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 kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by smtp.lore.kernel.org (Postfix) with ESMTP id 1D019C43334 for ; Wed, 6 Jul 2022 11:31:13 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 96A1D6B0071; Wed, 6 Jul 2022 07:31:12 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 919596B0073; Wed, 6 Jul 2022 07:31:12 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 808D16B0074; Wed, 6 Jul 2022 07:31:12 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0011.hostedemail.com [216.40.44.11]) by kanga.kvack.org (Postfix) with ESMTP id 6DCED6B0071 for ; Wed, 6 Jul 2022 07:31:12 -0400 (EDT) Received: from smtpin06.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay13.hostedemail.com (Postfix) with ESMTP id 40F7360CCD for ; Wed, 6 Jul 2022 11:31:12 +0000 (UTC) X-FDA: 79656458784.06.519BA7D Received: from theia.8bytes.org (8bytes.org [81.169.241.247]) by imf25.hostedemail.com (Postfix) with ESMTP id 371C8A0057 for ; Wed, 6 Jul 2022 11:31:11 +0000 (UTC) Received: by theia.8bytes.org (Postfix, from userid 1000) id 626004CC; Wed, 6 Jul 2022 13:31:09 +0200 (CEST) Date: Wed, 6 Jul 2022 13:31:08 +0200 From: Joerg Roedel To: Feng Tang Cc: Will Deacon , Robin Murphy , John Garry , iommu@lists.linux-foundation.org, iommu@lists.linux.dev, Andrew Morton , Christoph Lameter , Vlastimil Babka , linux-mm@kvack.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH v2] iommu/iova: change IOVA_MAG_SIZE to 127 to save memory Message-ID: References: <20220703114450.15184-1-feng.tang@intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20220703114450.15184-1-feng.tang@intel.com> ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1657107071; a=rsa-sha256; cv=none; b=6tc8LapH4DxXiH1pycc6VRZraZtDm2StfXnQ1nhZettPoiAyFcPSKeVQs8X3VpxaJ5esRY nXNdOg73NqtF7LkLGJfUlLguIYRQyAQjBeL+YufCctFJ0GbTJxnveUET18g5RqbELDnr0w Z+MWF5wV9PDZGeb7D5H3HvshlcF/gpw= ARC-Authentication-Results: i=1; imf25.hostedemail.com; dkim=none; dmarc=pass (policy=none) header.from=8bytes.org; spf=pass (imf25.hostedemail.com: domain of joro@8bytes.org designates 81.169.241.247 as permitted sender) smtp.mailfrom=joro@8bytes.org ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1657107071; h=from:from:sender:reply-to:subject:subject:date:date: message-id:message-id:to:to:cc:cc:mime-version:mime-version: content-type:content-type:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=VwgUWHA8jAjkcF2fUdnHXPiRBKxjmkc0wYXLb88AfOo=; b=Z9OgFTxN2QxUPruN/pIUKEvXoL8qeqVsYDhv5E4IwNUH2OwGB0+s4LRr0x0da0Vm2YFrU3 aTnu8sedzhG7/Mn3325kF6KDUkuJt49dgjpzMLqj61xTASL0uu6h0Yq/LR1wG86MeFuuwj W6Rtdqt0DlWSBW8bOYRjMryOztRpTPk= X-Rspam-User: X-Rspamd-Server: rspam02 X-Rspamd-Queue-Id: 371C8A0057 Authentication-Results: imf25.hostedemail.com; dkim=none; dmarc=pass (policy=none) header.from=8bytes.org; spf=pass (imf25.hostedemail.com: domain of joro@8bytes.org designates 81.169.241.247 as permitted sender) smtp.mailfrom=joro@8bytes.org X-Stat-Signature: jh7646xi55zcujhbnsmi9i1x58diypqk X-HE-Tag: 1657107071-523274 X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: On Sun, Jul 03, 2022 at 07:44:50PM +0800, Feng Tang wrote: > kmalloc will round up the request size to power of 2, and current > iova_magazine's size is 1032 (1024+8) bytes, so each instance > allocated will get 2048 bytes from kmalloc, causing around 1KB > waste. > > Change IOVA_MAG_SIZE from 128 to 127 to make size of 'iova_magazine' > 1024 bytes so that no memory will be wasted. > > Signed-off-by: Feng Tang > Acked-by: Robin Murphy Applied, thanks.