bdev/qos: add the QoS setting in conf file

For application like vhost/iSCSI target/NVMe-oF target/etc,
a new section as below can be added for the QoS rate limiting.

[QoS]
  Limit_IOPS Malloc0 100000
  Limit_IOPS Nvme0n1 500000

Also added a sample change at test/lib/bdev/bdev.conf.in

Change-Id: I7c7d951fbe1352ca2571f135c657bc4fa43b56c7
Signed-off-by: GangCao <gang.cao@intel.com>
Reviewed-on: https://review.gerrithub.io/393221
Reviewed-by: Shuhei Matsumoto <shuhei.matsumoto.xt@hitachi.com>
Tested-by: SPDK Automated Test System <sys_sgsw@intel.com>
Reviewed-by: Daniel Verkamp <daniel.verkamp@intel.com>

lib/bdev/bdev.c

@@ -35,6 +35,7 @@
 #include "spdk/stdinc.h"
 
 #include "spdk/bdev.h"
+#include "spdk/conf.h"
 
 #include "spdk/env.h"
 #include "spdk/event.h"
@@ -64,6 +65,7 @@ int __itt_init_ittlib(const char *, __itt_group_id);
 #define SPDK_BDEV_QOS_TIMESLICE_IN_USEC		1000
 #define SPDK_BDEV_SEC_TO_USEC			1000000ULL
 #define SPDK_BDEV_QOS_MIN_IO_PER_TIMESLICE	1
+#define SPDK_BDEV_QOS_MIN_IOS_PER_SEC		10000
 
 typedef TAILQ_HEAD(, spdk_bdev_io) bdev_io_tailq_t;
 typedef STAILQ_HEAD(, spdk_bdev_io) bdev_io_stailq_t;
@@ -2400,6 +2402,52 @@ spdk_bdev_io_get_thread(struct spdk_bdev_io *bdev_io)
 	return spdk_io_channel_get_thread(bdev_io->ch->channel);
 }
 
+static void
+_spdk_bdev_qos_config(struct spdk_bdev *bdev)
+{
+	struct spdk_conf_section	*sp = NULL;
+	const char			*val = NULL;
+	int				ios_per_sec = 0;
+	int				i = 0;
+
+	sp = spdk_conf_find_section(NULL, "QoS");
+	if (!sp) {
+		return;
+	}
+
+	while (true) {
+		val = spdk_conf_section_get_nmval(sp, "Limit_IOPS", i, 0);
+		if (!val) {
+			break;
+		}
+
+		if (strcmp(bdev->name, val) != 0) {
+			i++;
+			continue;
+		}
+
+		val = spdk_conf_section_get_nmval(sp, "Limit_IOPS", i, 1);
+		if (!val) {
+			return;
+		}
+
+		ios_per_sec = (int)strtol(val, NULL, 10);
+		if (ios_per_sec > 0) {
+			if (ios_per_sec % SPDK_BDEV_QOS_MIN_IOS_PER_SEC) {
+				SPDK_ERRLOG("Assigned IOPS %u on bdev %s is not multiple of %u\n",
+					    ios_per_sec, bdev->name, SPDK_BDEV_QOS_MIN_IOS_PER_SEC);
+				SPDK_ERRLOG("Failed to enable QoS on this bdev %s\n", bdev->name);
+			} else {
+				bdev->ios_per_sec = (uint64_t)ios_per_sec;
+				SPDK_DEBUGLOG(SPDK_LOG_BDEV, "Bdev:%s QoS:%lu\n",
+					      bdev->name, bdev->ios_per_sec);
+			}
+		}
+
+		return;
+	}
+}
+
 static int
 spdk_bdev_init(struct spdk_bdev *bdev)
 {
@@ -2423,6 +2471,8 @@ spdk_bdev_init(struct spdk_bdev *bdev)
 
 	bdev->reset_in_progress = NULL;
 
+	_spdk_bdev_qos_config(bdev);
+
 	spdk_io_device_register(__bdev_to_io_dev(bdev),
 				spdk_bdev_channel_create, spdk_bdev_channel_destroy,
 				sizeof(struct spdk_bdev_channel));

test/bdev/bdev.conf.in

@@ -20,3 +20,15 @@
 
 [Ioat]
   Disable Yes
+
+[QoS]
+  # QoS section defines limitation on performance
+  # metric like IOPS
+  #
+  # Format: Limit_IOPS Bdev_Name IOPS_Limit_Value
+  #
+  # IOPS limit must be 10000 or greater and be multiple
+  # of 10000
+  #
+  # Assign 20000 IOPS for the Malloc0 block device
+  Limit_IOPS Malloc0 20000

test/unit/lib/bdev/bdev.c/bdev_ut.c

@@ -41,6 +41,20 @@
 
 #include "bdev/bdev.c"
 
+/* Return NULL to test hardcoded defaults. */
+struct spdk_conf_section *
+spdk_conf_find_section(struct spdk_conf *cp, const char *name)
+{
+	return NULL;
+}
+
+/* Return NULL to test hardcoded defaults. */
+char *
+spdk_conf_section_get_nmval(struct spdk_conf_section *sp, const char *key, int idx1, int idx2)
+{
+	return NULL;
+}
+
 void
 spdk_scsi_nvme_translate(const struct spdk_bdev_io *bdev_io,
 			 int *sc, int *sk, int *asc, int *ascq)

test/unit/lib/bdev/mt/bdev.c/bdev_ut.c

@@ -47,6 +47,20 @@
 DEFINE_STUB_V(spdk_scsi_nvme_translate, (const struct spdk_bdev_io *bdev_io,
 		int *sc, int *sk, int *asc, int *ascq));
 
+/* Return NULL to test hardcoded defaults. */
+struct spdk_conf_section *
+spdk_conf_find_section(struct spdk_conf *cp, const char *name)
+{
+	return NULL;
+}
+
+/* Return NULL to test hardcoded defaults. */
+char *
+spdk_conf_section_get_nmval(struct spdk_conf_section *sp, const char *key, int idx1, int idx2)
+{
+	return NULL;
+}
+
 struct ut_bdev {
 	struct spdk_bdev	bdev;
 	void			*io_target;

test/unit/lib/bdev/part.c/part_ut.c

@@ -42,6 +42,20 @@
 #include "bdev/bdev.c"
 #include "bdev/part.c"
 
+/* Return NULL to test hardcoded defaults. */
+struct spdk_conf_section *
+spdk_conf_find_section(struct spdk_conf *cp, const char *name)
+{
+	return NULL;
+}
+
+/* Return NULL to test hardcoded defaults. */
+char *
+spdk_conf_section_get_nmval(struct spdk_conf_section *sp, const char *key, int idx1, int idx2)
+{
+	return NULL;
+}
+
 void
 spdk_scsi_nvme_translate(const struct spdk_bdev_io *bdev_io,
 			 int *sc, int *sk, int *asc, int *ascq)