From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by smtp.lore.kernel.org (Postfix) with ESMTP id 8039FC433F5 for ; Tue, 24 May 2022 19:52:31 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 00AE68D0003; Tue, 24 May 2022 15:52:31 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id EFC238D0002; Tue, 24 May 2022 15:52:30 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id DC2658D0003; Tue, 24 May 2022 15:52:30 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0014.hostedemail.com [216.40.44.14]) by kanga.kvack.org (Postfix) with ESMTP id CDB718D0002 for ; Tue, 24 May 2022 15:52:30 -0400 (EDT) Received: from smtpin23.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay12.hostedemail.com (Postfix) with ESMTP id A90281207C7 for ; Tue, 24 May 2022 19:52:30 +0000 (UTC) X-FDA: 79501683660.23.9E863E9 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.133.124]) by imf18.hostedemail.com (Postfix) with ESMTP id 8F7EE1C002E for ; Tue, 24 May 2022 19:52:13 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1653421949; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=vsoL5BUtwGtn8srjaBAKLRmvlrQ5HvOClw2yb5AYOdQ=; b=I6b/Sg6xRFEddizAox7nYkFlPNM41+MZObaEe2Y0gWME+TLjXUGwC9c8GS7N3Vghogz7Vh gh3wP2g6UFjhYecjg8BBcGZF7bYZycaaSVC3iu9PHY3/qCgkiYJqRmwcG3RxDfjGCncqyw tUIaz96pt9KEfCGA6rdPECOWNzu/ZfM= Received: from mimecast-mx02.redhat.com (mimecast-mx02.redhat.com [66.187.233.88]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id us-mta-416--36m1xhvMhaLbWszLzkDTg-1; Tue, 24 May 2022 15:52:23 -0400 X-MC-Unique: -36m1xhvMhaLbWszLzkDTg-1 Received: from smtp.corp.redhat.com (int-mx10.intmail.prod.int.rdu2.redhat.com [10.11.54.10]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx02.redhat.com (Postfix) with ESMTPS id 11160185A7B2; Tue, 24 May 2022 19:52:23 +0000 (UTC) Received: from [10.22.8.146] (unknown [10.22.8.146]) by smtp.corp.redhat.com (Postfix) with ESMTP id 876CE401E4C; Tue, 24 May 2022 19:52:22 +0000 (UTC) Message-ID: <78de6197-7de6-9fe7-9567-1321c06c6e9b@redhat.com> Date: Tue, 24 May 2022 15:52:22 -0400 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:91.0) Gecko/20100101 Thunderbird/91.8.0 Subject: Re: [PATCH v4 04/11] mm: vmscan: rework move_pages_to_lru() Content-Language: en-US To: Muchun Song , hannes@cmpxchg.org, mhocko@kernel.org, roman.gushchin@linux.dev, shakeelb@google.com Cc: cgroups@vger.kernel.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org, duanxiongchun@bytedance.com References: <20220524060551.80037-1-songmuchun@bytedance.com> <20220524060551.80037-5-songmuchun@bytedance.com> From: Waiman Long In-Reply-To: <20220524060551.80037-5-songmuchun@bytedance.com> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit X-Scanned-By: MIMEDefang 2.85 on 10.11.54.10 Authentication-Results: imf18.hostedemail.com; dkim=pass header.d=redhat.com header.s=mimecast20190719 header.b="I6b/Sg6x"; spf=none (imf18.hostedemail.com: domain of longman@redhat.com has no SPF policy when checking 170.10.133.124) smtp.mailfrom=longman@redhat.com; dmarc=pass (policy=none) header.from=redhat.com X-Rspam-User: X-Stat-Signature: k3btmn8w1xqe1jgfora4dna8ciky1es4 X-Rspamd-Queue-Id: 8F7EE1C002E X-Rspamd-Server: rspam01 X-HE-Tag: 1653421933-297216 X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: On 5/24/22 02:05, Muchun Song wrote: > In the later patch, we will reparent the LRU pages. The pages moved to > appropriate LRU list can be reparented during the process of the > move_pages_to_lru(). So holding a lruvec lock by the caller is wrong, we > should use the more general interface of folio_lruvec_relock_irq() to > acquire the correct lruvec lock. > > Signed-off-by: Muchun Song > --- > mm/vmscan.c | 49 +++++++++++++++++++++++++------------------------ > 1 file changed, 25 insertions(+), 24 deletions(-) > > diff --git a/mm/vmscan.c b/mm/vmscan.c > index 1678802e03e7..761d5e0dd78d 100644 > --- a/mm/vmscan.c > +++ b/mm/vmscan.c > @@ -2230,23 +2230,28 @@ static int too_many_isolated(struct pglist_data *pgdat, int file, > * move_pages_to_lru() moves pages from private @list to appropriate LRU list. > * On return, @list is reused as a list of pages to be freed by the caller. > * > - * Returns the number of pages moved to the given lruvec. > + * Returns the number of pages moved to the appropriate LRU list. > + * > + * Note: The caller must not hold any lruvec lock. > */ > -static unsigned int move_pages_to_lru(struct lruvec *lruvec, > - struct list_head *list) > +static unsigned int move_pages_to_lru(struct list_head *list) > { > - int nr_pages, nr_moved = 0; > + int nr_moved = 0; > + struct lruvec *lruvec = NULL; > LIST_HEAD(pages_to_free); > - struct page *page; > > while (!list_empty(list)) { > - page = lru_to_page(list); > + int nr_pages; > + struct folio *folio = lru_to_folio(list); > + struct page *page = &folio->page; > + > + lruvec = folio_lruvec_relock_irq(folio, lruvec); > VM_BUG_ON_PAGE(PageLRU(page), page); > list_del(&page->lru); > if (unlikely(!page_evictable(page))) { > - spin_unlock_irq(&lruvec->lru_lock); > + unlock_page_lruvec_irq(lruvec); > putback_lru_page(page); > - spin_lock_irq(&lruvec->lru_lock); > + lruvec = NULL; > continue; > } > > @@ -2267,20 +2272,16 @@ static unsigned int move_pages_to_lru(struct lruvec *lruvec, > __clear_page_lru_flags(page); > > if (unlikely(PageCompound(page))) { > - spin_unlock_irq(&lruvec->lru_lock); > + unlock_page_lruvec_irq(lruvec); > destroy_compound_page(page); > - spin_lock_irq(&lruvec->lru_lock); > + lruvec = NULL; > } else > list_add(&page->lru, &pages_to_free); > > continue; > } > > - /* > - * All pages were isolated from the same lruvec (and isolation > - * inhibits memcg migration). > - */ > - VM_BUG_ON_PAGE(!folio_matches_lruvec(page_folio(page), lruvec), page); > + VM_BUG_ON_PAGE(!folio_matches_lruvec(folio, lruvec), page); > add_page_to_lru_list(page, lruvec); > nr_pages = thp_nr_pages(page); > nr_moved += nr_pages; > @@ -2288,6 +2289,8 @@ static unsigned int move_pages_to_lru(struct lruvec *lruvec, > workingset_age_nonresident(lruvec, nr_pages); > } > > + if (lruvec) > + unlock_page_lruvec_irq(lruvec); > /* > * To save our caller's stack, now use input list for pages to free. > */ > @@ -2359,16 +2362,16 @@ shrink_inactive_list(unsigned long nr_to_scan, struct lruvec *lruvec, > > nr_reclaimed = shrink_page_list(&page_list, pgdat, sc, &stat, false); > > - spin_lock_irq(&lruvec->lru_lock); > - move_pages_to_lru(lruvec, &page_list); > + move_pages_to_lru(&page_list); > > + local_irq_disable(); > __mod_node_page_state(pgdat, NR_ISOLATED_ANON + file, -nr_taken); > item = current_is_kswapd() ? PGSTEAL_KSWAPD : PGSTEAL_DIRECT; > if (!cgroup_reclaim(sc)) > __count_vm_events(item, nr_reclaimed); > __count_memcg_events(lruvec_memcg(lruvec), item, nr_reclaimed); > __count_vm_events(PGSTEAL_ANON + file, nr_reclaimed); > - spin_unlock_irq(&lruvec->lru_lock); > + local_irq_enable(); > > lru_note_cost(lruvec, file, stat.nr_pageout); > mem_cgroup_uncharge_list(&page_list); > @@ -2498,18 +2501,16 @@ static void shrink_active_list(unsigned long nr_to_scan, > /* > * Move pages back to the lru list. > */ > - spin_lock_irq(&lruvec->lru_lock); > - > - nr_activate = move_pages_to_lru(lruvec, &l_active); > - nr_deactivate = move_pages_to_lru(lruvec, &l_inactive); > + nr_activate = move_pages_to_lru(&l_active); > + nr_deactivate = move_pages_to_lru(&l_inactive); > /* Keep all free pages in l_active list */ > list_splice(&l_inactive, &l_active); > > + local_irq_disable(); > __count_vm_events(PGDEACTIVATE, nr_deactivate); > __count_memcg_events(lruvec_memcg(lruvec), PGDEACTIVATE, nr_deactivate); > - > __mod_node_page_state(pgdat, NR_ISOLATED_ANON + file, -nr_taken); > - spin_unlock_irq(&lruvec->lru_lock); > + local_irq_enable(); > > mem_cgroup_uncharge_list(&l_active); > free_unref_page_list(&l_active); Note that the RT engineers will likely change the local_irq_disable()/local_irq_enable() to local_lock_irq()/local_unlock_irq(). Cheers, Longman