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=-1.1 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_PASS 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 2DA4EC46470 for ; Wed, 8 Aug 2018 01:12:32 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id D6E072174B for ; Wed, 8 Aug 2018 01:12:31 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=canb.auug.org.au header.i=@canb.auug.org.au header.b="camr7Lxh" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org D6E072174B Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=canb.auug.org.au Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726893AbeHHD3e (ORCPT ); Tue, 7 Aug 2018 23:29:34 -0400 Received: from ozlabs.org ([203.11.71.1]:48277 "EHLO ozlabs.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726254AbeHHD3e (ORCPT ); Tue, 7 Aug 2018 23:29:34 -0400 Received: from authenticated.ozlabs.org (localhost [127.0.0.1]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ozlabs.org (Postfix) with ESMTPSA id 41lYJn0sz1z9s4V; Wed, 8 Aug 2018 11:12:25 +1000 (AEST) Authentication-Results: ozlabs.org; dmarc=none (p=none dis=none) header.from=canb.auug.org.au DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=canb.auug.org.au; s=201702; t=1533690745; bh=GA6M2+hINIWaVbN/sXCBEASmIt/43LJCpNAYz86BW/M=; h=Date:From:To:Cc:Subject:In-Reply-To:References:From; b=camr7LxhesFe8DPj6nAxpTlZLKUw9Lp7BMRf1PIVW1Ss1X40kH55YYT1QZqu8ZNDG SjEsFu+1xyjqcT3juwZ8W099A1OpUTFS1Rmh9kWwRLV9bAAQw05PleYigJIF5Wlu+B Aen2FQrqn55a8J7tkrxvJwjrTZCeOgfF/MIE9g+wnMGwNbLSzuUK2ctqgtjW9YMhXb 8Jw/w9voXiMYVPF2PvM6W+qJwwS+hzY6vYwJwUo6Am9CiLAKFa2EvV63E9s3WcNtJU tizF83MbK1Mjv2xfRHIVt9EYFLTpqvjzwBB5RF8IBvE3CZhQc8sNYNEEBr0r8/vt5x HdIlnTFllLB5A== Date: Wed, 8 Aug 2018 11:12:24 +1000 From: Stephen Rothwell To: Kirill Tkhai Cc: akpm@linux-foundation.org, gregkh@linuxfoundation.org, rafael@kernel.org, viro@zeniv.linux.org.uk, darrick.wong@oracle.com, paulmck@linux.vnet.ibm.com, josh@joshtriplett.org, rostedt@goodmis.org, mathieu.desnoyers@efficios.com, jiangshanlai@gmail.com, hughd@google.com, shuah@kernel.org, robh@kernel.org, ulf.hansson@linaro.org, aspriel@gmail.com, vivek.gautam@codeaurora.org, robin.murphy@arm.com, joe@perches.com, heikki.krogerus@linux.intel.com, vdavydov.dev@gmail.com, mhocko@suse.com, chris@chris-wilson.co.uk, penguin-kernel@I-love.SAKURA.ne.jp, aryabinin@virtuozzo.com, willy@infradead.org, ying.huang@intel.com, shakeelb@google.com, jbacik@fb.com, mingo@kernel.org, mhiramat@kernel.org, linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org, linux-mm@kvack.org Subject: Re: [PATCH RFC 00/10] Introduce lockless shrink_slab() Message-ID: <20180808111224.52a451d9@canb.auug.org.au> In-Reply-To: <153365347929.19074.12509495712735843805.stgit@localhost.localdomain> References: <153365347929.19074.12509495712735843805.stgit@localhost.localdomain> MIME-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha256; boundary="Sig_/yFMBaxGy2JljibeAimkhX54"; protocol="application/pgp-signature" Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org --Sig_/yFMBaxGy2JljibeAimkhX54 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: quoted-printable Hi Kirill, On Tue, 07 Aug 2018 18:37:19 +0300 Kirill Tkhai wrot= e: > > After bitmaps of not-empty memcg shrinkers were implemented > (see "[PATCH v9 00/17] Improve shrink_slab() scalability..." > series, which is already in mm tree), all the evil in perf > trace has moved from shrink_slab() to down_read_trylock(). > As reported by Shakeel Butt: >=20 > > I created 255 memcgs, 255 ext4 mounts and made each memcg create a > > file containing few KiBs on corresponding mount. Then in a separate > > memcg of 200 MiB limit ran a fork-bomb. > > > > I ran the "perf record -ag -- sleep 60" and below are the results: > > + 47.49% fb.sh [kernel.kallsyms] [k] down_read_try= lock > > + 30.72% fb.sh [kernel.kallsyms] [k] up_read > > + 9.51% fb.sh [kernel.kallsyms] [k] mem_cgroup_it= er > > + 1.69% fb.sh [kernel.kallsyms] [k] shrink_node_m= emcg > > + 1.35% fb.sh [kernel.kallsyms] [k] mem_cgroup_pr= otected > > + 1.05% fb.sh [kernel.kallsyms] [k] queued_spin_l= ock_slowpath > > + 0.85% fb.sh [kernel.kallsyms] [k] _raw_spin_lock > > + 0.78% fb.sh [kernel.kallsyms] [k] lruvec_lru_si= ze > > + 0.57% fb.sh [kernel.kallsyms] [k] shrink_node > > + 0.54% fb.sh [kernel.kallsyms] [k] queue_work_on > > + 0.46% fb.sh [kernel.kallsyms] [k] shrink_slab_m= emcg =20 >=20 > The patchset continues to improve shrink_slab() scalability and makes > it lockless completely. Here are several steps for that: So do you have any numbers for after theses changes? --=20 Cheers, Stephen Rothwell --Sig_/yFMBaxGy2JljibeAimkhX54 Content-Type: application/pgp-signature Content-Description: OpenPGP digital signature -----BEGIN PGP SIGNATURE----- iQEzBAEBCAAdFiEENIC96giZ81tWdLgKAVBC80lX0GwFAltqQ3gACgkQAVBC80lX 0GxavQf9EKFejil3+n6vL60fNlHSHDQnmX05ed6HsGTXza/1bbyxBdOOk6PkbbkR Am2K5yPPUShKvsfwpy8pwJCzt8xxPcGSwtEg17G/JKGTEnd4zs8zEC8+z1RtZgzn XtytDz87/XRfM9dX7thRhY2z6tUpNu5ZcuKOgJ912XJ8riurODEOb212V+vc/G9G 8g0Q4J1Pb99/sgoEljl+iQL5ZsFqCADCBaFwmYL0zLfNgs9zrUimflnNWOBQUYbQ bzxrY5qbdaWRCmVh6f5FSrzXoxoOk+WJ+Ekoq//mTTceZWFuZdNvh9qXWy8S+dN2 KqisepOQ0+Dh+0GGXSanG+jFbPyFzg== =26Fb -----END PGP SIGNATURE----- --Sig_/yFMBaxGy2JljibeAimkhX54--