commit 58a2e3f5c37be02dac3086b81bdda9414b931edf
author Stefan Hajnoczi <stefanha@redhat.com> Mon May 01 13:34:43 2023 -0400
committer Kevin Wolf <kwolf@redhat.com> Wed May 10 14:16:54 2023 +0200
tree c7d848ec1ee79f0b784decade1800867e67f0315
parent e19b157f3c66c44e3b89cb50a2030f0187b968e9

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>

meson.build

diff --git a/meson.build b/meson.build
index c56e0fe..6465554 100644
--- a/meson.build
+++ b/meson.build
@@ -1963,6 +1963,7 @@
   have_coroutine_pool = false
 endif
 config_host_data.set10('CONFIG_COROUTINE_POOL', have_coroutine_pool)
+config_host_data.set('CONFIG_DEBUG_GRAPH_LOCK', get_option('debug_graph_lock'))
 config_host_data.set('CONFIG_DEBUG_MUTEX', get_option('debug_mutex'))
 config_host_data.set('CONFIG_DEBUG_STACK_USAGE', get_option('debug_stack_usage'))
 config_host_data.set('CONFIG_GPROF', get_option('gprof'))
@@ -3841,6 +3842,7 @@
 summary_info += {'static build':      config_host.has_key('CONFIG_STATIC')}
 summary_info += {'malloc trim support': has_malloc_trim}
 summary_info += {'membarrier':        have_membarrier}
+summary_info += {'debug graph lock':  get_option('debug_graph_lock')}
 summary_info += {'debug stack usage': get_option('debug_stack_usage')}
 summary_info += {'mutex debugging':   get_option('debug_mutex')}
 summary_info += {'memory allocator':  get_option('malloc')}