Re: [PATCH v2 1/2] memcg: use seq_buf_do_printk() with mem_cgroup_print_oom_meminfo()

[Muchun Song <muchun.song-fxUVXftIFDnyG1zEObXtfA@public.gmane.org>]

> On Apr 28, 2023, at 21:24, Yosry Ahmed <yosryahmed-hpIqsD4AKlfQT0dZR+AlfA@public.gmane.org> wrote:
> 
> Currently, we format all the memcg stats into a buffer in
> mem_cgroup_print_oom_meminfo() and use pr_info() to dump it to the logs.
> However, this buffer is large in size. Although it is currently working
> as intended, ther is a dependency between the memcg stats buffer and the
> printk record size limit.
> 
> If we add more stats in the future and the buffer becomes larger than
> the printk record size limit, or if the prink record size limit is
> reduced, the logs may be truncated.
> 
> It is safer to use seq_buf_do_printk(), which will automatically break
> up the buffer at line breaks and issue small printk() calls.
> 
> Refactor the code to move the seq_buf from memory_stat_format() to its
> callers, and use seq_buf_do_printk() to print the seq_buf in
> mem_cgroup_print_oom_meminfo().
> 
> Signed-off-by: Yosry Ahmed <yosryahmed-hpIqsD4AKlfQT0dZR+AlfA@public.gmane.org>
> Acked-by: Michal Hocko <mhocko-IBi9RG/b67k@public.gmane.org>
> Reviewed-by: Sergey Senozhatsky <senozhatsky-F7+t8E8rja9g9hUCZPvPmw@public.gmane.org>

Reviewed-by: Muchun Song <songmuchun-EC8Uxl6Npydl57MIdRCFDg@public.gmane.org>

Thanks.