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 X-Spam-Level: X-Spam-Status: No, score=-8.2 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS, URIBL_BLOCKED,USER_AGENT_SANE_1 autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 03526C433DF for ; Thu, 4 Jun 2020 13:35:34 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id 9CE3B206E6 for ; Thu, 4 Jun 2020 13:35:33 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 9CE3B206E6 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=suse.cz Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id 28A408E0007; Thu, 4 Jun 2020 09:35:33 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 25F248E0006; Thu, 4 Jun 2020 09:35:33 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 175888E0007; Thu, 4 Jun 2020 09:35:33 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0178.hostedemail.com [216.40.44.178]) by kanga.kvack.org (Postfix) with ESMTP id 0040E8E0006 for ; Thu, 4 Jun 2020 09:35:32 -0400 (EDT) Received: from smtpin01.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay03.hostedemail.com (Postfix) with ESMTP id AD4C28248047 for ; Thu, 4 Jun 2020 13:35:32 +0000 (UTC) X-FDA: 76891626504.01.tin63_6a86c327a8a59 Received: from filter.hostedemail.com (10.5.16.251.rfc1918.com [10.5.16.251]) by smtpin01.hostedemail.com (Postfix) with ESMTP id 89CED18027686 for ; Thu, 4 Jun 2020 13:35:32 +0000 (UTC) X-HE-Tag: tin63_6a86c327a8a59 X-Filterd-Recvd-Size: 11014 Received: from mx2.suse.de (mx2.suse.de [195.135.220.15]) by imf44.hostedemail.com (Postfix) with ESMTP for ; Thu, 4 Jun 2020 13:35:31 +0000 (UTC) X-Virus-Scanned: by amavisd-new at test-mx.suse.de Received: from relay2.suse.de (unknown [195.135.220.254]) by mx2.suse.de (Postfix) with ESMTP id E74FFAB64; Thu, 4 Jun 2020 13:35:32 +0000 (UTC) Subject: Re: [PATCH 05/14] mm: workingset: let cache workingset challenge anon To: Johannes Weiner , Joonsoo Kim Cc: Linux Memory Management List , Rik van Riel , Minchan Kim , Michal Hocko , Andrew Morton , Joonsoo Kim , LKML , kernel-team@fb.com References: <20200520232525.798933-1-hannes@cmpxchg.org> <20200520232525.798933-6-hannes@cmpxchg.org> <20200527134333.GF6781@cmpxchg.org> <20200528170155.GA69521@cmpxchg.org> <20200529151228.GA92892@cmpxchg.org> <20200601155615.GA131075@cmpxchg.org> <20200601204424.GA212944@cmpxchg.org> From: Vlastimil Babka Message-ID: <561b79e8-48c7-f2eb-6081-cd82ad7e6010@suse.cz> Date: Thu, 4 Jun 2020 15:35:27 +0200 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.8.1 MIME-Version: 1.0 In-Reply-To: <20200601204424.GA212944@cmpxchg.org> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit X-Rspamd-Queue-Id: 89CED18027686 X-Spamd-Result: default: False [0.00 / 100.00] X-Rspamd-Server: rspam04 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 6/1/20 10:44 PM, Johannes Weiner wrote: > From a8faceabc1454dfd878caee2a8422493d937a394 Mon Sep 17 00:00:00 2001 > From: Johannes Weiner > Date: Mon, 1 Jun 2020 14:04:09 -0400 > Subject: [PATCH] mm: workingset: let cache workingset challenge anon fix Looks like the whole series is now in mainline (that was quick!) without this followup? As such it won't be squashed so perhaps the subject should be more "standalone" now, description referencing commit 34e58cac6d8f ("mm: workingset: let cache workingset challenge anon"), possibly with Fixes: tag etc... > We compare refault distances to active_file + anon. But age of the > non-resident information is only driven by the file LRU. As a result, > we may overestimate the recency of any incoming refaults and activate > them too eagerly, causing unnecessary LRU churn in certain situations. > > Make anon aging drive nonresident age as well to address that. > > Reported-by: Joonsoo Kim > Signed-off-by: Johannes Weiner > --- > include/linux/memcontrol.h | 13 +++++++++++ > include/linux/mmzone.h | 4 ++-- > include/linux/swap.h | 1 + > mm/vmscan.c | 3 +++ > mm/workingset.c | 46 ++++++++++++++++++++++---------------- > 5 files changed, 46 insertions(+), 21 deletions(-) > > diff --git a/include/linux/memcontrol.h b/include/linux/memcontrol.h > index 32a0b4d47540..d982c80da157 100644 > --- a/include/linux/memcontrol.h > +++ b/include/linux/memcontrol.h > @@ -1303,6 +1303,19 @@ static inline void dec_lruvec_page_state(struct page *page, > mod_lruvec_page_state(page, idx, -1); > } > > +static inline struct lruvec *parent_lruvec(struct lruvec *lruvec) > +{ > + struct mem_cgroup *memcg; > + > + memcg = lruvec_memcg(lruvec); > + if (!memcg) > + return NULL; > + memcg = parent_mem_cgroup(memcg); > + if (!memcg) > + return NULL; > + return mem_cgroup_lruvec(memcg, lruvec_pgdat(lruvec)); > +} > + > #ifdef CONFIG_CGROUP_WRITEBACK > > struct wb_domain *mem_cgroup_wb_domain(struct bdi_writeback *wb); > diff --git a/include/linux/mmzone.h b/include/linux/mmzone.h > index c1fbda9ddd1f..7cccbb8bc2d7 100644 > --- a/include/linux/mmzone.h > +++ b/include/linux/mmzone.h > @@ -262,8 +262,8 @@ enum lruvec_flags { > struct lruvec { > struct list_head lists[NR_LRU_LISTS]; > struct zone_reclaim_stat reclaim_stat; > - /* Evictions & activations on the inactive file list */ > - atomic_long_t inactive_age; > + /* Non-resident age, driven by LRU movement */ > + atomic_long_t nonresident_age; > /* Refaults at the time of last reclaim cycle */ > unsigned long refaults; > /* Various lruvec state flags (enum lruvec_flags) */ > diff --git a/include/linux/swap.h b/include/linux/swap.h > index 30fd4641890e..f0d2dca28c99 100644 > --- a/include/linux/swap.h > +++ b/include/linux/swap.h > @@ -312,6 +312,7 @@ struct vma_swap_readahead { > }; > > /* linux/mm/workingset.c */ > +void workingset_age_nonresident(struct lruvec *lruvec, unsigned long nr_pages); > void *workingset_eviction(struct page *page, struct mem_cgroup *target_memcg); > void workingset_refault(struct page *page, void *shadow); > void workingset_activation(struct page *page); > diff --git a/mm/vmscan.c b/mm/vmscan.c > index 43f88b1a4f14..3033f1c951cd 100644 > --- a/mm/vmscan.c > +++ b/mm/vmscan.c > @@ -898,6 +898,7 @@ static int __remove_mapping(struct address_space *mapping, struct page *page, > __delete_from_swap_cache(page, swap); > xa_unlock_irqrestore(&mapping->i_pages, flags); > put_swap_page(page, swap); > + workingset_eviction(page, target_memcg); > } else { > void (*freepage)(struct page *); > void *shadow = NULL; > @@ -1876,6 +1877,8 @@ static unsigned noinline_for_stack move_pages_to_lru(struct lruvec *lruvec, > list_add(&page->lru, &pages_to_free); > } else { > nr_moved += nr_pages; > + if (PageActive(page)) > + workingset_age_nonresident(lruvec, nr_pages); > } > } > > diff --git a/mm/workingset.c b/mm/workingset.c > index e69865739539..98b91e623b85 100644 > --- a/mm/workingset.c > +++ b/mm/workingset.c > @@ -156,8 +156,8 @@ > * > * Implementation > * > - * For each node's file LRU lists, a counter for inactive evictions > - * and activations is maintained (node->inactive_age). > + * For each node's LRU lists, a counter for inactive evictions and > + * activations is maintained (node->nonresident_age). > * > * On eviction, a snapshot of this counter (along with some bits to > * identify the node) is stored in the now empty page cache > @@ -213,7 +213,17 @@ static void unpack_shadow(void *shadow, int *memcgidp, pg_data_t **pgdat, > *workingsetp = workingset; > } > > -static void advance_inactive_age(struct mem_cgroup *memcg, pg_data_t *pgdat) > +/** > + * workingset_age_nonresident - age non-resident entries as LRU ages > + * @memcg: the lruvec that was aged > + * @nr_pages: the number of pages to count > + * > + * As in-memory pages are aged, non-resident pages need to be aged as > + * well, in order for the refault distances later on to be comparable > + * to the in-memory dimensions. This function allows reclaim and LRU > + * operations to drive the non-resident aging along in parallel. > + */ > +void workingset_age_nonresident(struct lruvec *lruvec, unsigned long nr_pages) > { > /* > * Reclaiming a cgroup means reclaiming all its children in a > @@ -227,11 +237,8 @@ static void advance_inactive_age(struct mem_cgroup *memcg, pg_data_t *pgdat) > * the root cgroup's, age as well. > */ > do { > - struct lruvec *lruvec; > - > - lruvec = mem_cgroup_lruvec(memcg, pgdat); > - atomic_long_inc(&lruvec->inactive_age); > - } while (memcg && (memcg = parent_mem_cgroup(memcg))); > + atomic_long_add(nr_pages, &lruvec->nonresident_age); > + } while ((lruvec = parent_lruvec(lruvec))); > } > > /** > @@ -254,12 +261,11 @@ void *workingset_eviction(struct page *page, struct mem_cgroup *target_memcg) > VM_BUG_ON_PAGE(page_count(page), page); > VM_BUG_ON_PAGE(!PageLocked(page), page); > > - advance_inactive_age(page_memcg(page), pgdat); > - > lruvec = mem_cgroup_lruvec(target_memcg, pgdat); > + workingset_age_nonresident(lruvec, hpage_nr_pages(page)); > /* XXX: target_memcg can be NULL, go through lruvec */ > memcgid = mem_cgroup_id(lruvec_memcg(lruvec)); > - eviction = atomic_long_read(&lruvec->inactive_age); > + eviction = atomic_long_read(&lruvec->nonresident_age); > return pack_shadow(memcgid, pgdat, eviction, PageWorkingset(page)); > } > > @@ -309,20 +315,20 @@ void workingset_refault(struct page *page, void *shadow) > if (!mem_cgroup_disabled() && !eviction_memcg) > goto out; > eviction_lruvec = mem_cgroup_lruvec(eviction_memcg, pgdat); > - refault = atomic_long_read(&eviction_lruvec->inactive_age); > + refault = atomic_long_read(&eviction_lruvec->nonresident_age); > > /* > * Calculate the refault distance > * > * The unsigned subtraction here gives an accurate distance > - * across inactive_age overflows in most cases. There is a > + * across nonresident_age overflows in most cases. There is a > * special case: usually, shadow entries have a short lifetime > * and are either refaulted or reclaimed along with the inode > * before they get too old. But it is not impossible for the > - * inactive_age to lap a shadow entry in the field, which can > - * then result in a false small refault distance, leading to a > - * false activation should this old entry actually refault > - * again. However, earlier kernels used to deactivate > + * nonresident_age to lap a shadow entry in the field, which > + * can then result in a false small refault distance, leading > + * to a false activation should this old entry actually > + * refault again. However, earlier kernels used to deactivate > * unconditionally with *every* reclaim invocation for the > * longest time, so the occasional inappropriate activation > * leading to pressure on the active list is not a problem. > @@ -359,7 +365,7 @@ void workingset_refault(struct page *page, void *shadow) > goto out; > > SetPageActive(page); > - advance_inactive_age(memcg, pgdat); > + workingset_age_nonresident(lruvec, hpage_nr_pages(page)); > inc_lruvec_state(lruvec, WORKINGSET_ACTIVATE); > > /* Page was active prior to eviction */ > @@ -378,6 +384,7 @@ void workingset_refault(struct page *page, void *shadow) > void workingset_activation(struct page *page) > { > struct mem_cgroup *memcg; > + struct lruvec *lruvec; > > rcu_read_lock(); > /* > @@ -390,7 +397,8 @@ void workingset_activation(struct page *page) > memcg = page_memcg_rcu(page); > if (!mem_cgroup_disabled() && !memcg) > goto out; > - advance_inactive_age(memcg, page_pgdat(page)); > + lruvec = mem_cgroup_page_lruvec(page, page_pgdat(page)); > + workingset_age_nonresident(lruvec, hpage_nr_pages(page)); > out: > rcu_read_unlock(); > } >