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authorAlex Shi <alex.shi@linux.alibaba.com>2020-12-15 23:33:29 +0300
committerLinus Torvalds <torvalds@linux-foundation.org>2020-12-16 01:48:03 +0300
commit6dbb57412c62a8537663dc786e27faa0e084ddce (patch)
treef5b6c84e25e8771ed136529fa237e5a7215ce65e /mm/huge_memory.c
parent94866635372d37ab6b849942900eb98674a94f04 (diff)
downloadlinux-6dbb57412c62a8537663dc786e27faa0e084ddce.tar.xz
mm/thp: simplify lru_add_page_tail()
Simplify lru_add_page_tail(), there are actually only two cases possible: split_huge_page_to_list(), with list supplied and head isolated from lru by its caller; or split_huge_page(), with NULL list and head on lru - because when head is racily isolated from lru, the isolator's reference will stop the split from getting any further than its page_ref_freeze(). So decide between the two cases by "list", but add VM_WARN_ON()s to verify that they match our lru expectations. [Hugh Dickins: rewrite commit log] Link: https://lkml.kernel.org/r/1604566549-62481-4-git-send-email-alex.shi@linux.alibaba.com Signed-off-by: Alex Shi <alex.shi@linux.alibaba.com> Reviewed-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Acked-by: Hugh Dickins <hughd@google.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Matthew Wilcox <willy@infradead.org> Cc: Mika Penttilä <mika.penttila@nextfour.com> Cc: Alexander Duyck <alexander.duyck@gmail.com> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: Andrey Ryabinin <aryabinin@virtuozzo.com> Cc: "Chen, Rong A" <rong.a.chen@intel.com> Cc: Daniel Jordan <daniel.m.jordan@oracle.com> Cc: "Huang, Ying" <ying.huang@intel.com> Cc: Jann Horn <jannh@google.com> Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com> Cc: Kirill A. Shutemov <kirill@shutemov.name> Cc: Konstantin Khlebnikov <khlebnikov@yandex-team.ru> Cc: Mel Gorman <mgorman@techsingularity.net> Cc: Michal Hocko <mhocko@kernel.org> Cc: Michal Hocko <mhocko@suse.com> Cc: Minchan Kim <minchan@kernel.org> Cc: Shakeel Butt <shakeelb@google.com> Cc: Tejun Heo <tj@kernel.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Vladimir Davydov <vdavydov.dev@gmail.com> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: Wei Yang <richard.weiyang@gmail.com> Cc: Yang Shi <yang.shi@linux.alibaba.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'mm/huge_memory.c')
-rw-r--r--mm/huge_memory.c20
1 files changed, 6 insertions, 14 deletions
diff --git a/mm/huge_memory.c b/mm/huge_memory.c
index f33a6148e4c2..e8ccf8979648 100644
--- a/mm/huge_memory.c
+++ b/mm/huge_memory.c
@@ -2367,24 +2367,16 @@ static void lru_add_page_tail(struct page *head, struct page *tail,
VM_BUG_ON_PAGE(PageLRU(tail), head);
lockdep_assert_held(&lruvec_pgdat(lruvec)->lru_lock);
- if (!list)
- SetPageLRU(tail);
-
- if (likely(PageLRU(head)))
- list_add_tail(&tail->lru, &head->lru);
- else if (list) {
+ if (list) {
/* page reclaim is reclaiming a huge page */
+ VM_WARN_ON(PageLRU(head));
get_page(tail);
list_add_tail(&tail->lru, list);
} else {
- /*
- * Head page has not yet been counted, as an hpage,
- * so we must account for each subpage individually.
- *
- * Put tail on the list at the correct position
- * so they all end up in order.
- */
- add_page_to_lru_list_tail(tail, lruvec, page_lru(tail));
+ /* head is still on lru (and we have it frozen) */
+ VM_WARN_ON(!PageLRU(head));
+ SetPageLRU(tail);
+ list_add_tail(&tail->lru, &head->lru);
}
}