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 CE06BC433F5 for ; Wed, 18 May 2022 00:46:23 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231401AbiERAqW (ORCPT ); Tue, 17 May 2022 20:46:22 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:35470 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230250AbiERApz (ORCPT ); Tue, 17 May 2022 20:45:55 -0400 Received: from dfw.source.kernel.org (dfw.source.kernel.org [139.178.84.217]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 6DF9CB859 for ; Tue, 17 May 2022 17:45:53 -0700 (PDT) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by dfw.source.kernel.org (Postfix) with ESMTPS id 0735A61536 for ; Wed, 18 May 2022 00:45:53 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 9DD69C385B8; Wed, 18 May 2022 00:45:51 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1652834752; bh=z87A6O404utXiyMmeUJk5rvEJSIRfaB4gJrHWtw8+Hw=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=nFsSdXWdtKlbxUZSiC2c7p48q1Q+bRx6Wqgt5Tu683rk9lOpXP/1saoR+mP7kmDtM 9CjIdHav5zFaS3qCW4OLu8kVKa+fbyjBVtffeGHNwAcXwd9obULbip+82vtyhmttCV QWiXDis2wu8C45h+Pd+hS9NP1rcGowizZDopxH4P3/Sk9i4SgMNNgJuREyjTAOYhkc T0lPflbWK1EX9hL2JS4r+MJtw/D6is3z2uBie6qRNLb/nlyYha7BH76lTpPLZpq3Xd YZ1OMwq18qNJgYJBexB/yrT3PpCY6tPtV/+wsbSIBGz+X8jIRoZoYy3J+7t5yzo/vC Lj9evcq4Q/29g== Date: Wed, 18 May 2022 03:47:32 +0300 From: Jarkko Sakkinen To: Dave Hansen Cc: linux-sgx@vger.kernel.org, "dave.hansen@linux.intel.com" , reinette.chatre@intel.com Subject: Re: VMA's not getting merged Message-ID: References: <884c7ea454cf2eb0ba2e95f7c25bd42018824f97.camel@kernel.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: Precedence: bulk List-ID: X-Mailing-List: linux-sgx@vger.kernel.org On Mon, May 16, 2022 at 09:45:56PM +0300, Jarkko Sakkinen wrote: > On Mon, May 16, 2022 at 07:13:42AM -0700, Dave Hansen wrote: > > On 5/14/22 18:20, Jarkko Sakkinen wrote: > > > Looks like VMA's do not get merged properly: > > ... > > > 7f8f0800b000-7f8f08014000 rw-s 00000000 00:05 84 /dev/sgx_enclave > > > 7f8f08014000-7f8f08025000 rw-s 00000000 00:05 84 /dev/sgx_enclave > > > 7f8f08025000-7f8f08046000 rw-s 00000000 00:05 84 /dev/sgx_enclave > > > 7f8f08046000-7f8f0804a000 rw-s 00000000 00:05 84 /dev/sgx_enclave > > > 7f8f0804a000-7f8f0804b000 rw-s 00000000 00:05 84 /dev/sgx_enclave > > > 7f8f0804b000-7f8f0804c000 rw-s 00000000 00:05 84 /dev/sgx_enclave > > > 7f8f0804c000-7f8f0804d000 rw-s 00000000 00:05 84 /dev/sgx_enclave > > > 7f8f0804d000-7f8f0804e000 rw-s 00000000 00:05 84 /dev/sgx_enclave > > > > I remember some issue with VM_IO VMAs not getting merged, but I don't > > remember how we fixed or addressed it. > > > > Seems like something we can and should fix, though. > > Access pattern here is series of small adjacent mmaps (brk()). > > During upstreaming vma_close callback was eliminated to allow VMA's getting > merged. I'll try to trace the condition in the call path triggering this. > > BR, Jarkko I wrote a small bpftrace script: #include k:vma_merge /strncmp(str(((struct vm_area_struct *)arg1)->vm_file->f_path.dentry->d_name.name), "sgx_enclave", 11) == 0/ { @merge[tid] = true; } kr:vma_merge /@merge[tid] && retval > 0/ { @merged = count(); delete(@merge[tid]); } kr:vma_merge /@merge[tid]/ { @unmerged = count(); delete(@merge[tid]); } When running with the same payload, I get: @merged: 0 @unmerged: 209 So it gets down to vma_merge but each time the function returns NULL. BR, Jarkko