From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-yb1-f174.google.com (mail-yb1-f174.google.com [209.85.219.174]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id C467A8614C for ; Mon, 29 Apr 2024 17:35:51 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.219.174 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1714412153; cv=none; b=pDMGnLtI/JcOzp+pPBUVHEEeihASGAEiNN3WnZJgSVGprw8DIAe5HD/FNTN6n6qBO+N86oAfrNuQQmntU5soLBlK+uKArbUnFGeEyg7PSsjM5M1c66uM1JhX1d4IspPBuFFOwUEVQ7fVOgY1aIOhBWq5AVvvx96x3tjBLjsriI8= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1714412153; c=relaxed/simple; bh=kKB+Gx4VijAcXAdpEnC7HogMPoCF3TjIDI8x/Ckk8xo=; h=MIME-Version:References:In-Reply-To:From:Date:Message-ID:Subject: To:Cc:Content-Type; b=hgkIu6zoY8VDBSAIcW9pDtn+9smTvf8rqAQ98eiFRw7Jw7yVEiEe67rr2m9J4xPH6We/gPi022kRkojUlq12W8NE84JGEUSbk6u59Ca4JNYqxwS24u9H72yxhPfiIjn9h/3LjlBICOZmiR80+V2/5g2cDRHDYeBrH/rOZv+HqRk= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=google.com; spf=pass smtp.mailfrom=google.com; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b=pJAGWBjX; arc=none smtp.client-ip=209.85.219.174 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=google.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=google.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b="pJAGWBjX" Received: by mail-yb1-f174.google.com with SMTP id 3f1490d57ef6-de5ea7edb90so1616514276.1 for ; Mon, 29 Apr 2024 10:35:51 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20230601; t=1714412151; x=1715016951; darn=vger.kernel.org; h=content-transfer-encoding:cc:to:subject:message-id:date:from :in-reply-to:references:mime-version:from:to:cc:subject:date :message-id:reply-to; bh=e7wVsqLptnLKS5hiDCshs3Dr+pCekMHSh0FCkw4ggDQ=; b=pJAGWBjXDatZeJpx+adtQsGQXp/TgaWgNtc7yd6s3s4yiVKwCC81GlXeBLA55B1hY+ tbo2XD6g1Y1p7iTVNC7xMDMOx/qheZpGkQRg9YvHxA6K21h7I8zrfQPGRsV1+lJJSQ5w M1J5nJScD7vVF7ArdueghTFrJ2Xyy+L6aipUebsjOlJ8reAgEBF4hvFJICIlqYMHodGh cIjL2nojM83/ITiE4I7QIuqh04jzS3lM29R0HzFn+nKl0dhGuB6NoqZ39ChXe/i4gelz YtJMbrVZT2iB+EUvqO57z9O28vfqz8x783pKJVmVTjGQmQN4QB7gBqE/ELwm5s9iR6DU JMuw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1714412151; x=1715016951; h=content-transfer-encoding:cc:to:subject:message-id:date:from :in-reply-to:references:mime-version:x-gm-message-state:from:to:cc :subject:date:message-id:reply-to; bh=e7wVsqLptnLKS5hiDCshs3Dr+pCekMHSh0FCkw4ggDQ=; b=WBo41CVab17ndYexa26E3Y2Qg3ZTKnEJok5EpQfEcNGbFJeZIJjw79QuldbHW2FtJ4 xfS4nsh75AORbQBJjr+BFg1uXCedLirD2wVQjdn1ZlJxS60HNQc4Rg76/hspS4org6MQ 6q/u47ZYF3ZQ8laMFw0UHL8cYbfjv3HLn4EW6zCDweVsUWZ5XywbF6HSDJbdvaoRzaFJ eyBo7c12zsHsXdbhbeGrKn9fVj9nWrLj4MGQAEWdVp2+hoY7ewhwD6jYJf+YtfsR/zOP jV6zgcbBG0qDN3y2bI9EEPSAhLa+94VPtwiReow2tWpEu2H9L+Yqe0CyMUxtVaGdP1hH tgEQ== X-Forwarded-Encrypted: i=1; AJvYcCWUqTOe/EFr4x4auSF3w4t/enQPUBFfuzUPu0rjJOaJHbgQ6FJFkW+wmo/O2Y9+nsssEOXMm35mUjE5X6zM/TW0EBgI42bvwVlOEAPs X-Gm-Message-State: AOJu0Yw6gwoJZ19vIT3RM/Y2E+SNQYSMpyYDc8g/sBPetxXafbtN588J Y5FUpbESplXW+7mLjgq0mTNJHaT6ksBIgy6C1qrZR+cGMiJ2wLeK+/4EwFHqy6e1nue4mWkOPMk 8tGFqJk0vm1YZM4cs30cL0JOtnEB62thxo9G8 X-Google-Smtp-Source: AGHT+IGze69SzvgF+laQKVNenGfnhfSWQBgrc5CamDWJtv+XCFQ6jEAcsZk7GmgDzGBWxcDr4R7RpmZIhxez25z/hY4= X-Received: by 2002:a25:5:0:b0:de5:588e:40c8 with SMTP id 5-20020a250005000000b00de5588e40c8mr11793575yba.56.1714412150470; Mon, 29 Apr 2024 10:35:50 -0700 (PDT) Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 References: <20240427003733.3898961-1-shakeel.butt@linux.dev> <20240427003733.3898961-4-shakeel.butt@linux.dev> In-Reply-To: <20240427003733.3898961-4-shakeel.butt@linux.dev> From: "T.J. Mercier" Date: Mon, 29 Apr 2024 10:35:38 -0700 Message-ID: Subject: Re: [PATCH v2 3/7] memcg: reduce memory for the lruvec and memcg stats To: Shakeel Butt Cc: Andrew Morton , Johannes Weiner , Michal Hocko , Roman Gushchin , Muchun Song , linux-mm@kvack.org, linux-kernel@vger.kernel.org Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable On Fri, Apr 26, 2024 at 5:37=E2=80=AFPM Shakeel Butt wrote: > > At the moment, the amount of memory allocated for stats related structs > in the mem_cgroup corresponds to the size of enum node_stat_item. > However not all fields in enum node_stat_item has corresponding memcg > stats. So, let's use indirection mechanism similar to the one used for > memcg vmstats management. > > For a given x86_64 config, the size of stats with and without patch is: > > structs size in bytes w/o with > > struct lruvec_stats 1128 648 > struct lruvec_stats_percpu 752 432 > struct memcg_vmstats 1832 1352 > struct memcg_vmstats_percpu 1280 960 > > The memory savings is further compounded by the fact that these structs > are allocated for each cpu and for each node. To be precise, for each > memcg the memory saved would be: > > Memory saved =3D ((21 * 3 * NR_NODES) + (21 * 2 * NR_NODS * NR_CPUS) + > (21 * 3) + (21 * 2 * NR_CPUS)) * sizeof(long) > > Where 21 is the number of fields eliminated. > > Signed-off-by: Shakeel Butt > --- > mm/memcontrol.c | 138 ++++++++++++++++++++++++++++++++++++++++-------- > 1 file changed, 115 insertions(+), 23 deletions(-) > > diff --git a/mm/memcontrol.c b/mm/memcontrol.c > index 5e337ed6c6bf..c164bc9b8ed6 100644 > --- a/mm/memcontrol.c > +++ b/mm/memcontrol.c > @@ -576,35 +576,105 @@ mem_cgroup_largest_soft_limit_node(struct mem_cgro= up_tree_per_node *mctz) > return mz; > } > > +/* Subset of node_stat_item for memcg stats */ > +static const unsigned int memcg_node_stat_items[] =3D { > + NR_INACTIVE_ANON, > + NR_ACTIVE_ANON, > + NR_INACTIVE_FILE, > + NR_ACTIVE_FILE, > + NR_UNEVICTABLE, > + NR_SLAB_RECLAIMABLE_B, > + NR_SLAB_UNRECLAIMABLE_B, > + WORKINGSET_REFAULT_ANON, > + WORKINGSET_REFAULT_FILE, > + WORKINGSET_ACTIVATE_ANON, > + WORKINGSET_ACTIVATE_FILE, > + WORKINGSET_RESTORE_ANON, > + WORKINGSET_RESTORE_FILE, > + WORKINGSET_NODERECLAIM, > + NR_ANON_MAPPED, > + NR_FILE_MAPPED, > + NR_FILE_PAGES, > + NR_FILE_DIRTY, > + NR_WRITEBACK, > + NR_SHMEM, > + NR_SHMEM_THPS, > + NR_FILE_THPS, > + NR_ANON_THPS, > + NR_KERNEL_STACK_KB, > + NR_PAGETABLE, > + NR_SECONDARY_PAGETABLE, > +#ifdef CONFIG_SWAP > + NR_SWAPCACHE, > +#endif > +}; > + > +static const unsigned int memcg_stat_items[] =3D { > + MEMCG_SWAP, > + MEMCG_SOCK, > + MEMCG_PERCPU_B, > + MEMCG_VMALLOC, > + MEMCG_KMEM, > + MEMCG_ZSWAP_B, > + MEMCG_ZSWAPPED, > +}; Unsigned for these? All the values are positive now, but I don't think we'll get a build warning if a negative one ever got added, just a crash or corruption. BUG_ON in init_memcg_stats if a memcg_stat_items[i] < 0?