[RFC][PATCH] Add support for oom_score_adj

[Scott James Remnant]

Thanks for the patch, a few comments inline below...

On Sun, Mar 13, 2011 at 11:29 AM, Marc - A. Dahlhaus <mad at wol.de> wrote:
> --- a/init/job_class.h
> +++ b/init/job_class.h
> @@ -94,6 +94,7 @@ typedef enum console_type {
>  * @umask: file mode creation mask,
>  * @nice: process priority,
>  * @oom_adj: OOM killer adjustment,
> + * @oom_score_adj: OOM killer score adjustment,
>  * @limits: resource limits indexed by resource,
>  * @chroot: root directory of process (implies @chdir if not set),
>  * @chdir: working directory of process,
> @@ -142,6 +143,7 @@ typedef struct job_class {
>        mode_t          umask;
>        int             nice;
>        int             oom_adj;
> +       int             oom_score_adj;
>        struct rlimit  *limits[RLIMIT_NLIMITS];
>        char           *chroot;
>        char           *chdir;

Why keep both oom_adj and oom_score_adj in the struct? If you only
kept the oom_score_adj in the struct, you could multiple the oom_adj
values to it, and divide later.

> --- a/init/job_process.c
> +++ b/init/job_process.c
> @@ -487,14 +487,20 @@ job_process_spawn (JobClass     *class,
>                fd = fopen (filename, "w");
>                if (! fd) {
> +                       snprintf (filename, sizeof (filename),
> +                                 "/proc/%d/oom_adj", getpid ());
> +                       oom_value = class->oom_adj;
> +                       fd = fopen (filename, "w");
> +               }
> +               if (! fd) {
>
There's no errno checking here - the file could fail to open for any
number of reasons, it should only fall back to the old interface in
the one reason that the new interface doesn't exist.

Scott