fsdev: add IO throttle support to fsdev devices

This patchset adds the throttle support for the 9p-local driver.
For now this functionality can be enabled only through qemu cli options.
QMP interface and support to other drivers need further extensions.
To make it simple for other 9p drivers, the throttle code has been put in
separate files.

Signed-off-by: Pradeep Jagadeesh <pradeep.jagadeesh@huawei.com>
Reviewed-by: Alberto Garcia <berto@igalia.com>
(pass extra NULL CoMutex * argument to qemu_co_queue_wait(),
 added options to qemu-options.hx, Greg Kurz)
Signed-off-by: Greg Kurz <groug@kaod.org>

1 files changed, 118 insertions, 0 deletions

diff --git a/fsdev/qemu-fsdev-throttle.c b/fsdev/qemu-fsdev-throttle.c
new file mode 100644
index 0000000..7ae4e86
--- /dev/null
+++ b/fsdev/qemu-fsdev-throttle.c
@@ -0,0 +1,118 @@
+/*
+ * Fsdev Throttle
+ *
+ * Copyright (C) 2016 Huawei Technologies Duesseldorf GmbH
+ *
+ * Author: Pradeep Jagadeesh <pradeep.jagadeesh@huawei.com>
+ *
+ * This work is licensed under the terms of the GNU GPL, version 2 or
+ * (at your option) any later version.
+ *
+ * See the COPYING file in the top-level directory for details.
+ *
+ */
+
+#include "qemu/osdep.h"
+#include "qemu/error-report.h"
+#include "qemu-fsdev-throttle.h"
+#include "qemu/iov.h"
+
+static void fsdev_throttle_read_timer_cb(void *opaque)
+{
+    FsThrottle *fst = opaque;
+    qemu_co_enter_next(&fst->throttled_reqs[false]);
+}
+
+static void fsdev_throttle_write_timer_cb(void *opaque)
+{
+    FsThrottle *fst = opaque;
+    qemu_co_enter_next(&fst->throttled_reqs[true]);
+}
+
+void fsdev_throttle_parse_opts(QemuOpts *opts, FsThrottle *fst, Error **errp)
+{
+    throttle_config_init(&fst->cfg);
+    fst->cfg.buckets[THROTTLE_BPS_TOTAL].avg =
+        qemu_opt_get_number(opts, "throttling.bps-total", 0);
+    fst->cfg.buckets[THROTTLE_BPS_READ].avg  =
+        qemu_opt_get_number(opts, "throttling.bps-read", 0);
+    fst->cfg.buckets[THROTTLE_BPS_WRITE].avg =
+        qemu_opt_get_number(opts, "throttling.bps-write", 0);
+    fst->cfg.buckets[THROTTLE_OPS_TOTAL].avg =
+        qemu_opt_get_number(opts, "throttling.iops-total", 0);
+    fst->cfg.buckets[THROTTLE_OPS_READ].avg =
+        qemu_opt_get_number(opts, "throttling.iops-read", 0);
+    fst->cfg.buckets[THROTTLE_OPS_WRITE].avg =
+        qemu_opt_get_number(opts, "throttling.iops-write", 0);
+
+    fst->cfg.buckets[THROTTLE_BPS_TOTAL].max =
+        qemu_opt_get_number(opts, "throttling.bps-total-max", 0);
+    fst->cfg.buckets[THROTTLE_BPS_READ].max  =
+        qemu_opt_get_number(opts, "throttling.bps-read-max", 0);
+    fst->cfg.buckets[THROTTLE_BPS_WRITE].max =
+        qemu_opt_get_number(opts, "throttling.bps-write-max", 0);
+    fst->cfg.buckets[THROTTLE_OPS_TOTAL].max =
+        qemu_opt_get_number(opts, "throttling.iops-total-max", 0);
+    fst->cfg.buckets[THROTTLE_OPS_READ].max =
+        qemu_opt_get_number(opts, "throttling.iops-read-max", 0);
+    fst->cfg.buckets[THROTTLE_OPS_WRITE].max =
+        qemu_opt_get_number(opts, "throttling.iops-write-max", 0);
+
+    fst->cfg.buckets[THROTTLE_BPS_TOTAL].burst_length =
+        qemu_opt_get_number(opts, "throttling.bps-total-max-length", 1);
+    fst->cfg.buckets[THROTTLE_BPS_READ].burst_length  =
+        qemu_opt_get_number(opts, "throttling.bps-read-max-length", 1);
+    fst->cfg.buckets[THROTTLE_BPS_WRITE].burst_length =
+        qemu_opt_get_number(opts, "throttling.bps-write-max-length", 1);
+    fst->cfg.buckets[THROTTLE_OPS_TOTAL].burst_length =
+        qemu_opt_get_number(opts, "throttling.iops-total-max-length", 1);
+    fst->cfg.buckets[THROTTLE_OPS_READ].burst_length =
+        qemu_opt_get_number(opts, "throttling.iops-read-max-length", 1);
+    fst->cfg.buckets[THROTTLE_OPS_WRITE].burst_length =
+        qemu_opt_get_number(opts, "throttling.iops-write-max-length", 1);
+    fst->cfg.op_size =
+        qemu_opt_get_number(opts, "throttling.iops-size", 0);
+
+    throttle_is_valid(&fst->cfg, errp);
+}
+
+void fsdev_throttle_init(FsThrottle *fst)
+{
+    if (throttle_enabled(&fst->cfg)) {
+        throttle_init(&fst->ts);
+        throttle_timers_init(&fst->tt,
+                             qemu_get_aio_context(),
+                             QEMU_CLOCK_REALTIME,
+                             fsdev_throttle_read_timer_cb,
+                             fsdev_throttle_write_timer_cb,
+                             fst);
+        throttle_config(&fst->ts, &fst->tt, &fst->cfg);
+        qemu_co_queue_init(&fst->throttled_reqs[0]);
+        qemu_co_queue_init(&fst->throttled_reqs[1]);
+    }
+}
+
+void coroutine_fn fsdev_co_throttle_request(FsThrottle *fst, bool is_write,
+                                            struct iovec *iov, int iovcnt)
+{
+    if (throttle_enabled(&fst->cfg)) {
+        if (throttle_schedule_timer(&fst->ts, &fst->tt, is_write) ||
+            !qemu_co_queue_empty(&fst->throttled_reqs[is_write])) {
+            qemu_co_queue_wait(&fst->throttled_reqs[is_write], NULL);
+        }
+
+        throttle_account(&fst->ts, is_write, iov_size(iov, iovcnt));
+
+        if (!qemu_co_queue_empty(&fst->throttled_reqs[is_write]) &&
+            !throttle_schedule_timer(&fst->ts, &fst->tt, is_write)) {
+            qemu_co_queue_next(&fst->throttled_reqs[is_write]);
+        }
+    }
+}
+
+void fsdev_throttle_cleanup(FsThrottle *fst)
+{
+    if (throttle_enabled(&fst->cfg)) {
+        throttle_timers_destroy(&fst->tt);
+    }
+}