From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-oi1-f179.google.com (mail-oi1-f179.google.com [209.85.167.179]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 3A01C29CA for ; Thu, 9 Dec 2021 06:20:52 +0000 (UTC) Received: by mail-oi1-f179.google.com with SMTP id t23so7387049oiw.3 for ; Wed, 08 Dec 2021 22:20:52 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20210112; h=date:from:to:cc:subject:in-reply-to:message-id:references :mime-version; bh=mQ7hWd5y/cX7pLN703rPlCh10s+JfDxjIeGD1iE5U+w=; b=VVd/Vy0aUpLV0wPA3tkVRJTPDJumIspBWsIUMUZqp3ogZzhlejrhrOoacWWRRXOKBP 2z28YaLT09BCFeUkUE/GZKFsxieiuhxkBuJkE+L3PfEqi6CplG7A9tBKK2tZ2nLSC/6q wo4Orp1r0FrIv0piod0w/ATkSOGZI6qnoK2WPNPZaZDH7WX+yhjXACOAR0KUkAurt+2p 9biAtg6Vd/vWcAq0ysww0v1zO26wH6ZyQheczyWkWibHPulj/VF0oVCtKY0YQCu7KiS9 0Dk+TskA4as/z/+0PbT8KezyiZFQcvOTAYWepspIEcuwflYWqs6aF8NF7mrtRAXIj6I+ 44bw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:date:from:to:cc:subject:in-reply-to:message-id :references:mime-version; bh=mQ7hWd5y/cX7pLN703rPlCh10s+JfDxjIeGD1iE5U+w=; b=WC+Ee6F6Queo+EhNt0uDAxmjTyn3BhvMqELMB+5pRl4bbN6YWiov2HUF5cyn8g/9wc XeCeG0vtUGB9ZyL6FZQGAM74Ycrs6egChVe3hrLueskIqs+d3K1Z1oQYjwBs4jhqwrgC Pv3GDsgJgmcB3Z/X1/UWknEr1+8YXQRElo0krbpp0guxNCl55dxkLMVN+hla1L/g8tZR 79m5PBIdZv8XuKzFO5xLKYyagsW+kNLWvsVPvpXejl9AknaUeLgIN6jxI/uA117pkFm7 hIoczIlbbAIuohHH+D9thow+ZTEjqbSEvvTi5YaS8UDM7pELVCfUYIMuN3bVCCNFowrA J94g== X-Gm-Message-State: AOAM5331TTEMorLEeOAnSVOSlgTGuakj/kW5iu38876bsb2fgfgWp8uA qr0vfylbFonTS3WCXo99ZDnLRg== X-Google-Smtp-Source: ABdhPJw9OPID56vDdJCFPIcuD4PvDWMFAxEx/AK93Z9FXNeZLG/dSHWRSGT0eS42J2loD9GXN3YCjA== X-Received: by 2002:aca:2207:: with SMTP id b7mr4219069oic.24.1639030851177; Wed, 08 Dec 2021 22:20:51 -0800 (PST) Received: from ripple.attlocal.net (172-10-233-147.lightspeed.sntcca.sbcglobal.net. [172.10.233.147]) by smtp.gmail.com with ESMTPSA id t14sm919606oth.81.2021.12.08.22.20.49 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 08 Dec 2021 22:20:50 -0800 (PST) Date: Wed, 8 Dec 2021 22:20:47 -0800 (PST) From: Hugh Dickins X-X-Sender: hugh@ripple.anvils To: Mel Gorman cc: Andrew Morton , Michal Hocko , Vlastimil Babka , Alexey Avramov , Rik van Riel , Mike Galbraith , Darrick Wong , Shakeel Butt , regressions@lists.linux.dev, Linux-fsdevel , Linux-MM , LKML Subject: Re: [PATCH v4 1/1] mm: vmscan: Reduce throttling due to a failure to make progress In-Reply-To: <20211202150614.22440-1-mgorman@techsingularity.net> Message-ID: References: <20211202150614.22440-1-mgorman@techsingularity.net> Precedence: bulk X-Mailing-List: regressions@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII On Thu, 2 Dec 2021, Mel Gorman wrote: ... > --- a/mm/vmscan.c > +++ b/mm/vmscan.c ... > @@ -3478,14 +3520,18 @@ static void shrink_zones(struct zonelist *zonelist, struct scan_control *sc) > /* need some check for avoid more shrink_zone() */ > } > > + if (!first_pgdat) > + first_pgdat = zone->zone_pgdat; > + > /* See comment about same check for global reclaim above */ > if (zone->zone_pgdat == last_pgdat) > continue; > last_pgdat = zone->zone_pgdat; > shrink_node(zone->zone_pgdat, sc); > - consider_reclaim_throttle(zone->zone_pgdat, sc); > } > > + consider_reclaim_throttle(first_pgdat, sc); My tmpfs swapping load (tweaked to use huge pages more heavily than in real life) is far from being a realistic load: but it was notably slowed down by your throttling mods in 5.16-rc, and this patch makes it well again - thanks. But: it very quickly hit NULL pointer until I changed that last line to if (first_pgdat) consider_reclaim_throttle(first_pgdat, sc); I've given no thought as to whether that is the correct fix, or if first_pgdat should be set earlier in the loop above. Hugh