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=-17.4 required=3.0 tests=BAYES_00,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 B82F4C433E4 for ; Tue, 25 Aug 2020 23:27:26 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 8FFE82075F for ; Tue, 25 Aug 2020 23:27:26 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b="MivpLulG" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726180AbgHYX1Y (ORCPT ); Tue, 25 Aug 2020 19:27:24 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:60516 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726542AbgHYX1X (ORCPT ); Tue, 25 Aug 2020 19:27:23 -0400 Received: from mail-lj1-x243.google.com (mail-lj1-x243.google.com [IPv6:2a00:1450:4864:20::243]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 1904CC061756 for ; Tue, 25 Aug 2020 16:27:23 -0700 (PDT) Received: by mail-lj1-x243.google.com with SMTP id v12so191158ljc.10 for ; Tue, 25 Aug 2020 16:27:22 -0700 (PDT) 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=4aOowIVQKsAzoG/P7qB+XM1QLU3nXt4GRb8Wo9/pT9s=; b=MivpLulGK4Df48K69jSdRc8nfiLb1OWc2/wR1DW9HP1UG9qr6eck3TpeDaRdIaIjdG rxm5jZM11EHi+oItPdIngPTflqJTW525HxxUOW32sq5Gory52QXBrrZD+9XtLvW2iAQy 6IlL8dhtXq8YuUQhq57cX2xfGeb+y7uEVCIGil0nToLklCaDAbCqy1RMsFiLN0B0qYK1 uk9yDHbHzMTVF8FdqTUhmw5BWyLbgq5Bsa6Hrwi5mcRMCo8mBoeOAqeWHfKqU8P/tyS1 IVYPdEA4R1k0Yj70tBH82ddD4ZTizX6+qLjNd4E2c/qlhsZDbLCznDNPJD/e4ZHNU/fq nDYA== 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=4aOowIVQKsAzoG/P7qB+XM1QLU3nXt4GRb8Wo9/pT9s=; b=VPaS6j8kos7/9HkAHb5iQG7AvcedDU6M75/IpZEdpze9Ft0BdlBvShW0P4n1JlUULD 7ZLgQHtv2Dv3AEBpr5QrQ9eY8PEdJoddFOWgfaIn3rvQsFBWT9bU3/UUG2nkGI+viABq n9CyTt12MOgIkCmhp92gFCbym4fmzAngPMiB+6vuD9oZmmXqfwrXGhMApiMbEs+/AFhR 4IW1aACJt/PTQdSXGutg051UzevEn6LA6dz5RR/PO9RvaRx60Kqygvo6+NSmK2qf7mqV 9MWPt457vzJrFm34o4XHHBefEElSeC4PnkaYUE1ME6mzkwIgwtECJzOBcwfoyh2G3keC RLlg== X-Gm-Message-State: AOAM530tmbwLgplEpj8+IWVKJES1FSv3zeNo2RbjvvJ6yYuGXPbvzzsk pqd9KSNEliHggbpuI6v7fAFzJj+08MFltbw5qnC4C0OVfiOOKw== X-Google-Smtp-Source: ABdhPJwOL01yVem6yxTF35XI/WnXhkpj83kmMggS8kPiQlIzw7frhGlHAbXcxnwtMKqkWQ2mxYEgWoZt/di+VkJ6PAs= X-Received: by 2002:a2e:5d8:: with SMTP id 207mr5279398ljf.58.1598398040350; Tue, 25 Aug 2020 16:27:20 -0700 (PDT) MIME-Version: 1.0 References: <20200821150134.2581465-1-guro@fb.com> <20200821150134.2581465-4-guro@fb.com> In-Reply-To: <20200821150134.2581465-4-guro@fb.com> From: Shakeel Butt Date: Tue, 25 Aug 2020 16:27:09 -0700 Message-ID: Subject: Re: [PATCH bpf-next v4 03/30] bpf: memcg-based memory accounting for bpf maps To: Roman Gushchin Cc: bpf@vger.kernel.org, netdev , Alexei Starovoitov , Daniel Borkmann , Kernel Team , LKML , Johannes Weiner , Linux MM Content-Type: text/plain; charset="UTF-8" Sender: bpf-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: bpf@vger.kernel.org On Fri, Aug 21, 2020 at 8:01 AM Roman Gushchin wrote: > > This patch enables memcg-based memory accounting for memory allocated > by __bpf_map_area_alloc(), which is used by most map types for > large allocations. > > If a map is updated from an interrupt context, and the update > results in memory allocation, the memory cgroup can't be determined > from the context of the current process. To address this case, > bpf map preserves a pointer to the memory cgroup of the process, > which created the map. This memory cgroup is charged for allocations > from interrupt context. > > Following patches in the series will refine the accounting for > some map types. > > Signed-off-by: Roman Gushchin > --- > include/linux/bpf.h | 4 ++++ > kernel/bpf/helpers.c | 37 ++++++++++++++++++++++++++++++++++++- > kernel/bpf/syscall.c | 27 ++++++++++++++++++++++++++- > 3 files changed, 66 insertions(+), 2 deletions(-) > > diff --git a/include/linux/bpf.h b/include/linux/bpf.h > index a9b7185a6b37..b5f178afde94 100644 > --- a/include/linux/bpf.h > +++ b/include/linux/bpf.h > @@ -34,6 +34,7 @@ struct btf_type; > struct exception_table_entry; > struct seq_operations; > struct bpf_iter_aux_info; > +struct mem_cgroup; > > extern struct idr btf_idr; > extern spinlock_t btf_idr_lock; > @@ -138,6 +139,9 @@ struct bpf_map { > u32 btf_value_type_id; > struct btf *btf; > struct bpf_map_memory memory; > +#ifdef CONFIG_MEMCG_KMEM > + struct mem_cgroup *memcg; > +#endif > char name[BPF_OBJ_NAME_LEN]; > u32 btf_vmlinux_value_type_id; > bool bypass_spec_v1; > diff --git a/kernel/bpf/helpers.c b/kernel/bpf/helpers.c > index be43ab3e619f..f8ce7bc7003f 100644 > --- a/kernel/bpf/helpers.c > +++ b/kernel/bpf/helpers.c > @@ -14,6 +14,7 @@ > #include > #include > #include > +#include > > #include "../../lib/kstrtox.h" > > @@ -41,11 +42,45 @@ const struct bpf_func_proto bpf_map_lookup_elem_proto = { > .arg2_type = ARG_PTR_TO_MAP_KEY, > }; > > +#ifdef CONFIG_MEMCG_KMEM > +static __always_inline int __bpf_map_update_elem(struct bpf_map *map, void *key, > + void *value, u64 flags) > +{ > + struct mem_cgroup *old_memcg; > + bool in_interrupt; > + int ret; > + > + /* > + * If update from an interrupt context results in a memory allocation, > + * the memory cgroup to charge can't be determined from the context > + * of the current task. Instead, we charge the memory cgroup, which > + * contained a process created the map. > + */ > + in_interrupt = in_interrupt(); > + if (in_interrupt) > + old_memcg = memalloc_use_memcg(map->memcg); > + The memcg_kmem_bypass() will bypass all __GFP_ACCOUNT allocations even before looking at current->active_memcg, so, this patch will be a noop. > + ret = map->ops->map_update_elem(map, key, value, flags); > + > + if (in_interrupt) > + memalloc_use_memcg(old_memcg); > + > + return ret; > +} > +#else > +static __always_inline int __bpf_map_update_elem(struct bpf_map *map, void *key, > + void *value, u64 flags) > +{ > + return map->ops->map_update_elem(map, key, value, flags); > +} > +#endif > + > BPF_CALL_4(bpf_map_update_elem, struct bpf_map *, map, void *, key, > void *, value, u64, flags) > { > WARN_ON_ONCE(!rcu_read_lock_held()); > - return map->ops->map_update_elem(map, key, value, flags); > + > + return __bpf_map_update_elem(map, key, value, flags); > } > > const struct bpf_func_proto bpf_map_update_elem_proto = { > diff --git a/kernel/bpf/syscall.c b/kernel/bpf/syscall.c > index 689d736b6904..683614c17a95 100644 > --- a/kernel/bpf/syscall.c > +++ b/kernel/bpf/syscall.c > @@ -29,6 +29,7 @@ > #include > #include > #include > +#include > > #define IS_FD_ARRAY(map) ((map)->map_type == BPF_MAP_TYPE_PERF_EVENT_ARRAY || \ > (map)->map_type == BPF_MAP_TYPE_CGROUP_ARRAY || \ > @@ -275,7 +276,7 @@ static void *__bpf_map_area_alloc(u64 size, int numa_node, bool mmapable) > * __GFP_RETRY_MAYFAIL to avoid such situations. > */ > > - const gfp_t gfp = __GFP_NOWARN | __GFP_ZERO; > + const gfp_t gfp = __GFP_NOWARN | __GFP_ZERO | __GFP_ACCOUNT; > unsigned int flags = 0; > unsigned long align = 1; > void *area; > @@ -452,6 +453,27 @@ void bpf_map_free_id(struct bpf_map *map, bool do_idr_lock) > __release(&map_idr_lock); > } > > +#ifdef CONFIG_MEMCG_KMEM > +static void bpf_map_save_memcg(struct bpf_map *map) > +{ > + map->memcg = get_mem_cgroup_from_mm(current->mm); > +} > + > +static void bpf_map_release_memcg(struct bpf_map *map) > +{ > + mem_cgroup_put(map->memcg); > +} > + > +#else > +static void bpf_map_save_memcg(struct bpf_map *map) > +{ > +} > + > +static void bpf_map_release_memcg(struct bpf_map *map) > +{ > +} > +#endif > + > /* called from workqueue */ > static void bpf_map_free_deferred(struct work_struct *work) > { > @@ -463,6 +485,7 @@ static void bpf_map_free_deferred(struct work_struct *work) > /* implementation dependent freeing */ > map->ops->map_free(map); > bpf_map_charge_finish(&mem); > + bpf_map_release_memcg(map); > } > > static void bpf_map_put_uref(struct bpf_map *map) > @@ -869,6 +892,8 @@ static int map_create(union bpf_attr *attr) > if (err) > goto free_map_sec; > > + bpf_map_save_memcg(map); > + > err = bpf_map_new_fd(map, f_flags); > if (err < 0) { > /* failed to allocate fd. > -- > 2.26.2 >