[RHEL7,COMMIT] target/iscsi: add an ability to set io limits for iscsi targets

Submitted by Konstantin Khorenko on March 15, 2018, 12:34 p.m.

Details

Message ID 201803151234.w2FCYK67013795@finist_ce7.work
State New
Series "target/iscsi: add an ability to set io limits for iscsi targets"
Headers show

Commit Message

Konstantin Khorenko March 15, 2018, 12:34 p.m.
The commit is pushed to "branch-rh7-3.10.0-693.17.1.vz7.45.x-ovz" and will appear at https://src.openvz.org/scm/ovz/vzkernel.git
after rh7-3.10.0-693.17.1.vz7.45.7
------>
commit 69522a6e5628c209ad47e09fcae5275749a952e9
Author: Andrei Vagin <avagin@openvz.org>
Date:   Thu Mar 15 15:34:20 2018 +0300

    target/iscsi: add an ability to set io limits for iscsi targets
    
    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@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(-)

Patch hide | download patch | download mbox

diff --git a/drivers/target/iscsi/iscsi_target_configfs.c b/drivers/target/iscsi/iscsi_target_configfs.c
index e6631abc9d0c..6d754cfe3fc4 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 c20b561f759f..4f594164ce47 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;
 out_tx:
 	send_sig(SIGINT, conn->tx_thread, 1);
 	kthread_stop(conn->tx_thread);
@@ -753,6 +782,9 @@  int iscsit_start_kthreads(struct iscsi_conn *conn)
 	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 2426b0bae643..792d3eecc16f 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 b2f49c0fd13a..416b9290ef28 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 3e3b2f9e902b..83eb63bbec0d 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 dd808689aee6..e17e9529b2fd 100644
--- a/kernel/cgroup.c
+++ b/kernel/cgroup.c
@@ -5927,6 +5927,7 @@  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)
 {