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 4079FC4332F for ; Fri, 2 Dec 2022 22:17:45 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S234860AbiLBWRo (ORCPT ); Fri, 2 Dec 2022 17:17:44 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:37718 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S234851AbiLBWRh (ORCPT ); Fri, 2 Dec 2022 17:17:37 -0500 Received: from mga04.intel.com (mga04.intel.com [192.55.52.120]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id F2DD02721; Fri, 2 Dec 2022 14:17:36 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1670019457; x=1701555457; h=message-id:subject:from:to:cc:date:in-reply-to: references:content-transfer-encoding:mime-version; bh=woJvw+26RYRp5fwYNc0dyE37E+dcjcSWCS7ZFowb7NY=; b=X2xtfO+TIVNNuxP1SyuVsbQa+6NVlQvN3eVgHqY5D5392IFpqYHUBTnq MlbfPlwtXm3BMmGv7RkzSqBhD+cO6P9l0ppJHtSkHzQwcLg6u35ucIFVy WkES56pdMBhl9AN0E3KKCNQEoaCUv8IKYSykDJEEKItlYyF/T4ItxsEL7 iImSSVD+W0QKTA44E1tu0KEWkygp2rFEpiW9AaViADhwOmmYAQLpkhGno mMBULPjPYKW8c2GgflXmDItYj83HGtlbCKDQGBlGlUEdVKk8mlh4Jjd0d jZhR2t7+ohKNk/pe+E9VJrbcuOO4H7MKssECUXhF013IeB1c/UT5m0fs9 w==; X-IronPort-AV: E=McAfee;i="6500,9779,10549"; a="314764568" X-IronPort-AV: E=Sophos;i="5.96,213,1665471600"; d="scan'208";a="314764568" Received: from orsmga001.jf.intel.com ([10.7.209.18]) by fmsmga104.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 02 Dec 2022 14:17:35 -0800 X-IronPort-AV: E=McAfee;i="6500,9779,10549"; a="677752478" X-IronPort-AV: E=Sophos;i="5.96,213,1665471600"; d="scan'208";a="677752478" Received: from kcaskeyx-mobl1.amr.corp.intel.com (HELO [10.251.1.207]) ([10.251.1.207]) by orsmga001-auth.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 02 Dec 2022 14:17:34 -0800 Message-ID: <307b43aa5908c489913110287044e611f574db0a.camel@linux.intel.com> Subject: Re: [PATCH v2 01/18] x86/sgx: Call cond_resched() at the end of sgx_reclaim_pages() From: Kristen Carlson Accardi To: Dave Hansen , jarkko@kernel.org, dave.hansen@linux.intel.com, tj@kernel.org, linux-kernel@vger.kernel.org, linux-sgx@vger.kernel.org, cgroups@vger.kernel.org, Thomas Gleixner , Ingo Molnar , Borislav Petkov , x86@kernel.org, "H. Peter Anvin" Cc: zhiquan1.li@intel.com, Sean Christopherson Date: Fri, 02 Dec 2022 14:17:33 -0800 In-Reply-To: <746adf31-e70c-e32d-a35d-72d352af613b@intel.com> References: <20221202183655.3767674-1-kristen@linux.intel.com> <20221202183655.3767674-2-kristen@linux.intel.com> <37de083d-a63b-b2ff-d00a-e890a1ba5eea@intel.com> <746adf31-e70c-e32d-a35d-72d352af613b@intel.com> Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable User-Agent: Evolution 3.44.4 (3.44.4-2.fc36) MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, 2022-12-02 at 13:45 -0800, Dave Hansen wrote: > On 12/2/22 13:37, Kristen Carlson Accardi wrote: > > > > +static void sgx_reclaim_pages(void) > > > > +{ > > > > +=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0__sgx_reclaim_pages(); > > > > +=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0cond_resched(); > > > > +} > > > Why bother with the wrapper?=C2=A0 Can't we just put cond_resched() i= n > > > the > > > existing sgx_reclaim_pages()? > > Because sgx_reclaim_direct() needs to call sgx_reclaim_pages() but > > not > > do the cond_resched(). It was this or add a boolean or something to > > let > > caller's opt out of the resched. >=20 > Is there a reason sgx_reclaim_direct() *can't* or shouldn't call > cond_resched()? Yes, it is due to performance concerns. It is explained most succinctly by Reinette here: https://lore.kernel.org/linux-sgx/a4eb5ab0-bf83-17a4-8bc0-a90aaf438a8e@inte= l.com/