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authorPaul Menzel <pmenzel@molgen.mpg.de>2020-08-11 11:29:23 +0200
committerPetr Mladek <pmladek@suse.com>2020-11-03 09:34:40 +0100
commit0f7636e1654338c34e3c220c02b2ffad78b6ccc0 (patch)
tree91f98c59bdc35b0b0f849c2fdfd1959f5bb8e1c0
parent8119c4332d253660e0a6b8748fe0749961cfbc97 (diff)
downloadlinux-0f7636e1654338c34e3c220c02b2ffad78b6ccc0.tar.bz2
init/Kconfig: Fix CPU number in LOG_CPU_MAX_BUF_SHIFT description
Currently, LOG_BUF_SHIFT defaults to 17, which is 2 ^ 17 bytes = 128 KB, and LOG_CPU_MAX_BUF_SHIFT defaults to 12, which is 2 ^ 12 bytes = 4 KB. Half of 128 KB is 64 KB, so more than 16 CPUs are required for the value to be used, as then the sum of contributions is greater than 64 KB for the first time. My guess is, that the description was written with the configuration values used in the SUSE in mind. Fixes: 23b2899f7f194f06e ("printk: allow increasing the ring buffer depending on the number of CPUs") Cc: Luis R. Rodriguez <mcgrof@suse.com> Cc: linux-kernel@vger.kernel.org Signed-off-by: Paul Menzel <pmenzel@molgen.mpg.de> Reviewed-by: Petr Mladek <pmladek@suse.com> Signed-off-by: Petr Mladek <pmladek@suse.com> Link: https://lore.kernel.org/r/20200811092924.6256-1-pmenzel@molgen.mpg.de
-rw-r--r--init/Kconfig2
1 files changed, 1 insertions, 1 deletions
diff --git a/init/Kconfig b/init/Kconfig
index c9446911cf41..02d13ae27abb 100644
--- a/init/Kconfig
+++ b/init/Kconfig
@@ -719,7 +719,7 @@ config LOG_CPU_MAX_BUF_SHIFT
with more CPUs. Therefore this value is used only when the sum of
contributions is greater than the half of the default kernel ring
buffer as defined by LOG_BUF_SHIFT. The default values are set
- so that more than 64 CPUs are needed to trigger the allocation.
+ so that more than 16 CPUs are needed to trigger the allocation.
Also this option is ignored when "log_buf_len" kernel parameter is
used as it forces an exact (power of two) size of the ring buffer.