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From: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
To: qemu-block@nongnu.org
Cc: kwolf@redhat.com, vsementsov@virtuozzo.com,
	wencongyang2@huawei.com, xiechanglong.d@gmail.com,
	qemu-devel@nongnu.org, armbru@redhat.com, jsnow@redhat.com,
	den@openvz.org, mreitz@redhat.com
Subject: [PATCH v4 06/23] block/block-copy: add ratelimit to block-copy
Date: Sun, 17 Jan 2021 00:46:48 +0300
Message-ID: <20210116214705.822267-7-vsementsov@virtuozzo.com> (raw)
In-Reply-To: <20210116214705.822267-1-vsementsov@virtuozzo.com>

We are going to directly use one async block-copy operation for backup
job, so we need rate limiter.

We want to maintain current backup behavior: only background copying is
limited and copy-before-write operations only participate in limit
calculation. Therefore we need one rate limiter for block-copy state
and boolean flag for block-copy call state for actual limitation.

Note, that we can't just calculate each chunk in limiter after
successful copying: it will not save us from starting a lot of async
sub-requests which will exceed limit too much. Instead let's use the
following scheme on sub-request creation:
1. If at the moment limit is not exceeded, create the request and
account it immediately.
2. If at the moment limit is already exceeded, drop create sub-request
and handle limit instead (by sleep).
With this approach we'll never exceed the limit more than by one
sub-request (which pretty much matches current backup behavior).

Note also, that if there is in-flight block-copy async call,
block_copy_kick() should be used after set-speed to apply new setup
faster. For that block_copy_kick() published in this patch.

Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
Reviewed-by: Max Reitz <mreitz@redhat.com>
---
 include/block/block-copy.h |  5 ++++-
 block/backup-top.c         |  2 +-
 block/backup.c             |  2 +-
 block/block-copy.c         | 46 +++++++++++++++++++++++++++++++++++++-
 4 files changed, 51 insertions(+), 4 deletions(-)

diff --git a/include/block/block-copy.h b/include/block/block-copy.h
index 22372aa375..b5a53ad59e 100644
--- a/include/block/block-copy.h
+++ b/include/block/block-copy.h
@@ -41,7 +41,7 @@ int64_t block_copy_reset_unallocated(BlockCopyState *s,
                                      int64_t offset, int64_t *count);
 
 int coroutine_fn block_copy(BlockCopyState *s, int64_t offset, int64_t bytes,
-                            bool *error_is_read);
+                            bool ignore_ratelimit, bool *error_is_read);
 
 /*
  * Run block-copy in a coroutine, create corresponding BlockCopyCallState
@@ -76,6 +76,9 @@ bool block_copy_call_succeeded(BlockCopyCallState *call_state);
 bool block_copy_call_failed(BlockCopyCallState *call_state);
 int block_copy_call_status(BlockCopyCallState *call_state, bool *error_is_read);
 
+void block_copy_set_speed(BlockCopyState *s, uint64_t speed);
+void block_copy_kick(BlockCopyCallState *call_state);
+
 BdrvDirtyBitmap *block_copy_dirty_bitmap(BlockCopyState *s);
 void block_copy_set_skip_unallocated(BlockCopyState *s, bool skip);
 
diff --git a/block/backup-top.c b/block/backup-top.c
index 789acf6965..779956ddc2 100644
--- a/block/backup-top.c
+++ b/block/backup-top.c
@@ -61,7 +61,7 @@ static coroutine_fn int backup_top_cbw(BlockDriverState *bs, uint64_t offset,
     off = QEMU_ALIGN_DOWN(offset, s->cluster_size);
     end = QEMU_ALIGN_UP(offset + bytes, s->cluster_size);
 
-    return block_copy(s->bcs, off, end - off, NULL);
+    return block_copy(s->bcs, off, end - off, true, NULL);
 }
 
 static int coroutine_fn backup_top_co_pdiscard(BlockDriverState *bs,
diff --git a/block/backup.c b/block/backup.c
index 4b07e9115d..09ff5a92ef 100644
--- a/block/backup.c
+++ b/block/backup.c
@@ -72,7 +72,7 @@ static int coroutine_fn backup_do_cow(BackupBlockJob *job,
 
     trace_backup_do_cow_enter(job, start, offset, bytes);
 
-    ret = block_copy(job->bcs, start, end - start, error_is_read);
+    ret = block_copy(job->bcs, start, end - start, true, error_is_read);
 
     trace_backup_do_cow_return(job, offset, bytes, ret);
 
diff --git a/block/block-copy.c b/block/block-copy.c
index 6bf1735b93..fa27450b14 100644
--- a/block/block-copy.c
+++ b/block/block-copy.c
@@ -26,6 +26,7 @@
 #define BLOCK_COPY_MAX_BUFFER (1 * MiB)
 #define BLOCK_COPY_MAX_MEM (128 * MiB)
 #define BLOCK_COPY_MAX_WORKERS 64
+#define BLOCK_COPY_SLICE_TIME 100000000ULL /* ns */
 
 static coroutine_fn int block_copy_task_entry(AioTask *task);
 
@@ -36,6 +37,7 @@ typedef struct BlockCopyCallState {
     int64_t bytes;
     int max_workers;
     int64_t max_chunk;
+    bool ignore_ratelimit;
     BlockCopyAsyncCallbackFunc cb;
     void *cb_opaque;
 
@@ -48,6 +50,7 @@ typedef struct BlockCopyCallState {
     /* State */
     int ret;
     bool finished;
+    QemuCoSleepState *sleep_state;
 
     /* OUT parameters */
     bool error_is_read;
@@ -111,6 +114,9 @@ typedef struct BlockCopyState {
     void *progress_opaque;
 
     SharedResource *mem;
+
+    uint64_t speed;
+    RateLimit rate_limit;
 } BlockCopyState;
 
 static BlockCopyTask *find_conflicting_task(BlockCopyState *s,
@@ -623,6 +629,21 @@ block_copy_dirty_clusters(BlockCopyCallState *call_state)
         }
         task->zeroes = ret & BDRV_BLOCK_ZERO;
 
+        if (s->speed) {
+            if (!call_state->ignore_ratelimit) {
+                uint64_t ns = ratelimit_calculate_delay(&s->rate_limit, 0);
+                if (ns > 0) {
+                    block_copy_task_end(task, -EAGAIN);
+                    g_free(task);
+                    qemu_co_sleep_ns_wakeable(QEMU_CLOCK_REALTIME, ns,
+                                              &call_state->sleep_state);
+                    continue;
+                }
+            }
+
+            ratelimit_calculate_delay(&s->rate_limit, task->bytes);
+        }
+
         trace_block_copy_process(s, task->offset);
 
         co_get_from_shres(s->mem, task->bytes);
@@ -661,6 +682,13 @@ out:
     return ret < 0 ? ret : found_dirty;
 }
 
+void block_copy_kick(BlockCopyCallState *call_state)
+{
+    if (call_state->sleep_state) {
+        qemu_co_sleep_wake(call_state->sleep_state);
+    }
+}
+
 /*
  * block_copy_common
  *
@@ -707,12 +735,13 @@ static int coroutine_fn block_copy_common(BlockCopyCallState *call_state)
 }
 
 int coroutine_fn block_copy(BlockCopyState *s, int64_t start, int64_t bytes,
-                            bool *error_is_read)
+                            bool ignore_ratelimit, bool *error_is_read)
 {
     BlockCopyCallState call_state = {
         .s = s,
         .offset = start,
         .bytes = bytes,
+        .ignore_ratelimit = ignore_ratelimit,
         .max_workers = BLOCK_COPY_MAX_WORKERS,
     };
 
@@ -798,3 +827,18 @@ void block_copy_set_skip_unallocated(BlockCopyState *s, bool skip)
 {
     s->skip_unallocated = skip;
 }
+
+void block_copy_set_speed(BlockCopyState *s, uint64_t speed)
+{
+    s->speed = speed;
+    if (speed > 0) {
+        ratelimit_set_speed(&s->rate_limit, speed, BLOCK_COPY_SLICE_TIME);
+    }
+
+    /*
+     * Note: it's good to kick all call states from here, but it should be done
+     * only from a coroutine, to not crash if s->calls list changed while
+     * entering one call. So for now, the only user of this function kicks its
+     * only one call_state by hand.
+     */
+}
-- 
2.29.2



  parent reply index

Thread overview: 45+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-01-16 21:46 [PATCH v4 00/23] backup performance: block_status + async Vladimir Sementsov-Ogievskiy
2021-01-16 21:46 ` [PATCH v4 01/23] qapi: backup: add perf.use-copy-range parameter Vladimir Sementsov-Ogievskiy
2021-01-16 21:46 ` [PATCH v4 02/23] block/block-copy: More explicit call_state Vladimir Sementsov-Ogievskiy
2021-01-16 21:46 ` [PATCH v4 03/23] block/block-copy: implement block_copy_async Vladimir Sementsov-Ogievskiy
2021-01-16 21:46 ` [PATCH v4 04/23] block/block-copy: add max_chunk and max_workers parameters Vladimir Sementsov-Ogievskiy
2021-01-16 21:46 ` [PATCH v4 05/23] block/block-copy: add list of all call-states Vladimir Sementsov-Ogievskiy
2021-01-16 21:46 ` Vladimir Sementsov-Ogievskiy [this message]
2021-01-16 21:46 ` [PATCH v4 07/23] block/block-copy: add block_copy_cancel Vladimir Sementsov-Ogievskiy
2021-01-16 21:46 ` [PATCH v4 08/23] blockjob: add set_speed to BlockJobDriver Vladimir Sementsov-Ogievskiy
2021-01-16 21:46 ` [PATCH v4 09/23] job: call job_enter from job_pause Vladimir Sementsov-Ogievskiy
2021-01-18 13:45   ` Max Reitz
2021-01-18 14:20     ` Max Reitz
2021-04-07 11:19   ` Max Reitz
2021-04-07 11:38     ` Vladimir Sementsov-Ogievskiy
2021-04-21  8:31       ` Vladimir Sementsov-Ogievskiy
2021-01-16 21:46 ` [PATCH v4 10/23] qapi: backup: add max-chunk and max-workers to x-perf struct Vladimir Sementsov-Ogievskiy
2021-01-16 21:46 ` [PATCH v4 11/23] iotests: 56: prepare for backup over block-copy Vladimir Sementsov-Ogievskiy
2021-01-16 21:46 ` [PATCH v4 12/23] iotests: 185: " Vladimir Sementsov-Ogievskiy
2021-01-16 21:46 ` [PATCH v4 13/23] iotests: 219: " Vladimir Sementsov-Ogievskiy
2021-01-16 21:46 ` [PATCH v4 14/23] iotests: 257: " Vladimir Sementsov-Ogievskiy
2021-01-16 21:46 ` [PATCH v4 15/23] block/block-copy: make progress_bytes_callback optional Vladimir Sementsov-Ogievskiy
2021-01-16 21:46 ` [PATCH v4 16/23] block/backup: drop extra gotos from backup_run() Vladimir Sementsov-Ogievskiy
2021-01-16 21:46 ` [PATCH v4 17/23] backup: move to block-copy Vladimir Sementsov-Ogievskiy
2021-01-16 21:47 ` [PATCH v4 18/23] qapi: backup: disable copy_range by default Vladimir Sementsov-Ogievskiy
2021-01-16 21:47 ` [PATCH v4 19/23] block/block-copy: drop unused block_copy_set_progress_callback() Vladimir Sementsov-Ogievskiy
2021-01-16 21:47 ` [PATCH v4 20/23] block/block-copy: drop unused argument of block_copy() Vladimir Sementsov-Ogievskiy
2021-01-16 21:47 ` [PATCH v4 21/23] simplebench/bench_block_job: use correct shebang line with python3 Vladimir Sementsov-Ogievskiy
2021-01-16 21:47 ` [PATCH v4 22/23] simplebench: bench_block_job: add cmd_options argument Vladimir Sementsov-Ogievskiy
2021-01-16 21:47 ` [PATCH v4 23/23] simplebench: add bench-backup.py Vladimir Sementsov-Ogievskiy
2021-01-18 14:01   ` Max Reitz
2021-01-18 15:07 ` [PATCH v4 00/23] backup performance: block_status + async Max Reitz
2021-01-18 17:04   ` Vladimir Sementsov-Ogievskiy
2021-01-19 18:40 ` Max Reitz
2021-01-19 19:22   ` Vladimir Sementsov-Ogievskiy
2021-01-19 19:29     ` Vladimir Sementsov-Ogievskiy
2021-01-20 10:39     ` Max Reitz
2021-01-20 13:50       ` Max Reitz
2021-01-20 14:34         ` Max Reitz
2021-01-20 14:44           ` Max Reitz
2021-01-20 15:53             ` Max Reitz
2021-01-20 16:00               ` Max Reitz
2021-01-20 16:04               ` Daniel P. Berrangé
2021-01-20 16:40                 ` Max Reitz
2021-01-20 10:20 ` [PATCH v4 11.5/23] iotests/129: Limit backup's max-chunk/max-workers Max Reitz
2021-01-20 11:24   ` Vladimir Sementsov-Ogievskiy

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