How can I change the size of dmesg ? [linux 2.4]

Question

I'm writing some code with printk [i'm printing while in kernel mode] , but because dmesg is too small I'm losing the first few printk's.

How can I increase the size of dmesg ?

thanks in advance for the help!

Answer 1

You need to set CONFIG_LOG_BUF_SHIFT during compile time. The size of the buffer can not be modified in run time.

The size of the buffer is 2^CONFIG_LOG_BUF_SHIFT bytes

Answer 2

You can use the log_buf_len kernel parameter at boot time to set the kernel's printk() ring buffer size.

See: https://www.kernel.org/doc/Documentation/admin-guide/kernel-parameters.txt

(You mentioned Linux 2.4; I don't know whether log_buf_len was present in Linux 2.4, which is very old.)