diff options
author | Matthew Wilcox (Oracle) <willy@infradead.org> | 2024-03-21 14:24:39 +0000 |
---|---|---|
committer | Andrew Morton <akpm@linux-foundation.org> | 2024-04-25 20:55:59 -0700 |
commit | b7b098cf00a2b65d5654a86dc8edf82f125289c1 (patch) | |
tree | fb38a5cbb30ce4eb6ab9f8abaf3d2b280ab01e2c | |
parent | 3b89ec41747a6b6b8c7b6ad4fe13e063cb6dfe7f (diff) |
mm: always initialise folio->_deferred_list
Patch series "Various significant MM patches".
These patches all interact in annoying ways which make it tricky to send
them out in any way other than a big batch, even though there's not really
an overarching theme to connect them.
The big effects of this patch series are:
- folio_test_hugetlb() becomes reliable, even when called without a
page reference
- We free up PG_slab, and we could always use more page flags
- We no longer need to check PageSlab before calling page_mapcount()
This patch (of 9):
For compound pages which are at least order-2 (and hence have a
deferred_list), initialise it and then we can check at free that the page
is not part of a deferred list. We recently found this useful to rule out
a source of corruption.
[peterx@redhat.com: always initialise folio->_deferred_list]
Link: https://lkml.kernel.org/r/20240417211836.2742593-2-peterx@redhat.com
Link: https://lkml.kernel.org/r/20240321142448.1645400-1-willy@infradead.org
Link: https://lkml.kernel.org/r/20240321142448.1645400-2-willy@infradead.org
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Signed-off-by: Peter Xu <peterx@redhat.com>
Reviewed-by: David Hildenbrand <david@redhat.com>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Cc: Miaohe Lin <linmiaohe@huawei.com>
Cc: Muchun Song <muchun.song@linux.dev>
Cc: Oscar Salvador <osalvador@suse.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
-rw-r--r-- | mm/huge_memory.c | 2 | ||||
-rw-r--r-- | mm/hugetlb.c | 3 | ||||
-rw-r--r-- | mm/internal.h | 2 | ||||
-rw-r--r-- | mm/memcontrol.c | 3 | ||||
-rw-r--r-- | mm/page_alloc.c | 9 |
5 files changed, 12 insertions, 7 deletions
diff --git a/mm/huge_memory.c b/mm/huge_memory.c index 25191ab70631..4cc7133aaa4b 100644 --- a/mm/huge_memory.c +++ b/mm/huge_memory.c @@ -793,8 +793,6 @@ void folio_prep_large_rmappable(struct folio *folio) { if (!folio || !folio_test_large(folio)) return; - if (folio_order(folio) > 1) - INIT_LIST_HEAD(&folio->_deferred_list); folio_set_large_rmappable(folio); } diff --git a/mm/hugetlb.c b/mm/hugetlb.c index ce7be5c24442..378181547b7b 100644 --- a/mm/hugetlb.c +++ b/mm/hugetlb.c @@ -1796,7 +1796,8 @@ static void __update_and_free_hugetlb_folio(struct hstate *h, destroy_compound_gigantic_folio(folio, huge_page_order(h)); free_gigantic_folio(folio, huge_page_order(h)); } else { - __free_pages(&folio->page, huge_page_order(h)); + INIT_LIST_HEAD(&folio->_deferred_list); + folio_put(folio); } } diff --git a/mm/internal.h b/mm/internal.h index 85c3db43454d..5c0c57c9cd19 100644 --- a/mm/internal.h +++ b/mm/internal.h @@ -525,6 +525,8 @@ static inline void prep_compound_head(struct page *page, unsigned int order) atomic_set(&folio->_entire_mapcount, -1); atomic_set(&folio->_nr_pages_mapped, 0); atomic_set(&folio->_pincount, 0); + if (order > 1) + INIT_LIST_HEAD(&folio->_deferred_list); } static inline void prep_compound_tail(struct page *head, int tail_idx) diff --git a/mm/memcontrol.c b/mm/memcontrol.c index 896b4bf05b9c..45dd20901282 100644 --- a/mm/memcontrol.c +++ b/mm/memcontrol.c @@ -7400,6 +7400,9 @@ static void uncharge_folio(struct folio *folio, struct uncharge_gather *ug) struct obj_cgroup *objcg; VM_BUG_ON_FOLIO(folio_test_lru(folio), folio); + VM_BUG_ON_FOLIO(folio_order(folio) > 1 && + !folio_test_hugetlb(folio) && + !list_empty(&folio->_deferred_list), folio); /* * Nobody should be changing or seriously looking at diff --git a/mm/page_alloc.c b/mm/page_alloc.c index e1241ecef271..7e8f4b751801 100644 --- a/mm/page_alloc.c +++ b/mm/page_alloc.c @@ -1007,10 +1007,11 @@ static int free_tail_page_prepare(struct page *head_page, struct page *page) } break; case 2: - /* - * the second tail page: ->mapping is - * deferred_list.next -- ignore value. - */ + /* the second tail page: deferred_list overlaps ->mapping */ + if (unlikely(!list_empty(&folio->_deferred_list))) { + bad_page(page, "on deferred list"); + goto out; + } break; default: if (page->mapping != TAIL_MAPPING) { |