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=-2.0 required=3.0 tests=DKIM_INVALID,DKIM_SIGNED, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, USER_AGENT_SANE_1 autolearn=no 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 31163C432C3 for ; Sat, 23 Nov 2019 02:33:36 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id E35572071C for ; Sat, 23 Nov 2019 02:33:35 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (2048-bit key) header.d=infradead.org header.i=@infradead.org header.b="UMaVsJij" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726744AbfKWCdf (ORCPT ); Fri, 22 Nov 2019 21:33:35 -0500 Received: from bombadil.infradead.org ([198.137.202.133]:57076 "EHLO bombadil.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725962AbfKWCde (ORCPT ); Fri, 22 Nov 2019 21:33:34 -0500 DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=bombadil.20170209; h=In-Reply-To:Content-Type:MIME-Version :References:Message-ID:Subject:Cc:To:From:Date:Sender:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Id: List-Help:List-Unsubscribe:List-Subscribe:List-Post:List-Owner:List-Archive; bh=nPuduIsmzT4eyNy6AgYyeWm8a3lye8lEUGi+OFLWHQE=; b=UMaVsJijpyg+a0E75vUQkK7rg XWQcUQCgvHIOltFSFQ8of0MXhAXTDQ+LEgp/aZPcsKfZWDNuJMxrT+JnVRsrnGPLN4ZTHWN/1P61s IRlUCeGaPjd+/enFAGSylVBReBSPyMYmb2poYTrDXEoIRo9Xdjp6/XFZp9AesW02vXhaItc8wJ/9q YKBaQA6k8wkdU9IdCLgjSxKrEJvzglgm7vDvCvdzkjRqsqpwUrqjCh9ObctTA1RPyVJQoU/4FQVXQ YZUp89zmv4AAxj9Sgx/hYqgCrKN0wB34ICyv7xwzPvoRtQWW68GhucrtJL9ijKCjACkcod6bd4vhd ves1wV+4w==; Received: from willy by bombadil.infradead.org with local (Exim 4.92.3 #3 (Red Hat Linux)) id 1iYLEj-0004Ol-JZ; Sat, 23 Nov 2019 02:33:25 +0000 Date: Fri, 22 Nov 2019 18:33:25 -0800 From: Matthew Wilcox To: "zhengbin (A)" Cc: Hugh Dickins , viro@zeniv.linux.org.uk, linux-mm@kvack.org, linux-kernel@vger.kernel.org, houtao1@huawei.com, yi.zhang@huawei.com, "J. R. Okajima" , Eric Dumazet Subject: Re: [PATCH] tmpfs: use ida to get inode number Message-ID: <20191123023325.GY20752@bombadil.infradead.org> References: <1574259798-144561-1-git-send-email-zhengbin13@huawei.com> <20191120154552.GS20752@bombadil.infradead.org> <1c64e7c2-6460-49cf-6db0-ec5f5f7e09c4@huawei.com> <5423a199-eefb-0a02-6e86-1f6210939c11@huawei.com> <20191122221327.GW20752@bombadil.infradead.org> <77f67d7a-4a93-4319-e6af-54daffcc37e2@huawei.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <77f67d7a-4a93-4319-e6af-54daffcc37e2@huawei.com> User-Agent: Mutt/1.12.1 (2019-06-15) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Sat, Nov 23, 2019 at 10:16:39AM +0800, zhengbin (A) wrote: > By the way, percpu IDA is for reducing performance impact? This patch has 2.16% > performance degradation(Use perf to get the cost of ida_alloc_range) 2.16% degradation in your tests ... I bet Eric didn't make it so complex for only 2% performance impact. Unfortunately, he didn't give any numbers in his patch submission, but it's going to be a bigger problem on multi-socket machines than on a laptop. Eric, any memories from 2010? Commit f991bd2e14210fb93d722cb23e54991de20e8a3d if it helps.