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=-23.2 required=3.0 tests=BAYES_00,DKIMWL_WL_MED, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_CR_TRAILER,INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, URIBL_BLOCKED,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 03EC5C433E0 for ; Wed, 23 Dec 2020 21:22:49 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id B9BFF22273 for ; Wed, 23 Dec 2020 21:22:48 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729110AbgLWVWc (ORCPT ); Wed, 23 Dec 2020 16:22:32 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:41634 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729080AbgLWVWc (ORCPT ); Wed, 23 Dec 2020 16:22:32 -0500 Received: from mail-lf1-x12b.google.com (mail-lf1-x12b.google.com [IPv6:2a00:1450:4864:20::12b]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 61A5EC061794 for ; Wed, 23 Dec 2020 13:21:51 -0800 (PST) Received: by mail-lf1-x12b.google.com with SMTP id s26so509017lfc.8 for ; Wed, 23 Dec 2020 13:21:51 -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=wF35nXj0WqYzyWdTSecMciE07b/6u11vJiyvqK4gz6s=; b=hRMjxvObgBylB6uesmR8k4mhN2Pag25RaGN4pEInOqMyvL7N0xNsE42tWYXG4UfS/K +XsNltY2tXUStsjEFN1DCG4drR9Yei1e1pwXBxYqxPOOmhk+RzpuwJEBcJEJBYbBaIWu THr2sXxeIA+/WiiHyFx6LUFoHZYjin8MgtY/Fqd5CQJswDcVyzUMDtXTGiPAs8ZJBB4L 1CoQWXGNI/OdkwADgVzfhifxid1LxM5XDGRYxrB3/R4eaYk1AtIE4JAQz8bGZBRTVKOW aQIZawR3t/pSfsVITaeUVJCoYWC5LAIFLAm210rOtmgvOq0Z8rwRmedSpAVH38lM7HqO bQog== 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=wF35nXj0WqYzyWdTSecMciE07b/6u11vJiyvqK4gz6s=; b=hRBvrQhGIS7PXbyYVROe7fKJFMLZN8F8piXIuycv4W8oXi4wz8Cn/EQPkQ0pkQvyZ+ R513niU54qWq3dW/xUdzXWxMc/TcD8Fnrk5AxG/JhA2UObGOWKXOvYnbzyo8iZyiH8qb 3Z0QqsNrxivV9spIOlB3JcdG+mkFk/4YXwn6DNxef8nmlSb2zehKRsi/U/oJhU98RvHs UiUSX1apNpm2eFNEa0KJ5ynUUxH2r+UmEfsH1ReG3axGOhmnwy8D/dvO1As1HSH3A2GC G0Y2J3F7m5NKsUJg4LeBT+R/XASV7JZSHa1wFFnYzFwmrf/8u5j58t5YpezHxeSqsLb2 IcvQ== X-Gm-Message-State: AOAM533cc0nIKI9FW/tUsnppmyZZWbuUFfKJ4WcOTGMykunu+O0iy0vb kdAaTDThJHlM33So7dNJJejwgE5uNLMyrswlx/jGgg== X-Google-Smtp-Source: ABdhPJzHt5QoMR2hM01ksgvBri5qImtglXl7UpYz9rRyEvNbcOkgf4IEhhYCab297w4wPrrjMQKaK7bSjP/7n6Ddrt4= X-Received: by 2002:a05:6512:32ad:: with SMTP id q13mr3919043lfe.83.1608758509561; Wed, 23 Dec 2020 13:21:49 -0800 (PST) MIME-Version: 1.0 References: <20201217034356.4708-1-songmuchun@bytedance.com> <20201217034356.4708-8-songmuchun@bytedance.com> In-Reply-To: <20201217034356.4708-8-songmuchun@bytedance.com> From: Shakeel Butt Date: Wed, 23 Dec 2020 13:21:38 -0800 Message-ID: Subject: Re: [PATCH v5 7/7] mm: memcontrol: make the slab calculation consistent To: Muchun Song Cc: Greg Kroah-Hartman , rafael@kernel.org, Alexey Dobriyan , Andrew Morton , Johannes Weiner , Michal Hocko , Vladimir Davydov , Hugh Dickins , Roman Gushchin , Sami Tolvanen , Feng Tang , Neil Brown , Joonsoo Kim , Randy Dunlap , LKML , linux-fsdevel , Linux MM , Cgroups Content-Type: text/plain; charset="UTF-8" Precedence: bulk List-ID: X-Mailing-List: linux-fsdevel@vger.kernel.org On Wed, Dec 16, 2020 at 7:46 PM Muchun Song wrote: > > Although the ratio of the slab is one, we also should read the ratio > from the related memory_stats instead of hard-coding. And the local > variable of size is already the value of slab_unreclaimable. So we > do not need to read again. > > To do this we need some code like below: > > if (unlikely(memory_stats[i].idx == NR_SLAB_UNRECLAIMABLE_B)) { > - size = memcg_page_state(memcg, NR_SLAB_RECLAIMABLE_B) + > - memcg_page_state(memcg, NR_SLAB_UNRECLAIMABLE_B); > + size += memcg_page_state(memcg, memory_stats[i - 1].idx) * > + memory_stats[i - 1].ratio; > > It requires a series of BUG_ONs or comments to ensure these two > items are actually adjacent and in the right order. So it would > probably be easier to implement this using a wrapper that has a > big switch() for unit conversion. > > This would fix the ratio inconsistency and get rid of the order > guarantee. > The commit message is really confusing. It is explaining a situation which it did not do. I don't see any benefit of mentioning BUG_ONs or [i-1]s in the message. The patch makes sure that we use the right ratio for slab. Can you rewrite the commit message and motivate in just that regard? > Signed-off-by: Muchun Song > --- > mm/memcontrol.c | 105 +++++++++++++++++++++++++++++++++++--------------------- > 1 file changed, 66 insertions(+), 39 deletions(-) > > diff --git a/mm/memcontrol.c b/mm/memcontrol.c > index a40797a27f87..eec44918d373 100644 > --- a/mm/memcontrol.c > +++ b/mm/memcontrol.c > @@ -1511,49 +1511,71 @@ static bool mem_cgroup_wait_acct_move(struct mem_cgroup *memcg) > > struct memory_stat { > const char *name; > - unsigned int ratio; > unsigned int idx; > }; > > static const struct memory_stat memory_stats[] = { > - { "anon", PAGE_SIZE, NR_ANON_MAPPED }, > - { "file", PAGE_SIZE, NR_FILE_PAGES }, > - { "kernel_stack", 1024, NR_KERNEL_STACK_KB }, > - { "pagetables", PAGE_SIZE, NR_PAGETABLE }, > - { "percpu", 1, MEMCG_PERCPU_B }, > - { "sock", PAGE_SIZE, MEMCG_SOCK }, > - { "shmem", PAGE_SIZE, NR_SHMEM }, > - { "file_mapped", PAGE_SIZE, NR_FILE_MAPPED }, > - { "file_dirty", PAGE_SIZE, NR_FILE_DIRTY }, > - { "file_writeback", PAGE_SIZE, NR_WRITEBACK }, > + { "anon", NR_ANON_MAPPED }, > + { "file", NR_FILE_PAGES }, > + { "kernel_stack", NR_KERNEL_STACK_KB }, > + { "pagetables", NR_PAGETABLE }, > + { "percpu", MEMCG_PERCPU_B }, > + { "sock", MEMCG_SOCK }, > + { "shmem", NR_SHMEM }, > + { "file_mapped", NR_FILE_MAPPED }, > + { "file_dirty", NR_FILE_DIRTY }, > + { "file_writeback", NR_WRITEBACK }, > #ifdef CONFIG_TRANSPARENT_HUGEPAGE > - { "anon_thp", PAGE_SIZE, NR_ANON_THPS }, > - { "file_thp", PAGE_SIZE, NR_FILE_THPS }, > - { "shmem_thp", PAGE_SIZE, NR_SHMEM_THPS }, > + { "anon_thp", NR_ANON_THPS }, > + { "file_thp", NR_FILE_THPS }, > + { "shmem_thp", NR_SHMEM_THPS }, > #endif > - { "inactive_anon", PAGE_SIZE, NR_INACTIVE_ANON }, > - { "active_anon", PAGE_SIZE, NR_ACTIVE_ANON }, > - { "inactive_file", PAGE_SIZE, NR_INACTIVE_FILE }, > - { "active_file", PAGE_SIZE, NR_ACTIVE_FILE }, > - { "unevictable", PAGE_SIZE, NR_UNEVICTABLE }, > - > - /* > - * Note: The slab_reclaimable and slab_unreclaimable must be > - * together and slab_reclaimable must be in front. > - */ > - { "slab_reclaimable", 1, NR_SLAB_RECLAIMABLE_B }, > - { "slab_unreclaimable", 1, NR_SLAB_UNRECLAIMABLE_B }, > + { "inactive_anon", NR_INACTIVE_ANON }, > + { "active_anon", NR_ACTIVE_ANON }, > + { "inactive_file", NR_INACTIVE_FILE }, > + { "active_file", NR_ACTIVE_FILE }, > + { "unevictable", NR_UNEVICTABLE }, > + { "slab_reclaimable", NR_SLAB_RECLAIMABLE_B }, > + { "slab_unreclaimable", NR_SLAB_UNRECLAIMABLE_B }, > > /* The memory events */ > - { "workingset_refault_anon", 1, WORKINGSET_REFAULT_ANON }, > - { "workingset_refault_file", 1, WORKINGSET_REFAULT_FILE }, > - { "workingset_activate_anon", 1, WORKINGSET_ACTIVATE_ANON }, > - { "workingset_activate_file", 1, WORKINGSET_ACTIVATE_FILE }, > - { "workingset_restore_anon", 1, WORKINGSET_RESTORE_ANON }, > - { "workingset_restore_file", 1, WORKINGSET_RESTORE_FILE }, > - { "workingset_nodereclaim", 1, WORKINGSET_NODERECLAIM }, > + { "workingset_refault_anon", WORKINGSET_REFAULT_ANON }, > + { "workingset_refault_file", WORKINGSET_REFAULT_FILE }, > + { "workingset_activate_anon", WORKINGSET_ACTIVATE_ANON }, > + { "workingset_activate_file", WORKINGSET_ACTIVATE_FILE }, > + { "workingset_restore_anon", WORKINGSET_RESTORE_ANON }, > + { "workingset_restore_file", WORKINGSET_RESTORE_FILE }, > + { "workingset_nodereclaim", WORKINGSET_NODERECLAIM }, > }; > > +/* Translate stat items to the correct unit for memory.stat output */ > +static int memcg_page_state_unit(int item) > +{ > + switch (item) { > + case MEMCG_PERCPU_B: > + case NR_SLAB_RECLAIMABLE_B: > + case NR_SLAB_UNRECLAIMABLE_B: > + case WORKINGSET_REFAULT_ANON: > + case WORKINGSET_REFAULT_FILE: > + case WORKINGSET_ACTIVATE_ANON: > + case WORKINGSET_ACTIVATE_FILE: > + case WORKINGSET_RESTORE_ANON: > + case WORKINGSET_RESTORE_FILE: > + case WORKINGSET_NODERECLAIM: > + return 1; > + case NR_KERNEL_STACK_KB: > + return SZ_1K; > + default: > + return PAGE_SIZE; > + } > +} > + > +static inline unsigned long memcg_page_state_output(struct mem_cgroup *memcg, > + int item) > +{ > + return memcg_page_state(memcg, item) * memcg_page_state_unit(item); > +} > + > static char *memory_stat_format(struct mem_cgroup *memcg) > { > struct seq_buf s; > @@ -1577,13 +1599,12 @@ static char *memory_stat_format(struct mem_cgroup *memcg) > for (i = 0; i < ARRAY_SIZE(memory_stats); i++) { > u64 size; > > - size = memcg_page_state(memcg, memory_stats[i].idx); > - size *= memory_stats[i].ratio; > + size = memcg_page_state_output(memcg, memory_stats[i].idx); > seq_buf_printf(&s, "%s %llu\n", memory_stats[i].name, size); > > if (unlikely(memory_stats[i].idx == NR_SLAB_UNRECLAIMABLE_B)) { > - size = memcg_page_state(memcg, NR_SLAB_RECLAIMABLE_B) + > - memcg_page_state(memcg, NR_SLAB_UNRECLAIMABLE_B); > + size += memcg_page_state_output(memcg, > + NR_SLAB_RECLAIMABLE_B); > seq_buf_printf(&s, "slab %llu\n", size); > } > } > @@ -6377,6 +6398,12 @@ static int memory_stat_show(struct seq_file *m, void *v) > } > > #ifdef CONFIG_NUMA > +static inline unsigned long lruvec_page_state_output(struct lruvec *lruvec, > + int item) > +{ > + return lruvec_page_state(lruvec, item) * memcg_page_state_unit(item); > +} > + No need to have lruvec_page_state_output() separately as there is just one user. Just inline it. > static int memory_numa_stat_show(struct seq_file *m, void *v) > { > int i; > @@ -6394,8 +6421,8 @@ static int memory_numa_stat_show(struct seq_file *m, void *v) > struct lruvec *lruvec; > > lruvec = mem_cgroup_lruvec(memcg, NODE_DATA(nid)); > - size = lruvec_page_state(lruvec, memory_stats[i].idx); > - size *= memory_stats[i].ratio; > + size = lruvec_page_state_output(lruvec, > + memory_stats[i].idx); > seq_printf(m, " N%d=%llu", nid, size); > } > seq_putc(m, '\n'); > -- > 2.11.0 >