Re: [PATCH 04/10] mm/hugetlb: count file_region to be added when regions_needed != NULL

Baoquan He
2020-08-07T12:54:33Z

On 08/07/20 at 05:12pm, Wei Yang wrote:
> There are only two cases of function add_reservation_in_range()
>
> * count file_region and return the number in regions_needed
> * do the real list operation without counting
>
> This means it is not necessary to have two parameters to classify these
> two cases.
>
> Just use regions_needed to separate them.
>
> Signed-off-by: Wei Yang <richard.weiyang@linux.alibaba.com>

Nice clean up.

Reviewed-by: Baoquan He <bhe@redhat.com>

> ---
> mm/hugetlb.c | 33 +++++++++++++++++----------------
> 1 file changed, 17 insertions(+), 16 deletions(-)
>
> diff --git a/mm/hugetlb.c b/mm/hugetlb.c
> index 929256c130f9..d775e514eb2e 100644
> --- a/mm/hugetlb.c
> +++ b/mm/hugetlb.c
> @@ -321,16 +321,17 @@ static void coalesce_file_region(struct resv_map *resv, struct file_region *rg)
> }
> }
>
> -/* Must be called with resv->lock held. Calling this with count_only == true
> - * will count the number of pages to be added but will not modify the linked
> - * list. If regions_needed != NULL and count_only == true, then regions_needed
> - * will indicate the number of file_regions needed in the cache to carry out to
> - * add the regions for this range.
> +/*
> + * Must be called with resv->lock held.
> + *
> + * Calling this with regions_needed != NULL will count the number of pages
> + * to be added but will not modify the linked list. And regions_needed will
> + * indicate the number of file_regions needed in the cache to carry out to add
> + * the regions for this range.
> */
> static long add_reservation_in_range(struct resv_map *resv, long f, long t,
> struct hugetlb_cgroup *h_cg,
> - struct hstate *h, long *regions_needed,
> - bool count_only)
> + struct hstate *h, long *regions_needed)
> {
> long add = 0;
> struct list_head *head = &resv->regions;
> @@ -366,14 +367,14 @@ static long add_reservation_in_range(struct resv_map *resv, long f, long t,
> */
> if (rg->from > last_accounted_offset) {
> add += rg->from - last_accounted_offset;
> - if (!count_only) {
> + if (!regions_needed) {
> nrg = get_file_region_entry_from_cache(
> resv, last_accounted_offset, rg->from);
> record_hugetlb_cgroup_uncharge_info(h_cg, h,
> resv, nrg);
> list_add(&nrg->link, rg->link.prev);
> coalesce_file_region(resv, nrg);
> - } else if (regions_needed)
> + } else
> *regions_needed += 1;
> }
>
> @@ -385,13 +386,13 @@ static long add_reservation_in_range(struct resv_map *resv, long f, long t,
> */
> if (last_accounted_offset < t) {
> add += t - last_accounted_offset;
> - if (!count_only) {
> + if (!regions_needed) {
> nrg = get_file_region_entry_from_cache(
> resv, last_accounted_offset, t);
> record_hugetlb_cgroup_uncharge_info(h_cg, h, resv, nrg);
> list_add(&nrg->link, rg->link.prev);
> coalesce_file_region(resv, nrg);
> - } else if (regions_needed)
> + } else
> *regions_needed += 1;
> }
>
> @@ -484,8 +485,8 @@ static long region_add(struct resv_map *resv, long f, long t,
> retry:
>
> /* Count how many regions are actually needed to execute this add. */
> - add_reservation_in_range(resv, f, t, NULL, NULL, &actual_regions_needed,
> - true);
> + add_reservation_in_range(resv, f, t, NULL, NULL,
> + &actual_regions_needed);
>
> /*
> * Check for sufficient descriptors in the cache to accommodate
> @@ -513,7 +514,7 @@ static long region_add(struct resv_map *resv, long f, long t,
> goto retry;
> }
>
> - add = add_reservation_in_range(resv, f, t, h_cg, h, NULL, false);
> + add = add_reservation_in_range(resv, f, t, h_cg, h, NULL);
>
> resv->adds_in_progress -= in_regions_needed;
>
> @@ -549,9 +550,9 @@ static long region_chg(struct resv_map *resv, long f, long t,
>
> spin_lock(&resv->lock);
>
> - /* Count how many hugepages in this range are NOT respresented. */
> + /* Count how many hugepages in this range are NOT represented. */
> chg = add_reservation_in_range(resv, f, t, NULL, NULL,
> - out_regions_needed, true);
> + out_regions_needed);
>
> if (*out_regions_needed == 0)
> *out_regions_needed = 1;
> --
> 2.20.1 (Apple Git-117)
>
>