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=-14.3 required=3.0 tests=DKIMWL_WL_MED,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH, MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED, USER_IN_DEF_DKIM_WL 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 41E3AFC6194 for ; Thu, 7 Nov 2019 02:51:28 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id CF6FD217D7 for ; Thu, 7 Nov 2019 02:51:27 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b="rlCeuEiC" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org CF6FD217D7 Authentication-Results: mail.kernel.org; dmarc=fail (p=reject dis=none) header.from=google.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id 852116B000A; Wed, 6 Nov 2019 21:51:27 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id 803016B000C; Wed, 6 Nov 2019 21:51:27 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 7189D6B000D; Wed, 6 Nov 2019 21:51:27 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0045.hostedemail.com [216.40.44.45]) by kanga.kvack.org (Postfix) with ESMTP id 5C14D6B000A for ; Wed, 6 Nov 2019 21:51:27 -0500 (EST) Received: from smtpin13.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay05.hostedemail.com (Postfix) with SMTP id CBBBD181AEF21 for ; Thu, 7 Nov 2019 02:51:26 +0000 (UTC) X-FDA: 76127955372.13.grip76_c940eb036814 X-HE-Tag: grip76_c940eb036814 X-Filterd-Recvd-Size: 10310 Received: from mail-oi1-f196.google.com (mail-oi1-f196.google.com [209.85.167.196]) by imf18.hostedemail.com (Postfix) with ESMTP for ; Thu, 7 Nov 2019 02:51:26 +0000 (UTC) Received: by mail-oi1-f196.google.com with SMTP id k2so622087oij.12 for ; Wed, 06 Nov 2019 18:51:26 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20161025; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc; bh=ZJgjLii01IGGdUCsYrzd4gYjlTvDiWueI/o8CqoLYI4=; b=rlCeuEiCGh7lsXngMqUCH816OSSAwW5c+4c+hmAyE/ruz/i3CAd226pxUWdOkAwMV5 Y2vPchFkJoWzr8dSiKPbmMnzTpqFNJbj/npNbC+nwyeUh+2na5zPYMcupa7V219gY5QQ n18znZB1l1X3eI473qpX5oK0eCLoYA1B+m8r/7RLgqyYxLeGsMSaAOjhI+N86Bf62IRp UOSmS6XrKL8AfEu3nxL5/D2WQILh4cipww7Lqj2buj1l4CStbh2qig/SIowcQlgTPawz SQDRqJ1/U/o4JxfoC54TRxE+NvVH3iM7YDzr9FAMUxVkuWmKtifVYfYytRvlQiN8++am c88g== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc; bh=ZJgjLii01IGGdUCsYrzd4gYjlTvDiWueI/o8CqoLYI4=; b=AXrOciPE88PQETZkcAPMVxn3knZaJMGW5N3kVsHZFf9ILDvQEJ7kOszdN5hnNTuk+C Rqk/sI8rQHixz8pV9dMN7egwLY1BJ1RQxZRBt424kddooD9LIfEmtdrJtBVpeN8HgWf6 aJT83NWQ+tgwVYlTiMcOtTWJIw8FLIlFHWLVT7Sg0EQWQvIKEOgc5Jv5zTSY1wNCKcvh 2HKPRZLBeyDc6+irrco6WXAPwbcTKNQ/miCczWUwXay0oVmOr5u3XFhw9uHQIl1ACThX lv5VQgA0DT4XovYV172wh8eQ4lmCNiYVi4Gl3KRyLci72i4GGzWjRQrghcJ9QLRH5nzJ QbOw== X-Gm-Message-State: APjAAAViQjV+dgzUOtbk/2wVTvJBL+xWmVjfNnagSEtfwMN+2RBe6RAv Py7akPlCpiMdgaxjyaCDS5CHjGJKOJk/dA7eDG0YeA== X-Google-Smtp-Source: APXvYqxVb+X95mYEAd2Ugk1BumgEAruoupSYZRK2d7E+6AIUYLX4CVCCjXCrigXtcqjbBQQP/G/PAGC9+XuoVmpaskU= X-Received: by 2002:aca:f506:: with SMTP id t6mr1159853oih.69.1573095085224; Wed, 06 Nov 2019 18:51:25 -0800 (PST) MIME-Version: 1.0 References: <20190603210746.15800-1-hannes@cmpxchg.org> <20190603210746.15800-5-hannes@cmpxchg.org> In-Reply-To: <20190603210746.15800-5-hannes@cmpxchg.org> From: Shakeel Butt Date: Wed, 6 Nov 2019 18:51:14 -0800 Message-ID: Subject: Re: [PATCH 04/11] mm: vmscan: naming fixes: cgroup_reclaim() and writeback_working() To: Johannes Weiner Cc: Andrew Morton , Andrey Ryabinin , Suren Baghdasaryan , Michal Hocko , Linux MM , Cgroups , LKML , Kernel Team Content-Type: text/plain; charset="UTF-8" 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 Mon, Jun 3, 2019 at 3:02 PM Johannes Weiner wrote: > > Seven years after introducing the global_reclaim() function, I still > have to double take when reading a callsite. I don't know how others > do it. This is a terrible name. > > Invert the meaning and rename it to cgroup_reclaim(). > > [ After all, "global reclaim" is just regular reclaim invoked from the > page allocator. It's reclaim on behalf of a cgroup limit that is a > special case of reclaim, and should be explicit - not the reverse. ] > Not really confusing for me at least but no objection on cgroup_reclaim(). > sane_reclaim() isn't very descriptive either: it tests whether we can > use the regular writeback throttling - available during regular page > reclaim or cgroup2 limit reclaim - or need to use the broken > wait_on_page_writeback() method. Rename it to writeback_working(). Totally agree here. > > Signed-off-by: Johannes Weiner Reviewed-by: Shakeel Butt > --- > mm/vmscan.c | 38 ++++++++++++++++++-------------------- > 1 file changed, 18 insertions(+), 20 deletions(-) > > diff --git a/mm/vmscan.c b/mm/vmscan.c > index 69c4c82a9b5a..afd5e2432a8e 100644 > --- a/mm/vmscan.c > +++ b/mm/vmscan.c > @@ -239,13 +239,13 @@ static void unregister_memcg_shrinker(struct shrinker *shrinker) > #endif /* CONFIG_MEMCG_KMEM */ > > #ifdef CONFIG_MEMCG > -static bool global_reclaim(struct scan_control *sc) > +static bool cgroup_reclaim(struct scan_control *sc) > { > - return !sc->target_mem_cgroup; > + return sc->target_mem_cgroup; > } > > /** > - * sane_reclaim - is the usual dirty throttling mechanism operational? > + * writeback_working - is the usual dirty throttling mechanism unavailable? > * @sc: scan_control in question > * > * The normal page dirty throttling mechanism in balance_dirty_pages() is > @@ -257,11 +257,9 @@ static bool global_reclaim(struct scan_control *sc) > * This function tests whether the vmscan currently in progress can assume > * that the normal dirty throttling mechanism is operational. > */ > -static bool sane_reclaim(struct scan_control *sc) > +static bool writeback_working(struct scan_control *sc) > { > - struct mem_cgroup *memcg = sc->target_mem_cgroup; > - > - if (!memcg) > + if (!cgroup_reclaim(sc)) > return true; > #ifdef CONFIG_CGROUP_WRITEBACK > if (cgroup_subsys_on_dfl(memory_cgrp_subsys)) > @@ -293,12 +291,12 @@ static bool memcg_congested(pg_data_t *pgdat, > > } > #else > -static bool global_reclaim(struct scan_control *sc) > +static bool cgroup_reclaim(struct scan_control *sc) > { > - return true; > + return false; > } > > -static bool sane_reclaim(struct scan_control *sc) > +static bool writeback_working(struct scan_control *sc) > { > return true; > } > @@ -1211,7 +1209,7 @@ static unsigned long shrink_page_list(struct list_head *page_list, > goto activate_locked; > > /* Case 2 above */ > - } else if (sane_reclaim(sc) || > + } else if (writeback_working(sc) || > !PageReclaim(page) || !may_enter_fs) { > /* > * This is slightly racy - end_page_writeback() > @@ -1806,7 +1804,7 @@ static int too_many_isolated(struct pglist_data *pgdat, int file, > if (current_is_kswapd()) > return 0; > > - if (!sane_reclaim(sc)) > + if (!writeback_working(sc)) > return 0; > > if (file) { > @@ -1957,7 +1955,7 @@ shrink_inactive_list(unsigned long nr_to_scan, struct lruvec *lruvec, > reclaim_stat->recent_scanned[file] += nr_taken; > > item = current_is_kswapd() ? PGSCAN_KSWAPD : PGSCAN_DIRECT; > - if (global_reclaim(sc)) > + if (!cgroup_reclaim(sc)) > __count_vm_events(item, nr_scanned); > __count_memcg_events(lruvec_memcg(lruvec), item, nr_scanned); > spin_unlock_irq(&pgdat->lru_lock); > @@ -1971,7 +1969,7 @@ shrink_inactive_list(unsigned long nr_to_scan, struct lruvec *lruvec, > spin_lock_irq(&pgdat->lru_lock); > > item = current_is_kswapd() ? PGSTEAL_KSWAPD : PGSTEAL_DIRECT; > - if (global_reclaim(sc)) > + if (!cgroup_reclaim(sc)) > __count_vm_events(item, nr_reclaimed); > __count_memcg_events(lruvec_memcg(lruvec), item, nr_reclaimed); > reclaim_stat->recent_rotated[0] += stat.nr_activate[0]; > @@ -2239,7 +2237,7 @@ static void get_scan_count(struct lruvec *lruvec, struct mem_cgroup *memcg, > * using the memory controller's swap limit feature would be > * too expensive. > */ > - if (!global_reclaim(sc) && !swappiness) { > + if (cgroup_reclaim(sc) && !swappiness) { > scan_balance = SCAN_FILE; > goto out; > } > @@ -2263,7 +2261,7 @@ static void get_scan_count(struct lruvec *lruvec, struct mem_cgroup *memcg, > * thrashing file LRU becomes infinitely more attractive than > * anon pages. Try to detect this based on file LRU size. > */ > - if (global_reclaim(sc)) { > + if (!cgroup_reclaim(sc)) { > unsigned long pgdatfile; > unsigned long pgdatfree; > int z; > @@ -2494,7 +2492,7 @@ static void shrink_node_memcg(struct pglist_data *pgdat, struct mem_cgroup *memc > * abort proportional reclaim if either the file or anon lru has already > * dropped to zero at the first pass. > */ > - scan_adjusted = (global_reclaim(sc) && !current_is_kswapd() && > + scan_adjusted = (!cgroup_reclaim(sc) && !current_is_kswapd() && > sc->priority == DEF_PRIORITY); > > blk_start_plug(&plug); > @@ -2816,7 +2814,7 @@ static bool shrink_node(pg_data_t *pgdat, struct scan_control *sc) > * Legacy memcg will stall in page writeback so avoid forcibly > * stalling in wait_iff_congested(). > */ > - if (!global_reclaim(sc) && sane_reclaim(sc) && > + if (cgroup_reclaim(sc) && writeback_working(sc) && > sc->nr.dirty && sc->nr.dirty == sc->nr.congested) > set_memcg_congestion(pgdat, root, true); > > @@ -2911,7 +2909,7 @@ static void shrink_zones(struct zonelist *zonelist, struct scan_control *sc) > * Take care memory controller reclaiming has small influence > * to global LRU. > */ > - if (global_reclaim(sc)) { > + if (!cgroup_reclaim(sc)) { > if (!cpuset_zone_allowed(zone, > GFP_KERNEL | __GFP_HARDWALL)) > continue; > @@ -3011,7 +3009,7 @@ static unsigned long do_try_to_free_pages(struct zonelist *zonelist, > retry: > delayacct_freepages_start(); > > - if (global_reclaim(sc)) > + if (!cgroup_reclaim(sc)) > __count_zid_vm_events(ALLOCSTALL, sc->reclaim_idx, 1); > > do { > -- > 2.21.0 >