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 vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 348D5C433FE for ; Fri, 7 Jan 2022 13:11:34 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1347473AbiAGNLd (ORCPT ); Fri, 7 Jan 2022 08:11:33 -0500 Received: from smtp-out2.suse.de ([195.135.220.29]:42126 "EHLO smtp-out2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1347437AbiAGNLc (ORCPT ); Fri, 7 Jan 2022 08:11:32 -0500 Received: from relay2.suse.de (relay2.suse.de [149.44.160.134]) by smtp-out2.suse.de (Postfix) with ESMTP id A1AD81F3A2; Fri, 7 Jan 2022 13:11:30 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=suse.com; s=susede1; t=1641561090; h=from:from:reply-to:date:date:message-id:message-id:to:to:cc:cc: mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=gc7RESSovFXbtCRI/cp6kE8Jiq0QYX7ZdbQPcYT0MvA=; b=QQw+dSw+MkkBXaVdJafoPeNUIflGmPW62gMUEi4yCfxCFFaRd1W7t932jUYgp7Mgr5PuoE srfYFRdT74WF7lt4tiRTIm1asMrtXugn8eQtn7Nr3gv2qwEjA42CIBDjXrmnQIV6m4wUMG /NyHXMZwFyKT20uxbjX+N6aeU7sX+cw= Received: from suse.cz (unknown [10.100.201.86]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by relay2.suse.de (Postfix) with ESMTPS id 8D93FA3B8B; Fri, 7 Jan 2022 13:11:29 +0000 (UTC) Date: Fri, 7 Jan 2022 14:11:29 +0100 From: Michal Hocko To: Yu Zhao Cc: Andrew Morton , Linus Torvalds , Andi Kleen , Catalin Marinas , Dave Hansen , Hillf Danton , Jens Axboe , Jesse Barnes , Johannes Weiner , Jonathan Corbet , Matthew Wilcox , Mel Gorman , Michael Larabel , Rik van Riel , Vlastimil Babka , Will Deacon , Ying Huang , linux-arm-kernel@lists.infradead.org, linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org, page-reclaim@google.com, x86@kernel.org, Konstantin Kharlamov Subject: Re: [PATCH v6 6/9] mm: multigenerational lru: aging Message-ID: References: <20220104202227.2903605-1-yuzhao@google.com> <20220104202227.2903605-7-yuzhao@google.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20220104202227.2903605-7-yuzhao@google.com> Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue 04-01-22 13:22:25, Yu Zhao wrote: [...] > +static void lru_gen_age_node(struct pglist_data *pgdat, struct scan_control *sc) > +{ > + struct mem_cgroup *memcg; > + bool success = false; > + unsigned long min_ttl = READ_ONCE(lru_gen_min_ttl); > + > + VM_BUG_ON(!current_is_kswapd()); > + > + current->reclaim_state->mm_walk = &pgdat->mm_walk; > + > + memcg = mem_cgroup_iter(NULL, NULL, NULL); > + do { > + struct lruvec *lruvec = mem_cgroup_lruvec(memcg, pgdat); > + > + if (age_lruvec(lruvec, sc, min_ttl)) > + success = true; > + > + cond_resched(); > + } while ((memcg = mem_cgroup_iter(NULL, memcg, NULL))); > + > + if (!success && mutex_trylock(&oom_lock)) { > + struct oom_control oc = { > + .gfp_mask = sc->gfp_mask, > + .order = sc->order, > + }; > + > + if (!oom_reaping_in_progress()) > + out_of_memory(&oc); > + > + mutex_unlock(&oom_lock); > + } Why do you need to trigger oom killer from this path? Why cannot you rely on the page allocator to do that like we do now? -- Michal Hocko SUSE Labs