[pve-devel] [PATCH common 3/4] add helper to fetch value from smaps_rollup for pid

[Thomas Lamprecht]

Short summary about what that file contains and why it can be useful (for us)
would be great to have as context here.

Am 23.05.25 um 18:37 schrieb Aaron Lauterer:
> Signed-off-by: Aaron Lauterer <a.lauterer at proxmox.com>
> ---
>  src/PVE/ProcFSTools.pm | 14 ++++++++++++++
>  1 file changed, 14 insertions(+)
> 
> diff --git a/src/PVE/ProcFSTools.pm b/src/PVE/ProcFSTools.pm
> index 382e6c5..185b2b3 100644
> --- a/src/PVE/ProcFSTools.pm
> +++ b/src/PVE/ProcFSTools.pm
> @@ -344,6 +344,20 @@ sub read_meminfo {
>      return $res;
>  }
>  
> +# extract memory data from /proc/$pid/smaps_rollup for PID. $value is e.g. "Pss".
> +sub read_smaps_rollup {
> +    my ($pid, $value) = @_;
> +
> +    my $res = 0;
> +    return $res if !$pid || !$value;
> +
> +    my $mem_stats = eval { PVE::Tools::file_get_contents("/proc/${pid}/smaps_rollup") };
> +    if ($mem_stats && $mem_stats =~ m/^${value}:\s+(\d+)\s*kB$/m) {

is this an efficient interface? A caller needing more than one handful will
cause a full read of the file and regex match applied to that, granted, it's
not huge, but that's still not really a good excuse...

As of now this is really not better than just doing the same on a call site
directly. A method in such a generic interface should do better and return
a parsed list of values as hash.

> +	$res = $1 * 1024;
> +    }
> +    return $res;
> +}
> +
>  # memory usage of current process
>  sub read_memory_usage {
>