Re: [PATCH 1/4] hugetlb: Dedup the code to add a new file_region

Miaohe Lin
2021-02-04T02:00:41Z

Hi:
On 2021/2/4 5:08, Peter Xu wrote:
> Introduce hugetlb_resv_map_add() helper to add a new file_region rather than
> duplication the similar code twice in add_reservation_in_range().
>

This cleanup is also in my plan. But I was too sluggish to do this. Many thanks for doing this.
Reviewed-by: Miaohe Lin <linmiaohe@huawei.com>

> Signed-off-by: Peter Xu <peterx@redhat.com>
> ---
> mm/hugetlb.c | 51 +++++++++++++++++++++++++++------------------------
> 1 file changed, 27 insertions(+), 24 deletions(-)
>
> diff --git a/mm/hugetlb.c b/mm/hugetlb.c
> index 18f6ee317900..d2859c2aecc9 100644
> --- a/mm/hugetlb.c
> +++ b/mm/hugetlb.c
> @@ -321,6 +321,24 @@ static void coalesce_file_region(struct resv_map *resv, struct file_region *rg)
> }
> }
>
> +static inline long
> +hugetlb_resv_map_add(struct resv_map *map, struct file_region *rg, long from,
> + long to, struct hstate *h, struct hugetlb_cgroup *cg,
> + long *regions_needed)
> +{
> + struct file_region *nrg;
> +
> + if (!regions_needed) {
> + nrg = get_file_region_entry_from_cache(map, from, to);
> + record_hugetlb_cgroup_uncharge_info(cg, h, map, nrg);
> + list_add(&nrg->link, rg->link.prev);
> + coalesce_file_region(map, nrg);
> + } else
> + *regions_needed += 1;
> +
> + return to - from;
> +}
> +
> /*
> * Must be called with resv->lock held.
> *
> @@ -336,7 +354,7 @@ static long add_reservation_in_range(struct resv_map *resv, long f, long t,
> long add = 0;
> struct list_head *head = &resv->regions;
> long last_accounted_offset = f;
> - struct file_region *rg = NULL, *trg = NULL, *nrg = NULL;
> + struct file_region *rg = NULL, *trg = NULL;
>
> if (regions_needed)
> *regions_needed = 0;
> @@ -365,18 +383,11 @@ static long add_reservation_in_range(struct resv_map *resv, long f, long t,
> /* Add an entry for last_accounted_offset -> rg->from, and
> * update last_accounted_offset.
> */
> - if (rg->from > last_accounted_offset) {
> - add += rg->from - last_accounted_offset;
> - 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
> - *regions_needed += 1;
> - }
> + if (rg->from > last_accounted_offset)
> + add += hugetlb_resv_map_add(resv, rg,
> + last_accounted_offset,
> + rg->from, h, h_cg,
> + regions_needed);
>
> last_accounted_offset = rg->to;
> }
> @@ -384,17 +395,9 @@ static long add_reservation_in_range(struct resv_map *resv, long f, long t,
> /* Handle the case where our range extends beyond
> * last_accounted_offset.
> */
> - if (last_accounted_offset < t) {
> - add += t - last_accounted_offset;
> - 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
> - *regions_needed += 1;
> - }
> + if (last_accounted_offset < t)
> + add += hugetlb_resv_map_add(resv, rg, last_accounted_offset,
> + t, h, h_cg, regions_needed);
>
> VM_BUG_ON(add < 0);
> return add;
>