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 447CFEB64DD for ; Tue, 11 Jul 2023 18:28:41 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232306AbjGKS2k (ORCPT ); Tue, 11 Jul 2023 14:28:40 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:38436 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232389AbjGKS2a (ORCPT ); Tue, 11 Jul 2023 14:28:30 -0400 Received: from dfw.source.kernel.org (dfw.source.kernel.org [IPv6:2604:1380:4641:c500::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id EA638171C for ; Tue, 11 Jul 2023 11:28:26 -0700 (PDT) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits)) (No client certificate requested) by dfw.source.kernel.org (Postfix) with ESMTPS id 7F0EF615C1 for ; Tue, 11 Jul 2023 18:28:26 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 72E93C433C8; Tue, 11 Jul 2023 18:28:25 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linux-foundation.org; s=korg; t=1689100105; bh=Q63ErUhKx/B8A6oY/cTvhH9I36Jjdmsq5mKxh0Ap7gA=; h=Date:From:To:Cc:Subject:In-Reply-To:References:From; b=CSH7LPGqrEdpjtkdclZcxbTuw+ib2iklGOxdCpbY1snhbwHXsJ/uRKmSHrm57Uebr gx1PwFYI6t1Xovi1RBuiOvAxW4V3VDF6YKorvkJVhyx5AatHT0EqFMr4ug0++qI3mL KMRPTumraPS1vi63DCc4W7wjIIsMX4oLhq3cfaeQ= Date: Tue, 11 Jul 2023 11:28:24 -0700 From: Andrew Morton To: Yu Ma Cc: Liam.Howlett@Oracle.com, kirill@shutemov.name, dan.j.williams@intel.com, dave.hansen@intel.com, linux-kernel@vger.kernel.org, linux-mm@kvack.org, lipeng.zhu@intel.com, pan.deng@intel.com, shakeelb@google.com, tianyou.li@intel.com, tim.c.chen@intel.com, tim.c.chen@linux.intel.com Subject: Re: [PATCH v2] mm/mmap: move vma operations to mm_struct out of the critical section of file mapping lock Message-Id: <20230711112824.e559065488b08ce649cccfd7@linux-foundation.org> In-Reply-To: <20230711172020.562250-1-yu.ma@intel.com> References: <20230711172020.562250-1-yu.ma@intel.com> X-Mailer: Sylpheed 3.8.0beta1 (GTK+ 2.24.33; x86_64-pc-linux-gnu) Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, 11 Jul 2023 13:20:20 -0400 Yu Ma wrote: > UnixBench/Execl represents a class of workload where bash scripts are > spawned frequently to do some short jobs. When running multiple parallel > tasks, hot osq_lock is observed from do_mmap and exit_mmap. Both of them > come from load_elf_binary through the call chain > "execl->do_execveat_common->bprm_execve->load_elf_binary". In do_mmap,it will > call mmap_region to create vma node, initialize it and insert it to vma > maintain structure in mm_struct and i_mmap tree of the mapping file, then > increase map_count to record the number of vma nodes used. The hot osq_lock > is to protect operations on file’s i_mmap tree. For the mm_struct member > change like vma insertion and map_count update, they do not affect i_mmap > tree. Move those operations out of the lock's critical section, to reduce > hold time on the lock. > > With this change, on Intel Sapphire Rapids 112C/224T platform, based on > v6.0-rc6, the 160 parallel score improves by 12%. The patch has no > obvious performance gain on v6.4-rc4 due to regression of this benchmark > from this commit f1a7941243c102a44e8847e3b94ff4ff3ec56f25 (mm: convert > mm's rss stats into percpu_counter). Related discussion and conclusion > can be referred at the mail thread initiated by 0day as below: > Link: https://lore.kernel.org/linux-mm/a4aa2e13-7187-600b-c628-7e8fb108def0@intel.com/ Could you please redo/retest this against a kernel which has 1c7873e3364 ("mm: lock newly mapped VMA with corrected ordering")? mainline, mm-unstable or linux-next. Thanks.