How to Change Linux Kernel dmesg buffer size

Printk is implemented by using a ring buffer in the kernel with a size of __LOG_BUF_LEN bytes where __LOG_BUF_LEN equals (1 << CONFIG_LOG_BUF_SHIFT).

dmesg buffer size can be changed using “CONFIG_LOG_BUF_SHIFT” Kconfig.

As per kernel source (4.1.0), default value of this config is 17 (i.e. 1 << 17 = 128KB). The range for this config is 12 to 21.

Addign  below line in defconfig sets

Note: If invalid value (out of range value) is set, default value is taken.

CONFIG_LOG_BUF_SHIFT can be changed from menuconfig or from defconfig as below:

CONFIG_LOG_BUF_SHIFT=21
Advertisements

Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out / Change )

Twitter picture

You are commenting using your Twitter account. Log Out / Change )

Facebook photo

You are commenting using your Facebook account. Log Out / Change )

Google+ photo

You are commenting using your Google+ account. Log Out / Change )

Connecting to %s