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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 1E2F5C25B0F for ; Sat, 13 Aug 2022 00:07:48 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S233653AbiHMAHr (ORCPT ); Fri, 12 Aug 2022 20:07:47 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:37132 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229802AbiHMAHp (ORCPT ); Fri, 12 Aug 2022 20:07:45 -0400 Received: from mail-vs1-xe2a.google.com (mail-vs1-xe2a.google.com [IPv6:2607:f8b0:4864:20::e2a]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id DAB445C9EB; Fri, 12 Aug 2022 17:07:41 -0700 (PDT) Received: by mail-vs1-xe2a.google.com with SMTP id j2so2316336vsp.1; Fri, 12 Aug 2022 17:07:41 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20210112; h=cc:to:subject:message-id:date:from:in-reply-to:references :mime-version:from:to:cc; bh=e/GEPoh9oXwaicH1mqU0UxtQs3rb9zpYq6pzE3gMamU=; b=fI8PvmX9/t2PLgbwoyuy/E4fAMPOov0xE5a7OjGy1WUFHEUxwBcNvvqD5gSGVhNgOK WZw3lzfQQbHfVe/0Qj0NW4OPEGEgpST591KZOPILFcg+sqpKgN0t5MBjxK4tyAD/q4Lj jYCms26OXy4IHggn8pSfZFxRnAWvWI7Hd0dNIjAwzZLlX3bz+1tkMIrMO4RZcom9RklK xQ2xolwtYqrIeEOBL3tL/OTJkhg8kxtJk12IBEeDnKuGQZ6HXGmYTHY59ORJhR5EwtLT gIA0+1VDanZTFu0PZ9dsoj+ehsEartf/DGCZPFSZhYqTJV9VRPoUt4M2MC2+M2m6o8iv 0bSg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=cc:to:subject:message-id:date:from:in-reply-to:references :mime-version:x-gm-message-state:from:to:cc; bh=e/GEPoh9oXwaicH1mqU0UxtQs3rb9zpYq6pzE3gMamU=; b=H3dOLXhiAgOOYfg6sUPNDsDzNfTn1FoPEex2pRWZM8WnGutmmUXiAzXt4nVF59qQJR HU92ZGUYsYGBDbV+cDMmn+c0j15XHIY45b68S3wvy+hO/z17ZxWON691LIZYNXrgA9MG ft+gbFFV1PQf5ibEDObPKv+r22JnyD24pYm/Stk7oGBrmFdbXssRIEVs3llFaNvHgv/L Oe3Q8LtJHYH33DLXYcY93/EvFtXzPfI6RCZ8jh9VYYT3FPy3PNlFsy2BBthy8CnGTiun 6DhXjwEPo/hEKiVnMAOlQwvPPl5rNqCwRgajGb1SXuRugIbhMXOb582GWNC3hLs1v+vL xXzA== X-Gm-Message-State: ACgBeo3zDVEhFbwn1PMfickt9e3nspwOnRvdjavCqlhnlJPlIO+6j3ge ZAV8W08ZYq0GC6+tKw4NeeWwoZ87n8oETvSGGzI= X-Google-Smtp-Source: AA6agR6wxzw7R/QR4+tJWTD/bsN3E+UUPFlZUz6BEsv1/PilpMzsEYhAEcNJpaQv5Ng+IURcAxZqkfJ8+uoYx7n08b8= X-Received: by 2002:a05:6102:441c:b0:378:fcdd:d951 with SMTP id df28-20020a056102441c00b00378fcddd951mr2920620vsb.22.1660349261002; Fri, 12 Aug 2022 17:07:41 -0700 (PDT) MIME-Version: 1.0 References: <20220810151840.16394-1-laoar.shao@gmail.com> <20220810151840.16394-14-laoar.shao@gmail.com> <20220812165756.dxaqy3go567prr5s@google.com> In-Reply-To: <20220812165756.dxaqy3go567prr5s@google.com> From: Yafang Shao Date: Sat, 13 Aug 2022 08:07:04 +0800 Message-ID: Subject: Re: [PATCH bpf-next 13/15] mm, memcg: Add new helper get_obj_cgroup_from_cgroup To: Shakeel Butt Cc: Alexei Starovoitov , Daniel Borkmann , Andrii Nakryiko , Martin Lau , Song Liu , Yonghong Song , john fastabend , KP Singh , Stanislav Fomichev , Hao Luo , jolsa@kernel.org, Johannes Weiner , Michal Hocko , Roman Gushchin , Muchun Song , Andrew Morton , netdev , bpf , Linux MM Content-Type: text/plain; charset="UTF-8" Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org On Sat, Aug 13, 2022 at 12:57 AM Shakeel Butt wrote: > > On Wed, Aug 10, 2022 at 03:18:38PM +0000, Yafang Shao wrote: > > Introduce new helper get_obj_cgroup_from_cgroup() to get obj_cgroup from > > a specific cgroup. > > Can you please add couple of lines on why you need objcg? > Sure. will update in the next version. > > > > Signed-off-by: Yafang Shao > > --- > > include/linux/memcontrol.h | 1 + > > mm/memcontrol.c | 41 +++++++++++++++++++++++++++++++++++++++++ > > 2 files changed, 42 insertions(+) > > > > diff --git a/include/linux/memcontrol.h b/include/linux/memcontrol.h > > index 2f0a611..901a921 100644 > > --- a/include/linux/memcontrol.h > > +++ b/include/linux/memcontrol.h > > @@ -1713,6 +1713,7 @@ static inline void set_shrinker_bit(struct mem_cgroup *memcg, > > int __memcg_kmem_charge_page(struct page *page, gfp_t gfp, int order); > > void __memcg_kmem_uncharge_page(struct page *page, int order); > > > > +struct obj_cgroup *get_obj_cgroup_from_cgroup(struct cgroup *cgrp); > > struct obj_cgroup *get_obj_cgroup_from_current(void); > > struct obj_cgroup *get_obj_cgroup_from_page(struct page *page); > > > > diff --git a/mm/memcontrol.c b/mm/memcontrol.c > > index 618c366..762cffa 100644 > > --- a/mm/memcontrol.c > > +++ b/mm/memcontrol.c > > @@ -2908,6 +2908,47 @@ static struct obj_cgroup *__get_obj_cgroup_from_memcg(struct mem_cgroup *memcg) > > return objcg; > > } > > > > +static struct obj_cgroup *get_obj_cgroup_from_memcg(struct mem_cgroup *memcg) > > +{ > > + struct obj_cgroup *objcg; > > + > > + if (memcg_kmem_bypass()) > > + return NULL; > > + > > + rcu_read_lock(); > > + objcg = __get_obj_cgroup_from_memcg(memcg); > > + rcu_read_unlock(); > > + return objcg; > > +} > > + > > +struct obj_cgroup *get_obj_cgroup_from_cgroup(struct cgroup *cgrp) > > +{ > > + struct cgroup_subsys_state *css; > > + struct mem_cgroup *memcg; > > + struct obj_cgroup *objcg; > > + > > + rcu_read_lock(); > > + css = rcu_dereference(cgrp->subsys[memory_cgrp_id]); > > + if (!css || !css_tryget_online(css)) { > > + rcu_read_unlock(); > > + cgroup_put(cgrp); > > + return ERR_PTR(-EINVAL); > > + } > > + rcu_read_unlock(); > > + cgroup_put(cgrp); > > The above put seems out of place and buggy. > Thanks for pointing it out. The cgroup_put should be used in bpf_map_save_memcg(). I will update it. -- Regards Yafang