|
| From: | Het Gala |
| Subject: | Re: [PATCH 1/4] Modifying ‘migrate’ qmp command to add multi-FD socket on particular source and destination pair |
| Date: | Mon, 18 Jul 2022 20:47:53 +0530 |
| User-agent: | Mozilla/5.0 (Macintosh; Intel Mac OS X 10.15; rv:91.0) Gecko/20100101 Thunderbird/91.11.0 |
On 18/07/22 8:03 pm, Markus Armbruster wrote:
Het Gala <het.gala@nutanix.com> writes:On 18/07/22 2:05 pm, Markus Armbruster wrote:Het Gala <het.gala@nutanix.com> writes:i) Modified the format of the qemu monitor command : 'migrate' by adding a list, each element in the list consists of multi-FD connection parameters: source and destination uris and of the number of multi-fd channels between each pair. ii) Information of all multi-FD connection parameters’ list, length of the list and total number of multi-fd channels for all the connections together is stored in ‘OutgoingArgs’ struct. Suggested-by: Manish Mishra <manish.mishra@nutanix.com> Signed-off-by: Het Gala <het.gala@nutanix.com> --- include/qapi/util.h | 9 ++++++++ migration/migration.c | 47 ++++++++++++++++++++++++++++++-------- migration/socket.c | 53 ++++++++++++++++++++++++++++++++++++++++--- migration/socket.h | 17 +++++++++++++- monitor/hmp-cmds.c | 22 ++++++++++++++++-- qapi/migration.json | 43 +++++++++++++++++++++++++++++++---- 6 files changed, 170 insertions(+), 21 deletions(-) diff --git a/include/qapi/util.h b/include/qapi/util.h index 81a2b13a33..3041feb3d9 100644 --- a/include/qapi/util.h +++ b/include/qapi/util.h @@ -56,4 +56,13 @@ int parse_qapi_name(const char *name, bool complete); (tail) = &(*(tail))->next; \ } while (0) +#define QAPI_LIST_LENGTH(list) ({ \ + int _len = 0; \ + typeof(list) _elem; \ + for (_elem = list; _elem != NULL; _elem = _elem->next) { \ + _len++; \ + } \ + _len; \ +}) +Unless there is a compelling reason for open-coding this, make it a (non-inline) function.if kept as a function, the datatype of list is different every time in the qemu code, and that led to multiple copies of this function. So we decided, it would be best to keep it as a macro defined function. We would be happy to hear any suggstions to solve this problem while the function non-inline.Point taken. You could make it a function taking a GenericList *, but then you'd have to cast actual list pointers to GenericList, which isn't nice.#endif diff --git a/migration/migration.c b/migration/migration.c index 31739b2af9..c408175aeb 100644 --- a/migration/migration.c +++ b/migration/migration.c @@ -2328,13 +2328,14 @@ static bool migrate_prepare(MigrationState *s, bool blk, bool blk_inc, return true; } -void qmp_migrate(const char *uri, bool has_blk, bool blk, +void qmp_migrate(const char *uri, bool has_multi_fd_uri_list, + MigrateUriParameterList *cap, bool has_blk, bool blk, bool has_inc, bool inc, bool has_detach, bool detach, bool has_resume, bool resume, Error **errp) { Error *local_err = NULL; MigrationState *s = migrate_get_current(); - const char *p = NULL; + const char *dst_ptr = NULL; if (!migrate_prepare(s, has_blk && blk, has_inc && inc, has_resume && resume, errp)) { @@ -2348,20 +2349,46 @@ void qmp_migrate(const char *uri, bool has_blk, bool blk, } } + /* + * In case of Multi-FD migration parameters, if uri is provided, + * supports only tcp network protocol. + */ + if (has_multi_fd_uri_list) { + int length = QAPI_LIST_LENGTH(cap); + init_multifd_array(length); + for (int i = 0; i < length; i++) { + const char *p1 = NULL, *p2 = NULL; + const char *multifd_dst_uri = cap->value->destination_uri; + const char *multifd_src_uri = cap->value->source_uri; + uint8_t multifd_channels = cap->value->multifd_channels; + if (!strstart(multifd_dst_uri, "tcp:", &p1) || + !strstart(multifd_src_uri, "tcp:", &p2)) { + error_setg(errp, "multi-fd destination and multi-fd source " + "uri, both should be present and follows tcp protocol only"); + break; + } else { + store_multifd_migration_params(p1 ? p1 : multifd_dst_uri, + p2 ? p2 : multifd_src_uri, + multifd_channels, i, &local_err); + } + cap = cap->next; + } + } + migrate_protocol_allow_multi_channels(false); - if (strstart(uri, "tcp:", &p) || + if (strstart(uri, "tcp:", &dst_ptr) || strstart(uri, "unix:", NULL) || strstart(uri, "vsock:", NULL)) { migrate_protocol_allow_multi_channels(true); - socket_start_outgoing_migration(s, p ? p : uri, &local_err); + socket_start_outgoing_migration(s, dst_ptr ? dst_ptr : uri, &local_err); #ifdef CONFIG_RDMA - } else if (strstart(uri, "rdma:", &p)) { - rdma_start_outgoing_migration(s, p, &local_err); + } else if (strstart(uri, "rdma:", &dst_ptr)) { + rdma_start_outgoing_migration(s, dst_ptr, &local_err); #endif - } else if (strstart(uri, "exec:", &p)) { - exec_start_outgoing_migration(s, p, &local_err); - } else if (strstart(uri, "fd:", &p)) { - fd_start_outgoing_migration(s, p, &local_err); + } else if (strstart(uri, "exec:", &dst_ptr)) { + exec_start_outgoing_migration(s, dst_ptr, &local_err); + } else if (strstart(uri, "fd:", &dst_ptr)) { + fd_start_outgoing_migration(s, dst_ptr, &local_err); } else { if (!(has_resume && resume)) { yank_unregister_instance(MIGRATION_YANK_INSTANCE); diff --git a/migration/socket.c b/migration/socket.c index 4fd5e85f50..7ca6af8cca 100644 --- a/migration/socket.c +++ b/migration/socket.c @@ -32,6 +32,17 @@ struct SocketOutgoingArgs { SocketAddress *saddr; } outgoing_args; +struct SocketArgs { + struct SrcDestAddr data; + uint8_t multifd_channels; +}; + +struct OutgoingMigrateParams { + struct SocketArgs *socket_args; + size_t length;Length of what?length of the socket_args[] array. Thanks for pointing it out. I will be more specific for this variable in the v2 patchset series.+ uint64_t total_multifd_channel;@total_multifd_channels appears to be the sum of the socket_args[*].multifd_channels. Correct?Yes Markus, you are correct.Sure you need to keep the sum separately?
> So earlier, the idea behind this was that, we had this intention to depreciate the migrate_multifd_channels() API from the live migration process. We made total_multifd_channels() function, where it used to calculate total number of multifd channels every time, for whichever function called was computation internsive so we replaced it by returning sum of socket_args[*].multifd_channels i.e. total_multifd_channel in the later patches.
But now in the v2 patchset onwards, Thanks to inputs from Dr. David and Daniel, we are not depricating migrate_multifd_channels() API but the value from the API will be cross-referenced with sum of socket_args[*].multifd_channels i.e. total_multifd_channel, and error if they are not equal.
+} outgoing_migrate_params; + void socket_send_channel_create(QIOTaskFunc f, void *data) { QIOChannelSocket *sioc = qio_channel_socket_new(); @@ -47,6 +58,14 @@ int socket_send_channel_destroy(QIOChannel *send) qapi_free_SocketAddress(outgoing_args.saddr); outgoing_args.saddr = NULL; } + + if (outgoing_migrate_params.socket_args != NULL) { + g_free(outgoing_migrate_params.socket_args); + outgoing_migrate_params.socket_args = NULL; + } + if (outgoing_migrate_params.length) { + outgoing_migrate_params.length = 0; + } return 0; } @@ -117,13 +136,41 @@ socket_start_outgoing_migration_internal(MigrationState *s, } void socket_start_outgoing_migration(MigrationState *s, - const char *str, + const char *dst_str, Error **errp) { Error *err = NULL; - SocketAddress *saddr = socket_parse(str, &err); + SocketAddress *dst_saddr = socket_parse(dst_str, &err); + if (!err) { + socket_start_outgoing_migration_internal(s, dst_saddr, &err); + } + error_propagate(errp, err); +} + +void init_multifd_array(int length) +{ + outgoing_migrate_params.socket_args = g_new0(struct SocketArgs, length); + outgoing_migrate_params.length = length; + outgoing_migrate_params.total_multifd_channel = 0; +} + +void store_multifd_migration_params(const char *dst_uri, + const char *src_uri, + uint8_t multifd_channels, + int idx, Error **errp) +{ + Error *err = NULL; + SocketAddress *src_addr = NULL; + SocketAddress *dst_addr = socket_parse(dst_uri, &err); + if (src_uri) { + src_addr = socket_parse(src_uri, &err); + }Incorrect use of &err. error.h's big comment: * Receive and accumulate multiple errors (first one wins): * Error *err = NULL, *local_err = NULL; * foo(arg, &err); * bar(arg, &local_err); * error_propagate(&err, local_err); * if (err) { * handle the error... * } * * Do *not* "optimize" this to * Error *err = NULL; * foo(arg, &err); * bar(arg, &err); // WRONG! * if (err) { * handle the error... * } * because this may pass a non-null err to bar().Thankyou Markus for sharing this knowledge. I was unaware of the dont's with &err.The big comment should help you along. If it doesn't, just ask.
> I read the comment, and it is pretty well explained out there.
if (!err) { - socket_start_outgoing_migration_internal(s, saddr, &err); + outgoing_migrate_params.socket_args[idx].data.dst_addr = dst_addr; + outgoing_migrate_params.socket_args[idx].data.src_addr = src_addr; + outgoing_migrate_params.socket_args[idx].multifd_channels + = multifd_channels; + outgoing_migrate_params.total_multifd_channel += multifd_channels; } error_propagate(errp, err);Consider struct SocketArgs *sa = &outgoing_migrate_params.socket_args[idx]; SocketAddress *src_addr, *dst_addr; src_addr = socketaddress(src_uri, errp); if (!src_addr) { return; } dst_addr = socketaddress(dst_uri, errp); if (!dst_addr) { return; } sa->data.dst_addr = dst_addr; sa->data.src_addr = src_addr; sa->multifd_channels = multifd_channels; outgoing_migrate_params.total_multifd_channel += multifd_channels;Thanks Markus for this amazing suggestion. Your approach looks simpler to understand and also resolves the error it had with &err. I will surely implement this in the upcoming v2 patchset.You're welcome :)
> I just wanted to have a double check on the solution you gave above Markus. The suggestion you have given there has been deliberately written in that way right, because
src_addr = socketaddress(src_uri, errp);
dst_addr = socketaddress(dst_uri, errp);
if (!src_addr) {
return;
}
if (!dst_addr) {
return;
}
would still be an error right according to the &err guidelines from
error.h file.
} diff --git a/migration/socket.h b/migration/socket.h index 891dbccceb..bba7f177fe 100644 --- a/migration/socket.h +++ b/migration/socket.h @@ -19,12 +19,27 @@ #include "io/channel.h" #include "io/task.h" +#include "migration.h" + +/* info regarding destination and source uri */ +struct SrcDestAddr { + SocketAddress *dst_addr; + SocketAddress *src_addr; +};QEMU coding style wants a typedef.Okay, acknowledged.void socket_send_channel_create(QIOTaskFunc f, void *data); int socket_send_channel_destroy(QIOChannel *send); void socket_start_incoming_migration(const char *str, Error **errp); -void socket_start_outgoing_migration(MigrationState *s, const char *str, +void socket_start_outgoing_migration(MigrationState *s, const char *dst_str, Error **errp); + +int multifd_list_length(MigrateUriParameterList *list); + +void init_multifd_array(int length); + +void store_multifd_migration_params(const char *dst_uri, const char *src_uri, + uint8_t multifd_channels, int idx, + Error **erp); #endif diff --git a/monitor/hmp-cmds.c b/monitor/hmp-cmds.c index 622c783c32..2db539016a 100644 --- a/monitor/hmp-cmds.c +++ b/monitor/hmp-cmds.c @@ -56,6 +56,9 @@ #include "migration/snapshot.h" #include "migration/misc.h" +/* Default number of multi-fd channels */ +#define DEFAULT_MIGRATE_MULTIFD_CHANNELS 2 + #ifdef CONFIG_SPICE #include <spice/enums.h> #endif @@ -1574,10 +1577,25 @@ void hmp_migrate(Monitor *mon, const QDict *qdict) bool inc = qdict_get_try_bool(qdict, "inc", false); bool resume = qdict_get_try_bool(qdict, "resume", false); const char *uri = qdict_get_str(qdict, "uri"); + + const char *src_uri = qdict_get_str(qdict, "source-uri"); + const char *dst_uri = qdict_get_str(qdict, "destination-uri"); + uint8_t multifd_channels = qdict_get_try_int(qdict, "multifd-channels", + DEFAULT_MIGRATE_MULTIFD_CHANNELS); Error *err = NULL; + MigrateUriParameterList *caps = NULL; + MigrateUriParameter *value; + + value = g_malloc0(sizeof(*value)); + value->source_uri = (char *)src_uri; + value->destination_uri = (char *)dst_uri; + value->multifd_channels = multifd_channels; + QAPI_LIST_PREPEND(caps, value); + + qmp_migrate(uri, !!caps, caps, !!blk, blk, !!inc, + inc, false, false, true, resume, &err); + qapi_free_MigrateUriParameterList(caps); - qmp_migrate(uri, !!blk, blk, !!inc, inc, - false, false, true, resume, &err); if (hmp_handle_error(mon, err)) { return; } diff --git a/qapi/migration.json b/qapi/migration.json index 6130cd9fae..fb259d626b 100644 --- a/qapi/migration.json +++ b/qapi/migration.json @@ -1454,12 +1454,38 @@ ## { 'command': 'migrate-continue', 'data': {'state': 'MigrationStatus'} } +## +# @MigrateUriParameter: +# +# Information regarding which source interface is connected to which +# destination interface and number of multifd channels over each interface. +# +# @source-uri: the Uniform Resource Identifier of the source VM. +# Default port number is 0. +# +# @destination-uri: the Uniform Resource Identifier of the destination VM +# +# @multifd-channels: number of parallel multifd channels used to migrate data +# for specific source-uri and destination-uri. Default value +# in this case is 2 (Since 4.0)You mean "(Since 7.1)", I guess.Yes yes. Also David pointed this thing out. I will update the version in the v2 patchset.+# +## +{ 'struct' : 'MigrateUriParameter', + 'data' : { 'source-uri' : 'str', + 'destination-uri' : 'str', + '*multifd-channels' : 'uint8'} } + ## # @migrate: # # Migrates the current running guest to another Virtual Machine. # # @uri: the Uniform Resource Identifier of the destination VM +# for migration thread +# +# @multi-fd-uri-list: list of pair of source and destination VM Uniform +# Resource Identifiers with number of multifd-channels +# for each pair # # @blk: do block migration (full disk copy) # @@ -1479,20 +1505,27 @@ # 1. The 'query-migrate' command should be used to check migration's progress # and final result (this information is provided by the 'status' member) # -# 2. All boolean arguments default to false +# 2. The uri argument should have the Uniform Resource Identifier of default +# destination VM. This connection will be bound to default network +# +# 3. All boolean arguments default to false # -# 3. The user Monitor's "detach" argument is invalid in QMP and should not +# 4. The user Monitor's "detach" argument is invalid in QMP and should not # be used # # Example: # -# -> { "execute": "migrate", "arguments": { "uri": "tcp:0:4446" } } +# -> { "execute": "migrate", +# "arguments": { "uri": "tcp:0:4446", "multi-fd-uri-list": [ { +# "source-uri": "tcp::6900", "destination-uri": "tcp:0:4480", +# "multifd-channels": 4}, { "source-uri": "tcp:10.0.0.0: ", +# "destination-uri": "tcp:11.0.0.0:7789", "multifd-channels": 5} ] } } # <- { "return": {} } # ## { 'command': 'migrate', - 'data': {'uri': 'str', '*blk': 'bool', '*inc': 'bool', - '*detach': 'bool', '*resume': 'bool' } } + 'data': {'uri': 'str', '*multi-fd-uri-list': ['MigrateUriParameter'], '*blk': 'bool',??
> Sorry Markus, I think the statement I wrote did not make sense, I apologise for that. I meant to say example in the sense:
# Example:
#
# -> { "execute": "migrate", "arguments": { "uri": "tcp:0:4446" } }
# -> { "execute": "migrate",
# "arguments": { "uri": "tcp:0:4446", "multi-fd-uri-list": [ {
# "source-uri": "tcp::6900", "destination-uri":
"tcp:0:4480",
# "multifd-channels": 4}, { "source-uri":
"tcp:10.0.0.0: ",
# "destination-uri": "tcp:11.0.0.0:7789",
"multifd-channels": 5} ] } }
even this we should try to wrap within 80 character column right? or is
that okay to go beyond 80.
> Okay thanks again Markus for your valuable suggestion. I will try to wrap within 75 in almost all the cases.Long line.Okay, acknowledged. Even for example, should it be under 80 characters per line, or that is fine?docs/devel/style.rst: Line width ========== Lines should be 80 characters; try not to make them longer. Sometimes it is hard to do, especially when dealing with QEMU subsystems that use long function or symbol names. If wrapping the line at 80 columns is obviously less readable and more awkward, prefer not to wrap it; better to have an 85 character line than one which is awkwardly wrapped. Even in that case, try not to make lines much longer than 80 characters. (The checkpatch script will warn at 100 characters, but this is intended as a guard against obviously-overlength lines, not a target.) Personally, I very much prefer to wrap between 70 and 75 except where it impairs legibility.
+ '*inc': 'bool', '*detach': 'bool', '*resume': 'bool' } }### @migrate-incoming:Regards, Het Gala
Regards, Het Gala
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