Re: [PATCH V2] mm/hugetlb: add is_resv_equal_free() func

From: haoxin
Date: Fri Sep 16 2022 - 21:18:00 EST



在 2022/9/17 上午5:09, Mike Kravetz 写道:
On 09/16/22 13:12, Andrew Morton wrote:
On Fri, 16 Sep 2022 14:41:27 +0800 Xin Hao <xhao@xxxxxxxxxxxxxxxxx> wrote:

In hugetlb.c file, there are several places to compare the values of
'h->free_huge_pages' and 'h->resv_huge_pages', it looks a bit messy, so
there add a new is_resv_equal_free() func to do these.

...

--- a/mm/hugetlb.c
+++ b/mm/hugetlb.c
@@ -1191,6 +1191,11 @@ static struct page *dequeue_huge_page_nodemask(struct hstate *h, gfp_t gfp_mask,
return NULL;
}

+static inline bool is_resv_equal_free(struct hstate *h)
I'm not sure that's a well chosen name. A better name would reflect
the *meaning* of free_huge_pages being equal to resv_huge_pages. Maybe
something like reserves_exhausted()?
How about calling it free_non_reserved_huge_pages() and returning the actual
value (h->free_huge_pages - h->resv_huge_pages)?

Perhaps available_huge_pages()?
Ok, I am going to use available_huge_pages() in the patch v3, thanks.
It could then be used in at least one other place
- if (h->free_huge_pages - h->resv_huge_pages > 0)

This would all be clearer if we'd bothered to document the fields of
struct hstate :(
Agree, and discussed elsewhwere some may even be able to be eliminated. I can
add that to my todo list.