lkml.org 
[lkml]   [2020]   [Jun]   [25]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
From
Subjecttruncate dict: was: Re: [PATCH v3 3/3] printk: use the lockless ringbuffer
On Thu 2020-06-18 16:55:19, John Ogness wrote:
> Replace the existing ringbuffer usage and implementation with
> lockless ringbuffer usage. Even though the new ringbuffer does not
> require locking, all existing locking is left in place. Therefore,
> this change is purely replacing the underlining ringbuffer.

> --- a/kernel/printk/printk.c
> +++ b/kernel/printk/printk.c
> @@ -594,22 +473,26 @@ static u32 msg_used_size(u16 text_len, u16 dict_len, u32 *pad_len)
> #define MAX_LOG_TAKE_PART 4
> static const char trunc_msg[] = "<truncated>";
>
> -static u32 truncate_msg(u16 *text_len, u16 *trunc_msg_len,
> - u16 *dict_len, u32 *pad_len)
> +static void truncate_msg(u16 *text_len, u16 *trunc_msg_len, u16 *dict_len)
> {
> /*
> * The message should not take the whole buffer. Otherwise, it might
> * get removed too soon.
> */
> u32 max_text_len = log_buf_len / MAX_LOG_TAKE_PART;
> +
> if (*text_len > max_text_len)
> *text_len = max_text_len;
> - /* enable the warning message */
> +
> + /* enable the warning message (if there is room) */
> *trunc_msg_len = strlen(trunc_msg);
> + if (*text_len >= *trunc_msg_len)
> + *text_len -= *trunc_msg_len;
> + else
> + *trunc_msg_len = 0;
> +
> /* disable the "dict" completely */
> *dict_len = 0;

The dictionary does not longer need to be removed at this point.
It is stored in a separate buffer. It is ignored by prb_reserve()
when there is not enough space for it.

> - /* compute the size again, count also the warning message */
> - return msg_used_size(*text_len + *trunc_msg_len, 0, pad_len);
> }
>
> /* insert record into the buffer, discard old ones, update heads */

Best Regards,
Petr

PS: I am still in the middle of review of this patch. I decided to
send the tree comments that I already have separately.

\
 
 \ /
  Last update: 2020-06-25 10:17    [W:0.289 / U:0.048 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site