernel/cgroup.c
> +++ b/kernel/cgroup.c
> @@ -5924,6 +5924,7 @@ int cgroup_kernel_attach(struct cgroup *cgrp, struct task_struct *tsk)
> mutex_unlock(&cgroup_mutex);
> return ret;
> }
> +EXPORT_SYMBOL_GPL(cgroup_kernel_attach);
>
> void cgroup_kernel_close(struct cgroup *cgrp)
> {
>
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