On 12/04/2017 06:01 AM, Michal Hocko wrote:
> From: Michal Hocko <mhocko@xxxxxxxx>
>
> Gigantic hugetlb pages were ingrown to the hugetlb code as an alien
> specie with a lot of special casing. The allocation path is not an
> exception. Unnecessarily so to be honest. It is true that the underlying
> allocator is different but that is an implementation detail.
>
> This patch unifies the hugetlb allocation path that a prepares fresh
> pool pages. alloc_fresh_gigantic_page basically copies alloc_fresh_huge_page
> logic so we can move everything there. This will simplify set_max_huge_pages
> which doesn't have to care about what kind of huge page we allocate.
>
> Signed-off-by: Michal Hocko <mhocko@xxxxxxxx>
I agree with the analysis. Thanks for cleaning this up. There really is
no need for the separate allocation paths.
Reviewed-by: Mike Kravetz <mike.kravetz@xxxxxxxxxx>
--
Mike Kravetz
> ---
> mm/hugetlb.c | 53 ++++++++++++-----------------------------------------
> 1 file changed, 12 insertions(+), 41 deletions(-)
>
> diff --git a/mm/hugetlb.c b/mm/hugetlb.c
> index 8189c92fac82..ac105fb32620 100644
> --- a/mm/hugetlb.c
> +++ b/mm/hugetlb.c
> @@ -1106,7 +1106,8 @@ static bool zone_spans_last_pfn(const struct zone *zone,
> return zone_spans_pfn(zone, last_pfn);
> }
>
> -static struct page *alloc_gigantic_page(int nid, struct hstate *h)
> +static struct page *alloc_gigantic_page(struct hstate *h, gfp_t gfp_mask,
> + int nid, nodemask_t *nodemask)
> {
> unsigned int order = huge_page_order(h);
> unsigned long nr_pages = 1 << order;
> @@ -1114,11 +1115,9 @@ static struct page *alloc_gigantic_page(int nid, struct hstate *h)
> struct zonelist *zonelist;
> struct zone *zone;
> struct zoneref *z;
> - gfp_t gfp_mask;
>
> - gfp_mask = htlb_alloc_mask(h) | __GFP_THISNODE;
> zonelist = node_zonelist(nid, gfp_mask);
> - for_each_zone_zonelist_nodemask(zone, z, zonelist, gfp_zone(gfp_mask), NULL) {
> + for_each_zone_zonelist_nodemask(zone, z, zonelist, gfp_zone(gfp_mask), nodemask) {
> spin_lock_irqsave(&zone->lock, flags);
>
> pfn = ALIGN(zone->zone_start_pfn, nr_pages);
> @@ -1149,42 +1148,11 @@ static struct page *alloc_gigantic_page(int nid, struct hstate *h)
> static void prep_new_huge_page(struct hstate *h, struct page *page, int nid);
> static void prep_compound_gigantic_page(struct page *page, unsigned int order);
>
> -static struct page *alloc_fresh_gigantic_page_node(struct hstate *h, int nid)
> -{
> - struct page *page;
> -
> - page = alloc_gigantic_page(nid, h);
> - if (page) {
> - prep_compound_gigantic_page(page, huge_page_order(h));
> - prep_new_huge_page(h, page, nid);
> - put_page(page); /* free it into the hugepage allocator */
> - }
> -
> - return page;
> -}
> -
> -static int alloc_fresh_gigantic_page(struct hstate *h,
> - nodemask_t *nodes_allowed)
> -{
> - struct page *page = NULL;
> - int nr_nodes, node;
> -
> - for_each_node_mask_to_alloc(h, nr_nodes, node, nodes_allowed) {
> - page = alloc_fresh_gigantic_page_node(h, node);
> - if (page)
> - return 1;
> - }
> -
> - return 0;
> -}
> -
> #else /* !CONFIG_ARCH_HAS_GIGANTIC_PAGE */
> static inline bool gigantic_page_supported(void) { return false; }
> static inline void free_gigantic_page(struct page *page, unsigned int order) { }
> static inline void destroy_compound_gigantic_page(struct page *page,
> unsigned int order) { }
> -static inline int alloc_fresh_gigantic_page(struct hstate *h,
> - nodemask_t *nodes_allowed) { return 0; }
> #endif
>
> static void update_and_free_page(struct hstate *h, struct page *page)
> @@ -1410,8 +1378,12 @@ static int alloc_fresh_huge_page(struct hstate *h, nodemask_t *nodes_allowed)
> gfp_t gfp_mask = htlb_alloc_mask(h) | __GFP_THISNODE;
>
> for_each_node_mask_to_alloc(h, nr_nodes, node, nodes_allowed) {
> - page = __hugetlb_alloc_buddy_huge_page(h, gfp_mask,
> - node, nodes_allowed);
> + if (hstate_is_gigantic(h))
> + page = alloc_gigantic_page(h, gfp_mask,
> + node, nodes_allowed);
> + else
> + page = __hugetlb_alloc_buddy_huge_page(h, gfp_mask,
> + node, nodes_allowed);
> if (page)
> break;
>
> @@ -1420,6 +1392,8 @@ static int alloc_fresh_huge_page(struct hstate *h, nodemask_t *nodes_allowed)
> if (!page)
> return 0;
>
> + if (hstate_is_gigantic(h))
> + prep_compound_gigantic_page(page, huge_page_order(h));
> prep_new_huge_page(h, page, page_to_nid(page));
> put_page(page); /* free it into the hugepage allocator */
>
> @@ -2307,10 +2281,7 @@ static unsigned long set_max_huge_pages(struct hstate *h, unsigned long count,
> /* yield cpu to avoid soft lockup */
> cond_resched();
>
> - if (hstate_is_gigantic(h))
> - ret = alloc_fresh_gigantic_page(h, nodes_allowed);
> - else
> - ret = alloc_fresh_huge_page(h, nodes_allowed);
> + ret = alloc_fresh_huge_page(h, nodes_allowed);
> spin_lock(&hugetlb_lock);
> if (!ret)
> goto out;
>
--
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