From mboxrd@z Thu Jan 1 00:00:00 1970 From: Alex Shi Subject: [PATCH v18 05/32] mm/thp: remove code path which never got into Date: Mon, 24 Aug 2020 20:54:38 +0800 Message-ID: <1598273705-69124-6-git-send-email-alex.shi@linux.alibaba.com> References: <1598273705-69124-1-git-send-email-alex.shi@linux.alibaba.com> Return-path: In-Reply-To: <1598273705-69124-1-git-send-email-alex.shi-KPsoFbNs7GizrGE5bRqYAgC/G2K4zDHf@public.gmane.org> Sender: cgroups-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org List-ID: MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: akpm-de/tnXTf+JLsfHDXvbKv3WD2FQJk+8+b@public.gmane.org, mgorman-3eNAlZScCAx27rWaFMvyedHuzzzSOjJt@public.gmane.org, tj-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org, hughd-hpIqsD4AKlfQT0dZR+AlfA@public.gmane.org, khlebnikov-XoJtRXgx1JseBXzfvpsJ4g@public.gmane.org, daniel.m.jordan-QHcLZuEGTsvQT0dZR+AlfA@public.gmane.org, willy-wEGCiKHe2LqWVfeAwA7xHQ@public.gmane.org, hannes-druUgvl0LCNAfugRpC6u6w@public.gmane.org, lkp-ral2JQCrhuEAvxtiuMwx3w@public.gmane.org, linux-mm-Bw31MaZKKs3YtjvyW6yDsg@public.gmane.org, linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, cgroups-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, shakeelb-hpIqsD4AKlfQT0dZR+AlfA@public.gmane.org, iamjoonsoo.kim-Hm3cg6mZ9cc@public.gmane.org, richard.weiyang-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org, kirill-oKw7cIdHH8eLwutG50LtGA@public.gmane.org, alexander.duyck-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org, rong.a.chen-ral2JQCrhuEAvxtiuMwx3w@public.gmane.org, mhocko-IBi9RG/b67k@public.gmane.org, vdavydov.dev-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org, shy828301-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org split_huge_page() will never call on a page which isn't on lru list, so this code never got a chance to run, and should not be run, to add tail pages on a lru list which head page isn't there. Although the bug was never triggered, it'better be removed for code correctness, and add a warn for unexpected calling. Signed-off-by: Alex Shi Reviewed-by: Kirill A. Shutemov Cc: Kirill A. Shutemov Cc: Andrew Morton Cc: Johannes Weiner Cc: Matthew Wilcox Cc: Hugh Dickins Cc: linux-mm-Bw31MaZKKs3YtjvyW6yDsg@public.gmane.org Cc: linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org --- mm/huge_memory.c | 13 ++----------- 1 file changed, 2 insertions(+), 11 deletions(-) diff --git a/mm/huge_memory.c b/mm/huge_memory.c index 739497770a3d..247f53def87b 100644 --- a/mm/huge_memory.c +++ b/mm/huge_memory.c @@ -2330,17 +2330,8 @@ static void lru_add_page_tail(struct page *head, struct page *page_tail, /* page reclaim is reclaiming a huge page */ get_page(page_tail); list_add_tail(&page_tail->lru, list); - } else { - /* - * Head page has not yet been counted, as an hpage, - * so we must account for each subpage individually. - * - * Put page_tail on the list at the correct position - * so they all end up in order. - */ - add_page_to_lru_list_tail(page_tail, lruvec, - page_lru(page_tail)); - } + } else + VM_WARN_ON(!PageLRU(head)); } static void __split_huge_page_tail(struct page *head, int tail, -- 1.8.3.1