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=-2.2 required=3.0 tests=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 AB419C32793 for ; Thu, 26 Sep 2019 00:16:05 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id 7976021A4A for ; Thu, 26 Sep 2019 00:16:05 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 7976021A4A Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=linux.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id EC5F16B000A; Wed, 25 Sep 2019 20:16:04 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id E4D926B000C; Wed, 25 Sep 2019 20:16:04 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id D62546B000D; Wed, 25 Sep 2019 20:16:04 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0166.hostedemail.com [216.40.44.166]) by kanga.kvack.org (Postfix) with ESMTP id AC8CE6B000A for ; Wed, 25 Sep 2019 20:16:04 -0400 (EDT) Received: from smtpin05.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay03.hostedemail.com (Postfix) with SMTP id 5335F8243760 for ; Thu, 26 Sep 2019 00:16:04 +0000 (UTC) X-FDA: 75975154248.05.fall54_8c47c42b8de15 X-HE-Tag: fall54_8c47c42b8de15 X-Filterd-Recvd-Size: 2424 Received: from gentwo.org (gentwo.org [3.19.106.255]) by imf18.hostedemail.com (Postfix) with ESMTP for ; Thu, 26 Sep 2019 00:16:03 +0000 (UTC) Received: by gentwo.org (Postfix, from userid 1002) id 753313EEC6; Thu, 26 Sep 2019 00:16:03 +0000 (UTC) Received: from localhost (localhost [127.0.0.1]) by gentwo.org (Postfix) with ESMTP id 73A743E86C; Thu, 26 Sep 2019 00:16:03 +0000 (UTC) Date: Thu, 26 Sep 2019 00:16:03 +0000 (UTC) From: Christopher Lameter X-X-Sender: cl@www.lameter.com To: Vlastimil Babka cc: Andrew Morton , David Sterba , linux-mm@kvack.org, linux-kernel@vger.kernel.org, Pekka Enberg , David Rientjes , Ming Lei , Dave Chinner , Matthew Wilcox , "Darrick J . Wong" , Christoph Hellwig , linux-xfs@vger.kernel.org, linux-fsdevel@vger.kernel.org, linux-block@vger.kernel.org, James Bottomley , linux-btrfs@vger.kernel.org, Roman Gushchin , Johannes Weiner Subject: Re: [PATCH v2 2/2] mm, sl[aou]b: guarantee natural alignment for kmalloc(power-of-two) In-Reply-To: <34a45e87-5bad-5f01-7dcb-8a3f6cf37281@suse.cz> Message-ID: References: <20190826111627.7505-1-vbabka@suse.cz> <20190826111627.7505-3-vbabka@suse.cz> <20190923171710.GN2751@twin.jikos.cz> <20190924165425.a79a2dafbaf37828a931df2b@linux-foundation.org> <34a45e87-5bad-5f01-7dcb-8a3f6cf37281@suse.cz> User-Agent: Alpine 2.21 (DEB 202 2017-01-01) MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII 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 Wed, 25 Sep 2019, Vlastimil Babka wrote: > Most of the new code is for SLOB, which has no debugging and yet > misaligns. For SLUB and SLAB, it's just passing alignment argument to > kmem_cache_create() for kmalloc caches, which means just extra few > instructions during boot, and no extra code during kmalloc/kfree itself. SLOB follows the standards for alignments in slab allocators and will correctly align if you ask the allocator for a properly aligned object.