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.
Signed-off-by: Xin Hao <[email protected]>
---
mm/hugetlb.c | 14 +++++++++-----
1 file changed, 9 insertions(+), 5 deletions(-)
diff --git a/mm/hugetlb.c b/mm/hugetlb.c
index 66496fc424f4..db6f63fb083f 100644
--- 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)
+{
+ return (h->free_huge_pages - h->resv_huge_pages == 0) ? true : false;
+}
+
static struct page *dequeue_huge_page_vma(struct hstate *h,
struct vm_area_struct *vma,
unsigned long address, int avoid_reserve,
@@ -1207,12 +1212,11 @@ static struct page *dequeue_huge_page_vma(struct hstate *h,
* have no page reserves. This check ensures that reservations are
* not "stolen". The child may still get SIGKILLed
*/
- if (!vma_has_reserves(vma, chg) &&
- h->free_huge_pages - h->resv_huge_pages == 0)
+ if (!vma_has_reserves(vma, chg) && is_resv_equal_free(h))
goto err;
/* If reserves cannot be used, ensure enough pages are in the pool */
- if (avoid_reserve && h->free_huge_pages - h->resv_huge_pages == 0)
+ if (avoid_reserve && is_resv_equal_free(h))
goto err;
gfp_mask = htlb_alloc_mask(h);
@@ -2105,7 +2109,7 @@ int dissolve_free_huge_page(struct page *page)
if (!page_count(page)) {
struct page *head = compound_head(page);
struct hstate *h = page_hstate(head);
- if (h->free_huge_pages - h->resv_huge_pages == 0)
+ if (is_resv_equal_free(h))
goto out;
/*
@@ -2315,7 +2319,7 @@ struct page *alloc_huge_page_nodemask(struct hstate *h, int preferred_nid,
nodemask_t *nmask, gfp_t gfp_mask)
{
spin_lock_irq(&hugetlb_lock);
- if (h->free_huge_pages - h->resv_huge_pages > 0) {
+ if (!is_resv_equal_free(h)) {
struct page *page;
page = dequeue_huge_page_nodemask(h, gfp_mask, preferred_nid, nmask);
--
2.31.0
On Fri, 16 Sep 2022 14:41:27 +0800 Xin Hao <[email protected]> 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()?
This would all be clearer if we'd bothered to document the fields of
struct hstate :(
> +{
> + return (h->free_huge_pages - h->resv_huge_pages == 0) ? true : false;
return h->free_huge_pages == h->resv_huge_pages;
> +}
On 09/16/22 13:12, Andrew Morton wrote:
> On Fri, 16 Sep 2022 14:41:27 +0800 Xin Hao <[email protected]> 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()?
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.
--
Mike Kravetz
>
>
> > +{
> > + return (h->free_huge_pages - h->resv_huge_pages == 0) ? true : false;
>
> return h->free_huge_pages == h->resv_huge_pages;
>
> > +}
>
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 <[email protected]> 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.