[PATCH v2 20/29] migration/multifd: Add incoming QIOChannelFile support

Fabiano Rosas posted 29 patches 2 years, 2 months ago
Maintainers: Juan Quintela <quintela@redhat.com>, Peter Xu <peterx@redhat.com>, Fabiano Rosas <farosas@suse.de>, Leonardo Bras <leobras@redhat.com>, Paolo Bonzini <pbonzini@redhat.com>, David Hildenbrand <david@redhat.com>, "Philippe Mathieu-Daudé" <philmd@linaro.org>, "Daniel P. Berrangé" <berrange@redhat.com>, Eric Blake <eblake@redhat.com>, Markus Armbruster <armbru@redhat.com>, Thomas Huth <thuth@redhat.com>, Laurent Vivier <lvivier@redhat.com>
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[PATCH v2 20/29] migration/multifd: Add incoming QIOChannelFile support
Posted by Fabiano Rosas 2 years, 2 months ago
On the receiving side we don't need to differentiate between main
channel and threads, so whichever channel is defined first gets to be
the main one. And since there are no packets, use the atomic channel
count to index into the params array.

Signed-off-by: Fabiano Rosas <farosas@suse.de>
---
 migration/file.c      | 39 +++++++++++++++++++++++++++++----------
 migration/migration.c |  2 ++
 migration/multifd.c   |  7 ++++++-
 migration/multifd.h   |  1 +
 4 files changed, 38 insertions(+), 11 deletions(-)

diff --git a/migration/file.c b/migration/file.c
index 93b9b7bf5d..ad75225f43 100644
--- a/migration/file.c
+++ b/migration/file.c
@@ -6,13 +6,15 @@
  */
 
 #include "qemu/osdep.h"
-#include "qemu/cutils.h"
 #include "qapi/error.h"
+#include "qemu/cutils.h"
+#include "qemu/error-report.h"
 #include "channel.h"
 #include "file.h"
 #include "migration.h"
 #include "io/channel-file.h"
 #include "io/channel-util.h"
+#include "options.h"
 #include "trace.h"
 
 #define OFFSET_OPTION ",offset="
@@ -136,7 +138,8 @@ void file_start_incoming_migration(const char *filespec, Error **errp)
     g_autofree char *filename = g_strdup(filespec);
     QIOChannelFile *fioc = NULL;
     uint64_t offset = 0;
-    QIOChannel *ioc;
+    int channels = 1;
+    int i = 0, fd;
 
     trace_migration_file_incoming(filename);
 
@@ -146,16 +149,32 @@ void file_start_incoming_migration(const char *filespec, Error **errp)
 
     fioc = qio_channel_file_new_path(filename, O_RDONLY, 0, errp);
     if (!fioc) {
-        return;
+        goto out;
+    }
+
+    if (migrate_multifd()) {
+        channels += migrate_multifd_channels();
     }
 
-    ioc = QIO_CHANNEL(fioc);
-    if (offset && qio_channel_io_seek(ioc, offset, SEEK_SET, errp) < 0) {
+    fd = fioc->fd;
+
+    do {
+        QIOChannel *ioc = QIO_CHANNEL(fioc);
+
+        if (offset && qio_channel_io_seek(ioc, offset, SEEK_SET, errp) < 0) {
+            return;
+        }
+
+        qio_channel_set_name(ioc, "migration-file-incoming");
+        qio_channel_add_watch_full(ioc, G_IO_IN,
+                                   file_accept_incoming_migration,
+                                   NULL, NULL,
+                                   g_main_context_get_thread_default());
+    } while (++i < channels && (fioc = qio_channel_file_new_fd(fd)));
+
+out:
+    if (!fioc) {
+        error_report("Error creating migration incoming channel");
         return;
     }
-    qio_channel_set_name(QIO_CHANNEL(ioc), "migration-file-incoming");
-    qio_channel_add_watch_full(ioc, G_IO_IN,
-                               file_accept_incoming_migration,
-                               NULL, NULL,
-                               g_main_context_get_thread_default());
 }
diff --git a/migration/migration.c b/migration/migration.c
index ba806cea55..5fa726f6d4 100644
--- a/migration/migration.c
+++ b/migration/migration.c
@@ -756,6 +756,8 @@ void migration_ioc_process_incoming(QIOChannel *ioc, Error **errp)
         }
 
         default_channel = (channel_magic == cpu_to_be32(QEMU_VM_FILE_MAGIC));
+    } else if (migrate_multifd() && migrate_fixed_ram()) {
+        default_channel = multifd_recv_first_channel();
     } else {
         default_channel = !mis->from_src_file;
     }
diff --git a/migration/multifd.c b/migration/multifd.c
index 75a17ea8ab..ad51210f13 100644
--- a/migration/multifd.c
+++ b/migration/multifd.c
@@ -1242,6 +1242,11 @@ int multifd_load_setup(Error **errp)
     return 0;
 }
 
+bool multifd_recv_first_channel(void)
+{
+    return !multifd_recv_state;
+}
+
 bool multifd_recv_all_channels_created(void)
 {
     int thread_count = migrate_multifd_channels();
@@ -1284,7 +1289,7 @@ void multifd_recv_new_channel(QIOChannel *ioc, Error **errp)
         /* initial packet */
         num_packets = 1;
     } else {
-        id = 0;
+        id = qatomic_read(&multifd_recv_state->count);
     }
 
     p = &multifd_recv_state->params[id];
diff --git a/migration/multifd.h b/migration/multifd.h
index a835643b48..a112ec7ac6 100644
--- a/migration/multifd.h
+++ b/migration/multifd.h
@@ -18,6 +18,7 @@ void multifd_save_cleanup(void);
 int multifd_load_setup(Error **errp);
 void multifd_load_cleanup(void);
 void multifd_load_shutdown(void);
+bool multifd_recv_first_channel(void);
 bool multifd_recv_all_channels_created(void);
 void multifd_recv_new_channel(QIOChannel *ioc, Error **errp);
 void multifd_recv_sync_main(void);
-- 
2.35.3
Re: [PATCH v2 20/29] migration/multifd: Add incoming QIOChannelFile support
Posted by Daniel P. Berrangé 2 years, 2 months ago
On Mon, Oct 23, 2023 at 05:35:59PM -0300, Fabiano Rosas wrote:
> On the receiving side we don't need to differentiate between main
> channel and threads, so whichever channel is defined first gets to be
> the main one. And since there are no packets, use the atomic channel
> count to index into the params array.
> 
> Signed-off-by: Fabiano Rosas <farosas@suse.de>
> ---
>  migration/file.c      | 39 +++++++++++++++++++++++++++++----------
>  migration/migration.c |  2 ++
>  migration/multifd.c   |  7 ++++++-
>  migration/multifd.h   |  1 +
>  4 files changed, 38 insertions(+), 11 deletions(-)
> 
> diff --git a/migration/file.c b/migration/file.c
> index 93b9b7bf5d..ad75225f43 100644
> --- a/migration/file.c
> +++ b/migration/file.c
> @@ -6,13 +6,15 @@
>   */
>  
>  #include "qemu/osdep.h"
> -#include "qemu/cutils.h"
>  #include "qapi/error.h"
> +#include "qemu/cutils.h"
> +#include "qemu/error-report.h"
>  #include "channel.h"
>  #include "file.h"
>  #include "migration.h"
>  #include "io/channel-file.h"
>  #include "io/channel-util.h"
> +#include "options.h"
>  #include "trace.h"
>  
>  #define OFFSET_OPTION ",offset="
> @@ -136,7 +138,8 @@ void file_start_incoming_migration(const char *filespec, Error **errp)
>      g_autofree char *filename = g_strdup(filespec);
>      QIOChannelFile *fioc = NULL;
>      uint64_t offset = 0;
> -    QIOChannel *ioc;
> +    int channels = 1;
> +    int i = 0, fd;
>  
>      trace_migration_file_incoming(filename);
>  
> @@ -146,16 +149,32 @@ void file_start_incoming_migration(const char *filespec, Error **errp)
>  
>      fioc = qio_channel_file_new_path(filename, O_RDONLY, 0, errp);
>      if (!fioc) {
> -        return;
> +        goto out;
> +    }
> +
> +    if (migrate_multifd()) {
> +        channels += migrate_multifd_channels();
>      }
>  
> -    ioc = QIO_CHANNEL(fioc);
> -    if (offset && qio_channel_io_seek(ioc, offset, SEEK_SET, errp) < 0) {
> +    fd = fioc->fd;
> +
> +    do {
> +        QIOChannel *ioc = QIO_CHANNEL(fioc);
> +
> +        if (offset && qio_channel_io_seek(ioc, offset, SEEK_SET, errp) < 0) {
> +            return;
> +        }
> +
> +        qio_channel_set_name(ioc, "migration-file-incoming");
> +        qio_channel_add_watch_full(ioc, G_IO_IN,
> +                                   file_accept_incoming_migration,
> +                                   NULL, NULL,
> +                                   g_main_context_get_thread_default());
> +    } while (++i < channels && (fioc = qio_channel_file_new_fd(fd)));

IIUC, this loop is failing to call qio_channel_io_seek to set
the offset on the last 'fioc' that is created.


With regards,
Daniel
-- 
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Re: [PATCH v2 20/29] migration/multifd: Add incoming QIOChannelFile support
Posted by Fabiano Rosas 2 years, 2 months ago
Daniel P. Berrangé <berrange@redhat.com> writes:

> On Mon, Oct 23, 2023 at 05:35:59PM -0300, Fabiano Rosas wrote:
>> On the receiving side we don't need to differentiate between main
>> channel and threads, so whichever channel is defined first gets to be
>> the main one. And since there are no packets, use the atomic channel
>> count to index into the params array.
>> 
>> Signed-off-by: Fabiano Rosas <farosas@suse.de>
>> ---
>>  migration/file.c      | 39 +++++++++++++++++++++++++++++----------
>>  migration/migration.c |  2 ++
>>  migration/multifd.c   |  7 ++++++-
>>  migration/multifd.h   |  1 +
>>  4 files changed, 38 insertions(+), 11 deletions(-)
>> 
>> diff --git a/migration/file.c b/migration/file.c
>> index 93b9b7bf5d..ad75225f43 100644
>> --- a/migration/file.c
>> +++ b/migration/file.c
>> @@ -6,13 +6,15 @@
>>   */
>>  
>>  #include "qemu/osdep.h"
>> -#include "qemu/cutils.h"
>>  #include "qapi/error.h"
>> +#include "qemu/cutils.h"
>> +#include "qemu/error-report.h"
>>  #include "channel.h"
>>  #include "file.h"
>>  #include "migration.h"
>>  #include "io/channel-file.h"
>>  #include "io/channel-util.h"
>> +#include "options.h"
>>  #include "trace.h"
>>  
>>  #define OFFSET_OPTION ",offset="
>> @@ -136,7 +138,8 @@ void file_start_incoming_migration(const char *filespec, Error **errp)
>>      g_autofree char *filename = g_strdup(filespec);
>>      QIOChannelFile *fioc = NULL;
>>      uint64_t offset = 0;
>> -    QIOChannel *ioc;
>> +    int channels = 1;
>> +    int i = 0, fd;
>>  
>>      trace_migration_file_incoming(filename);
>>  
>> @@ -146,16 +149,32 @@ void file_start_incoming_migration(const char *filespec, Error **errp)
>>  
>>      fioc = qio_channel_file_new_path(filename, O_RDONLY, 0, errp);
>>      if (!fioc) {
>> -        return;
>> +        goto out;
>> +    }
>> +
>> +    if (migrate_multifd()) {
>> +        channels += migrate_multifd_channels();
>>      }
>>  
>> -    ioc = QIO_CHANNEL(fioc);
>> -    if (offset && qio_channel_io_seek(ioc, offset, SEEK_SET, errp) < 0) {
>> +    fd = fioc->fd;
>> +
>> +    do {
>> +        QIOChannel *ioc = QIO_CHANNEL(fioc);
>> +
>> +        if (offset && qio_channel_io_seek(ioc, offset, SEEK_SET, errp) < 0) {
>> +            return;
>> +        }
>> +
>> +        qio_channel_set_name(ioc, "migration-file-incoming");
>> +        qio_channel_add_watch_full(ioc, G_IO_IN,
>> +                                   file_accept_incoming_migration,
>> +                                   NULL, NULL,
>> +                                   g_main_context_get_thread_default());
>> +    } while (++i < channels && (fioc = qio_channel_file_new_fd(fd)));
>
> IIUC, this loop is failing to call qio_channel_io_seek to set
> the offset on the last 'fioc' that is created.
>

Ah, this is actually bogus. We don't need to offset the secondary
channels. That does nothing since we carry pointers to everything in the
fixed-ram header. This should be out of the loop.