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=-4.1 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE, SPF_PASS autolearn=no 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 3C55CC433DF for ; Thu, 11 Jun 2020 09:35:31 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 11439204EC for ; Thu, 11 Jun 2020 09:35:31 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1591868131; bh=SFu6ijIwLu9L/2DkNn7ff4c2xan6U+236bF9FN93/sE=; h=Date:From:To:Cc:Subject:References:In-Reply-To:List-ID:From; b=AELPnagTHh+FR80WCWYbHwDkfzFTbVE9QKaAlkg1NUASqDA0eqx1QZ0/xnEMf7FqZ vPTUNqzqIwswsHGgxyGkIDMDUgVq9SkwR3z2TMKfJwYENshGbkPzUHTF3KfsFQDHXs 5kDpSTKV4m+hLSA1hW2kNxSCL7nSf0kKur4pwxW0= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726864AbgFKJf3 (ORCPT ); Thu, 11 Jun 2020 05:35:29 -0400 Received: from mail-wr1-f66.google.com ([209.85.221.66]:41199 "EHLO mail-wr1-f66.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726560AbgFKJf2 (ORCPT ); Thu, 11 Jun 2020 05:35:28 -0400 Received: by mail-wr1-f66.google.com with SMTP id j10so5401760wrw.8; Thu, 11 Jun 2020 02:35:27 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:from:to:cc:subject:message-id:references :mime-version:content-disposition:in-reply-to; bh=fCziW7D9RQqCEqfz7/IGRWHPMeEiWE2daJvcDBf0ZPA=; b=sd4niBTvsJr+OjxfwYzZy/zmX5UHFSvgUubOcCTS9TucQ/Gl569kvXpMmLFDdjXkZm ub/McMAoMmNiFgY/8WtTY4l6GyPeBY5RenXfQThl5pH2cmEk4F5oiNK+jMEeL/RLEwwT 0r6TXOTuij1gWvAKu2MUnUi/hu05bJemhjh2k2mjqkeLMyIsQI8lTh4YHAp2jvzCJt69 1v1fv7mzoDJTylwvc8FJRPfv5D1wz6mluXTlKglTzCzssFn6Rw/kmYwa2HmK+Z0AySM9 MH/sZ/7Vgb+cMOaorTtKPJDjfYnPDg4jdinRvItoFrl7t9N1RGOj6R0VmTEAo/UgYMY2 riLg== X-Gm-Message-State: AOAM531em3EIDz6qvd4lL7aThNi++5PafH3yP0a3G3bkbpTbY1kkL1k7 eTDpDfnfGVcVJM7RPLLCj9M= X-Google-Smtp-Source: ABdhPJwH0mDt5sHqy/XukKQyC767OzXT3IpOZMbx+o8zAQCUAY/T6Fsnyv8bfwIUq0D76RR8+m6TOg== X-Received: by 2002:a5d:484b:: with SMTP id n11mr8689943wrs.356.1591868126445; Thu, 11 Jun 2020 02:35:26 -0700 (PDT) Received: from localhost (ip-37-188-174-201.eurotel.cz. [37.188.174.201]) by smtp.gmail.com with ESMTPSA id y19sm3165036wmi.6.2020.06.11.02.35.24 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 11 Jun 2020 02:35:25 -0700 (PDT) Date: Thu, 11 Jun 2020 11:35:23 +0200 From: Michal Hocko To: Johannes Weiner Cc: Andrew Morton , Alex Shi , Joonsoo Kim , Shakeel Butt , Hugh Dickins , "Kirill A. Shutemov" , Roman Gushchin , linux-mm@kvack.org, cgroups@vger.kernel.org, linux-kernel@vger.kernel.org, kernel-team@fb.com Subject: Re: [PATCH 16/19] mm: memcontrol: charge swapin pages on instantiation Message-ID: <20200611093523.GB20450@dhcp22.suse.cz> References: <20200508183105.225460-1-hannes@cmpxchg.org> <20200508183105.225460-17-hannes@cmpxchg.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20200508183105.225460-17-hannes@cmpxchg.org> Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri 08-05-20 14:31:03, Johannes Weiner wrote: [...] > diff --git a/mm/memory.c b/mm/memory.c > index 832ee914cbcf..93900b121b6e 100644 > --- a/mm/memory.c > +++ b/mm/memory.c > @@ -3125,9 +3125,20 @@ vm_fault_t do_swap_page(struct vm_fault *vmf) > page = alloc_page_vma(GFP_HIGHUSER_MOVABLE, vma, > vmf->address); > if (page) { > + int err; > + > __SetPageLocked(page); > __SetPageSwapBacked(page); > set_page_private(page, entry.val); > + > + /* Tell memcg to use swap ownership records */ > + SetPageSwapCache(page); > + err = mem_cgroup_charge(page, vma->vm_mm, > + GFP_KERNEL, false); > + ClearPageSwapCache(page); > + if (err) > + goto out_page; err would be a return value from try_charge and that can be -ENOMEM. Now we almost never return ENOMEM for GFP_KERNEL single page charge. Except for async OOM handling (oom_disabled v1). So this needs translation to VM_FAULT_OOM. I am not an expert on the swap code so I might have missed some subtle issues but the rest of the patch seems reasonable to me. -- Michal Hocko SUSE Labs