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=-14.4 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,USER_IN_DEF_DKIM_WL autolearn=unavailable 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 29E08C11D19 for ; Thu, 20 Feb 2020 18:14:59 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id F2A6A2467D for ; Thu, 20 Feb 2020 18:14:58 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b="uEXDpSnv" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728759AbgBTSO5 (ORCPT ); Thu, 20 Feb 2020 13:14:57 -0500 Received: from mail-ot1-f67.google.com ([209.85.210.67]:44060 "EHLO mail-ot1-f67.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728512AbgBTSO5 (ORCPT ); Thu, 20 Feb 2020 13:14:57 -0500 Received: by mail-ot1-f67.google.com with SMTP id h9so4532076otj.11 for ; Thu, 20 Feb 2020 10:14:56 -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=uUKdgkaufxLmLYOt3TduZTiePIKaOkl8sejxXEeQJug=; b=uEXDpSnvxNGx/1g8in8h2Lps6UF2cwI0Ci30lm3NqVXZaApTkzuDK+720dgSH9vb6k KPzL7duyHh9m0BqEDV45tazOognY/d0scMRdl2OcG1JPE/lSbuZQK0NgSRFEE6JZ1ocE bqLEMcVwBuFDRo16e9ImN9DFgGBbY4Rh3WKWen7Cz5Tan7f1NIIGTAN0UdCsrXlhKb2x xp82sXN5MddaQ9Fo3jlxRRZOvEG5C3dmzkLPX1is1Moe0S017U8Ajd4vA0J68kr+ivdJ DDHGyxImOHKFItW4eCZUYeAX2LdHOyh93fukcpNbkzLACAa56EL81Jnugc/MS1xxyks7 aVSg== 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=uUKdgkaufxLmLYOt3TduZTiePIKaOkl8sejxXEeQJug=; b=mDgo7bipT/BBc4dgsJkozwq7yOX91Ad9baDNnnsNff0JakXwnTr3ongtKh8QmBt+z+ r89NxHCNR31/E4bwNFysNW30wVSf2nPHQ9vjOiv7ZRzTPyVIsMhUnD74Qu661ZXN3di8 cRROye21B3vEVLHjPcqSaolKaDg1D6Fh3K6S02bFDtZmkrXR7udJCm+Il3LqR6GWRHLd N8IfFlpn05HnzGz1TphgTMnP+OXRgCGuiPuEQ1LL3ucTgnok6bH53zJAEyWoupYCum6n PGiTA1XdTNBHdrD3+ncNA1TloUOcr6e0XyOdX8kh43bJVLnuHBTkgsBbRU9+lalyomEn QuTw== X-Gm-Message-State: APjAAAXJjiJfERmF0UD13I0gyiH6esMwxO202nG3oeQ6+luKa8AuTvhj ox1NAyFQ6gV3cOINH7ma1ja9rBayzRzryb8C2A36rw== X-Google-Smtp-Source: APXvYqwEhtHawQMBwvmDc5WZ+GbpmKPP7mgN5ZpRyswR3p1ZNH4wKythp6ijBG51PHDBpY+92/+km74sS2lSGrcqxRE= X-Received: by 2002:a05:6830:11:: with SMTP id c17mr24335278otp.360.1582222496058; Thu, 20 Feb 2020 10:14:56 -0800 (PST) MIME-Version: 1.0 References: <0a27b6fcbd1f7af104d7f4cf0adc6a31e0e7dd19.1582216294.git.schatzberg.dan@gmail.com> In-Reply-To: <0a27b6fcbd1f7af104d7f4cf0adc6a31e0e7dd19.1582216294.git.schatzberg.dan@gmail.com> From: Shakeel Butt Date: Thu, 20 Feb 2020 10:14:45 -0800 Message-ID: Subject: Re: [PATCH v3 2/3] mm: Charge active memcg when no mm is set To: Dan Schatzberg Cc: Jens Axboe , Tejun Heo , Li Zefan , Johannes Weiner , Michal Hocko , Vladimir Davydov , Andrew Morton , Hugh Dickins , Roman Gushchin , Chris Down , Yang Shi , Thomas Gleixner , "open list:BLOCK LAYER" , open list , "open list:CONTROL GROUP (CGROUP)" , "open list:CONTROL GROUP - MEMORY RESOURCE CONTROLLER (MEMCG)" Content-Type: text/plain; charset="UTF-8" Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, Feb 20, 2020 at 8:52 AM Dan Schatzberg wrote: > > memalloc_use_memcg() worked for kernel allocations but was silently > ignored for user pages. > > This patch establishes a precedence order for who gets charged: > > 1. If there is a memcg associated with the page already, that memcg is > charged. This happens during swapin. > > 2. If an explicit mm is passed, mm->memcg is charged. This happens > during page faults, which can be triggered in remote VMs (eg gup). > > 3. Otherwise consult the current process context. If it has configured > a current->active_memcg, use that. What if css_tryget_online(current->active_memcg) in get_mem_cgroup_from_current() fails? Do we want to change this to css_tryget() and even if that fails should we fallback to root_mem_cgroup or current->mm->memcg? > Otherwise, current->mm->memcg. > > Previously, if a NULL mm was passed to mem_cgroup_try_charge (case 3) it > would always charge the root cgroup. Now it looks up the current > active_memcg first (falling back to charging the root cgroup if not > set). > > Signed-off-by: Dan Schatzberg > Acked-by: Johannes Weiner > Acked-by: Tejun Heo > --- > mm/memcontrol.c | 11 ++++++++--- > mm/shmem.c | 2 +- > 2 files changed, 9 insertions(+), 4 deletions(-) > > diff --git a/mm/memcontrol.c b/mm/memcontrol.c > index 6f6dc8712e39..b174aff4f069 100644 > --- a/mm/memcontrol.c > +++ b/mm/memcontrol.c > @@ -6317,7 +6317,8 @@ enum mem_cgroup_protection mem_cgroup_protected(struct mem_cgroup *root, > * @compound: charge the page as compound or small page > * > * Try to charge @page to the memcg that @mm belongs to, reclaiming > - * pages according to @gfp_mask if necessary. > + * pages according to @gfp_mask if necessary. If @mm is NULL, try to > + * charge to the active memcg. > * > * Returns 0 on success, with *@memcgp pointing to the charged memcg. > * Otherwise, an error code is returned. > @@ -6361,8 +6362,12 @@ int mem_cgroup_try_charge(struct page *page, struct mm_struct *mm, > } > } > > - if (!memcg) > - memcg = get_mem_cgroup_from_mm(mm); > + if (!memcg) { > + if (!mm) > + memcg = get_mem_cgroup_from_current(); > + else > + memcg = get_mem_cgroup_from_mm(mm); > + } > > ret = try_charge(memcg, gfp_mask, nr_pages); > > diff --git a/mm/shmem.c b/mm/shmem.c > index c8f7540ef048..7c7f5acf89d6 100644 > --- a/mm/shmem.c > +++ b/mm/shmem.c > @@ -1766,7 +1766,7 @@ static int shmem_getpage_gfp(struct inode *inode, pgoff_t index, > } > > sbinfo = SHMEM_SB(inode->i_sb); > - charge_mm = vma ? vma->vm_mm : current->mm; > + charge_mm = vma ? vma->vm_mm : NULL; > > page = find_lock_entry(mapping, index); > if (xa_is_value(page)) { > -- > 2.17.1 >