Re: [PATCH v4] qga: add guest-get-diskstats command for Linux guests

[Marc-André Lureau]

On Thu, May 19, 2022 at 3:28 PM luzhipeng <luzhipeng@cestc.cn> wrote:
>
> Add a new 'guest-get-diskstats' command for report disk io statistics
> for Linux guests. This can be useful for getting io flow or handling
> IO fault, no need to enter guests.
>
> Signed-off-by: luzhipeng <luzhipeng@cestc.cn>

Reviewed-by: Marc-André Lureau <marcandre.lureau@redhat.com>

> ---
>  Changes v3->v4: 
> 20220515095437.1291-1-luzhipeng@cestc.cn/">https://patchew.org/QEMU/20220515095437.1291-1-luzhipeng@cestc.cn/
>  Changes v2->v3: bugfix for memory leak
>  Changes v1->v2: 
> v1:20220512011930.214-1-luzhipeng@cestc.cn/">https://patchew.org/QEMU/20220512011930.214-1-luzhipeng@cestc.cn/
>
>  qga/commands-posix.c | 123 +++++++++++++++++++++++++++++++++++++++++++
>  qga/commands-win32.c |   6 +++
>  qga/qapi-schema.json |  86 ++++++++++++++++++++++++++++++
>  3 files changed, 215 insertions(+)
>
> diff --git a/qga/commands-posix.c b/qga/commands-posix.c
> index 69f209af87..12b50b7124 100644
> --- a/qga/commands-posix.c
> +++ b/qga/commands-posix.c
> @@ -2783,6 +2783,122 @@ GuestMemoryBlockInfo 
> *qmp_guest_get_memory_block_info(Error **errp)
>      return info;
>  }
>
> +#define MAX_NAME_LEN 128
> +static GuestDiskStatsInfoList *guest_get_diskstats(Error **errp)
> +{
> +#ifdef CONFIG_LINUX
> +    GuestDiskStatsInfoList *head = NULL, **tail = &head;
> +    const char *diskstats = "/proc/diskstats";
> +    FILE *fp;
> +    size_t n;
> +    char *line = NULL;
> +
> +    fp = fopen(diskstats, "r");
> +    if (fp  == NULL) {
> +        error_setg_errno(errp, errno, "open(\"%s\")", diskstats);
> +        return NULL;
> +    }
> +
> +    while (getline(&line, &n, fp) != -1) {
> +        g_autofree GuestDiskStatsInfo *diskstatinfo = NULL;
> +        g_autofree GuestDiskStats *diskstat = NULL;
> +        char dev_name[MAX_NAME_LEN];
> +        unsigned int ios_pgr, tot_ticks, rq_ticks, wr_ticks, dc_ticks, 
> fl_ticks;
> +        unsigned long rd_ios, rd_merges_or_rd_sec, rd_ticks_or_wr_sec, 
> wr_ios;
> +        unsigned long wr_merges, rd_sec_or_wr_ios, wr_sec;
> +        unsigned long dc_ios, dc_merges, dc_sec, fl_ios;
> +        unsigned int major, minor;
> +        int i;
> +
> +        i = sscanf(line, "%u %u %s %lu %lu %lu"
> +                   "%lu %lu %lu %lu %u %u %u %u"
> +                   "%lu %lu %lu %u %lu %u",
> +                   &major, &minor, dev_name,
> +                   &rd_ios, &rd_merges_or_rd_sec, &rd_sec_or_wr_ios,
> +                   &rd_ticks_or_wr_sec, &wr_ios, &wr_merges, &wr_sec,
> +                   &wr_ticks, &ios_pgr, &tot_ticks, &rq_ticks,
> +                   &dc_ios, &dc_merges, &dc_sec, &dc_ticks,
> +                   &fl_ios, &fl_ticks);
> +
> +        if (i < 7) {
> +            continue;
> B
> +        }
> +
> +        diskstatinfo = g_new0(GuestDiskStatsInfo, 1);
> +        diskstatinfo->name = g_strdup(dev_name);
> +        diskstatinfo->major = major;
> +        diskstatinfo->minor = minor;
> +
> +        diskstat = g_new0(GuestDiskStats, 1);
> +        if (i == 7) {
> +            diskstat->has_read_ios = true;
> +            diskstat->read_ios = rd_ios;
> +            diskstat->has_read_sectors = true;
> +            diskstat->read_sectors = rd_merges_or_rd_sec;
> +            diskstat->has_write_ios = true;
> +            diskstat->write_ios = rd_sec_or_wr_ios;
> +            diskstat->has_write_sectors = true;
> +            diskstat->write_sectors = rd_ticks_or_wr_sec;
> +        }
> +        if (i >= 14) {
> +            diskstat->has_read_ios = true;
> +            diskstat->read_ios = rd_ios;
> +            diskstat->has_read_sectors = true;
> +            diskstat->read_sectors = rd_sec_or_wr_ios;
> +            diskstat->has_read_merges = true;
> +            diskstat->read_merges = rd_merges_or_rd_sec;
> +            diskstat->has_read_ticks = true;
> +            diskstat->read_ticks = rd_ticks_or_wr_sec;
> +            diskstat->has_write_ios = true;
> +            diskstat->write_ios = wr_ios;
> +            diskstat->has_write_sectors = true;
> +            diskstat->write_sectors = wr_sec;
> +            diskstat->has_write_merges = true;
> +            diskstat->write_merges = wr_merges;
> +            diskstat->has_write_ticks = true;
> +            diskstat->write_ticks = wr_ticks;
> +            diskstat->has_ios_pgr = true;
> +            diskstat->ios_pgr = ios_pgr;
> +            diskstat->has_total_ticks = true;
> +            diskstat->total_ticks = tot_ticks;
> +            diskstat->has_weight_ticks = true;
> +            diskstat->weight_ticks = rq_ticks;
> +        }
> +        if (i >= 18) {
> +            diskstat->has_discard_ios = true;
> +            diskstat->discard_ios = dc_ios;
> +            diskstat->has_discard_merges = true;
> +            diskstat->discard_merges = dc_merges;
> +            diskstat->has_discard_sectors = true;
> +            diskstat->discard_sectors = dc_sec;
> +            diskstat->has_discard_ticks = true;
> +            diskstat->discard_ticks = dc_ticks;
> +        }
> +        if (i >= 20) {
> +            diskstat->has_flush_ios = true;
> +            diskstat->flush_ios = fl_ios;
> +            diskstat->has_flush_ticks = true;
> +            diskstat->flush_ticks = fl_ticks;
> +        }
> +
> +        diskstatinfo->stats = g_steal_pointer(&diskstat);
> +        QAPI_LIST_APPEND(tail, diskstatinfo);
> +        diskstatinfo = NULL;
> +    }
> +    free(line);
> +    fclose(fp);
> +    return head;
> +#else
> +    g_debug("disk stats reporting available only for Linux");
> +    return NULL;
> +#endif
> +}
> +
> +GuestDiskStatsInfoList *qmp_guest_get_diskstats(Error **errp)
> +{
> +    return guest_get_diskstats(errp);
> +}
> +
>  #else /* defined(__linux__) */
>
>  void qmp_guest_suspend_disk(Error **errp)
> @@ -3131,6 +3247,13 @@ GuestDiskInfoList *qmp_guest_get_disks(Error **errp)
>      return NULL;
>  }
>
> +GuestDiskStatsInfoList *qmp_guest_get_diskstats(Error **errp)
> +{
> +    error_setg(errp, QERR_UNSUPPORTED);
> +    return NULL;
> +}
> +
> +
>  #endif /* CONFIG_FSFREEZE */
>
>  #if !defined(CONFIG_FSTRIM)
> diff --git a/qga/commands-win32.c b/qga/commands-win32.c
> index d56b5fd2a7..dcdeb76a68 100644
> --- a/qga/commands-win32.c
> +++ b/qga/commands-win32.c
> @@ -2532,3 +2532,9 @@ char *qga_get_host_name(Error **errp)
>
>      return g_utf16_to_utf8(tmp, size, NULL, NULL, NULL);
>  }
> +
> +GuestDiskStatsInfoList *qmp_guest_get_diskstats(Error **errp)
> +{
> +    error_setg(errp, QERR_UNSUPPORTED);
> +    return NULL;
> +}
> diff --git a/qga/qapi-schema.json b/qga/qapi-schema.json
> index 4d8e506c9e..75d2bddf4b 100644
> --- a/qga/qapi-schema.json
> +++ b/qga/qapi-schema.json
> @@ -1490,3 +1490,89 @@
>  { 'command': 'guest-ssh-remove-authorized-keys',
>    'data': { 'username': 'str', 'keys': ['str'] },
>    'if': 'CONFIG_POSIX' }
> +
> +##
> +# @GuestDiskStats:
> +#
> +# @read-sectors: sectors read
> +#
> +# @write-sectors: sectors written
> +#
> +# @discard-sectors: sectors discarded
> +#
> +# @read-ios: reads completed successfully
> +#
> +# @read-merges: Number of read requests merged
> +#
> +# @write-ios: writes completed
> +#
> +# @write-merges: Number of write requests merged
> +#
> +# @discard-ios: Number of discards completed successfully
> +#
> +# @discard-merges: NUmber of discard requests merged
> +#
> +# @flush-ios: Number of flush requests completed successfully
> +#
> +# @read-ticks: time spent reading(ms)
> +#
> +# @write-ticks: time spent writing(ms)
> +#
> +# @discard-ticks: time spent discarding(ms)
> +#
> +# @flush-ticks: time spent flushing(ms)
> +#
> +# @ios-pgr: Number of I/Os currently in flight
> +#
> +# @total-ticks: time spent doing I/Os (ms)
> +#
> +# @weight-ticks: weighted time spent doing I/Os since the last update of 
> this field(ms)
> +#
> +# Since: 7.1
> +##
> +{ 'struct': 'GuestDiskStats',
> +  'data': {'*read-sectors': 'uint64',
> +           '*write-sectors': 'uint64',
> +           '*discard-sectors': 'uint64',
> +           '*read-ios': 'uint64',
> +           '*read-merges': 'uint64',
> +           '*write-ios': 'uint64',
> +           '*write-merges': 'uint64',
> +           '*discard-ios': 'uint64',
> +           '*discard-merges': 'uint64',
> +           '*flush-ios': 'uint64',
> +           '*read-ticks': 'uint64',
> +           '*write-ticks': 'uint64',
> +           '*discard-ticks': 'uint64',
> +           '*flush-ticks': 'uint64',
> +           '*ios-pgr': 'uint64',
> +           '*total-ticks': 'uint64',
> +           '*weight-ticks': 'uint64'
> +           } }
> +
> +##
> +# @GuestDiskStatsInfo:
> +#
> +# @name disk name
> +#
> +# @major major of disk
> +#
> +# @minor minor of disk
> +##
> +{ 'struct': 'GuestDiskStatsInfo',
> +  'data': {'name': 'str',
> +           'major': 'uint64',
> +           'minor': 'uint64',
> +           'stats': 'GuestDiskStats' } }
> +
> +##
> +# @guest-get-diskstats:
> +#
> +# Retrieve information about disk stats.
> +# Returns: List of disk stats of guest.
> +#
> +# Since: 7.1
> +##
> +{ 'command': 'guest-get-diskstats',
> +  'returns': ['GuestDiskStatsInfo']
> +}
> --
> 2.31.1
>
>
>