Re: [PATCH-cpuset v6 0/2] Add Union-Find and use it to optimize cpuset

[Tejun Heo <tj@kernel.org>]

Hello, Xavier.

On Sat, Jun 22, 2024 at 03:14:22PM +0800, Xavier wrote:
> To Tejun,
> Since union_find operation does not require contiguous physical memory, I
> have replaced the previous allocation method with vzalloc.

Oh, that's not what I meant. Sorry about not being clearer. What I was
trying to say was that requiring consecutive allocation whether kzalloc or
vzalloc is unlikely to work for kernel data structures. The reason why I
mentioned vmalloc was because it's easy to end up in sizes that require
vmalloc with consecutive allocations and vmallocs are rather expensive and
not that great - ie. having to use vmalloc may negate the benefits of better
algorithm in most cases.

Skimming the code, there's nothing requiring consecutive allocations. Is
there a reason why this can't follow the usual convention that kernel data
structures follow (e.g. list, rbtree) where allocation is left to the users?

Thanks.

-- 
tejun