diff options
| author | Stefan Hajnoczi <stefanha@redhat.com> | 2023-05-01 13:34:43 -0400 |
|---|---|---|
| committer | Michael Tokarev <mjt@tls.msk.ru> | 2023-05-22 20:53:40 +0300 |
| commit | 84d839e4998bf3845a2e16ea482a3da3d1598346 (patch) | |
| tree | c1236f1e5c09ddcff78a0c3a633c3b9f1eac2249 /block | |
| parent | a0b89ba8458072677d5ab5f0ebafbf6bbb2606c9 (diff) | |
block: compile out assert_bdrv_graph_readable() by default
reader_count() is a performance bottleneck because the global
aio_context_list_lock mutex causes thread contention. Put this debugging
assertion behind a new ./configure --enable-debug-graph-lock option and
disable it by default.
The --enable-debug-graph-lock option is also enabled by the more general
--enable-debug option.
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Message-Id: <20230501173443.153062-1-stefanha@redhat.com>
Reviewed-by: Kevin Wolf <kwolf@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
(cherry picked from commit 58a2e3f5c37be02dac3086b81bdda9414b931edf)
Signed-off-by: Michael Tokarev <mjt@tls.msk.ru>
(Mjt: pick this one up so the next patch which disables this applies cleanly)
Diffstat (limited to 'block')
| -rw-r--r-- | block/graph-lock.c | 3 |
1 files changed, 3 insertions, 0 deletions
diff --git a/block/graph-lock.c b/block/graph-lock.c index 454c31e691..259a7a0bde 100644 --- a/block/graph-lock.c +++ b/block/graph-lock.c @@ -265,7 +265,10 @@ void bdrv_graph_rdunlock_main_loop(void) void assert_bdrv_graph_readable(void) { + /* reader_count() is slow due to aio_context_list_lock lock contention */ +#ifdef CONFIG_DEBUG_GRAPH_LOCK assert(qemu_in_main_thread() || reader_count()); +#endif } void assert_bdrv_graph_writable(void) |