[RFC][PATCH] printk: add boot_quiet param to support deferred printk while booting

[Barry Song]

Hi Baruch,
Thanks!

> -----Original Message-----
> From: Baruch Siach [mailto:baruch at tkos.co.il]
> Sent: Friday, November 23, 2012 11:07 AM
> To: Barry Song
> Cc: gregkh at linuxfoundation.org; DL-SHA-WorkGroupLinux;
> linux-pm at lists.linux-foundation.org; linux-kernel at vger.kernel.org;
> linux-arm-kernel at lists.infradead.org
> Subject: Re: [RFC][PATCH] printk: add boot_quiet param to support deferred
> printk while booting
> 
> Hi Barry,
> 
> On Fri, Nov 23, 2012 at 10:50:22AM +0800, Barry Song wrote:
> 
> [...]
> 
> > diff --git a/kernel/printk.c b/kernel/printk.c
> > index 2d607f4..0b88d6bf 100644
> > --- a/kernel/printk.c
> > +++ b/kernel/printk.c
> > @@ -250,6 +250,9 @@ static u32 clear_idx;
> >  #define LOG_ALIGN __alignof__(struct log)
> >  #endif
> >  #define __LOG_BUF_LEN (1 << CONFIG_LOG_BUF_SHIFT)
> > +static char __boot_log_buf[__LOG_BUF_LEN] __aligned(LOG_ALIGN);
> 
> Since we do not use this buffer when the system is running, is there a way to
> release it once its content has been written to console?
> 

Definitely yes. at this moment the code is just a RFC to get people's agreement about the idea.

i have a note in my RFC if you didn't miss :-)
" Note: This is only a RFC, after we agree about the idea, i will move the boot_log_buf to __initdata."

> baruch
> 
> > +static int boot_log_len;
> > +
> >  static char __log_buf[__LOG_BUF_LEN] __aligned(LOG_ALIGN);
> >  static char *log_buf = __log_buf;
> >  static u32 log_buf_len = __LOG_BUF_LEN;
> > @@ -1247,6 +1250,16 @@ module_param(ignore_loglevel, bool, S_IRUGO |
> S_IWUSR);
> 

-barry



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