This reverts two commits: 671326201dac8fe91222ba0045709f04a8ec3af4 1b1f4ab69c41279a45ccd0d3178e83471e6e4ec1
Meanwhile it adds an entry to removed-features.rst for the query-migrationthreads QMP command. This patch originates from another patchset [1] that wanted to cleanup the interface and add corresponding HMP command, as lots of things are missing in the query report; so far it only reports the main thread and multifd sender threads; all the rest migration threads are not reported, including multifd recv threads. As pointed out by Dan in the follow up discussions [1], the API is designed in an awkward way where CPU pinning may not cover the whole lifecycle of even the thread being reported. When asked, we also didn't get chance to hear from the developer who introduced this feature to explain how this API can be properly used. OTOH, this feature from debugging POV isn't very helpful either, as all these information can be easily obtained by GDB. Esepcially, if with "-name $VM,debug-threads=on" we do already have names for each migration threads (which covers more than multifd sender threads). So it looks like the API isn't helpful in any form as of now, besides it only adds maintenance burden to migration code, even if not much. Considering that so far there's totally no justification on how to use this interface correctly, let's remove this interface instead of cleaning it up. In this special case, we even go beyond normal deprecation procedure, because a deprecation process would only make sense when there are existing users. In this specific case, we expect zero serious users with this API. [1] https://lore.kernel.org/qemu-devel/20240930195837.825728-1-pet...@redhat.com/ Cc: Jiang Jiacheng <jiangjiach...@huawei.com> Signed-off-by: Peter Xu <pet...@redhat.com> --- docs/about/removed-features.rst | 6 ++++ qapi/migration.json | 27 -------------- migration/threadinfo.h | 25 ------------- migration/migration.c | 6 ---- migration/multifd.c | 5 --- migration/threadinfo.c | 64 --------------------------------- migration/meson.build | 1 - 7 files changed, 6 insertions(+), 128 deletions(-) delete mode 100644 migration/threadinfo.h delete mode 100644 migration/threadinfo.c diff --git a/docs/about/removed-features.rst b/docs/about/removed-features.rst index c76b91a88d..02ca43dec7 100644 --- a/docs/about/removed-features.rst +++ b/docs/about/removed-features.rst @@ -693,6 +693,12 @@ Use ``multifd-channels`` instead. Use ``multifd-compression`` instead. +``query-migrationthreads`` (removed in 9.2) +''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''' + +Removed with no replacement. For debugging purpose, please use ``-name +$VM,debug-threads=on`` instead. + QEMU Machine Protocol (QMP) events ---------------------------------- diff --git a/qapi/migration.json b/qapi/migration.json index 3af6aa1740..5520a51553 100644 --- a/qapi/migration.json +++ b/qapi/migration.json @@ -2264,33 +2264,6 @@ { 'command': 'query-vcpu-dirty-limit', 'returns': [ 'DirtyLimitInfo' ] } -## -# @MigrationThreadInfo: -# -# Information about migrationthreads -# -# @name: the name of migration thread -# -# @thread-id: ID of the underlying host thread -# -# Since: 7.2 -## -{ 'struct': 'MigrationThreadInfo', - 'data': {'name': 'str', - 'thread-id': 'int'} } - -## -# @query-migrationthreads: -# -# Returns information of migration threads -# -# Returns: @MigrationThreadInfo -# -# Since: 7.2 -## -{ 'command': 'query-migrationthreads', - 'returns': ['MigrationThreadInfo'] } - ## # @snapshot-save: # diff --git a/migration/threadinfo.h b/migration/threadinfo.h deleted file mode 100644 index 2f356ff312..0000000000 --- a/migration/threadinfo.h +++ /dev/null @@ -1,25 +0,0 @@ -/* - * Migration Threads info - * - * Copyright (c) 2022 HUAWEI TECHNOLOGIES CO., LTD. - * - * Authors: - * Jiang Jiacheng <jiangjiach...@huawei.com> - * - * This work is licensed under the terms of the GNU GPL, version 2 or later. - * See the COPYING file in the top-level directory. - */ - -#include "qapi/error.h" -#include "qapi/qapi-commands-migration.h" - -typedef struct MigrationThread MigrationThread; - -struct MigrationThread { - const char *name; /* the name of migration thread */ - int thread_id; /* ID of the underlying host thread */ - QLIST_ENTRY(MigrationThread) node; -}; - -MigrationThread *migration_threads_add(const char *name, int thread_id); -void migration_threads_remove(MigrationThread *info); diff --git a/migration/migration.c b/migration/migration.c index 7609e0feed..12388c451d 100644 --- a/migration/migration.c +++ b/migration/migration.c @@ -57,7 +57,6 @@ #include "net/announce.h" #include "qemu/queue.h" #include "multifd.h" -#include "threadinfo.h" #include "qemu/yank.h" #include "sysemu/cpus.h" #include "yank_functions.h" @@ -3466,16 +3465,12 @@ static void qemu_savevm_wait_unplug(MigrationState *s, int old_state, static void *migration_thread(void *opaque) { MigrationState *s = opaque; - MigrationThread *thread = NULL; int64_t setup_start = qemu_clock_get_ms(QEMU_CLOCK_HOST); MigThrError thr_error; bool urgent = false; Error *local_err = NULL; int ret; - thread = migration_threads_add(MIGRATION_THREAD_SRC_MAIN, - qemu_get_thread_id()); - rcu_register_thread(); object_ref(OBJECT(s)); @@ -3573,7 +3568,6 @@ out: migration_iteration_finish(s); object_unref(OBJECT(s)); rcu_unregister_thread(); - migration_threads_remove(thread); return NULL; } diff --git a/migration/multifd.c b/migration/multifd.c index 697fe86fdf..659022e817 100644 --- a/migration/multifd.c +++ b/migration/multifd.c @@ -26,7 +26,6 @@ #include "qemu-file.h" #include "trace.h" #include "multifd.h" -#include "threadinfo.h" #include "options.h" #include "qemu/yank.h" #include "io/channel-file.h" @@ -570,13 +569,10 @@ int multifd_send_sync_main(void) static void *multifd_send_thread(void *opaque) { MultiFDSendParams *p = opaque; - MigrationThread *thread = NULL; Error *local_err = NULL; int ret = 0; bool use_packets = multifd_use_packets(); - thread = migration_threads_add(p->name, qemu_get_thread_id()); - trace_multifd_send_thread_start(p->id); rcu_register_thread(); @@ -669,7 +665,6 @@ out: } rcu_unregister_thread(); - migration_threads_remove(thread); trace_multifd_send_thread_end(p->id, p->packets_sent); return NULL; diff --git a/migration/threadinfo.c b/migration/threadinfo.c deleted file mode 100644 index 262990dd75..0000000000 --- a/migration/threadinfo.c +++ /dev/null @@ -1,64 +0,0 @@ -/* - * Migration Threads info - * - * Copyright (c) 2022 HUAWEI TECHNOLOGIES CO., LTD. - * - * Authors: - * Jiang Jiacheng <jiangjiach...@huawei.com> - * - * This work is licensed under the terms of the GNU GPL, version 2 or later. - * See the COPYING file in the top-level directory. - */ - -#include "qemu/osdep.h" -#include "qemu/queue.h" -#include "qemu/lockable.h" -#include "threadinfo.h" - -QemuMutex migration_threads_lock; -static QLIST_HEAD(, MigrationThread) migration_threads; - -static void __attribute__((constructor)) migration_threads_init(void) -{ - qemu_mutex_init(&migration_threads_lock); -} - -MigrationThread *migration_threads_add(const char *name, int thread_id) -{ - MigrationThread *thread = g_new0(MigrationThread, 1); - thread->name = name; - thread->thread_id = thread_id; - - WITH_QEMU_LOCK_GUARD(&migration_threads_lock) { - QLIST_INSERT_HEAD(&migration_threads, thread, node); - } - - return thread; -} - -void migration_threads_remove(MigrationThread *thread) -{ - QEMU_LOCK_GUARD(&migration_threads_lock); - if (thread) { - QLIST_REMOVE(thread, node); - g_free(thread); - } -} - -MigrationThreadInfoList *qmp_query_migrationthreads(Error **errp) -{ - MigrationThreadInfoList *head = NULL; - MigrationThreadInfoList **tail = &head; - MigrationThread *thread = NULL; - - QEMU_LOCK_GUARD(&migration_threads_lock); - QLIST_FOREACH(thread, &migration_threads, node) { - MigrationThreadInfo *info = g_new0(MigrationThreadInfo, 1); - info->name = g_strdup(thread->name); - info->thread_id = thread->thread_id; - - QAPI_LIST_APPEND(tail, info); - } - - return head; -} diff --git a/migration/meson.build b/migration/meson.build index 66d3de86f0..28a680e5e2 100644 --- a/migration/meson.build +++ b/migration/meson.build @@ -29,7 +29,6 @@ system_ss.add(files( 'savevm.c', 'socket.c', 'tls.c', - 'threadinfo.c', ), gnutls, zlib) if get_option('replication').allowed() -- 2.45.0
