From mboxrd@z Thu Jan 1 00:00:00 1970 From: Alex Shi Subject: [PATCH v12 01/16] mm/vmscan: remove unnecessary lruvec adding Date: Thu, 11 Jun 2020 14:16:34 +0800 Message-ID: <1591856209-166869-2-git-send-email-alex.shi@linux.alibaba.com> References: <1591856209-166869-1-git-send-email-alex.shi@linux.alibaba.com> Return-path: In-Reply-To: <1591856209-166869-1-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, yang.shi-KPsoFbNs7GizrGE5bRqYAgC/G2K4zDHf@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 We don't have to add a freeable page into lru and then remove from it. This change saves a couple of actions and makes the moving more clear. The SetPageLRU needs to be kept here for list intergrity. Otherwise: #0 mave_pages_to_lru #1 release_pages if (put_page_testzero()) if !put_page_testzero !PageLRU //skip lru_lock list_add(&page->lru,) list_add(&page->lru,) //corrupt [akpm-de/tnXTf+JLsfHDXvbKv3WD2FQJk+8+b@public.gmane.org: coding style fixes] Signed-off-by: Alex Shi Cc: Andrew Morton Cc: Johannes Weiner Cc: Tejun Heo Cc: Matthew Wilcox Cc: Hugh Dickins Cc: linux-mm-Bw31MaZKKs3YtjvyW6yDsg@public.gmane.org Cc: linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org --- mm/vmscan.c | 32 +++++++++++++++++++++----------- 1 file changed, 21 insertions(+), 11 deletions(-) diff --git a/mm/vmscan.c b/mm/vmscan.c index b6d84326bdf2..81228334f7d6 100644 --- a/mm/vmscan.c +++ b/mm/vmscan.c @@ -1855,26 +1855,29 @@ static unsigned noinline_for_stack move_pages_to_lru(struct lruvec *lruvec, while (!list_empty(list)) { page = lru_to_page(list); VM_BUG_ON_PAGE(PageLRU(page), page); + list_del(&page->lru); if (unlikely(!page_evictable(page))) { - list_del(&page->lru); spin_unlock_irq(&pgdat->lru_lock); putback_lru_page(page); spin_lock_irq(&pgdat->lru_lock); continue; } - lruvec = mem_cgroup_page_lruvec(page, pgdat); + /* + * The SetPageLRU needs to be kept here for list intergrity. + * Otherwise: + * #0 mave_pages_to_lru #1 release_pages + * if (put_page_testzero()) + * if !put_page_testzero + * !PageLRU //skip lru_lock + * list_add(&page->lru,) + * list_add(&page->lru,) //corrupt + */ SetPageLRU(page); - lru = page_lru(page); - - nr_pages = hpage_nr_pages(page); - update_lru_size(lruvec, lru, page_zonenum(page), nr_pages); - list_move(&page->lru, &lruvec->lists[lru]); - if (put_page_testzero(page)) { + if (unlikely(put_page_testzero(page))) { __ClearPageLRU(page); __ClearPageActive(page); - del_page_from_lru_list(page, lruvec, lru); if (unlikely(PageCompound(page))) { spin_unlock_irq(&pgdat->lru_lock); @@ -1882,9 +1885,16 @@ static unsigned noinline_for_stack move_pages_to_lru(struct lruvec *lruvec, spin_lock_irq(&pgdat->lru_lock); } else list_add(&page->lru, &pages_to_free); - } else { - nr_moved += nr_pages; + continue; } + + lruvec = mem_cgroup_page_lruvec(page, pgdat); + lru = page_lru(page); + nr_pages = hpage_nr_pages(page); + + update_lru_size(lruvec, lru, page_zonenum(page), nr_pages); + list_add(&page->lru, &lruvec->lists[lru]); + nr_moved += nr_pages; } /* -- 1.8.3.1