Re: [Qemu-devel] [PATCH v7 03/11] dump-guest-memory: using static DumpState, add DumpStatus

[Andrew Jones <drjones@redhat.com>]

On Tue, Feb 16, 2016 at 03:50:53PM +0800, Peter Xu wrote:
> Instead of malloc/free each time for DumpState, make it
> static. Added DumpStatus to show status for dump.

I see that the motivation for making DumpState static is for
dump_in_progress(). DumpState isn't massive, but it isn't tiny
either, so maybe we should just have a global pointer instead?
dump_in_progress() can report DUMP_STATUS_NONE when the pointer
is NULL, or whatever the status is, when it's not.

drew

> 
> This is to be used for detached dump.
> 
> Signed-off-by: Peter Xu <peterx@redhat.com>
> Reviewed-by: Fam Zheng <famz@redhat.com>
> ---
>  dump.c                | 21 ++++++++++++++++-----
>  include/sysemu/dump.h |  2 ++
>  qapi-schema.json      | 18 ++++++++++++++++++
>  3 files changed, 36 insertions(+), 5 deletions(-)
> 
> diff --git a/dump.c b/dump.c
> index c4a62d9..434bc60 100644
> --- a/dump.c
> +++ b/dump.c
> @@ -1442,6 +1442,14 @@ static void get_max_mapnr(DumpState *s)
>      s->max_mapnr = dump_paddr_to_pfn(s, last_block->target_end);
>  }
>  
> +static DumpState dump_state_global = { .status = DUMP_STATUS_NONE };
> +
> +static void dump_state_prepare(DumpState *s)
> +{
> +    /* zero the struct, setting status to active */
> +    *s = (DumpState) { .status = DUMP_STATUS_ACTIVE };
> +}
> +
>  static void dump_init(DumpState *s, int fd, bool has_format,
>                        DumpGuestMemoryFormat format, bool paging, bool has_filter,
>                        int64_t begin, int64_t length, Error **errp)
> @@ -1676,24 +1684,27 @@ void qmp_dump_guest_memory(bool paging, const char *file,
>          return;
>      }
>  
> -    s = g_malloc0(sizeof(DumpState));
> +    s = &dump_state_global;
> +    dump_state_prepare(s);
>  
>      dump_init(s, fd, has_format, format, paging, has_begin,
>                begin, length, &local_err);
>      if (local_err) {
> -        g_free(s);
>          error_propagate(errp, local_err);
> +        s->status = DUMP_STATUS_FAILED;
>          return;
>      }
>  
>      if (has_format && format != DUMP_GUEST_MEMORY_FORMAT_ELF) {
> -        create_kdump_vmcore(s, errp);
> +        create_kdump_vmcore(s, &local_err);
>      } else {
> -        create_vmcore(s, errp);
> +        create_vmcore(s, &local_err);
>      }
>  
> +    s->status = (local_err ? DUMP_STATUS_FAILED : DUMP_STATUS_COMPLETED);
> +    error_propagate(errp, local_err);
> +
>      dump_cleanup(s);
> -    g_free(s);
>  }
>  
>  DumpGuestMemoryCapability *qmp_query_dump_guest_memory_capability(Error **errp)
> diff --git a/include/sysemu/dump.h b/include/sysemu/dump.h
> index 2f04b24..21fc02d 100644
> --- a/include/sysemu/dump.h
> +++ b/include/sysemu/dump.h
> @@ -38,6 +38,7 @@
>  
>  #include "sysemu/dump-arch.h"
>  #include "sysemu/memory_mapping.h"
> +#include "qapi-types.h"
>  
>  typedef struct QEMU_PACKED MakedumpfileHeader {
>      char signature[16];     /* = "makedumpfile" */
> @@ -176,6 +177,7 @@ typedef struct DumpState {
>      off_t offset_page;          /* offset of page part in vmcore */
>      size_t num_dumpable;        /* number of page that can be dumped */
>      uint32_t flag_compress;     /* indicate the compression format */
> +    DumpStatus status;          /* current dump status */
>  } DumpState;
>  
>  uint16_t cpu_to_dump16(DumpState *s, uint16_t val);
> diff --git a/qapi-schema.json b/qapi-schema.json
> index caff580..ccd30c8 100644
> --- a/qapi-schema.json
> +++ b/qapi-schema.json
> @@ -2219,6 +2219,24 @@
>              '*format': 'DumpGuestMemoryFormat'} }
>  
>  ##
> +# @DumpStatus
> +#
> +# Describe the status of a long-running background guest memory dump.
> +#
> +# @none: no dump-guest-memory has started yet.
> +#
> +# @active: there is one dump running in background.
> +#
> +# @completed: the last dump has finished successfully.
> +#
> +# @failed: the last dump has failed.
> +#
> +# Since 2.6
> +##
> +{ 'enum': 'DumpStatus',
> +  'data': [ 'none', 'active', 'completed', 'failed' ] }
> +
> +##
>  # @DumpGuestMemoryCapability:
>  #
>  # A list of the available formats for dump-guest-memory
> -- 
> 2.4.3
> 
>