On 5/2/07, Rajat Jain <rajat.noida.india@xxxxxxxxx> wrote:
Hi Pradeep, > > > Can you please recheck if you are not holding any spinlocks.Also check > > > if you are not doing a memory allocation with spinlock held or in > > > interrupt context.May be you are doing something like printk which may > > > sleep IMO.Rechcek any methods you are calling which may sleep. > > > > printk will not sleep. Thus it is safe to call printk from any where > > except from very few restricted locations like some scheduler etc. > > Can you please help me out in understanding why? > Printk involves allocating buffer for the message to be printed, > right?Which can sleep, isnt it? > What am i missing here? No, printk does not allocate any buffer. printk has a compile time circular buffer (log_buf) whose size is determined by compile time constant. So what prink does is mere dump the message in this circular buffer.
Oh... got it.but this raises a silly doubt for me. this means you cannot just keep on priniting a lot of data using a single printk right? May be log_buf has a buffer size limit because it is a compile time constant. What am i missing here? Thanks ~psr
Thanks, Rajat
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