From 6eb4e88a6d27022ea8aff424d47a0a5dfc9fcb34 Mon Sep 17 00:00:00 2001 From: Mike Kravetz Date: Tue, 4 May 2021 18:34:55 -0700 Subject: [PATCH] hugetlb: create remove_hugetlb_page() to separate functionality The new remove_hugetlb_page() routine is designed to remove a hugetlb page from hugetlbfs processing. It will remove the page from the active or free list, update global counters and set the compound page destructor to NULL so that PageHuge() will return false for the 'page'. After this call, the 'page' can be treated as a normal compound page or a collection of base size pages. update_and_free_page no longer decrements h->nr_huge_pages{_node} as this is performed in remove_hugetlb_page. The only functionality performed by update_and_free_page is to free the base pages to the lower level allocators. update_and_free_page is typically called after remove_hugetlb_page. remove_hugetlb_page is to be called with the hugetlb_lock held. Creating this routine and separating functionality is in preparation for restructuring code to reduce lock hold times. This commit should not introduce any changes to functionality. Link: https://lkml.kernel.org/r/20210409205254.242291-5-mike.kravetz@oracle.com Signed-off-by: Mike Kravetz Acked-by: Michal Hocko Reviewed-by: Miaohe Lin Reviewed-by: Muchun Song Reviewed-by: Oscar Salvador Cc: "Aneesh Kumar K . V" Cc: Barry Song Cc: David Hildenbrand Cc: David Rientjes Cc: Hillf Danton Cc: HORIGUCHI NAOYA Cc: Joonsoo Kim Cc: Matthew Wilcox Cc: Mina Almasry Cc: Peter Xu Cc: Peter Zijlstra Cc: Roman Gushchin Cc: Shakeel Butt Cc: Waiman Long Cc: Will Deacon Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- mm/hugetlb.c | 65 +++++++++++++++++++++++++++++++++++++----------------------- 1 file changed, 40 insertions(+), 25 deletions(-) diff --git a/mm/hugetlb.c b/mm/hugetlb.c index 067fd29..9a263a1 100644 --- a/mm/hugetlb.c +++ b/mm/hugetlb.c @@ -1333,6 +1333,41 @@ static inline void destroy_compound_gigantic_page(struct page *page, unsigned int order) { } #endif +/* + * Remove hugetlb page from lists, and update dtor so that page appears + * as just a compound page. A reference is held on the page. + * + * Must be called with hugetlb lock held. + */ +static void remove_hugetlb_page(struct hstate *h, struct page *page, + bool adjust_surplus) +{ + int nid = page_to_nid(page); + + VM_BUG_ON_PAGE(hugetlb_cgroup_from_page(page), page); + VM_BUG_ON_PAGE(hugetlb_cgroup_from_page_rsvd(page), page); + + if (hstate_is_gigantic(h) && !gigantic_page_runtime_supported()) + return; + + list_del(&page->lru); + + if (HPageFreed(page)) { + h->free_huge_pages--; + h->free_huge_pages_node[nid]--; + } + if (adjust_surplus) { + h->surplus_huge_pages--; + h->surplus_huge_pages_node[nid]--; + } + + set_page_refcounted(page); + set_compound_page_dtor(page, NULL_COMPOUND_DTOR); + + h->nr_huge_pages--; + h->nr_huge_pages_node[nid]--; +} + static void update_and_free_page(struct hstate *h, struct page *page) { int i; @@ -1341,8 +1376,6 @@ static void update_and_free_page(struct hstate *h, struct page *page) if (hstate_is_gigantic(h) && !gigantic_page_runtime_supported()) return; - h->nr_huge_pages--; - h->nr_huge_pages_node[page_to_nid(page)]--; for (i = 0; i < pages_per_huge_page(h); i++, subpage = mem_map_next(subpage, page, i)) { subpage->flags &= ~(1 << PG_locked | 1 << PG_error | @@ -1350,10 +1383,6 @@ static void update_and_free_page(struct hstate *h, struct page *page) 1 << PG_active | 1 << PG_private | 1 << PG_writeback); } - VM_BUG_ON_PAGE(hugetlb_cgroup_from_page(page), page); - VM_BUG_ON_PAGE(hugetlb_cgroup_from_page_rsvd(page), page); - set_compound_page_dtor(page, NULL_COMPOUND_DTOR); - set_page_refcounted(page); if (hstate_is_gigantic(h)) { destroy_compound_gigantic_page(page, huge_page_order(h)); free_gigantic_page(page, huge_page_order(h)); @@ -1421,15 +1450,12 @@ static void __free_huge_page(struct page *page) h->resv_huge_pages++; if (HPageTemporary(page)) { - list_del(&page->lru); - ClearHPageTemporary(page); + remove_hugetlb_page(h, page, false); update_and_free_page(h, page); } else if (h->surplus_huge_pages_node[nid]) { /* remove the page from active list */ - list_del(&page->lru); + remove_hugetlb_page(h, page, true); update_and_free_page(h, page); - h->surplus_huge_pages--; - h->surplus_huge_pages_node[nid]--; } else { arch_clear_hugepage_flags(page); enqueue_huge_page(h, page); @@ -1714,13 +1740,7 @@ static int free_pool_huge_page(struct hstate *h, nodemask_t *nodes_allowed, struct page *page = list_entry(h->hugepage_freelists[node].next, struct page, lru); - list_del(&page->lru); - h->free_huge_pages--; - h->free_huge_pages_node[node]--; - if (acct_surplus) { - h->surplus_huge_pages--; - h->surplus_huge_pages_node[node]--; - } + remove_hugetlb_page(h, page, acct_surplus); update_and_free_page(h, page); ret = 1; break; @@ -1758,7 +1778,6 @@ retry: if (!page_count(page)) { struct page *head = compound_head(page); struct hstate *h = page_hstate(head); - int nid = page_to_nid(head); if (h->free_huge_pages - h->resv_huge_pages == 0) goto out; @@ -1789,9 +1808,7 @@ retry: SetPageHWPoison(page); ClearPageHWPoison(head); } - list_del(&head->lru); - h->free_huge_pages--; - h->free_huge_pages_node[nid]--; + remove_hugetlb_page(h, page, false); h->max_huge_pages--; update_and_free_page(h, head); rc = 0; @@ -2558,10 +2575,8 @@ static void try_to_free_low(struct hstate *h, unsigned long count, return; if (PageHighMem(page)) continue; - list_del(&page->lru); + remove_hugetlb_page(h, page, false); update_and_free_page(h, page); - h->free_huge_pages--; - h->free_huge_pages_node[page_to_nid(page)]--; } } } -- 2.7.4