Re: [PATCH v3 18/21] migration: Make no compression operations into its own structure

["Dr. David Alan Gilbert" <dgilbert@redhat.com>]

* Juan Quintela (quintela@redhat.com) wrote:
> It will be used later.
> 
> Signed-off-by: Juan Quintela <quintela@redhat.com>
> 
> ---
> Move setup of ->ops helper to proper place (wei)
> Rename s/none/nocomp/ (dave)
> Introduce MULTIFD_FLAG_NOCOMP
> right order of arguments for print
> ---
>  migration/migration.c |   9 +++
>  migration/migration.h |   1 +
>  migration/multifd.c   | 183 ++++++++++++++++++++++++++++++++++++++++--
>  migration/multifd.h   |  22 +++++
>  migration/ram.c       |   1 +
>  5 files changed, 208 insertions(+), 8 deletions(-)
> 
> diff --git a/migration/migration.c b/migration/migration.c
> index 3501bc3353..d25fdb3e6b 100644
> --- a/migration/migration.c
> +++ b/migration/migration.c
> @@ -2245,6 +2245,15 @@ int migrate_multifd_channels(void)
>      return s->parameters.multifd_channels;
>  }
>  
> +int migrate_multifd_method(void)
> +{
> +    MigrationState *s;
> +
> +    s = migrate_get_current();
> +
> +    return s->parameters.multifd_compress;
> +}

Shouldn't that be a MultifdCompress enum returned?

> +
>  int migrate_use_xbzrle(void)
>  {
>      MigrationState *s;
> diff --git a/migration/migration.h b/migration/migration.h
> index 8473ddfc88..3b0b413a93 100644
> --- a/migration/migration.h
> +++ b/migration/migration.h
> @@ -300,6 +300,7 @@ bool migrate_auto_converge(void);
>  bool migrate_use_multifd(void);
>  bool migrate_pause_before_switchover(void);
>  int migrate_multifd_channels(void);
> +int migrate_multifd_method(void);
>  
>  int migrate_use_xbzrle(void);
>  int64_t migrate_xbzrle_cache_size(void);
> diff --git a/migration/multifd.c b/migration/multifd.c
> index 1875bb3aaa..353140cd25 100644
> --- a/migration/multifd.c
> +++ b/migration/multifd.c
> @@ -38,6 +38,132 @@ typedef struct {
>      uint64_t unused2[4];    /* Reserved for future use */
>  } __attribute__((packed)) MultiFDInit_t;
>  
> +/* Multifd without compression */
> +
> +/**
> + * nocomp_send_setup: setup send side
> + *
> + * For no compression this function does nothing.
> + *
> + * Returns 0 for success or -1 for error
> + *
> + * @p: Params for the channel that we are using
> + * @errp: pointer to an error
> + */
> +static int nocomp_send_setup(MultiFDSendParams *p, Error **errp)
> +{
> +    return 0;
> +}
> +
> +/**
> + * nocomp_send_cleanup: cleanup send side
> + *
> + * For no compression this function does nothing.
> + *
> + * @p: Params for the channel that we are using
> + */
> +static void nocomp_send_cleanup(MultiFDSendParams *p, Error **errp)
> +{
> +    return;
> +}
> +
> +/**
> + * nocomp_send_prepare: prepare date to be able to send
> + *
> + * For no compression we just have to calculate the size of the
> + * packet.
> + *
> + * Returns 0 for success or -1 for error
> + *
> + * @p: Params for the channel that we are using
> + * @used: number of pages used
> + * @errp: pointer to an error
> + */
> +static int nocomp_send_prepare(MultiFDSendParams *p, uint32_t used,
> +                               Error **errp)
> +{
> +    p->next_packet_size = used * qemu_target_page_size();
> +    p->flags |= MULTIFD_FLAG_NOCOMP;
> +    return 0;
> +}
> +
> +/**
> + * nocomp_send_write: do the actual write of the data
> + *
> + * For no compression we just have to write the data.
> + *
> + * Returns 0 for success or -1 for error
> + *
> + * @p: Params for the channel that we are using
> + * @used: number of pages used
> + * @errp: pointer to an error
> + */
> +static int nocomp_send_write(MultiFDSendParams *p, uint32_t used, Error **errp)
> +{
> +    return qio_channel_writev_all(p->c, p->pages->iov, used, errp);
> +}
> +
> +/**
> + * nocomp_recv_setup: setup receive side
> + *
> + * For no compression this function does nothing.
> + *
> + * Returns 0 for success or -1 for error
> + *
> + * @p: Params for the channel that we are using
> + * @errp: pointer to an error
> + */
> +static int nocomp_recv_setup(MultiFDRecvParams *p, Error **errp)
> +{
> +    return 0;
> +}
> +
> +/**
> + * nocomp_recv_cleanup: setup receive side
> + *
> + * For no compression this function does nothing.
> + *
> + * @p: Params for the channel that we are using
> + */
> +static void nocomp_recv_cleanup(MultiFDRecvParams *p)
> +{
> +}
> +
> +/**
> + * nocomp_recv_pages: read the data from the channel into actual pages
> + *
> + * For no compression we just need to read things into the correct place.
> + *
> + * Returns 0 for success or -1 for error
> + *
> + * @p: Params for the channel that we are using
> + * @used: number of pages used
> + * @errp: pointer to an error
> + */
> +static int nocomp_recv_pages(MultiFDRecvParams *p, uint32_t used, Error **errp)
> +{
> +    if (p->flags != MULTIFD_FLAG_NOCOMP) {
> +        error_setg(errp, "multifd %d: flags received %x flags expected %x",
> +                   p->id, p->flags, MULTIFD_FLAG_NOCOMP);
> +        return -1;
> +    }
> +    return qio_channel_readv_all(p->c, p->pages->iov, used, errp);
> +}
> +
> +static MultiFDMethods multifd_nocomp_ops = {
> +    .send_setup = nocomp_send_setup,
> +    .send_cleanup = nocomp_send_cleanup,
> +    .send_prepare = nocomp_send_prepare,
> +    .send_write = nocomp_send_write,
> +    .recv_setup = nocomp_recv_setup,
> +    .recv_cleanup = nocomp_recv_cleanup,
> +    .recv_pages = nocomp_recv_pages
> +};
> +
> +static MultiFDMethods *multifd_ops[MULTIFD_COMPRESS__MAX] = {
> +    [MULTIFD_COMPRESS_NONE] = &multifd_nocomp_ops,
> +};
> +
>  static int multifd_send_initial_packet(MultiFDSendParams *p, Error **errp)
>  {
>      MultiFDInit_t msg = {};
> @@ -246,6 +372,8 @@ struct {
>       * We will use atomic operations.  Only valid values are 0 and 1.
>       */
>      int exiting;
> +    /* multifd ops */
> +    MultiFDMethods *ops;
>  } *multifd_send_state;
>  
>  /*
> @@ -397,6 +525,7 @@ void multifd_save_cleanup(void)
>      }
>      for (i = 0; i < migrate_multifd_channels(); i++) {
>          MultiFDSendParams *p = &multifd_send_state->params[i];
> +        Error *local_err = NULL;
>  
>          socket_send_channel_destroy(p->c);
>          p->c = NULL;
> @@ -410,6 +539,10 @@ void multifd_save_cleanup(void)
>          p->packet_len = 0;
>          g_free(p->packet);
>          p->packet = NULL;
> +        multifd_send_state->ops->send_cleanup(p, &local_err);
> +        if (local_err) {
> +            migrate_set_error(migrate_get_current(), local_err);
> +        }
>      }
>      qemu_sem_destroy(&multifd_send_state->channels_ready);
>      g_free(multifd_send_state->params);
> @@ -494,7 +627,14 @@ static void *multifd_send_thread(void *opaque)
>              uint64_t packet_num = p->packet_num;
>              flags = p->flags;
>  
> -            p->next_packet_size = used * qemu_target_page_size();
> +            if (used) {
> +                ret = multifd_send_state->ops->send_prepare(p, used,
> +                                                            &local_err);
> +                if (ret != 0) {
> +                    qemu_mutex_unlock(&p->mutex);
> +                    break;
> +                }
> +            }
>              multifd_send_fill_packet(p);
>              p->flags = 0;
>              p->num_packets++;
> @@ -513,8 +653,7 @@ static void *multifd_send_thread(void *opaque)
>              }
>  
>              if (used) {
> -                ret = qio_channel_writev_all(p->c, p->pages->iov,
> -                                             used, &local_err);
> +                ret = multifd_send_state->ops->send_write(p, used, &local_err);
>                  if (ret != 0) {
>                      break;
>                  }
> @@ -596,6 +735,7 @@ int multifd_save_setup(Error **errp)
>      multifd_send_state->pages = multifd_pages_init(page_count);
>      qemu_sem_init(&multifd_send_state->channels_ready, 0);
>      atomic_set(&multifd_send_state->exiting, 0);
> +    multifd_send_state->ops = multifd_ops[migrate_multifd_method()];
>  
>      for (i = 0; i < thread_count; i++) {
>          MultiFDSendParams *p = &multifd_send_state->params[i];
> @@ -615,6 +755,18 @@ int multifd_save_setup(Error **errp)
>          p->name = g_strdup_printf("multifdsend_%d", i);
>          socket_send_channel_create(multifd_new_send_channel_async, p);
>      }
> +
> +    for (i = 0; i < thread_count; i++) {
> +        MultiFDSendParams *p = &multifd_send_state->params[i];
> +        Error *local_err = NULL;
> +        int ret;
> +
> +        ret = multifd_send_state->ops->send_setup(p, &local_err);
> +        if (ret) {
> +            error_propagate(errp, local_err);
> +            return ret;
> +        }
> +    }
>      return 0;
>  }
>  
> @@ -626,6 +778,8 @@ struct {
>      QemuSemaphore sem_sync;
>      /* global number of generated multifd packets */
>      uint64_t packet_num;
> +    /* multifd ops */
> +    MultiFDMethods *ops;
>  } *multifd_recv_state;
>  
>  static void multifd_recv_terminate_threads(Error *err)
> @@ -665,7 +819,6 @@ static void multifd_recv_terminate_threads(Error *err)
>  int multifd_load_cleanup(Error **errp)
>  {
>      int i;
> -    int ret = 0;
>  
>      if (!migrate_use_multifd()) {
>          return 0;
> @@ -698,6 +851,7 @@ int multifd_load_cleanup(Error **errp)
>          p->packet_len = 0;
>          g_free(p->packet);
>          p->packet = NULL;
> +        multifd_recv_state->ops->recv_cleanup(p);
>      }
>      qemu_sem_destroy(&multifd_recv_state->sem_sync);
>      g_free(multifd_recv_state->params);
> @@ -705,7 +859,7 @@ int multifd_load_cleanup(Error **errp)
>      g_free(multifd_recv_state);
>      multifd_recv_state = NULL;
>  
> -    return ret;
> +    return 0;
>  }
>  
>  void multifd_recv_sync_main(void)
> @@ -770,6 +924,8 @@ static void *multifd_recv_thread(void *opaque)
>  
>          used = p->pages->used;
>          flags = p->flags;
> +        /* recv methods don't know how to handle the SYNC flag */
> +        p->flags &= ~MULTIFD_FLAG_SYNC;
>          trace_multifd_recv(p->id, p->packet_num, used, flags,
>                             p->next_packet_size);
>          p->num_packets++;
> @@ -777,8 +933,7 @@ static void *multifd_recv_thread(void *opaque)
>          qemu_mutex_unlock(&p->mutex);
>  
>          if (used) {
> -            ret = qio_channel_readv_all(p->c, p->pages->iov,
> -                                        used, &local_err);
> +            ret = multifd_recv_state->ops->recv_pages(p, used, &local_err);
>              if (ret != 0) {
>                  break;
>              }
> @@ -817,6 +972,7 @@ int multifd_load_setup(Error **errp)
>      multifd_recv_state->params = g_new0(MultiFDRecvParams, thread_count);
>      atomic_set(&multifd_recv_state->count, 0);
>      qemu_sem_init(&multifd_recv_state->sem_sync, 0);
> +    multifd_recv_state->ops = multifd_ops[migrate_multifd_method()];
>  
>      for (i = 0; i < thread_count; i++) {
>          MultiFDRecvParams *p = &multifd_recv_state->params[i];
> @@ -831,6 +987,18 @@ int multifd_load_setup(Error **errp)
>          p->packet = g_malloc0(p->packet_len);
>          p->name = g_strdup_printf("multifdrecv_%d", i);
>      }
> +
> +    for (i = 0; i < thread_count; i++) {
> +        MultiFDRecvParams *p = &multifd_recv_state->params[i];
> +        Error *local_err = NULL;
> +        int ret;
> +
> +        ret = multifd_recv_state->ops->recv_setup(p, &local_err);
> +        if (ret) {
> +            error_propagate(errp, local_err);
> +            return ret;
> +        }
> +    }
>      return 0;
>  }
>  
> @@ -888,4 +1056,3 @@ bool multifd_recv_new_channel(QIOChannel *ioc, Error **errp)
>      return atomic_read(&multifd_recv_state->count) ==
>             migrate_multifd_channels();
>  }
> -
> diff --git a/migration/multifd.h b/migration/multifd.h
> index d8b0205977..8edea4fdac 100644
> --- a/migration/multifd.h
> +++ b/migration/multifd.h
> @@ -24,6 +24,7 @@ void multifd_send_sync_main(QEMUFile *f);
>  int multifd_queue_page(QEMUFile *f, RAMBlock *block, ram_addr_t offset);
>  
>  #define MULTIFD_FLAG_SYNC (1 << 0)
> +#define MULTIFD_FLAG_NOCOMP (1 << 1)

I don't think this should be a set of individual flags; in later patches
you define a flag for zlib and another for zstd etc etc - but you can't
combine them - you could never have FLAG_NOCOMP|FLAG_ZSTD|FLAG_ZLIB - so
this should be a 3 or 4 bit field which contains a compression id (0
being none).  The ID can't exactly be the migrate_multifd_method() enum
value - because I don't think that's defined to be stable (?).

Dave

>  /* This value needs to be a multiple of qemu_target_page_size() */
>  #define MULTIFD_PACKET_SIZE (512 * 1024)
> @@ -96,6 +97,8 @@ typedef struct {
>      uint64_t num_pages;
>      /* syncs main thread and channels */
>      QemuSemaphore sem_sync;
> +    /* used for compression methods */
> +    void *data;
>  }  MultiFDSendParams;
>  
>  typedef struct {
> @@ -133,7 +136,26 @@ typedef struct {
>      uint64_t num_pages;
>      /* syncs main thread and channels */
>      QemuSemaphore sem_sync;
> +    /* used for de-compression methods */
> +    void *data;
>  } MultiFDRecvParams;
>  
> +typedef struct {
> +    /* Setup for sending side */
> +    int (*send_setup)(MultiFDSendParams *p, Error **errp);
> +    /* Cleanup for sending side */
> +    void (*send_cleanup)(MultiFDSendParams *p, Error **errp);
> +    /* Prepare the send packet */
> +    int (*send_prepare)(MultiFDSendParams *p, uint32_t used, Error **errp);
> +    /* Write the send packet */
> +    int (*send_write)(MultiFDSendParams *p, uint32_t used, Error **errp);
> +    /* Setup for receiving side */
> +    int (*recv_setup)(MultiFDRecvParams *p, Error **errp);
> +    /* Cleanup for receiving side */
> +    void (*recv_cleanup)(MultiFDRecvParams *p);
> +    /* Read all pages */
> +    int (*recv_pages)(MultiFDRecvParams *p, uint32_t used, Error **errp);
> +} MultiFDMethods;
> +
>  #endif
>  
> diff --git a/migration/ram.c b/migration/ram.c
> index ed23ed1c7c..73a141bb60 100644
> --- a/migration/ram.c
> +++ b/migration/ram.c
> @@ -43,6 +43,7 @@
>  #include "page_cache.h"
>  #include "qemu/error-report.h"
>  #include "qapi/error.h"
> +#include "qapi/qapi-types-migration.h"
>  #include "qapi/qapi-events-migration.h"
>  #include "qapi/qmp/qerror.h"
>  #include "trace.h"

Unintended?


> -- 
> 2.24.1
> 
--
Dr. David Alan Gilbert / dgilbert@redhat.com / Manchester, UK