On 2018年09月25日 21:31, Sergey Senozhatsky wrote:
> On (09/25/18 14:23), Petr Mladek wrote:
>> The 32GB was mentioned as an example one year ego. This is not enough
>> for a new syscall from my point of view.
> I agree. I didn't think of syslog(); was merely thinking about logbuf
> and flushing it to the consoles. syslog() stuff is a bit complex. We
> sort of don't expect user space to allocate 64G to read all log_buf
> messages, do we.
>
> I'm wondering if we can do something like this
>
> ---
>
> diff --git a/kernel/printk/printk.c b/kernel/printk/printk.c
> index cf275f4d7912..1b48b61da8fe 100644
> --- a/kernel/printk/printk.c
> +++ b/kernel/printk/printk.c
> @@ -1110,9 +1110,15 @@ static void __init log_buf_len_update(unsigned size)
> /* save requested log_buf_len since it's too early to process it */
> static int __init log_buf_len_setup(char *str)
> {
> - unsigned size = memparse(str, &str);
> + u64 size = memparse(str, &str);
>
> - log_buf_len_update(size);
> + if (size > UINT_MAX) {
> + size = UINT_MAX;
> + pr_err("log_buf over 4G is not supported. "
> + "Please contact printk maintainers.\n");
> + }
> +
> + log_buf_len_update((unsigned int)size);
>
> return 0;
> }
>
> ---
>
> So we could know that "the day has come".
I agree on this idea, a good way to collect the potential requirement.
I can send v4 with it if no objection from other people.
Thanks,
Zhe
>
> -ss
>
