Re: [PATCH] mm/damon: improve damon_new_region strategy

[Andrew Morton]

On Mon, 12 Sep 2022 22:39:03 +0800 Dawei Li <set_pte_at@xxxxxxxxxxx> wrote:

> Kdamond is implemented as a periodical split-merge pattern, which will
> create and destroy regions possibly on high frequency(hundreds or even
> thousands of per sec), depending on number of regions and aggregation
> period.  In that case, kmalloc and kfree could bring considerable overhead
> to system, which can be improved by private kmem cache.
> 

A dedicated slab cache should be faster and will also consume less
memory, due to better packing into the underlying pages.  So I redid
the changelog thusly:

: Kdamond is implemented as a periodical split-merge pattern, which will
: create and destroy regions possibly at high frequency (hundreds or even
: thousands of per sec), depending on the number of regions and aggregation
: period.  In that case, kmalloc and kfree could bring speed and space
: overheads, which can be improved by using a private kmem cache.

> +static int __init damon_init(void)
> +{
> +	damon_region_cache = kmem_cache_create("damon_region_cache", sizeof(struct damon_region),

Should be able to use just

	damon_region_cache = KMEM_CACHE(damon_region, 0);

here.  Please test that and send along a fixup patch?