Re: [PATCH 2/3] lockdep: clarify size for LOCKDEP_*_BITS configs

From: Waiman Long
Date: Tue Aug 06 2024 - 10:54:34 EST



On 8/6/24 10:47, Carlos Llamas wrote:
On Mon, Aug 05, 2024 at 09:36:43PM -0400, Waiman Long wrote:
Many kernel developers understand that BITS refers to a size of 2^n. Besides
LOCKDEP, there are also many instances of such use in other kconfig entries.
It can be a bit odd to explicitly state that just for LOCKDEP.

Cheers,
Longman
Right, and similar to BITS there is SHIFT, which is also a common way to
specify the 2^n values. I'd point out though, that it is also common to
clarify the "power of two" explicitly. To name a few examples that are
doing so: SECURITY_SELINUX_SIDTAB_HASH_BITS, NODES_SHIFT, CMA_ALIGNMENT,
IP_VS_SH_TAB_BITS, LOG_BUF_SHIFT but there is more.

Perhaps this is because the audience for these configs is not always a
kernel developer?

Anyway, this is pretty much a trivial patch to address Andrew's comment
below. But let me know if you think I should drop it, it seems to me it
can be helpful.

[...]
btw, the help text "Bitsize for MAX_LOCKDEP_CHAINS" is odd. What's a
bitsize? Maybe "bit shift count for..." or such.

I am not against this patch. Currently I am neutral. Let's see what Boqun think about it.

Cheers,
Longman