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=-13.7 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED 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 CCDACC433E0 for ; Sat, 6 Mar 2021 05:27:08 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id 20B6064FEA for ; Sat, 6 Mar 2021 05:27:08 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 20B6064FEA Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=bytedance.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id 595E66B0006; Sat, 6 Mar 2021 00:27:07 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id 546F26B006C; Sat, 6 Mar 2021 00:27:07 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 3E6CF6B006E; Sat, 6 Mar 2021 00:27:07 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0229.hostedemail.com [216.40.44.229]) by kanga.kvack.org (Postfix) with ESMTP id 2154E6B0006 for ; Sat, 6 Mar 2021 00:27:07 -0500 (EST) Received: from smtpin28.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay01.hostedemail.com (Postfix) with ESMTP id BE819180ACF6C for ; Sat, 6 Mar 2021 05:27:06 +0000 (UTC) X-FDA: 77888315652.28.52F21D7 Received: from mail-pf1-f177.google.com (mail-pf1-f177.google.com [209.85.210.177]) by imf17.hostedemail.com (Postfix) with ESMTP id C0FE1407F8DB for ; Sat, 6 Mar 2021 05:27:03 +0000 (UTC) Received: by mail-pf1-f177.google.com with SMTP id l7so3647951pfd.3 for ; Fri, 05 Mar 2021 21:27:03 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=bytedance-com.20150623.gappssmtp.com; s=20150623; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc; bh=Uc7mXQTuHDzk+aDNNzQQX07oTLDrDNn3MiGGfXF4/WM=; b=Zz2xJ5ConvofN2Q21zhivY2nUjs7UpEQtJDX+ho5tWKNNQWsl8uaQWjvzZWU5sPWls h/q1rJ+T+0r8fKS/PtoPtosFNzvyfUjfiBNF/M/ixYJQH4Qr+t0crXIRfDDzuZv8HmmM SOcGb/gTXeeOQSqfbgGY9rLn2Uj7xdxnvnvEPSanwO381L000gNKlGKZiZEDQ7McnPDj P31Bt0C4c2BlLo+XEF6Npy+TvweKxQZrhC4y0Mj4TaSbfVZCJn91OaGO/J0mWqq20ssZ M6hMb12AQ8+vtG3lw9pBIX6wsN/iYEoau8BVVQYgxEu6q1gTz3tWxmLC/QarZNuqZbV2 vUWA== 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=Uc7mXQTuHDzk+aDNNzQQX07oTLDrDNn3MiGGfXF4/WM=; b=k3p1Etfyt7Ruyd+OguVZN4iVxGnFQGnfj2qhoMVzzM6NIQZzpN8i6LSU4Sd3Tx4Q60 lOJogQa0/ZvREZw3/u3es3zzD1gZrzhBAb8c7tv5rPIkPgw9w2W0m9OZpo0JdWLjc18a EknXmI/41FhhV/n4l4jsONJB4s11x5uXNn+2lM4PAc50db0VOaBE8oUa7Nq86YPLZdrp sXbchiABL9Hza+Y3bntX1UL9GasSOIFQ9HIvlLAjSLi+Zmnd0ypxsi9SKwgnS7D8B6FZ ZsM3CiTfAbHGrBc413Y4xYEdTFqM5BALxvbDxiIzlsGMG8RVugit0XlvXHSU+GTOc6dx /1FQ== X-Gm-Message-State: AOAM533X+m7N9ARDkH3D9skX7zTS2HZPedsZCEQhCq/EZd6McLDLn7AJ BnyNB8VNyRhxv4NEnzM6HUaiQtujnzqsfzRwSxyPow== X-Google-Smtp-Source: ABdhPJxiDBW/SysoysDGwuv3pMvN2NDBPV959/X5Vlh3+H1J5qHIM3V4hqpM6no/LkX8N8sC04Mx8Qz/Red7im6ikCM= X-Received: by 2002:a63:141e:: with SMTP id u30mr11847397pgl.31.1615008422782; Fri, 05 Mar 2021 21:27:02 -0800 (PST) MIME-Version: 1.0 References: <20210303055917.66054-1-songmuchun@bytedance.com> <20210303055917.66054-2-songmuchun@bytedance.com> In-Reply-To: From: Muchun Song Date: Sat, 6 Mar 2021 13:26:26 +0800 Message-ID: Subject: Re: [External] Re: [PATCH v2 1/5] mm: memcontrol: introduce obj_cgroup_{un}charge_page To: Roman Gushchin Cc: Johannes Weiner , Michal Hocko , Andrew Morton , Shakeel Butt , Vladimir Davydov , LKML , Linux Memory Management List , Xiongchun duan Content-Type: text/plain; charset="UTF-8" X-Stat-Signature: f8w3h358edzpmkqs353697c1jooafjj5 X-Rspamd-Server: rspam02 X-Rspamd-Queue-Id: C0FE1407F8DB Received-SPF: none (bytedance.com>: No applicable sender policy available) receiver=imf17; identity=mailfrom; envelope-from=""; helo=mail-pf1-f177.google.com; client-ip=209.85.210.177 X-HE-DKIM-Result: pass/pass X-HE-Tag: 1615008423-229146 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 Sat, Mar 6, 2021 at 2:56 AM Roman Gushchin wrote: > > On Wed, Mar 03, 2021 at 01:59:13PM +0800, Muchun Song wrote: > > We know that the unit of slab object charging is bytes, the unit of > > kmem page charging is PAGE_SIZE. If we want to reuse obj_cgroup APIs > > to charge the kmem pages, we should pass PAGE_SIZE (as third parameter) > > to obj_cgroup_charge(). Because the size is already PAGE_SIZE, we can > > skip touch the objcg stock. And obj_cgroup_{un}charge_page() are > > introduced to charge in units of page level. > > > > In the later patch, we also can reuse those two helpers to charge or > > uncharge a number of kernel pages to a object cgroup. This is just > > a code movement without any functional changes. > > > > Signed-off-by: Muchun Song > > This patch looks good to me, even as a standalone refactoring. > Please, rename obj_cgroup_charge_page() to obj_cgroup_charge_pages() > and the same with uncharge. It's because _page suffix usually means > we're dealing with a physical page (e.g. struct page * as an argument), > here it's not the case. Make sense. > > Please, add my Acked-by: Roman Gushchin > after the renaming. Will do. Thanks for your review. > > Thank you! > > > --- > > mm/memcontrol.c | 46 +++++++++++++++++++++++++++++++--------------- > > 1 file changed, 31 insertions(+), 15 deletions(-) > > > > diff --git a/mm/memcontrol.c b/mm/memcontrol.c > > index 845eec01ef9d..faae16def127 100644 > > --- a/mm/memcontrol.c > > +++ b/mm/memcontrol.c > > @@ -3056,6 +3056,34 @@ static void memcg_free_cache_id(int id) > > ida_simple_remove(&memcg_cache_ida, id); > > } > > > > +static inline void obj_cgroup_uncharge_page(struct obj_cgroup *objcg, > > + unsigned int nr_pages) > > +{ > > + rcu_read_lock(); > > + __memcg_kmem_uncharge(obj_cgroup_memcg(objcg), nr_pages); > > + rcu_read_unlock(); > > +} > > + > > +static int obj_cgroup_charge_page(struct obj_cgroup *objcg, gfp_t gfp, > > + unsigned int nr_pages) > > +{ > > + struct mem_cgroup *memcg; > > + int ret; > > + > > + rcu_read_lock(); > > +retry: > > + memcg = obj_cgroup_memcg(objcg); > > + if (unlikely(!css_tryget(&memcg->css))) > > + goto retry; > > + rcu_read_unlock(); > > + > > + ret = __memcg_kmem_charge(memcg, gfp, nr_pages); > > + > > + css_put(&memcg->css); > > + > > + return ret; > > +} > > + > > /** > > * __memcg_kmem_charge: charge a number of kernel pages to a memcg > > * @memcg: memory cgroup to charge > > @@ -3180,11 +3208,8 @@ static void drain_obj_stock(struct memcg_stock_pcp *stock) > > unsigned int nr_pages = stock->nr_bytes >> PAGE_SHIFT; > > unsigned int nr_bytes = stock->nr_bytes & (PAGE_SIZE - 1); > > > > - if (nr_pages) { > > - rcu_read_lock(); > > - __memcg_kmem_uncharge(obj_cgroup_memcg(old), nr_pages); > > - rcu_read_unlock(); > > - } > > + if (nr_pages) > > + obj_cgroup_uncharge_page(old, nr_pages); > > > > /* > > * The leftover is flushed to the centralized per-memcg value. > > @@ -3242,7 +3267,6 @@ static void refill_obj_stock(struct obj_cgroup *objcg, unsigned int nr_bytes) > > > > int obj_cgroup_charge(struct obj_cgroup *objcg, gfp_t gfp, size_t size) > > { > > - struct mem_cgroup *memcg; > > unsigned int nr_pages, nr_bytes; > > int ret; > > > > @@ -3259,24 +3283,16 @@ int obj_cgroup_charge(struct obj_cgroup *objcg, gfp_t gfp, size_t size) > > * refill_obj_stock(), called from this function or > > * independently later. > > */ > > - rcu_read_lock(); > > -retry: > > - memcg = obj_cgroup_memcg(objcg); > > - if (unlikely(!css_tryget(&memcg->css))) > > - goto retry; > > - rcu_read_unlock(); > > - > > nr_pages = size >> PAGE_SHIFT; > > nr_bytes = size & (PAGE_SIZE - 1); > > > > if (nr_bytes) > > nr_pages += 1; > > > > - ret = __memcg_kmem_charge(memcg, gfp, nr_pages); > > + ret = obj_cgroup_charge_page(objcg, gfp, nr_pages); > > if (!ret && nr_bytes) > > refill_obj_stock(objcg, PAGE_SIZE - nr_bytes); > > > > - css_put(&memcg->css); > > return ret; > > } > > > > -- > > 2.11.0 > >